Materiały źródłowe

• #1 Acute Appendicitis: Review and Update | AAFP

  https://www.aafp.org/pubs/afp/issues/1999/1101/p2027.html

  Appendicitis is common, with a lifetime occurrence of 7 percent. […] Appendicitis is the most common acute surgical condition of the abdomen.1 Approximately 7 percent of the population will have appendicitis in their lifetime,2 with the peak incidence occurring between the ages of 10 and 30 years.3 […] Obstruction of the narrow appendiceal lumen initiates the clinical illness of acute appendicitis. Obstruction has multiple causes, including lymphoid hyperplasia (related to viral illnesses, including upper respiratory infection, mononucleosis, gastroenteritis), fecaliths, parasites, foreign bodies, Crohn’s disease, primary or metastatic cancer and carcinoid syndrome. Lymphoid hyperplasia is more common in children and young adults, accounting for the increased incidence of appendicitis in these age groups.1,5

• #2 Compilation of Evidence Supporting the Role of a T Helper 2 Reaction in the Pathogenesis of Acute Appendicitis

  https://www.mdpi.com/1422-0067/25/8/4216

  Despite being the most common abdominal surgical emergency, the cause of acute appendicitis (AA) remains unclear, since in recent decades little progress has been made regarding its etiology. […] The common teaching is that AA is caused by appendix luminal obstruction. However, this is seldom seen in surgical clinical practice, where obstruction seems to be the consequence rather than the cause of AA. […] Tsuji was the first author to propose the occurrence of an immune process in AA. In fact, he noted that the lamina propria of the appendicular wall in cases of AA was infiltrated by lymphocytes. He postulated that an non-identified antigen could stimulate their presence at the appendicular wall, inducing inflammation-AA. […] Later, Aravindan, when studying AA specimens, noted the common presence of eosinophil infiltration in the tunica muscularis, intramuscular edema and mast-cell degranulation. He proposed that AA was initiated by a type I hypersensitivity reaction, as the histological features are similar to those found in type I hypersensitivity. […] Several recent studies have reinforced the hypothesis that there is a Th2 immune reaction in AA.

• #3 Pathophysiology of Acute Appendicitis

  https://www.jscimedcentral.com/jounal-article-info/JSM-Gastroenterology-and-Hepatology/Pathophysiology-of-Acute-Appendicitis-7440

  The function of the appendix is not clearly understood, although the presence of lymphatic tissue on it suggests a role in the immune system. […] The primary pathogenic event in most of patients with acute appendicitis is believed to be due to luminal obstruction. […] There is strong epidemiologic evidence supporting the proposition that perforated and non-perforated appendicitis are separate entities with a different pathogenesis. […] Recently, with the advent of neurogastroenterology, the concept of neuroimmune appendicitis has evolved. […] Considering that neurogenic disease may not include inflammatory signs, the name neurogenic appendicopathy seems to be a more appropriate term for appendices of morphological normal aspect in patients with clinical symptoms of acute appendicitis. […] As it can be perceived, based on the large number of studies related to acute appendicitis, it is not yet established the pathophysiology of this disease. […] More research is in need to understand this still mysterious disease.

• #4 Appendicitis – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK493193/

  Acute appendicitis is characterized by inflammation of the vermiform appendix, and patients typically present emergently within 24 hours of the onset of symptoms. […] Appendicitis is primarily caused by obstruction of the appendiceal lumen leading to inflammation. The obstruction can be due to various factors such as appendicoliths, appendiceal tumors, intestinal parasites, or hypertrophied lymphatic tissues. These mechanical obstructions result in the development of acute appendicitis. […] The appendix is known to naturally host aerobic and anaerobic bacteria, including Escherichia coli and Bacteroides spp. Obstruction of the appendiceal lumen by any mechanism can cause an overgrowth of bacteria leading to acute inflammation and abscess formation. Recent studies utilizing next-generation sequencing techniques have revealed that patients with complicated perforated appendicitis exhibit a significantly higher bacterial phyla load than those with uncomplicated appendicitis. This finding suggests that the severity and complications of appendicitis may be associated with an increased abundance of bacterial species.

• #5 Appendicitis – Gastrointestinal Disorders – Merck Manual Professional Edition

  https://www.merckmanuals.com/professional/gastrointestinal-disorders/acute-abdomen-and-surgical-gastroenterology/appendicitis

  Appendicitis is thought to result from obstruction of the appendiceal lumen, typically by lymphoid hyperplasia but occasionally by a fecalith, foreign body, tumor, or even worms. The obstruction leads to distention, bacterial overgrowth, ischemia, and inflammation. If untreated, necrosis, gangrene, and perforation occur. If the perforation is contained by the omentum, an appendiceal abscess results. […] Appendicitis remains primarily a clinical diagnosis. Selective and judicious use of imaging studies may reduce the rate of negative laparotomy. […] Although several studies of nonoperative management of appendicitis (ie, using antibiotics alone) have shown high rates of resolution during the initial hospitalization, a significant number of patients have a recurrence and require appendectomy during the following year. Thus, appendectomy is still recommended, particularly if an appendicolith is visible on CT.

• #6 Clinical Approach in the Diagnosis of Acute Appendicitis | IntechOpen

  https://www.intechopen.com/chapters/61365

  The etiology of acute appendicitis is not quite clear. The main theory is that obstruction of the lumen of the appendix is the cause of acute appendicitis. Obstruction probably plays a key role in the progression of appendicitis, but evidence for fecaliths as the most common cause of uncomplicated appendicitis is weak. Overall, fecaliths were found in 18.1% of appendicitis specimens and 28.6% of negative appendectomies. Fecaliths were associated with perforation more often than with uncomplicated appendicitis, and fecaliths are more common in pediatric cases than in adult appendicitis, independent of perforation. […] The lumen distal to the obstruction starts to fill with mucus and acts as closed loop obstruction. This leads to distension and an increase in the intraluminal and intramural pressure. As the condition progresses, the resident bacteria in the appendix rapidly multiply. Distension of the lumen of the appendix causes reflex anorexia, nausea and vomiting, and visceral pain. As the pressure of the lumen exceeds the venous pressure, the small venules and capillaries become thrombosed, but arterioles remain open, which lead to engorgement and congestion of the appendix. The inflammatory process soon involves the serosa of the appendix, hence the parietal peritoneum in the region, which causes classical right lower quadrant (RLQ) pain. Once the small arterioles are thrombosed, the area at the antimesenteric border becomes ischemic, and infarction and perforation ensue. Bacteria leak out through the dying walls, and pus forms within and around the appendix. Perforations are usually seen just beyond the obstruction rather than at the tip of the appendix.

• #7 Acute Appendicitis: Review and Update | AAFP

  https://www.aafp.org/pubs/afp/issues/1999/1101/p2027.html

  Appendicitis is common, with a lifetime occurrence of 7 percent. […] Appendicitis is the most common acute surgical condition of the abdomen.1 Approximately 7 percent of the population will have appendicitis in their lifetime,2 with the peak incidence occurring between the ages of 10 and 30 years.3 […] Obstruction of the narrow appendiceal lumen initiates the clinical illness of acute appendicitis. Obstruction has multiple causes, including lymphoid hyperplasia (related to viral illnesses, including upper respiratory infection, mononucleosis, gastroenteritis), fecaliths, parasites, foreign bodies, Crohn’s disease, primary or metastatic cancer and carcinoid syndrome. Lymphoid hyperplasia is more common in children and young adults, accounting for the increased incidence of appendicitis in these age groups.1,5

• #8 Appendicitis – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK493193/

  Acute appendicitis is characterized by inflammation of the vermiform appendix, and patients typically present emergently within 24 hours of the onset of symptoms. […] Appendicitis is primarily caused by obstruction of the appendiceal lumen leading to inflammation. The obstruction can be due to various factors such as appendicoliths, appendiceal tumors, intestinal parasites, or hypertrophied lymphatic tissues. These mechanical obstructions result in the development of acute appendicitis. […] The appendix is known to naturally host aerobic and anaerobic bacteria, including Escherichia coli and Bacteroides spp. Obstruction of the appendiceal lumen by any mechanism can cause an overgrowth of bacteria leading to acute inflammation and abscess formation. Recent studies utilizing next-generation sequencing techniques have revealed that patients with complicated perforated appendicitis exhibit a significantly higher bacterial phyla load than those with uncomplicated appendicitis. This finding suggests that the severity and complications of appendicitis may be associated with an increased abundance of bacterial species.

• #9 Appendicitis – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK493193/

  Acute appendicitis is characterized by inflammation of the vermiform appendix, and patients typically present emergently within 24 hours of the onset of symptoms. […] Appendicitis is primarily caused by obstruction of the appendiceal lumen leading to inflammation. The obstruction can be due to various factors such as appendicoliths, appendiceal tumors, intestinal parasites, or hypertrophied lymphatic tissues. These mechanical obstructions result in the development of acute appendicitis. […] The appendix is known to naturally host aerobic and anaerobic bacteria, including Escherichia coli and Bacteroides spp. Obstruction of the appendiceal lumen by any mechanism can cause an overgrowth of bacteria leading to acute inflammation and abscess formation. Recent studies utilizing next-generation sequencing techniques have revealed that patients with complicated perforated appendicitis exhibit a significantly higher bacterial phyla load than those with uncomplicated appendicitis. This finding suggests that the severity and complications of appendicitis may be associated with an increased abundance of bacterial species.

• #10 Appendicitis – Gastrointestinal Disorders – Merck Manual Professional Edition

  https://www.merckmanuals.com/professional/gastrointestinal-disorders/acute-abdomen-and-surgical-gastroenterology/appendicitis

  Appendicitis is thought to result from obstruction of the appendiceal lumen, typically by lymphoid hyperplasia but occasionally by a fecalith, foreign body, tumor, or even worms. The obstruction leads to distention, bacterial overgrowth, ischemia, and inflammation. If untreated, necrosis, gangrene, and perforation occur. If the perforation is contained by the omentum, an appendiceal abscess results. […] Appendicitis remains primarily a clinical diagnosis. Selective and judicious use of imaging studies may reduce the rate of negative laparotomy. […] Although several studies of nonoperative management of appendicitis (ie, using antibiotics alone) have shown high rates of resolution during the initial hospitalization, a significant number of patients have a recurrence and require appendectomy during the following year. Thus, appendectomy is still recommended, particularly if an appendicolith is visible on CT.

• #11 Appendicitis – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK493193/

  Regardless of its cause, appendiceal luminal obstruction causes a rise in both intraluminal and intramural pressure. This increased pressure leads to small vessel occlusion, thrombosis, and lymphatic stasis. As a result, the obstructed appendix fills with mucus and becomes distended. As lymphatic and vascular compromise continues to progress, the wall of the appendix undergoes ischemia and necrosis. In addition, bacterial overgrowth occurs within the obstructed appendix, initially dominated by aerobic organisms during the early stages of appendicitis and later transitioning to a mixture of aerobic and anaerobic bacteria as the disease progresses. Commonly involved organisms include E coli, Peptostreptococcus, Bacteroides, and Pseudomonas. […] Once significant inflammation and necrosis develop, the appendix becomes susceptible to perforation, which can form a localized abscess. In severe cases, this can progress to peritonitis.

• #12 Appendicitis – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK493193/

  Regardless of its cause, appendiceal luminal obstruction causes a rise in both intraluminal and intramural pressure. This increased pressure leads to small vessel occlusion, thrombosis, and lymphatic stasis. As a result, the obstructed appendix fills with mucus and becomes distended. As lymphatic and vascular compromise continues to progress, the wall of the appendix undergoes ischemia and necrosis. In addition, bacterial overgrowth occurs within the obstructed appendix, initially dominated by aerobic organisms during the early stages of appendicitis and later transitioning to a mixture of aerobic and anaerobic bacteria as the disease progresses. Commonly involved organisms include E coli, Peptostreptococcus, Bacteroides, and Pseudomonas. […] Once significant inflammation and necrosis develop, the appendix becomes susceptible to perforation, which can form a localized abscess. In severe cases, this can progress to peritonitis.

• #13 Appendicitis – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK493193/

  Regardless of its cause, appendiceal luminal obstruction causes a rise in both intraluminal and intramural pressure. This increased pressure leads to small vessel occlusion, thrombosis, and lymphatic stasis. As a result, the obstructed appendix fills with mucus and becomes distended. As lymphatic and vascular compromise continues to progress, the wall of the appendix undergoes ischemia and necrosis. In addition, bacterial overgrowth occurs within the obstructed appendix, initially dominated by aerobic organisms during the early stages of appendicitis and later transitioning to a mixture of aerobic and anaerobic bacteria as the disease progresses. Commonly involved organisms include E coli, Peptostreptococcus, Bacteroides, and Pseudomonas. […] Once significant inflammation and necrosis develop, the appendix becomes susceptible to perforation, which can form a localized abscess. In severe cases, this can progress to peritonitis.

• #14 The Radiology Assistant : Appendicitis – US findings

  https://radiologyassistant.nl/abdomen/acute-abdomen/appendicitis-us-findings

  The appendix is a blind-ending tube with a narrow lumen. It contains feces and is easily obstructed. […] When obstruction occurs, within hours the intraluminal pressure increases, due to continuous secretion of mucinous fluid by the appendix mucosa. When this pressure exceeds the pressure in the vessels of the appendix wall, ischemic necrosis may occur, leaving the mucosa defenseless against the bacteria present in the appendix lumen. […] Depending on the inflammatory reaction of the human defense mechanism, the pathophysiological cascade of obstruction – high pressure – ischemic necrosis – bacterial attack with perforation, results in a clinical presentation. […] The natural course of untreated appendicitis is reflected in this table. Exact mortality rates in the era before surgery and antibiotics are unknown, but were probably around 10 – 20 %. Nowadays, mortality due to appendicitis has decreased to around 0,1 %, mainly due to early surgery, antibiotics and better diagnosis: US, CT, MRI and also the important lab value CRP.

• #15 Appendicitis – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK493193/

  Regardless of its cause, appendiceal luminal obstruction causes a rise in both intraluminal and intramural pressure. This increased pressure leads to small vessel occlusion, thrombosis, and lymphatic stasis. As a result, the obstructed appendix fills with mucus and becomes distended. As lymphatic and vascular compromise continues to progress, the wall of the appendix undergoes ischemia and necrosis. In addition, bacterial overgrowth occurs within the obstructed appendix, initially dominated by aerobic organisms during the early stages of appendicitis and later transitioning to a mixture of aerobic and anaerobic bacteria as the disease progresses. Commonly involved organisms include E coli, Peptostreptococcus, Bacteroides, and Pseudomonas. […] Once significant inflammation and necrosis develop, the appendix becomes susceptible to perforation, which can form a localized abscess. In severe cases, this can progress to peritonitis.

• #16 Appendicitis – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK493193/

  Regardless of its cause, appendiceal luminal obstruction causes a rise in both intraluminal and intramural pressure. This increased pressure leads to small vessel occlusion, thrombosis, and lymphatic stasis. As a result, the obstructed appendix fills with mucus and becomes distended. As lymphatic and vascular compromise continues to progress, the wall of the appendix undergoes ischemia and necrosis. In addition, bacterial overgrowth occurs within the obstructed appendix, initially dominated by aerobic organisms during the early stages of appendicitis and later transitioning to a mixture of aerobic and anaerobic bacteria as the disease progresses. Commonly involved organisms include E coli, Peptostreptococcus, Bacteroides, and Pseudomonas. […] Once significant inflammation and necrosis develop, the appendix becomes susceptible to perforation, which can form a localized abscess. In severe cases, this can progress to peritonitis.

• #17 SciELO Brazil – The Impact of Smoking on the Complications of Acute Appendicitis The Impact of Smoking on the Complications of Acute Appendicitis

  https://www.scielo.br/j/jcol/a/khykYpQddJChQjzxHcNrBnC/?lang=en

  The pathophysiology of appendicitis likely stems from obstruction of the appendiceal orifice leading to an increase in intraluminal and intramural pressure, resulting in small vessel occlusion and lymphatic stasis. […] The pathology underneath acute appendicitis is mostly from appendicular lumen obstruction, which ends in inflammation, ischemia and perforation that can be rapid onset with peritonitis or slower and localized abscess formation. The obstruction leads to mucus accumulation in the lumen, distension an elevation of intraluminal and intramural pressure, causing occlusion in small vessel and lymphatic stasis ending in ischemia and necrosis, followed by aerobic bacterial overgrowth followed later by mixed aerobes and anaerobes including Escherichia coli, Peptostreptococcus, Bacteroides, and Pseudomonas.

• #18 Appendicitis – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK493193/

  Regardless of its cause, appendiceal luminal obstruction causes a rise in both intraluminal and intramural pressure. This increased pressure leads to small vessel occlusion, thrombosis, and lymphatic stasis. As a result, the obstructed appendix fills with mucus and becomes distended. As lymphatic and vascular compromise continues to progress, the wall of the appendix undergoes ischemia and necrosis. In addition, bacterial overgrowth occurs within the obstructed appendix, initially dominated by aerobic organisms during the early stages of appendicitis and later transitioning to a mixture of aerobic and anaerobic bacteria as the disease progresses. Commonly involved organisms include E coli, Peptostreptococcus, Bacteroides, and Pseudomonas. […] Once significant inflammation and necrosis develop, the appendix becomes susceptible to perforation, which can form a localized abscess. In severe cases, this can progress to peritonitis.

• #19 Compilation of Evidence Supporting the Role of a T Helper 2 Reaction in the Pathogenesis of Acute Appendicitis

  https://www.mdpi.com/1422-0067/25/8/4216

  Despite being the most common abdominal surgical emergency, the cause of acute appendicitis (AA) remains unclear, since in recent decades little progress has been made regarding its etiology. […] The common teaching is that AA is caused by appendix luminal obstruction. However, this is seldom seen in surgical clinical practice, where obstruction seems to be the consequence rather than the cause of AA. […] Tsuji was the first author to propose the occurrence of an immune process in AA. In fact, he noted that the lamina propria of the appendicular wall in cases of AA was infiltrated by lymphocytes. He postulated that an non-identified antigen could stimulate their presence at the appendicular wall, inducing inflammation-AA. […] Later, Aravindan, when studying AA specimens, noted the common presence of eosinophil infiltration in the tunica muscularis, intramuscular edema and mast-cell degranulation. He proposed that AA was initiated by a type I hypersensitivity reaction, as the histological features are similar to those found in type I hypersensitivity. […] Several recent studies have reinforced the hypothesis that there is a Th2 immune reaction in AA.

• #20

  https://journals.lww.com/md-journal/fulltext/2018/04130/poor_pathogenetic_role_of_luminal_obstruction_in.57.aspx

  In developed countries, the incidence of acute appendicitis is about 95 cases out of 100,000 per year, being one of the most common urgencies in general surgery worldwide. However, its pathogenesis is still poorly understood. Direct luminal obstruction (by a fecalith, lymphoid hyperplasia, or impacted stool) is reported to be the primary and principal cause of acute appendicitis. […] This finding seems to highlight the poor pathogenetic role of luminal obstruction in the development of acute appendicitis. […] We report a unique finding which casts doubt on the real role of luminal obstruction as a pathogenetic cause of acute appendicitis. […] This intraoperative finding is extremely interesting because it incontrovertibly highlights the poor pathogenetic role of luminal obstruction in the development of appendicitis. […] Although luminal obstruction could play a role in acute appendicitis, the development of other factors seems to be necessary to provoke acute inflammation.

• #21 Pathogenesis of acute appendicitis: review – MedCrave online

  https://medcraveonline.com/GHOA/pathogenesis-of-acute-appendicitis-review.html

  Based on the analysis of literature and our own studies we propose hypothesis of the pathogenesis of acute appendicitis (AA), which differs from the generally accepted by following provisions. Acute appendicitis develops as a result of immunological reaction and hyperplasia of the lymphoid tissue of the appendix. […] The inflammatory process in the appendix leads to increased tone especially in segments of the intestine, lying next to it. Which manifests in the form of spasm of the sigmoid colon and/or ileum, as well as the shortening of the dome of the cecum or/and as the concavity of its inner wall. An increase in the tone of the digestive tract is a nonspecific reaction to inflammation. […] The lumen of the AX sharply narrows as a result of the immunological reaction with an increase in the volume of its lymphoid tissue. This reaction may occur in response to an inflammatory process in the lymphoid tissue in another place, a viral infection, or an allergy. It is more likely with an increase in the level of sex hormones. In some number of cases the lumen of the AX completely overlaps, so that a closed cavity in the distal part of the AX is formed.

• #22 THE PATHOGENESIS OF ACUTE APPENDICITIS. THE NON-SPECIFIC RESPONSE OF THE DIGESTIVE TRACT IN ACUTE INFLAMMATION IN THE ABDOMEN – PubMed

  https://pubmed.ncbi.nlm.nih.gov/29874439/

  Based on the analysis of literature and our own studies we propose hypothesis of the pathogenesis of acute appendicitis (AA), which differs from the following generally accepted provisions. […] Acute appendidtis develops as a result of immunological reaction and hyperplasia of the mucous membrane of the appendix. […] Only a small percentage of cases of primary hyperplasia causes a complete occlusion of the lumen and destructive AA. […] Inflammation leads to increased tone of the stomach and colon, but strong in the segments of intestine lay next to the A. This is accompanied by increased of the anal canal pressure. Increased tone of the digestive tract is a nonspecific response to acute inflammation.

• #23 Pathogenesis of acute appendicitis: review – MedCrave online

  https://medcraveonline.com/GHOA/pathogenesis-of-acute-appendicitis-review.html

  Based on the analysis of literature and our own studies we propose hypothesis of the pathogenesis of acute appendicitis (AA), which differs from the generally accepted by following provisions. Acute appendicitis develops as a result of immunological reaction and hyperplasia of the lymphoid tissue of the appendix. […] The inflammatory process in the appendix leads to increased tone especially in segments of the intestine, lying next to it. Which manifests in the form of spasm of the sigmoid colon and/or ileum, as well as the shortening of the dome of the cecum or/and as the concavity of its inner wall. An increase in the tone of the digestive tract is a nonspecific reaction to inflammation. […] The lumen of the AX sharply narrows as a result of the immunological reaction with an increase in the volume of its lymphoid tissue. This reaction may occur in response to an inflammatory process in the lymphoid tissue in another place, a viral infection, or an allergy. It is more likely with an increase in the level of sex hormones. In some number of cases the lumen of the AX completely overlaps, so that a closed cavity in the distal part of the AX is formed.

• #24 Pathogenesis of acute appendicitis: review – MedCrave online

  https://medcraveonline.com/GHOA/pathogenesis-of-acute-appendicitis-review.html

  Based on the analysis of literature and our own studies we propose hypothesis of the pathogenesis of acute appendicitis (AA), which differs from the generally accepted by following provisions. Acute appendicitis develops as a result of immunological reaction and hyperplasia of the lymphoid tissue of the appendix. […] The inflammatory process in the appendix leads to increased tone especially in segments of the intestine, lying next to it. Which manifests in the form of spasm of the sigmoid colon and/or ileum, as well as the shortening of the dome of the cecum or/and as the concavity of its inner wall. An increase in the tone of the digestive tract is a nonspecific reaction to inflammation. […] The lumen of the AX sharply narrows as a result of the immunological reaction with an increase in the volume of its lymphoid tissue. This reaction may occur in response to an inflammatory process in the lymphoid tissue in another place, a viral infection, or an allergy. It is more likely with an increase in the level of sex hormones. In some number of cases the lumen of the AX completely overlaps, so that a closed cavity in the distal part of the AX is formed.

• #25 Pathogenesis of acute appendicitis: review – MedCrave online

  https://medcraveonline.com/GHOA/pathogenesis-of-acute-appendicitis-review.html

  Based on the analysis of literature and our own studies we propose hypothesis of the pathogenesis of acute appendicitis (AA), which differs from the generally accepted by following provisions. Acute appendicitis develops as a result of immunological reaction and hyperplasia of the lymphoid tissue of the appendix. […] The inflammatory process in the appendix leads to increased tone especially in segments of the intestine, lying next to it. Which manifests in the form of spasm of the sigmoid colon and/or ileum, as well as the shortening of the dome of the cecum or/and as the concavity of its inner wall. An increase in the tone of the digestive tract is a nonspecific reaction to inflammation. […] The lumen of the AX sharply narrows as a result of the immunological reaction with an increase in the volume of its lymphoid tissue. This reaction may occur in response to an inflammatory process in the lymphoid tissue in another place, a viral infection, or an allergy. It is more likely with an increase in the level of sex hormones. In some number of cases the lumen of the AX completely overlaps, so that a closed cavity in the distal part of the AX is formed.

• #26 Compilation of Evidence Supporting the Role of a T Helper 2 Reaction in the Pathogenesis of Acute Appendicitis

  https://www.mdpi.com/1422-0067/25/8/4216

  Despite being the most common abdominal surgical emergency, the cause of acute appendicitis (AA) remains unclear, since in recent decades little progress has been made regarding its etiology. […] The common teaching is that AA is caused by appendix luminal obstruction. However, this is seldom seen in surgical clinical practice, where obstruction seems to be the consequence rather than the cause of AA. […] Tsuji was the first author to propose the occurrence of an immune process in AA. In fact, he noted that the lamina propria of the appendicular wall in cases of AA was infiltrated by lymphocytes. He postulated that an non-identified antigen could stimulate their presence at the appendicular wall, inducing inflammation-AA. […] Later, Aravindan, when studying AA specimens, noted the common presence of eosinophil infiltration in the tunica muscularis, intramuscular edema and mast-cell degranulation. He proposed that AA was initiated by a type I hypersensitivity reaction, as the histological features are similar to those found in type I hypersensitivity. […] Several recent studies have reinforced the hypothesis that there is a Th2 immune reaction in AA.

• #27 Compilation of Evidence Supporting the Role of a T Helper 2 Reaction in the Pathogenesis of Acute Appendicitis

  https://www.mdpi.com/1422-0067/25/8/4216

  Despite being the most common abdominal surgical emergency, the cause of acute appendicitis (AA) remains unclear, since in recent decades little progress has been made regarding its etiology. […] The common teaching is that AA is caused by appendix luminal obstruction. However, this is seldom seen in surgical clinical practice, where obstruction seems to be the consequence rather than the cause of AA. […] Tsuji was the first author to propose the occurrence of an immune process in AA. In fact, he noted that the lamina propria of the appendicular wall in cases of AA was infiltrated by lymphocytes. He postulated that an non-identified antigen could stimulate their presence at the appendicular wall, inducing inflammation-AA. […] Later, Aravindan, when studying AA specimens, noted the common presence of eosinophil infiltration in the tunica muscularis, intramuscular edema and mast-cell degranulation. He proposed that AA was initiated by a type I hypersensitivity reaction, as the histological features are similar to those found in type I hypersensitivity. […] Several recent studies have reinforced the hypothesis that there is a Th2 immune reaction in AA.

• #28 Compilation of Evidence Supporting the Role of a T Helper 2 Reaction in the Pathogenesis of Acute Appendicitis

  https://www.mdpi.com/1422-0067/25/8/4216

  Despite being the most common abdominal surgical emergency, the cause of acute appendicitis (AA) remains unclear, since in recent decades little progress has been made regarding its etiology. […] The common teaching is that AA is caused by appendix luminal obstruction. However, this is seldom seen in surgical clinical practice, where obstruction seems to be the consequence rather than the cause of AA. […] Tsuji was the first author to propose the occurrence of an immune process in AA. In fact, he noted that the lamina propria of the appendicular wall in cases of AA was infiltrated by lymphocytes. He postulated that an non-identified antigen could stimulate their presence at the appendicular wall, inducing inflammation-AA. […] Later, Aravindan, when studying AA specimens, noted the common presence of eosinophil infiltration in the tunica muscularis, intramuscular edema and mast-cell degranulation. He proposed that AA was initiated by a type I hypersensitivity reaction, as the histological features are similar to those found in type I hypersensitivity. […] Several recent studies have reinforced the hypothesis that there is a Th2 immune reaction in AA.

• #29 An observational study of innate immune responses in patients with acute appendicitis | Scientific Reports

  https://www.nature.com/articles/s41598-020-73798-3

  During acute appendicitis, high IL-8 levels can be observed in the appendix, the peritoneal fluid, and according to some studies in the serum of patients. […] Gangrenous appendicitis is associated with inflammatory markers in serum, consistent with a Th17 response. […] High grade inflammation and tissue damage appear to be a mechanism in the development of appendicitis, possibly caused by deviant immune responses. […] The main aim of this study was to characterize potential deviant immune responses to stimulation by a large panel of gut bacteria, other commensals and relevant corresponding Pattern Recognition Receptor (PRR) ligands. […] This study illustrates involvement of the innate immune system in acute appendicitis, and its severity. There was a clear trend towards higher IL-10 responses in PBMCs from patients with a history of complicated compared to uncomplicated appendicitis, and responses towards a number of specific stimuli were significantly elevated.

• #30 Pathophysiology of Acute Appendicitis

  https://www.jscimedcentral.com/jounal-article-info/JSM-Gastroenterology-and-Hepatology/Pathophysiology-of-Acute-Appendicitis-7440

  The function of the appendix is not clearly understood, although the presence of lymphatic tissue on it suggests a role in the immune system. […] The primary pathogenic event in most of patients with acute appendicitis is believed to be due to luminal obstruction. […] There is strong epidemiologic evidence supporting the proposition that perforated and non-perforated appendicitis are separate entities with a different pathogenesis. […] Recently, with the advent of neurogastroenterology, the concept of neuroimmune appendicitis has evolved. […] Considering that neurogenic disease may not include inflammatory signs, the name neurogenic appendicopathy seems to be a more appropriate term for appendices of morphological normal aspect in patients with clinical symptoms of acute appendicitis. […] As it can be perceived, based on the large number of studies related to acute appendicitis, it is not yet established the pathophysiology of this disease. […] More research is in need to understand this still mysterious disease.

• #31 Pathophysiology of Acute Appendicitis

  https://www.jscimedcentral.com/jounal-article-info/JSM-Gastroenterology-and-Hepatology/Pathophysiology-of-Acute-Appendicitis-7440

  The function of the appendix is not clearly understood, although the presence of lymphatic tissue on it suggests a role in the immune system. […] The primary pathogenic event in most of patients with acute appendicitis is believed to be due to luminal obstruction. […] There is strong epidemiologic evidence supporting the proposition that perforated and non-perforated appendicitis are separate entities with a different pathogenesis. […] Recently, with the advent of neurogastroenterology, the concept of neuroimmune appendicitis has evolved. […] Considering that neurogenic disease may not include inflammatory signs, the name neurogenic appendicopathy seems to be a more appropriate term for appendices of morphological normal aspect in patients with clinical symptoms of acute appendicitis. […] As it can be perceived, based on the large number of studies related to acute appendicitis, it is not yet established the pathophysiology of this disease. […] More research is in need to understand this still mysterious disease.

• #32 THE PATHOGENESIS OF ACUTE APPENDICITIS. THE NON-SPECIFI C RESPONSE OF THE DIGESTIVE TRACT IN ACUTE INFL AMMATION IN THE ABDOMEN | Levin | Experimental and Clinical Gastroenterology

  https://www.nogr.org/jour/article/view/262?locale=en_US

  Based on the analysis of literature and our own studies we propose hypothesis of the pathogenesis of acute appendicitis (AA), which differs from the following generally accepted provisions. […] Acute appendicitis develops as a result of immunological reaction and hyperplasia of the mucous membrane of the appendix. […] Usually it is exposed to regression without causing the typical symptoms, but leaving the damaged nervous system and / or sclerotic changes that violate the peristalsis of the appendix. […] In the next fit of hyperplasia, the walls are stretched over fecolithe, causing obstruction of the lumen, the formation of a closed cavity and the known mechanisms of inflammation. […] Increased tone of the digestive tract is a nonspecific response to acute inflammation.

• #33 Pathogenesis of acute appendicitis: review – Gastroenterology & Hepatology: Open Access – MedCrave Publishing

  http://www.medcrave.com/articles/det/20535/Pathogenesis-of-acute-appendicitis-review

  Based on the analysis of literature and our own studies we propose hypothesis of the pathogenesis of acute appendicitis (AA), which differs from the generally accepted by following provisions. Acute appendicitis develops as a result of immunological reaction and hyperplasia of the lymphoid tissue of the appendix. The frequency of AA correlates with the rapid growth of sex hormones and depends on age, gender and time of year. Only a small percentage of primary hyperplasia causes a complete occlusion of the lumen and destructive AA. Usually it is exposed to regression without causing the typical symptoms but leaving the damaged nervous system and/or sclerotic changes that violate the peristalsis of the appendix. […] In one of the subsequent attacks of lymphoid hyperplasia, the walls of the appendix wrap around over fecalith, causing obstruction of the lumen, the formation of a closed cavity and the known mechanisms of inflammation. The formation of a closed cavity with high pressure leads to reflex strengthening of tone of the digestive tract, which explains the pain in the epigastrium and vomiting in the first hours of the disease. This is accompanied by increased of the anal canal pressure. The inflammatory process in the appendix leads to increased tone especially in segments of the intestine, lying next to it. Which manifests in the form of spasm of the sigmoid colon and/or ileum, as well as the shortening of the dome of the cecum or/and as the concavity of its inner wall. An increase in the tone of the digestive tract is a nonspecific reaction to inflammation.

• #34 Pathogenesis of acute appendicitis: review – Gastroenterology & Hepatology: Open Access – MedCrave Publishing

  http://www.medcrave.com/articles/det/20535/Pathogenesis-of-acute-appendicitis-review

  Based on the analysis of literature and our own studies we propose hypothesis of the pathogenesis of acute appendicitis (AA), which differs from the generally accepted by following provisions. Acute appendicitis develops as a result of immunological reaction and hyperplasia of the lymphoid tissue of the appendix. The frequency of AA correlates with the rapid growth of sex hormones and depends on age, gender and time of year. Only a small percentage of primary hyperplasia causes a complete occlusion of the lumen and destructive AA. Usually it is exposed to regression without causing the typical symptoms but leaving the damaged nervous system and/or sclerotic changes that violate the peristalsis of the appendix. […] In one of the subsequent attacks of lymphoid hyperplasia, the walls of the appendix wrap around over fecalith, causing obstruction of the lumen, the formation of a closed cavity and the known mechanisms of inflammation. The formation of a closed cavity with high pressure leads to reflex strengthening of tone of the digestive tract, which explains the pain in the epigastrium and vomiting in the first hours of the disease. This is accompanied by increased of the anal canal pressure. The inflammatory process in the appendix leads to increased tone especially in segments of the intestine, lying next to it. Which manifests in the form of spasm of the sigmoid colon and/or ileum, as well as the shortening of the dome of the cecum or/and as the concavity of its inner wall. An increase in the tone of the digestive tract is a nonspecific reaction to inflammation.

• #35 Pathogenesis of acute appendicitis: review – MedCrave online

  https://medcraveonline.com/GHOA/pathogenesis-of-acute-appendicitis-review.html

  Based on the analysis of literature and our own studies we propose hypothesis of the pathogenesis of acute appendicitis (AA), which differs from the generally accepted by following provisions. Acute appendicitis develops as a result of immunological reaction and hyperplasia of the lymphoid tissue of the appendix. […] The inflammatory process in the appendix leads to increased tone especially in segments of the intestine, lying next to it. Which manifests in the form of spasm of the sigmoid colon and/or ileum, as well as the shortening of the dome of the cecum or/and as the concavity of its inner wall. An increase in the tone of the digestive tract is a nonspecific reaction to inflammation. […] The lumen of the AX sharply narrows as a result of the immunological reaction with an increase in the volume of its lymphoid tissue. This reaction may occur in response to an inflammatory process in the lymphoid tissue in another place, a viral infection, or an allergy. It is more likely with an increase in the level of sex hormones. In some number of cases the lumen of the AX completely overlaps, so that a closed cavity in the distal part of the AX is formed.

• #36 Culture-Independent Evaluation of the Appendix and Rectum Microbiomes in Children with and without Appendicitis | PLOS One

  https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0095414

  The pathogenesis of appendicitis is classically thought to result, in part, from obstruction of the appendiceal lumen. Obstruction has been attributed to lymphoid hyperplasia, anatomic position, tumors and fecaliths, which are found in 11-52% of patients with acute appendicitis. Obstruction is then thought to lead to an accumulation of undrained secretions, alteration and overgrowth of appendiceal microbes, compromised perfusion, and epithelial damage. The precise sequence of events is not definitively established, but most authors count microbial overgrowth or distortion of the appendiceal microbial flora as key elements of the pathogenic cascade. […] Shifts in the appendiceal microbiota are believed to play a key role in the pathophysiology of acute appendicitis, a common pediatric and adult disorder.

• #37 Appendicitis – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK493193/

  Acute appendicitis is characterized by inflammation of the vermiform appendix, and patients typically present emergently within 24 hours of the onset of symptoms. […] Appendicitis is primarily caused by obstruction of the appendiceal lumen leading to inflammation. The obstruction can be due to various factors such as appendicoliths, appendiceal tumors, intestinal parasites, or hypertrophied lymphatic tissues. These mechanical obstructions result in the development of acute appendicitis. […] The appendix is known to naturally host aerobic and anaerobic bacteria, including Escherichia coli and Bacteroides spp. Obstruction of the appendiceal lumen by any mechanism can cause an overgrowth of bacteria leading to acute inflammation and abscess formation. Recent studies utilizing next-generation sequencing techniques have revealed that patients with complicated perforated appendicitis exhibit a significantly higher bacterial phyla load than those with uncomplicated appendicitis. This finding suggests that the severity and complications of appendicitis may be associated with an increased abundance of bacterial species.

• #38 Appendicitis – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK493193/

  Acute appendicitis is characterized by inflammation of the vermiform appendix, and patients typically present emergently within 24 hours of the onset of symptoms. […] Appendicitis is primarily caused by obstruction of the appendiceal lumen leading to inflammation. The obstruction can be due to various factors such as appendicoliths, appendiceal tumors, intestinal parasites, or hypertrophied lymphatic tissues. These mechanical obstructions result in the development of acute appendicitis. […] The appendix is known to naturally host aerobic and anaerobic bacteria, including Escherichia coli and Bacteroides spp. Obstruction of the appendiceal lumen by any mechanism can cause an overgrowth of bacteria leading to acute inflammation and abscess formation. Recent studies utilizing next-generation sequencing techniques have revealed that patients with complicated perforated appendicitis exhibit a significantly higher bacterial phyla load than those with uncomplicated appendicitis. This finding suggests that the severity and complications of appendicitis may be associated with an increased abundance of bacterial species.

• #39 Appendiceal microbiome in uncomplicated and complicated acute appendicitis: A prospective cohort study | PLOS One

  https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0276007

  Uncomplicated and complicated acute appendicitis seem to be two different forms of this common abdominal emergency. The contribution of appendiceal microbiota to appendicitis pathogenesis has been suggested, but differences between uncomplicated and complicated appendicitis are largely unknown. […] The understanding of both microbiological etiology of acute appendicitis and the potential differences in etiology and pathogenesis between uncomplicated and complicated acute appendicitis is very limited, but the involvement of bacteria or the appendicular microbiome has been suggested. […] In conclusion, uncomplicated and complicated acute appendicitis have different appendiceal microbiome profiles further supporting the disconnection between these two different forms of appendicitis severity.

• #40 Appendicitis – Wikipedia

  https://en.wikipedia.org/wiki/Appendicitis

  Appendicitis is primarily caused by a blockage of the hollow portion in the appendix. This blockage typically results from a faecolith, a calcified „stone” made of feces. Some studies show a correlation between appendicoliths and disease severity. Other factors such as inflamed lymphoid tissue from a viral infection, intestinal parasites, gallstone, or tumors may also lead to this blockage. When the appendix becomes blocked, it experiences increased pressure, reduced blood flow, and bacterial growth, resulting in inflammation. This combination of factors causes tissue injury and, ultimately, tissue death. If this process is left untreated, it can lead to the appendix rupturing, which releases bacteria into the abdominal cavity, potentially leading to severe complications. […] Acute appendicitis seems to be the result of a primary obstruction of the appendix. Once this obstruction occurs, the appendix becomes filled with mucus and swells. This continued production of mucus leads to increased pressures within the lumen and the walls of the appendix. The increased pressure results in thrombosis and occlusion of the small vessels, and stasis of lymphatic flow. At this point, spontaneous recovery rarely occurs. As the occlusion of blood vessels progresses, the appendix becomes ischemic and then necrotic. As bacteria begin to leak out through the dying walls, pus forms within and around the appendix (suppuration). The result is appendiceal rupture (a 'burst appendix’) causing peritonitis, which may lead to sepsis and in rare cases, death. These events are responsible for the slowly evolving abdominal pain and other commonly associated symptoms. […] Several studies offer evidence that a low fiber intake is involved in the pathogenesis of appendicitis. This low intake of dietary fiber is in accordance with the occurrence of a right-sided fecal reservoir and the fact that dietary fiber reduces transit time.

• #41 SciELO Brazil – The Impact of Smoking on the Complications of Acute Appendicitis The Impact of Smoking on the Complications of Acute Appendicitis

  https://www.scielo.br/j/jcol/a/khykYpQddJChQjzxHcNrBnC/?lang=en

  The aim of this study is to evaluate the effect of cigarette smoking on the incidence of complications of acute appendicitis (perforation, gangrene or mass) because all the beforehand complications are the sequelae of ischemia and the smoking is a leading cause of atherosclerosis which affects arteries and as the appendicular artery is an end artery then its involvement by atherosclerosis supposed to lead to more incidence of ischemia and complications of appendicitis. […] This study shows that significant association was noticed between smoking status and complicated appendicitis where OR was 5.91, 95% CI = 1.957- 17.84 and this goes in concordance with Sadr Azodi et al study which showed increased risk and rapid progress of acute appendicitis to perforation in currently tobacco smokers. […] Perforated acute appendicitis is higher among current tobacco smokers.

• #42 SciELO Brazil – The Impact of Smoking on the Complications of Acute Appendicitis The Impact of Smoking on the Complications of Acute Appendicitis

  https://www.scielo.br/j/jcol/a/khykYpQddJChQjzxHcNrBnC/?lang=en

  The aim of this study is to evaluate the effect of cigarette smoking on the incidence of complications of acute appendicitis (perforation, gangrene or mass) because all the beforehand complications are the sequelae of ischemia and the smoking is a leading cause of atherosclerosis which affects arteries and as the appendicular artery is an end artery then its involvement by atherosclerosis supposed to lead to more incidence of ischemia and complications of appendicitis. […] This study shows that significant association was noticed between smoking status and complicated appendicitis where OR was 5.91, 95% CI = 1.957- 17.84 and this goes in concordance with Sadr Azodi et al study which showed increased risk and rapid progress of acute appendicitis to perforation in currently tobacco smokers. […] Perforated acute appendicitis is higher among current tobacco smokers.

• #43

  https://www.pafmj.org/PAFMJ/article/view/12432

  Objective: To determine the role of high altitude in thrombosis of appendicular artery and pathogenesis of acute appendicitis. […] However, Extended exposure of high altitude can incite …. […] Six cases (6.9%) were found to have thrombosis of appendicular artery.

• #44 Endothelial Dysfunction in Appendicitis | IntechOpen

  https://www.intechopen.com/chapters/83816

  In an inflammation, including appendicitis, vascular adequacy is required to supply anti-inflammatory substances and nutrition due to inflamed tissue remodeling. […] This mechanism is impaired in the process of inflammation by inflammatory substances causing endothelial dysfunction. […] Severity and complications of appendicitis are known to be related with necrosis or ischemic tissue in the appendix vermiform. […] Basic consideration on factors affecting the vascularization patency to tissue damage in appendicitis. […] This means mucosal vascularization of the appendix was considered as a barrier preventing further damage to the mucosa from increased intraluminal pressure in appendicitis. […] The growth factor such as the vascular endothelial growth factor (VEGF) has a main role determining the strength of the endothelium against inflammation, especially in cases of appendicitis itself in the vascularization of the appendix.

• #45 Endothelial Dysfunction in Appendicitis | IntechOpen

  https://www.intechopen.com/chapters/83816

  In an inflammation, including appendicitis, vascular adequacy is required to supply anti-inflammatory substances and nutrition due to inflamed tissue remodeling. […] This mechanism is impaired in the process of inflammation by inflammatory substances causing endothelial dysfunction. […] Severity and complications of appendicitis are known to be related with necrosis or ischemic tissue in the appendix vermiform. […] Basic consideration on factors affecting the vascularization patency to tissue damage in appendicitis. […] This means mucosal vascularization of the appendix was considered as a barrier preventing further damage to the mucosa from increased intraluminal pressure in appendicitis. […] The growth factor such as the vascular endothelial growth factor (VEGF) has a main role determining the strength of the endothelium against inflammation, especially in cases of appendicitis itself in the vascularization of the appendix.

• #46 Endothelial Dysfunction in Appendicitis | IntechOpen

  https://www.intechopen.com/chapters/83816

  In an inflammation, including appendicitis, vascular adequacy is required to supply anti-inflammatory substances and nutrition due to inflamed tissue remodeling. […] This mechanism is impaired in the process of inflammation by inflammatory substances causing endothelial dysfunction. […] Severity and complications of appendicitis are known to be related with necrosis or ischemic tissue in the appendix vermiform. […] Basic consideration on factors affecting the vascularization patency to tissue damage in appendicitis. […] This means mucosal vascularization of the appendix was considered as a barrier preventing further damage to the mucosa from increased intraluminal pressure in appendicitis. […] The growth factor such as the vascular endothelial growth factor (VEGF) has a main role determining the strength of the endothelium against inflammation, especially in cases of appendicitis itself in the vascularization of the appendix.

• #47 Endothelial Dysfunction in Appendicitis | IntechOpen

  https://www.intechopen.com/chapters/83816

  In an inflammation, including appendicitis, vascular adequacy is required to supply anti-inflammatory substances and nutrition due to inflamed tissue remodeling. […] This mechanism is impaired in the process of inflammation by inflammatory substances causing endothelial dysfunction. […] Severity and complications of appendicitis are known to be related with necrosis or ischemic tissue in the appendix vermiform. […] Basic consideration on factors affecting the vascularization patency to tissue damage in appendicitis. […] This means mucosal vascularization of the appendix was considered as a barrier preventing further damage to the mucosa from increased intraluminal pressure in appendicitis. […] The growth factor such as the vascular endothelial growth factor (VEGF) has a main role determining the strength of the endothelium against inflammation, especially in cases of appendicitis itself in the vascularization of the appendix.

• #48 Pathophysiology of Acute Appendicitis

  https://www.jscimedcentral.com/jounal-article-info/JSM-Gastroenterology-and-Hepatology/Pathophysiology-of-Acute-Appendicitis-7440

  The function of the appendix is not clearly understood, although the presence of lymphatic tissue on it suggests a role in the immune system. […] The primary pathogenic event in most of patients with acute appendicitis is believed to be due to luminal obstruction. […] There is strong epidemiologic evidence supporting the proposition that perforated and non-perforated appendicitis are separate entities with a different pathogenesis. […] Recently, with the advent of neurogastroenterology, the concept of neuroimmune appendicitis has evolved. […] Considering that neurogenic disease may not include inflammatory signs, the name neurogenic appendicopathy seems to be a more appropriate term for appendices of morphological normal aspect in patients with clinical symptoms of acute appendicitis. […] As it can be perceived, based on the large number of studies related to acute appendicitis, it is not yet established the pathophysiology of this disease. […] More research is in need to understand this still mysterious disease.

• #49 Pathophysiology of acute appendicitis.

  https://www.repositorio.ufop.br/items/e27482d2-c6ea-46fc-9db0-f8802743d17e

  Background: Acute appendicitis, the most common abdominal emergency that requires surgical treatment, shows a lifetime risk of 7%. […] The primary pathogenic event in most of patients with acute appendicitis is believed to be due to luminal obstruction. Although being logical and likely to be true, this theory has not been proven. […] There is strong epidemiologic evidence supporting the proposition that perforated and non-perforated appendicitis are separate entities with a different pathogenesis. […] Recently, with the advent of neurogastroenterology, the concept of neuroimmune appendicitis has evolved. Considering that neurogenic disease may not include inflammatory signs, the name neurogenic appendicopathy seems to be a more appropriate term for appendices of morphological normal aspect in patients with clinical symptoms of acute appendicitis. […] As it can be perceived, based on the large number of studies related to acute appendicitis, it is not yet established the pathophysiology of this disease. More research is in need to understand this still mysterious disease.

• #50 Construction of a clinical prediction model for complicated appendicitis based on machine learning techniques | Scientific Reports

  https://www.nature.com/articles/s41598-024-67453-4

  The appendix is in the right lower abdomen, where food debris and bacteria accumulate and produce inflammation. Acute appendicitis is the most common surgical emergency worldwide, with a lifetime risk of 78%. […] Acute appendicitis can be categorized into two types: UA, which is defined as cellulitis appendicitis without signs of necrosis or perforation. And CA, this has focal or transmural necrosis that may eventually lead to perforation. It is essential to differentiate between these two conditions because UA can be treated conservatively with antibiotics without surgery and may even resolve independently without antibiotic therapy. Patients with CA require emergency appendectomy. […] Moreover, delayed diagnosis of complicated appendicitis may lead to associated complications such as perforation and peritonitis, resulting in severe morbidity and mortality, especially in the elderly patient population with comorbidities, as well as prolonged hospitalization, loss of employment, increased costs due to additional investigations, and psychosocial problems.

• #51 Construction of a clinical prediction model for complicated appendicitis based on machine learning techniques | Scientific Reports

  https://www.nature.com/articles/s41598-024-67453-4

  The appendix is in the right lower abdomen, where food debris and bacteria accumulate and produce inflammation. Acute appendicitis is the most common surgical emergency worldwide, with a lifetime risk of 78%. […] Acute appendicitis can be categorized into two types: UA, which is defined as cellulitis appendicitis without signs of necrosis or perforation. And CA, this has focal or transmural necrosis that may eventually lead to perforation. It is essential to differentiate between these two conditions because UA can be treated conservatively with antibiotics without surgery and may even resolve independently without antibiotic therapy. Patients with CA require emergency appendectomy. […] Moreover, delayed diagnosis of complicated appendicitis may lead to associated complications such as perforation and peritonitis, resulting in severe morbidity and mortality, especially in the elderly patient population with comorbidities, as well as prolonged hospitalization, loss of employment, increased costs due to additional investigations, and psychosocial problems.

• #52 Construction of a clinical prediction model for complicated appendicitis based on machine learning techniques | Scientific Reports

  https://www.nature.com/articles/s41598-024-67453-4

  The appendix is in the right lower abdomen, where food debris and bacteria accumulate and produce inflammation. Acute appendicitis is the most common surgical emergency worldwide, with a lifetime risk of 78%. […] Acute appendicitis can be categorized into two types: UA, which is defined as cellulitis appendicitis without signs of necrosis or perforation. And CA, this has focal or transmural necrosis that may eventually lead to perforation. It is essential to differentiate between these two conditions because UA can be treated conservatively with antibiotics without surgery and may even resolve independently without antibiotic therapy. Patients with CA require emergency appendectomy. […] Moreover, delayed diagnosis of complicated appendicitis may lead to associated complications such as perforation and peritonitis, resulting in severe morbidity and mortality, especially in the elderly patient population with comorbidities, as well as prolonged hospitalization, loss of employment, increased costs due to additional investigations, and psychosocial problems.

• #53 Chronic appendicitis: two case reports | Journal of Medical Case Reports | Full Text

  https://jmedicalcasereports.biomedcentral.com/articles/10.1186/s13256-022-03273-2

  Chronic appendicitis is a diagnosis unfamiliar to many clinicians, and with no official diagnostic criteria. […] The etiology of chronic appendicitis is unknown but is likewise believed to be a result of partial or transient obstruction of the appendiceal lumen. […] In our first case, gastroenteritis was possibly the initial cause of the chronic appendicitis, however, the travel history contributed to the delay in diagnosis as a tropical disease was suspected. […] The radiological findings by CT in chronic appendicitis have been estimated to be identical to the findings in acute appendicitis and include pericecal stranding, dilation of appendix, apical thickening, and adenopathy. […] The pathological findings of chronic appendicitis include infiltration by lymphocytes, histiocytes, and plasma cells in lamina propria; hyperplasia of lymphoid tissue; and fibrosis. […] In addition, these studies showed that 82-93% of the patients with chronic appendicitis became symptom-free after surgery. […] to our knowledge there are no clinical studies of antibiotic treatment in chronic appendicitis, hence optimal treatment strategy for this condition is unknown.

• #54 Chronic appendicitis: two case reports | Journal of Medical Case Reports | Full Text

  https://jmedicalcasereports.biomedcentral.com/articles/10.1186/s13256-022-03273-2

  Chronic appendicitis is a diagnosis unfamiliar to many clinicians, and with no official diagnostic criteria. […] The etiology of chronic appendicitis is unknown but is likewise believed to be a result of partial or transient obstruction of the appendiceal lumen. […] In our first case, gastroenteritis was possibly the initial cause of the chronic appendicitis, however, the travel history contributed to the delay in diagnosis as a tropical disease was suspected. […] The radiological findings by CT in chronic appendicitis have been estimated to be identical to the findings in acute appendicitis and include pericecal stranding, dilation of appendix, apical thickening, and adenopathy. […] The pathological findings of chronic appendicitis include infiltration by lymphocytes, histiocytes, and plasma cells in lamina propria; hyperplasia of lymphoid tissue; and fibrosis. […] In addition, these studies showed that 82-93% of the patients with chronic appendicitis became symptom-free after surgery. […] to our knowledge there are no clinical studies of antibiotic treatment in chronic appendicitis, hence optimal treatment strategy for this condition is unknown.

• #55 Chronic appendicitis: two case reports | Journal of Medical Case Reports | Full Text

  https://jmedicalcasereports.biomedcentral.com/articles/10.1186/s13256-022-03273-2

  Chronic appendicitis is a diagnosis unfamiliar to many clinicians, and with no official diagnostic criteria. […] The etiology of chronic appendicitis is unknown but is likewise believed to be a result of partial or transient obstruction of the appendiceal lumen. […] In our first case, gastroenteritis was possibly the initial cause of the chronic appendicitis, however, the travel history contributed to the delay in diagnosis as a tropical disease was suspected. […] The radiological findings by CT in chronic appendicitis have been estimated to be identical to the findings in acute appendicitis and include pericecal stranding, dilation of appendix, apical thickening, and adenopathy. […] The pathological findings of chronic appendicitis include infiltration by lymphocytes, histiocytes, and plasma cells in lamina propria; hyperplasia of lymphoid tissue; and fibrosis. […] In addition, these studies showed that 82-93% of the patients with chronic appendicitis became symptom-free after surgery. […] to our knowledge there are no clinical studies of antibiotic treatment in chronic appendicitis, hence optimal treatment strategy for this condition is unknown.

• #56 Chronic appendicitis: two case reports | Journal of Medical Case Reports | Full Text

  https://jmedicalcasereports.biomedcentral.com/articles/10.1186/s13256-022-03273-2

  Chronic appendicitis is a diagnosis unfamiliar to many clinicians, and with no official diagnostic criteria. […] The etiology of chronic appendicitis is unknown but is likewise believed to be a result of partial or transient obstruction of the appendiceal lumen. […] In our first case, gastroenteritis was possibly the initial cause of the chronic appendicitis, however, the travel history contributed to the delay in diagnosis as a tropical disease was suspected. […] The radiological findings by CT in chronic appendicitis have been estimated to be identical to the findings in acute appendicitis and include pericecal stranding, dilation of appendix, apical thickening, and adenopathy. […] The pathological findings of chronic appendicitis include infiltration by lymphocytes, histiocytes, and plasma cells in lamina propria; hyperplasia of lymphoid tissue; and fibrosis. […] In addition, these studies showed that 82-93% of the patients with chronic appendicitis became symptom-free after surgery. […] to our knowledge there are no clinical studies of antibiotic treatment in chronic appendicitis, hence optimal treatment strategy for this condition is unknown.

• #57 Signs and syndromes in acute appendicitis: A pathophysiologic approach

  https://www.wjgnet.com/1948-9366/full/v14/i7/727.htm

  The presence of right lower quadrant abdominal pain in acute appendicitis is caused by viscerosomatic (visceromotor, viscerosensory) and somatic (somatosensory and somatomotor) segmental reflexes. This pathophysiologic mechanism differs entirely from the usual initial viscerosensory reflex, where the pain is deep-seated, poorly localized, more widespread, and bilaterally distributed at the T8-T10 dermatomes, primarily at the epigastric and umbilical regions. […] In cases of early appendicitis where appendiceal distension is abrupt and severe, there may be spill-over of visceral to somatic afferent nerve impulses in the dorsal root ganglion, causing efferent activation of alpha-motor neurons and intercostal nerves in the right lower quadrant and abdominal spasm (guarding) in addition to pain at T10-T11 dermatomes (visceromotor and viscerosensory segmental reflexes).

• #58 Appendicitis | Calgary Guide

  https://calgaryguide.ucalgary.ca/appendicitis/appendicitis-2/

  Appendicitis: Pathogenesis and Clinical Findings […] Dull, crampy, diffuse peri- umbilical pain […] Focal, intense, persistent RLQ pain, abdominal guarding and peritoneal signs (i.e. percussion and rebound tenderness) […] The appendix is anatomically located in the RLQ; appendicitis may be confused with disorders of surrounding structures: Gynecological Diseases RuleoutpregnancywithHCG pregnancy test […] Meckelsdiverticulum (presents identically to appendicitis; surgically located 2 feet from ileocecal valve; mostly seen in children) […] Diverticulitis(presentsasleft sided appendicitis)

• #59 Appendicitis | Calgary Guide

  https://calgaryguide.ucalgary.ca/appendicitis/appendicitis-2/

  Appendicitis: Pathogenesis and Clinical Findings […] Dull, crampy, diffuse peri- umbilical pain […] Focal, intense, persistent RLQ pain, abdominal guarding and peritoneal signs (i.e. percussion and rebound tenderness) […] The appendix is anatomically located in the RLQ; appendicitis may be confused with disorders of surrounding structures: Gynecological Diseases RuleoutpregnancywithHCG pregnancy test […] Meckelsdiverticulum (presents identically to appendicitis; surgically located 2 feet from ileocecal valve; mostly seen in children) […] Diverticulitis(presentsasleft sided appendicitis)

• #60 Signs and syndromes in acute appendicitis: A pathophysiologic approach

  https://www.wjgnet.com/1948-9366/full/v14/i7/727.htm

  The presence of right lower quadrant abdominal pain in acute appendicitis is caused by viscerosomatic (visceromotor, viscerosensory) and somatic (somatosensory and somatomotor) segmental reflexes. This pathophysiologic mechanism differs entirely from the usual initial viscerosensory reflex, where the pain is deep-seated, poorly localized, more widespread, and bilaterally distributed at the T8-T10 dermatomes, primarily at the epigastric and umbilical regions. […] In cases of early appendicitis where appendiceal distension is abrupt and severe, there may be spill-over of visceral to somatic afferent nerve impulses in the dorsal root ganglion, causing efferent activation of alpha-motor neurons and intercostal nerves in the right lower quadrant and abdominal spasm (guarding) in addition to pain at T10-T11 dermatomes (visceromotor and viscerosensory segmental reflexes).

• #61 Signs and syndromes in acute appendicitis: A pathophysiologic approach

  https://www.wjgnet.com/1948-9366/full/v14/i7/727.htm

  The presence of right lower quadrant abdominal pain in acute appendicitis is caused by viscerosomatic (visceromotor, viscerosensory) and somatic (somatosensory and somatomotor) segmental reflexes. This pathophysiologic mechanism differs entirely from the usual initial viscerosensory reflex, where the pain is deep-seated, poorly localized, more widespread, and bilaterally distributed at the T8-T10 dermatomes, primarily at the epigastric and umbilical regions. […] In cases of early appendicitis where appendiceal distension is abrupt and severe, there may be spill-over of visceral to somatic afferent nerve impulses in the dorsal root ganglion, causing efferent activation of alpha-motor neurons and intercostal nerves in the right lower quadrant and abdominal spasm (guarding) in addition to pain at T10-T11 dermatomes (visceromotor and viscerosensory segmental reflexes).

• #62 Signs and syndromes in acute appendicitis: A pathophysiologic approach

  https://www.wjgnet.com/1948-9366/full/v14/i7/727.htm

  The presence of right lower quadrant abdominal pain in acute appendicitis is caused by viscerosomatic (visceromotor, viscerosensory) and somatic (somatosensory and somatomotor) segmental reflexes. This pathophysiologic mechanism differs entirely from the usual initial viscerosensory reflex, where the pain is deep-seated, poorly localized, more widespread, and bilaterally distributed at the T8-T10 dermatomes, primarily at the epigastric and umbilical regions. […] In cases of early appendicitis where appendiceal distension is abrupt and severe, there may be spill-over of visceral to somatic afferent nerve impulses in the dorsal root ganglion, causing efferent activation of alpha-motor neurons and intercostal nerves in the right lower quadrant and abdominal spasm (guarding) in addition to pain at T10-T11 dermatomes (visceromotor and viscerosensory segmental reflexes).

• #63 Appendicitis – Gastrointestinal Disorders – Merck Manual Professional Edition

  https://www.merckmanuals.com/professional/gastrointestinal-disorders/acute-abdomen-and-surgical-gastroenterology/appendicitis

  Appendicitis is thought to result from obstruction of the appendiceal lumen, typically by lymphoid hyperplasia but occasionally by a fecalith, foreign body, tumor, or even worms. The obstruction leads to distention, bacterial overgrowth, ischemia, and inflammation. If untreated, necrosis, gangrene, and perforation occur. If the perforation is contained by the omentum, an appendiceal abscess results. […] Appendicitis remains primarily a clinical diagnosis. Selective and judicious use of imaging studies may reduce the rate of negative laparotomy. […] Although several studies of nonoperative management of appendicitis (ie, using antibiotics alone) have shown high rates of resolution during the initial hospitalization, a significant number of patients have a recurrence and require appendectomy during the following year. Thus, appendectomy is still recommended, particularly if an appendicolith is visible on CT.

• #64 Appendicitis – Gastrointestinal Disorders – Merck Manual Professional Edition

  https://www.merckmanuals.com/professional/gastrointestinal-disorders/acute-abdomen-and-surgical-gastroenterology/appendicitis

  Appendicitis is thought to result from obstruction of the appendiceal lumen, typically by lymphoid hyperplasia but occasionally by a fecalith, foreign body, tumor, or even worms. The obstruction leads to distention, bacterial overgrowth, ischemia, and inflammation. If untreated, necrosis, gangrene, and perforation occur. If the perforation is contained by the omentum, an appendiceal abscess results. […] Appendicitis remains primarily a clinical diagnosis. Selective and judicious use of imaging studies may reduce the rate of negative laparotomy. […] Although several studies of nonoperative management of appendicitis (ie, using antibiotics alone) have shown high rates of resolution during the initial hospitalization, a significant number of patients have a recurrence and require appendectomy during the following year. Thus, appendectomy is still recommended, particularly if an appendicolith is visible on CT.

• #65 Appendicitis – Gastrointestinal Disorders – Merck Manual Professional Edition

  https://www.merckmanuals.com/professional/gastrointestinal-disorders/acute-abdomen-and-surgical-gastroenterology/appendicitis

  Appendicitis is thought to result from obstruction of the appendiceal lumen, typically by lymphoid hyperplasia but occasionally by a fecalith, foreign body, tumor, or even worms. The obstruction leads to distention, bacterial overgrowth, ischemia, and inflammation. If untreated, necrosis, gangrene, and perforation occur. If the perforation is contained by the omentum, an appendiceal abscess results. […] Appendicitis remains primarily a clinical diagnosis. Selective and judicious use of imaging studies may reduce the rate of negative laparotomy. […] Although several studies of nonoperative management of appendicitis (ie, using antibiotics alone) have shown high rates of resolution during the initial hospitalization, a significant number of patients have a recurrence and require appendectomy during the following year. Thus, appendectomy is still recommended, particularly if an appendicolith is visible on CT.

• #66 The Radiology Assistant : Appendicitis – US findings

  https://radiologyassistant.nl/abdomen/acute-abdomen/appendicitis-us-findings

  The increasing use of US and CT in patients with RLQ pain has learned that this phenomenon of so-called spontaneously resolving appendicitis is not rare. […] These images, the rather sudden resolution of symptoms and the usually low CRP, suggest that the cause of this phenomenon is relief of luminal obstruction at an early stage. […] The presence of a fecolith is considered a contra-indication for primary conservative treatment of appendicitis with antibiotics.

• #67 Complicated acute appendicitis with compromised append…

  https://ppch.pl/seo/article/01.3001.0053.6868/en

  In cases of complicated acute appendicitis, specifically gangrenous or perforated appendicitis, a subgroup of patients may have a compromised base of the appendix, that is, a perforation or gangrene at its base; therefore, its treatment represents a challenge, given that if the base is compromised, its closure is difficult and complications such as dehiscence of the closure of the appendicular base may appear, causing fecal peritonitis or fistulae and even leading to right colectomies. […] The appendicular base, compromised by necrosis or perforation, requires adequate treatment in order to prevent dehiscence of the appendicular stump sutures and fecal peritonitis. A number of surgical options have been reported.

• #68 Pathophysiology of Acute Appendicitis

  https://www.jscimedcentral.com/jounal-article-info/JSM-Gastroenterology-and-Hepatology/Pathophysiology-of-Acute-Appendicitis-7440

  The function of the appendix is not clearly understood, although the presence of lymphatic tissue on it suggests a role in the immune system. […] The primary pathogenic event in most of patients with acute appendicitis is believed to be due to luminal obstruction. […] There is strong epidemiologic evidence supporting the proposition that perforated and non-perforated appendicitis are separate entities with a different pathogenesis. […] Recently, with the advent of neurogastroenterology, the concept of neuroimmune appendicitis has evolved. […] Considering that neurogenic disease may not include inflammatory signs, the name neurogenic appendicopathy seems to be a more appropriate term for appendices of morphological normal aspect in patients with clinical symptoms of acute appendicitis. […] As it can be perceived, based on the large number of studies related to acute appendicitis, it is not yet established the pathophysiology of this disease. […] More research is in need to understand this still mysterious disease.

• #69 Pathophysiology of Acute Appendicitis

  https://www.jscimedcentral.com/jounal-article-info/JSM-Gastroenterology-and-Hepatology/Pathophysiology-of-Acute-Appendicitis-7440

  The function of the appendix is not clearly understood, although the presence of lymphatic tissue on it suggests a role in the immune system. […] The primary pathogenic event in most of patients with acute appendicitis is believed to be due to luminal obstruction. […] There is strong epidemiologic evidence supporting the proposition that perforated and non-perforated appendicitis are separate entities with a different pathogenesis. […] Recently, with the advent of neurogastroenterology, the concept of neuroimmune appendicitis has evolved. […] Considering that neurogenic disease may not include inflammatory signs, the name neurogenic appendicopathy seems to be a more appropriate term for appendices of morphological normal aspect in patients with clinical symptoms of acute appendicitis. […] As it can be perceived, based on the large number of studies related to acute appendicitis, it is not yet established the pathophysiology of this disease. […] More research is in need to understand this still mysterious disease.

• #70 Appendicitis in COVID-19-Positive Patient in Postpartum Period: Differential Diagnosis Dilemma | Savic | Journal of Clinical Gynecology and Obstetrics

  https://jcgo.org/index.php/jcgo/article/view/649/437

  Furthermore some studies showed also an important role of specific immunity in the appendicitis pathogenesis, although the significance of the Th1/Th2 balance in appendicitis has not been understood well yet. […] The coincidence of symptoms of SARS-CoV-2 infection and the symptoms of appendicitis mentioned above, as well as impaired immune status, make it difficult to detect appendicitis in a timely manner and also open the question if acute viral infection such as SARS-CoV-2 can trigger an acute appendicitis. […] This specific case is of a great importance to better understand etiology and pathophysiology of acute appendicitis. Further area of research should focus for novel diagnostic test and biomarkers particularly in high-risk groups.

• #71 Appendicitis in COVID-19-Positive Patient in Postpartum Period: Differential Diagnosis Dilemma | Savic | Journal of Clinical Gynecology and Obstetrics

  https://jcgo.org/index.php/jcgo/article/view/649/437

  Furthermore some studies showed also an important role of specific immunity in the appendicitis pathogenesis, although the significance of the Th1/Th2 balance in appendicitis has not been understood well yet. […] The coincidence of symptoms of SARS-CoV-2 infection and the symptoms of appendicitis mentioned above, as well as impaired immune status, make it difficult to detect appendicitis in a timely manner and also open the question if acute viral infection such as SARS-CoV-2 can trigger an acute appendicitis. […] This specific case is of a great importance to better understand etiology and pathophysiology of acute appendicitis. Further area of research should focus for novel diagnostic test and biomarkers particularly in high-risk groups.

• #72 A novel model of appendicitis and appendectomy to investigate inflammatory bowel disease pathogenesis and remediation | Biological Procedures Online | Full Text

  https://biologicalproceduresonline.biomedcentral.com/articles/10.1186/1480-9222-16-10

  Using this model, we have shown that AA performed in the most proximal colon induces the following gene expression changes in the most distal colon: Substantial curbing of T helper 17 cell -recruitment, -differentiation, -activation, and effector (interleukin) expression contributing to suppression of Th17 pathway-mediated immunopathologial damage in colitis. […] Significantly and globally curbing autophagy gene expression, contributing to suppression of autophagy-mediated immunopathology in colitis. […] Late but significant suppression of genes and gene-sets pertaining to endothelin activity – This would suppress endothelin vasoactivity-mediated immunopathologial damage and vascular remodelling in inflammatory colitis. […] Using our unique murine AA model, elucidating the pathways involved in these changes will enhance the development of approaches and techniques to manipulate different genes, enzymes, and proteins related to these pathways; towards improving therapeutic options in IBD.

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