Materiały źródłowe

• #1 Diagnosis and Management of Sodium Disorders: Hyponatremia and Hypernatremia | AAFP

  https://www.aafp.org/pubs/afp/issues/2015/0301/p299.html

  Hyponatremia is a common electrolyte disorder defined as a serum sodium level of less than 135 mEq per L. A Dutch systematic review of 53 studies showed that the prevalence of mild hyponatremia was 22.2% in geriatric hospital wards, 6.0% in nongeriatric wards, and 17.2% in the intensive care unit. The prevalence of severe hyponatremia (serum sodium level less than 125 mEq per L) was 4.5%, 0.8%, and 10.3%, respectively. It is estimated that hyponatremia occurs in 4% to 7% of the ambulatory population, with rates of 18.8% in nursing homes. […] Hyponatremia is associated with increased morbidity and mortality. In patients with heart failure who undergo cardiac surgery, hyponatremia increases rates of postoperative complications, length of hospital stay, and mortality. Mild hyponatremia in the ambulatory setting is associated with increased mortality (hazard ratio = 1.94) compared with normal sodium levels. Patients who develop hyponatremia during hospitalization have increased mortality rates compared with those who have hyponatremia on admission. It is unclear if hyponatremia is a marker for poor prognostic outcomes or merely a reflection of disease severity. Its presence suggests a worse prognosis in patients with liver cirrhosis, pulmonary hypertension, myocardial infarction, chronic kidney disease, hip fractures, and pulmonary embolism.

• #2 Hyponatremia

  https://mobile.fpnotebook.com/Renal/Sodium/Hypntrm.htm

  Most common Electrolyte abnormality in U.S. hospitalized patients (affects 15-30% of patients) […] Identified in up to 7% of outpatients in U.S. […] Hyponatremia is a water excess state […] Excessive free water replacement (with or without Sodium losses) […] Excessive Sodium renal excretion (salt wasting) […] Syndrome Inappropriate ADH Secretion (SIADH) […] Edematous States

• #3 Diagnosis and Management of Sodium Disorders: Hyponatremia and Hypernatremia | AAFP

  https://www.aafp.org/pubs/afp/issues/2015/0301/p299.html

  Hyponatremia is a common electrolyte disorder defined as a serum sodium level of less than 135 mEq per L. A Dutch systematic review of 53 studies showed that the prevalence of mild hyponatremia was 22.2% in geriatric hospital wards, 6.0% in nongeriatric wards, and 17.2% in the intensive care unit. The prevalence of severe hyponatremia (serum sodium level less than 125 mEq per L) was 4.5%, 0.8%, and 10.3%, respectively. It is estimated that hyponatremia occurs in 4% to 7% of the ambulatory population, with rates of 18.8% in nursing homes. […] Hyponatremia is associated with increased morbidity and mortality. In patients with heart failure who undergo cardiac surgery, hyponatremia increases rates of postoperative complications, length of hospital stay, and mortality. Mild hyponatremia in the ambulatory setting is associated with increased mortality (hazard ratio = 1.94) compared with normal sodium levels. Patients who develop hyponatremia during hospitalization have increased mortality rates compared with those who have hyponatremia on admission. It is unclear if hyponatremia is a marker for poor prognostic outcomes or merely a reflection of disease severity. Its presence suggests a worse prognosis in patients with liver cirrhosis, pulmonary hypertension, myocardial infarction, chronic kidney disease, hip fractures, and pulmonary embolism.

• #4 Hyponatremia – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK470386/

  Hyponatremia is defined as a serum sodium concentration of less than 135 mEq/L but can vary to a small extent in different laboratories. Hyponatremia is a common electrolyte abnormality caused by an excess of total body water when compared to total body sodium content. […] The etiology of hyponatremia can be classified based on the volume status of the extracellular fluid. […] Physiological stimuli that cause vasopressin release in adjunct with increased fluid intake can cause hyponatremia. Hypothyroidism and adrenal insufficiency may contribute to an increased release of vasopressin. Physiological stimuli for vasopressin release include loss of intravascular volume (hypovolemic hyponatremia) and the loss of effective intravascular volume (hypervolemic hyponatremia). […] Causes of Hypovolemic Hyponatremia (TBW decreases less than a decrease in total body sodium) include gastrointestinal fluid loss (diarrhea or vomiting), the third spacing of fluids (pancreatitis, hypoalbuminemia, small bowel obstruction), diuretics, osmotic diuresis (glucose, mannitol), salt-wasting nephropathies, cerebral salt-wasting syndrome (urinary salt wasting, possibly caused by increased brain natriuretic peptide), and mineralocorticoid deficiency.

• #5 Hyponatremia – Symptoms, causes, treatment | National Kidney Foundation

  https://www.kidney.org/kidney-topics/hyponatremia-low-sodium-level-blood

  Hyponatremia: Learn about low sodium in the blood, its symptoms, causes, and treatment options for better health management. […] The most common reason for hyponatremia is having too much fluid (water) in the body. This dilution (watering down) effect on the blood makes the amount of sodium seem low. Another common cause is when your body loses too much sodium in the urine and/or sweat. […] There are many reasons why your water and sodium levels can be out of balance. Some of the reasons that are more common for people living with kidney disease include: Acute kidney injury (AKI), advanced stages of chronic kidney disease (CKD), and kidney failure: the kidneys have trouble getting rid of extra fluid from the body which dilutes the blood. […] Other causes of hyponatremia that may not be directly related to kidney diseases include: Extreme hyperglycemia (very high blood sugar): extra fluid can build up in the blood to counteract the high level of sugar. […] Syndrome of inappropriate antidiuretic hormone secretion (SIADH): a medical condition where your body holds on to too much water and removes too much sodium in the urine.

• #6 Hyponatremia: A practical approach

  https://pmc.ncbi.nlm.nih.gov/articles/PMC4192979/

  Hyponatremia is an important and common clinical problem. The etiology is multifactorial. […] Hyponatremia results from the inability of the kidney to excrete a water load or excess water intake. […] Hyponatremia occurs if there is persistent ADH stimulation which is seen in following situations. […] The causes of hypovolemic hyponatremia may be renal or non-renal. […] The commonest cause of euvolemic hyponatremia is Syndrome of inappropriate secretion of Anti diuretic hormone (SIADH). […] The causes of SIADH are shown in Tables 3 and 4. […] Plasma sodium concentration (PNa) is given by ratio of the body’s content of exchangeable sodium and potassium (NaE and KE) and total body water (TBW): PNa NaE + KE/TBW. […] Hyponatremia occurs commonly in both acute and chronic renal failure, because the kidneys cannot maximally excrete excess ingested water.

• #7 Diagnosis and Management of Sodium Disorders: Hyponatremia and Hypernatremia | AAFP

  https://www.aafp.org/pubs/afp/issues/2015/0301/p299.html

  The most common classification system for hyponatremia is based on volume status: hypovolemic (decreased total body water with greater decrease in sodium level), euvolemic (increased total body water with normal sodium level), and hypervolemic (increased total body water compared with sodium). Plasma osmolality has a role in the pathophysiology of hyponatremia. Osmolality refers to the total concentration of solutes in water. Effective osmolality is the osmotic gradient created by solutes that do not cross the cell membrane. Effective osmolality determines the osmotic pressure and the flow of water. Plasma osmolality is maintained by strict regulation of the arginine vasopressin (also called antidiuretic hormone [ADH]) system and thirst. If plasma osmolality increases, ADH is secreted and water is retained by the kidneys, thus decreasing serum osmolality. If plasma osmolality decreases, ADH also decreases, resulting in diuresis of free water and a return to homeostasis.

• #8 Hyponatremia: Practice Essentials, Pathophysiology, Etiology

  https://emedicine.medscape.com/article/242166-overview

  Although the differential diagnosis is quite broad, most hyponatremia can be classified as hypertonic, normotonic, or hypotonic in origin. […] Patients with hypertonic hyponatremia often have normal total body sodium levels but a dilutional drop in the measured serum sodium due to the presence of osmotically active molecules in the serum, which causes a water shift from the intracellular compartment to the extracellular compartment. […] Hypotonic hyponatremia always reflects the inability of the kidneys to handle the excretion of free water to match the intake. Hypotonic hyponatremia with a urinary osmolality 100 mOsm/kg (due to presence of inappropriate ADH) can be divided pathophysiologically into the following categories, according to the effective intravascular volume: hypervolemic, euvolemic, and hypovolemic.

• #9 Hyponatremia – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK470386/

  Hyponatremia is defined as a serum sodium concentration of less than 135 mEq/L but can vary to a small extent in different laboratories. Hyponatremia is a common electrolyte abnormality caused by an excess of total body water when compared to total body sodium content. […] The etiology of hyponatremia can be classified based on the volume status of the extracellular fluid. […] Physiological stimuli that cause vasopressin release in adjunct with increased fluid intake can cause hyponatremia. Hypothyroidism and adrenal insufficiency may contribute to an increased release of vasopressin. Physiological stimuli for vasopressin release include loss of intravascular volume (hypovolemic hyponatremia) and the loss of effective intravascular volume (hypervolemic hyponatremia). […] Causes of Hypovolemic Hyponatremia (TBW decreases less than a decrease in total body sodium) include gastrointestinal fluid loss (diarrhea or vomiting), the third spacing of fluids (pancreatitis, hypoalbuminemia, small bowel obstruction), diuretics, osmotic diuresis (glucose, mannitol), salt-wasting nephropathies, cerebral salt-wasting syndrome (urinary salt wasting, possibly caused by increased brain natriuretic peptide), and mineralocorticoid deficiency.

• #10 Hyponatremia – WikEM

  https://wikem.org/wiki/Hyponatremia

  Defined as sodium concentration 135meq/L[1] […] Patients often not symptomatic until 120meq/L, although this level varies by patients and may be higher if the change occurred abruptly[2] […] Thiazide diuretic use […] Na-wasting nephropathy (RTA, CKD) […] Osmotic diuresis (glucose, urea) […] Aldosterone deficiency […] GI loss […] 3rd space loss […] Burns […] Pancreatitis […] Peritonitis […] Urinary Na 20 […] Renal failure […] Urinary Na 20 […] Nephrotic syndrome […] Cirrhosis […] CHF […] SIADH […] Pain, stress, nausea […] Psychogenic polydipsia […] Hypothyroidism […] Drugs[4][5] […] H20 intoxication […] Glucocorticoid deficiency […] Sodium decreases by 2.4mEq/L for each 100mg/dL increase in glucose over 100mg/dL[6] […] Hyperlipidemia […] Hyperproteinemia

• #11

  https://www.archivesofmedicalscience.com/Hyponatremia-in-patients-with-arterial-hypertension-pathophysiology-and-management,161578,0,2.html

  Hyponatremia is defined by a plasma sodium concentration lower than 135 mmol/l. […] In patients with arterial hypertension, the risk of hyponatremia is 1.5 times higher than in the general population. One of the causes of hyponatremia in patients with arterial hypertension is the use of thiazide or thiazide-like diuretics. […] The incidence of hyponatremia increases with age in patients using thiazide or thiazide-like diuretics. […] The use of diuretics significantly affects sodium homeostasis. […] Hyponatremia caused by the use of thiazide or thiazide-like diuretics (TIHs) was first described 35 years ago. […] The frequency of TIH has not yet been precisely defined. […] TIH was probably the cause of hyponatremia in some of the patients participating in the above-described epidemiological studies, who developed hyponatremia during the use of thiazide or thiazide-like diuretics. […] The pathogenesis of TIH is not fully understood.

• #12 Hyponatremia (Low Level of Sodium in the Blood) – Hormonal and Metabolic Disorders – Merck Manual Consumer Version

  https://www.merckmanuals.com/home/hormonal-and-metabolic-disorders/electrolyte-balance/hyponatremia-low-level-of-sodium-in-the-blood

  In hyponatremia, the level of sodium in blood is too low. […] A low sodium level has many causes, including consumption of too many fluids, kidney failure, heart failure, cirrhosis, and use of diuretics. […] Hyponatremia occurs when the body contains too little sodium for the amount of fluid it contains. […] Disorders, such as kidney disorders (for example, glomerulonephritis) and other disorders (for example, cirrhosis, and heart failure), can cause the body to retain sodium and fluid. […] Certain conditions may cause people to drink too much water (polydipsia), which can contribute to the development of hyponatremia. […] Thiazide diuretics (sometimes called water pills) are a common cause of hyponatremia. […] A frequent cause of hyponatremia is the syndrome of inappropriate secretion of antidiuretic hormone (SIADH), in which vasopressin is inappropriately secreted in a variety of other situations (such as certain cancers, infections, and brain disorders).

• #13 Hyponatremia: Practice Essentials, Pathophysiology, Etiology

  https://emedicine.medscape.com/article/242166-overview

  Cerebral salt wasting (CSW) is seen with intracranial disorders, such as subarachnoid hemorrhage, carcinomatous or infectious meningitis, metastatic carcinoma, traumatic brain injury, and pituitary disorders, but especially after neurologic procedures. […] Plasma renin and aldosterone levels fail to rise appropriately in patients with CSW despite a reduced plasma volume because of disruption of the sympathetic nervous system. […] Diuretics may induce hypovolemic hyponatremia. Note that thiazide diuretics, in contrast to loop diuretics, impair the diluting mechanism without limiting the concentrating mechanism, thereby impairing the ability to excrete a free-water load.

• #14 Hyponatremia – Symptoms and causes – Mayo Clinic

  https://www.mayoclinic.org/diseases-conditions/hyponatremia/symptoms-causes/syc-20373711

  Syndrome of inappropriate anti-diuretic hormone (SIADH). In this condition, high levels of the anti-diuretic hormone (ADH) are produced, causing your body to retain water instead of excreting it normally in your urine. […] Chronic, severe vomiting or diarrhea and other causes of dehydration. This causes your body to lose electrolytes, such as sodium, and also increases ADH levels. […] Drinking too much water. Drinking excessive amounts of water can cause low sodium by overwhelming the kidneys’ ability to excrete water. […] Hormonal changes. Adrenal gland insufficiency (Addison’s disease) affects your adrenal glands’ ability to produce hormones that help maintain your body’s balance of sodium, potassium and water. […] The recreational drug Ecstasy. This amphetamine increases the risk of severe and even fatal cases of hyponatremia.

• #15 Hyponatremia – Symptoms and causes – Mayo Clinic

  https://www.mayoclinic.org/diseases-conditions/hyponatremia/symptoms-causes/syc-20373711

  Syndrome of inappropriate anti-diuretic hormone (SIADH). In this condition, high levels of the anti-diuretic hormone (ADH) are produced, causing your body to retain water instead of excreting it normally in your urine. […] Chronic, severe vomiting or diarrhea and other causes of dehydration. This causes your body to lose electrolytes, such as sodium, and also increases ADH levels. […] Drinking too much water. Drinking excessive amounts of water can cause low sodium by overwhelming the kidneys’ ability to excrete water. […] Hormonal changes. Adrenal gland insufficiency (Addison’s disease) affects your adrenal glands’ ability to produce hormones that help maintain your body’s balance of sodium, potassium and water. […] The recreational drug Ecstasy. This amphetamine increases the risk of severe and even fatal cases of hyponatremia.

• #16 Hyponatremia – Wikipedia

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

  The specific causes of hyponatremia are generally divided into those with low tonicity (lower than normal concentration of solutes), without low tonicity, and falsely low sodiums. Those with low tonicity are then grouped by whether the person has high fluid volume, normal fluid volume, or low fluid volume. […] Hypovolemia (extracellular volume loss) is due to total body sodium loss. Hyponatremia is caused by a relatively smaller loss in total body water. Any cause of hypovolemia such as prolonged vomiting, decreased oral intake, severe diarrhea. Diuretic use (due to the diuretic causing a volume depleted state and thence ADH release, and not a direct result of diuretic-induced urine sodium loss). Addison’s disease and congenital adrenal hyperplasia in which the adrenal glands do not produce enough steroid hormones (combined glucocorticoid and mineralocorticoid deficiency). Prolonged exercise and sweating, combined with drinking water without electrolytes is the cause of exercise-associated hyponatremia (EAH). It is common in marathon runners and participants of other endurance events. The use of MDMA (ecstasy) can result in hyponatremia.

• #17 Hyponatremia – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK470386/

  Hyponatremia is defined as a serum sodium concentration of less than 135 mEq/L but can vary to a small extent in different laboratories. Hyponatremia is a common electrolyte abnormality caused by an excess of total body water when compared to total body sodium content. […] The etiology of hyponatremia can be classified based on the volume status of the extracellular fluid. […] Physiological stimuli that cause vasopressin release in adjunct with increased fluid intake can cause hyponatremia. Hypothyroidism and adrenal insufficiency may contribute to an increased release of vasopressin. Physiological stimuli for vasopressin release include loss of intravascular volume (hypovolemic hyponatremia) and the loss of effective intravascular volume (hypervolemic hyponatremia). […] Causes of Hypovolemic Hyponatremia (TBW decreases less than a decrease in total body sodium) include gastrointestinal fluid loss (diarrhea or vomiting), the third spacing of fluids (pancreatitis, hypoalbuminemia, small bowel obstruction), diuretics, osmotic diuresis (glucose, mannitol), salt-wasting nephropathies, cerebral salt-wasting syndrome (urinary salt wasting, possibly caused by increased brain natriuretic peptide), and mineralocorticoid deficiency.

• #18 Hyponatremia: Symptoms, Causes, and Treatments

  https://www.webmd.com/a-to-z-guides/what-is-hyponatremia

  Drinking too much water. It can dilute the amount of sodium in your blood. It usually happens when people drink too much during endurance events like marathons or triathlons and also lose sodium through their sweat. […] Drinking too much alcohol. Alcohol is a natural diuretic, which means it makes you pee more and lose sodium when you vomit. […] Ecstasy/molly (MDMA). This illegal amphetamine has been linked to serious cases of hyponatremia. […] Severe burns on a large part of the body. Loss of water from a burn wound can affect the balance of water in your body.

• #19 Hyponatremia: Practice Essentials, Pathophysiology, Etiology

  https://emedicine.medscape.com/article/242166-overview

  This is characterized by clinically detectable edema or ascites that signifies an increase in total body water and sodium. Paradoxically, however, a decrease in the effective circulating volume, critical for tissue perfusion, stimulates the same pathophysiologic mechanism of impaired water excretion by the kidney that is observed in hypovolemic hypotonic hyponatremia. […] Normovolemic (euvolemic) hypotonic hyponatremia is a very common cause of hyponatremia in hospitalized patients. It is associated with non-osmotic and nonvolume-related ADH secretion (ie, SIADH) secondary to a variety of clinical conditions. […] Hypovolemic hypotonic hyponatremia usually indicates concomitant solute depletion, with patients presenting with orthostatic symptoms. […] The pathophysiology underlying hypovolemic hypotonic hyponatremia is complex and involves the interplay of carotid baroreceptors, the sympathetic nervous system, the renin-angiotensin system, antidiuretic hormone (ADH; vasopressin) secretion, and renal tubular function.

• #20 Hyponatremia – Endocrine and Metabolic Disorders – Merck Manual Professional Edition

  https://www.merckmanuals.com/professional/endocrine-and-metabolic-disorders/electrolyte-disorders/hyponatremia

  Euvolemic hyponatremia may also result from excessive water intake in the presence of Addison disease, hypothyroidism, or nonosmotic vasopressin release. […] The syndrome of inappropriate ADH secretion (SIADH) is another cause of euvolemic hyponatremia. […] Hypervolemic hyponatremia is characterized by an increase in both total body sodium (and thus ECF volume) and total body water with a relatively greater increase in TBW. […] Various edematous disorders, including heart failure and cirrhosis, cause hypervolemic hyponatremia. […] The syndrome of inappropriate ADH (vasopressin) secretion is attributed to excessive vasopressin release. […] Hyponatremia has been reported in 50% of hospitalized patients with AIDS. […] Hyponatremia frequently occurs in patients with brain pathology, including concussion, intracranial hemorrhage, encephalitis, meningitis, and CNS tumors.

• #21 Diagnosis and Management of Sodium Disorders: Hyponatremia and Hypernatremia | AAFP

  https://www.aafp.org/pubs/afp/issues/2015/0301/p299.html

  There are numerous causes of hypovolemic hyponatremia. Patients typically have signs and symptoms associated with volume depletion (e.g., vomiting, diarrhea, tachycardia, elevated blood urea nitrogen-to-creatinine ratio). […] Euvolemic hyponatremia is most commonly caused by SIADH, but can also be caused by hypothyroidism and glucocorticoid deficiency. […] Hypervolemic hyponatremia occurs when the kidneys cannot excrete water efficiently. In volume overload states, the effective arterial blood volume is decreased compared with venous volume, resulting in excess ADH secretion. The most common causes of hypervolemic hyponatremia are heart failure, cirrhosis, and kidney injury.

• #22 SIADH (Syndrome of Inappropriate Antidiuretic Hormone Secretion)

  https://my.clevelandclinic.org/health/diseases/23976-siadh-syndrome-of-inappropriate-antidiuretic-hormone-secretion

  SIADH happens when your body makes excess amounts of antidiuretic hormone (ADH). SIADH causes your body to retain too much water and commonly leads to hyponatremia, which is low levels of sodium in your blood. […] The main sign and consequence of ADH is hyponatremia, which is when you have low levels of sodium (salt) in your blood. […] SIADH is the most common cause of the condition. […] Most commonly, SIADH happens due to another medical condition. […] Conditions and situations that frequently lead to SIADH include: Certain cancers: Certain tumors can produce their own ADH, leading to excess ADH in your body and SIADH. […] Central nervous system (CNS) issues: Your CNS includes your brain and spinal cord. Any abnormality in this system can lead to SIADH, including stroke, hemorrhage (bleeding), infection, trauma (injury) and psychosis (rare).

• #23 Hyponatremia causes – wikidoc

  https://www.wikidoc.org/index.php/Hyponatremia_causes

  Hyponatremia is caused by either increase ADH action/ secretion or kidney function impairment. SIAD is the most common cause of euvolemic hyponatremia. After SIAD, polydipsia, drugs and clinical disorders are the most encountered etiologies in clinical practice. […] Etiologies of SIAD: Conditions Malignant disorders Carcinoma: Lung (small cell carcinoma, mesothelioma), oropharynx, stomach, duodenum, pancreas, ureter, bladder, prostate, endometrium, thymoma. Lymphomas. Sarcomas: Ewing’s sarcoma. Olfactory neuroblastoma. Pulmonary diseases Infections: Bacterial pneumonia, viral pneumonia, pulmonary abscess, tuberculosis, aspergillosis. Others: Asthma, cystic fibrosis, respiratory failure, emphysema, COPD, coronavirus disease, positive-pressure ventilation. CNS disorders Infections: Encephalitis, meningitis, brain abscess, RMSF, AIDS, malaria. Vascular and SOP: Subarachnoid hemorrhage, stroke, brain tumors, head trauma. Others: Hydrocephalus, cavernous sinus thrombosis, Multiple sclerosis, GuillainBarr syndrome, ShyDrager syndrome, delirium tremens, acute intermittent porphyria, chronic psychosis, pituitary stalk section, transsphenoidal adenomectomy.

• #24 Hyponatremia – Symptoms and causes – Mayo Clinic

  https://www.mayoclinic.org/diseases-conditions/hyponatremia/symptoms-causes/syc-20373711

  Syndrome of inappropriate anti-diuretic hormone (SIADH). In this condition, high levels of the anti-diuretic hormone (ADH) are produced, causing your body to retain water instead of excreting it normally in your urine. […] Chronic, severe vomiting or diarrhea and other causes of dehydration. This causes your body to lose electrolytes, such as sodium, and also increases ADH levels. […] Drinking too much water. Drinking excessive amounts of water can cause low sodium by overwhelming the kidneys’ ability to excrete water. […] Hormonal changes. Adrenal gland insufficiency (Addison’s disease) affects your adrenal glands’ ability to produce hormones that help maintain your body’s balance of sodium, potassium and water. […] The recreational drug Ecstasy. This amphetamine increases the risk of severe and even fatal cases of hyponatremia.

• #25 Hyponatremia – Wikipedia

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

  Hyponatremia is a low concentration of sodium in the blood. It is generally defined as a sodium concentration of less than 135 mmol/L (135 mEq/L), with severe hyponatremia being below 120 mEq/L. The causes of hyponatremia are typically classified by a person’s body fluid status into low volume, normal volume, or high volume. Low volume hyponatremia can occur from diarrhea, vomiting, diuretics, and sweating. Normal volume hyponatremia is divided into cases with dilute urine and concentrated urine. Cases in which the urine is dilute include adrenal insufficiency, hypothyroidism, and drinking too much water or too much beer. Cases in which the urine is concentrated include syndrome of inappropriate antidiuretic hormone secretion (SIADH). High volume hyponatremia can occur from heart failure, liver failure, and kidney failure. Conditions that can lead to falsely low sodium measurements include high blood protein levels such as in multiple myeloma, high blood fat levels, and high blood sugar.

• #26 Hyponatremia – Sodium Disturbances – Electrolyte Disturbances – Electrolyte, Fluid, and Acid-Base Balance Disorders – Diseases – McMaster Textbook of Internal Medicine

  https://empendium.com/mcmtextbook/chapter/B31.II.19.1.3.1.

  Hyponatremia is defined as a serum [Na+] 135 mmol/L. […] In the majority of cases, hyponatremia is a consequence of water disturbances that result in a relative excess of body water compared with the body sodium content. The most frequent cause is impaired renal free water excretion due to inappropriate arginine vasopressin (AVP) hypersecretion caused by nonosmotic factors. Less frequently, the relative excess of body water may be due to excessive free water intake, which exceeds renal capacity for free water excretion. […] The most frequent cause of hypotonic hyponatremia is water retention due to syndrome of inappropriate antidiuresis (SIAD) (previously syndrome of inappropriate antidiuretic hormone secretion [SIADH]). […] Hypotonic hyponatremia with euvolemia, the most frequent type of hyponatremia, is caused by SIAD (see above), glucocorticoid deficiency, use of thiazide diuretics, prolonged strenuous exercise, primary polydipsia, long-term use of a low-sodium diet, hypothyroidism, increased sensitivity to AVP, or mutations of genes encoding V2 or aquaporin 2 receptors.

• #27 Hyponatremia – Symptoms and causes – Mayo Clinic

  https://www.mayoclinic.org/diseases-conditions/hyponatremia/symptoms-causes/syc-20373711

  Syndrome of inappropriate anti-diuretic hormone (SIADH). In this condition, high levels of the anti-diuretic hormone (ADH) are produced, causing your body to retain water instead of excreting it normally in your urine. […] Chronic, severe vomiting or diarrhea and other causes of dehydration. This causes your body to lose electrolytes, such as sodium, and also increases ADH levels. […] Drinking too much water. Drinking excessive amounts of water can cause low sodium by overwhelming the kidneys’ ability to excrete water. […] Hormonal changes. Adrenal gland insufficiency (Addison’s disease) affects your adrenal glands’ ability to produce hormones that help maintain your body’s balance of sodium, potassium and water. […] The recreational drug Ecstasy. This amphetamine increases the risk of severe and even fatal cases of hyponatremia.

• #28 Hyponatremia: Causes, Symptoms, Diagnosis & Treatment

  https://my.clevelandclinic.org/health/diseases/17762-hyponatremia

  Hyponatremia is when the amount of sodium in your blood is too low. Common causes include heart, liver, kidney and brain diseases, hormone issues and medications. […] In most cases, high levels of water in your body which dilute sodium levels cause hyponatremia. Losing a lot of sodium from your body can also cause it (this is less common). […] Specific causes of hyponatremia include: SIADH (syndrome of inappropriate antidiuretic hormone secretion), heart failure, kidney failure, liver cirrhosis, nephrotic syndrome, neurological conditions like brain tumors, excessive thirst (polydipsia), hypothyroidism, drinking too much beer or other alcohol (beer potomania), diarrhea or vomiting, certain medications, like diuretics (water pills) and SSRIs, nonmedical or recreational drugs, like MDMA (known as Molly, E or Ecstasy).

• #29 Hypoosmolar Hyponatremia

  https://mobile.fpnotebook.com/Renal/Sodium/HypsmlrHypntrm.htm

  Hyponatremia is a water excess state […] Identify the cause of Hyponatremia by identifying why the Kidney can not excrete excess water […] Hypoosmolar Hyponatremia (impaired water excretion) […] Gastrointestinal losses (especially Vomiting) with free water replacement […] Edematous State (e.g. CHF, Cirrhosis, Nephrosis) […] Sodium retention and continued free water intake […] Thiazide Diuretics […] Syndrome of Inappropriate ADH or SIADH (e.g. CNS disease, lung disease, cancer, medications, postoperative) […] Endocrine cause (Hypothyroidism, Adrenal Insufficiency) […] Excessive free water intake (or excessive or prolonged hypotonic infusion) […] „Tea and Toast” Diet (elderly) or excessive beer (Alcoholism) […] Kidney requires solute to effectively excrete water […] Hypervolemic Hypoosmolar Hyponatremia (Edematous State)

• #30 Hyponatremia – Knowledge @ AMBOSS

  https://www.amboss.com/us/knowledge/hyponatremia/

  Hyponatremia is typically caused by fluid imbalance; common causes are categorized as hypovolemic (e.g., dehydration), euvolemic (e.g., primary polydipsia, SIADH), or hypervolemic (e.g., CHF). […] Hyponatremia is classified according to serum osmolality and extracellular volume status. Multiple etiologies may be present. […] Causes: extrarenal and renal (see Causes of hypotonic hyponatremia). […] Thiazide diuretic use and SIADH are the most common causes of hyponatremia in the emergency department. […] Exercise-associated hyponatremia is most commonly associated with marathon running but has also been reported following other exertional activities such as football, cycling, fraternity hazing, and military training. […] Hyperglycemia, IV mannitol, and IV radiocontrast use are causes of hypertonic hyponatremia.

• #31 Hyponatremia – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK470386/

  Causes of Hypervolemic Hyponatremia (TBW increases greater than an increase in total body sodium) include renal causes (acute renal failure, chronic renal failure, nephrotic syndrome), extrarenal causes (congestive heart failure, cirrhosis), and iatrogenic factors. […] Causes of Euvolemic Hyponatremia (TBW increase with stable total body sodium) include drugs, syndrome of inappropriate antidiuretic hormone (SIADH), Addison’s disease, hypothyroidism, high fluid intake in conditions like primary polydipsia, medical testing related to excessive fluids, and iatrogenic factors. […] Many drugs cause hyponatremia, and the most common include vasopressin analogs such as desmopressin and oxytocin, medications that stimulate vasopressin release or potentiate the effects of vasopressin, medications that impair urinary dilution, and illicit drugs such as methylenedioxymethamphetamine (MDMA or ecstasy).

• #32 Diagnosis and Management of Sodium Disorders: Hyponatremia and Hypernatremia | AAFP

  https://www.aafp.org/pubs/afp/issues/2015/0301/p299.html

  There are numerous causes of hypovolemic hyponatremia. Patients typically have signs and symptoms associated with volume depletion (e.g., vomiting, diarrhea, tachycardia, elevated blood urea nitrogen-to-creatinine ratio). […] Euvolemic hyponatremia is most commonly caused by SIADH, but can also be caused by hypothyroidism and glucocorticoid deficiency. […] Hypervolemic hyponatremia occurs when the kidneys cannot excrete water efficiently. In volume overload states, the effective arterial blood volume is decreased compared with venous volume, resulting in excess ADH secretion. The most common causes of hypervolemic hyponatremia are heart failure, cirrhosis, and kidney injury.

• #33 Managing Hyponatremia in Heart Failure | USC Journal

  https://www.uscjournal.com/articles/managing-hyponatremia-heart-failure?language_content_entity=en

  Hyponatremia is the most common electrolytic abnormality in clinical practice and has a reported incidence of 15-30% in adults. […] It is particularly common in heart failure: the Organized Program to Initiate Life Saving Treatment in Patients Hospitalized for Heart Failure (OPTIMIZE-HF) registry recorded that 25.3% of 47,647 heart failure patients had hyponatremia on admission. […] Hyponatremia can be caused by either an excessive loss of sodium, known as depletional hyponatremia, or excessive retention of water, called dilutional hyponatremia. […] Depletional hyponatremia is caused by certain disorders or drugs that produce a decrease in extracellular fluid, leading to an excessive loss of renal salts. […] Hypervolemic hyponatremia is generally the result of fluid overload associated with raised AVP secretion, advanced liver cirrhosis, renal disease, or congestive heart failure.

• #34 Hyponatremia – Endocrine and Metabolic Disorders – Merck Manual Professional Edition

  https://www.merckmanuals.com/professional/endocrine-and-metabolic-disorders/electrolyte-disorders/hyponatremia

  Euvolemic hyponatremia may also result from excessive water intake in the presence of Addison disease, hypothyroidism, or nonosmotic vasopressin release. […] The syndrome of inappropriate ADH secretion (SIADH) is another cause of euvolemic hyponatremia. […] Hypervolemic hyponatremia is characterized by an increase in both total body sodium (and thus ECF volume) and total body water with a relatively greater increase in TBW. […] Various edematous disorders, including heart failure and cirrhosis, cause hypervolemic hyponatremia. […] The syndrome of inappropriate ADH (vasopressin) secretion is attributed to excessive vasopressin release. […] Hyponatremia has been reported in 50% of hospitalized patients with AIDS. […] Hyponatremia frequently occurs in patients with brain pathology, including concussion, intracranial hemorrhage, encephalitis, meningitis, and CNS tumors.

• #35 Hyponatremia: A practical approach

  https://pmc.ncbi.nlm.nih.gov/articles/PMC4192979/

  Hyponatremia is an important and common clinical problem. The etiology is multifactorial. […] Hyponatremia results from the inability of the kidney to excrete a water load or excess water intake. […] Hyponatremia occurs if there is persistent ADH stimulation which is seen in following situations. […] The causes of hypovolemic hyponatremia may be renal or non-renal. […] The commonest cause of euvolemic hyponatremia is Syndrome of inappropriate secretion of Anti diuretic hormone (SIADH). […] The causes of SIADH are shown in Tables 3 and 4. […] Plasma sodium concentration (PNa) is given by ratio of the body’s content of exchangeable sodium and potassium (NaE and KE) and total body water (TBW): PNa NaE + KE/TBW. […] Hyponatremia occurs commonly in both acute and chronic renal failure, because the kidneys cannot maximally excrete excess ingested water.

• #36 Hyponatremia – WikEM

  https://wikem.org/wiki/Hyponatremia

  Must have sufficient confidence that the symptoms are caused by hyponatraemia; see Clinical Features for definition of categories. […] Give normal saline, but be cautious of raising the serum sodium more than 10 mmol/L/day and causing osmotic demyelination syndrome (central pontine myelinolysis)[10] […] Water restrict […] Treat underlying cause […] Water restriction […] Diuresis […] Treat underlying cause […] Max correction 10mEq/L in first 24hr (8 mmol/l during every 24 h thereafter), until a serum sodium concentration of 130 mmol/l is reached (lowers risk of osmotic demyelination syndrome) [10] […] Limited evidence suggests usage of DDAVP in combination with HTS can safely increase sodium, while lowering risk for over-correction[12] […] Sodium bicarbonate should be given slowly (each ampule over 5-10 minutes). Bicarbonate is contraindicated in patients with metabolic alkalosis.

• #37 Hyponatremia: Practice Essentials, Pathophysiology, Etiology

  https://emedicine.medscape.com/article/242166-overview

  This is characterized by clinically detectable edema or ascites that signifies an increase in total body water and sodium. Paradoxically, however, a decrease in the effective circulating volume, critical for tissue perfusion, stimulates the same pathophysiologic mechanism of impaired water excretion by the kidney that is observed in hypovolemic hypotonic hyponatremia. […] Normovolemic (euvolemic) hypotonic hyponatremia is a very common cause of hyponatremia in hospitalized patients. It is associated with non-osmotic and nonvolume-related ADH secretion (ie, SIADH) secondary to a variety of clinical conditions. […] Hypovolemic hypotonic hyponatremia usually indicates concomitant solute depletion, with patients presenting with orthostatic symptoms. […] The pathophysiology underlying hypovolemic hypotonic hyponatremia is complex and involves the interplay of carotid baroreceptors, the sympathetic nervous system, the renin-angiotensin system, antidiuretic hormone (ADH; vasopressin) secretion, and renal tubular function.

• #38 Hyponatremia – Wikipedia

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

  Antipsychotics have been reported to cause hyponatremia in a review of medical articles from 1946 to 2016. Available evidence suggests that all classes of psychotropics, i.e., antidepressants, antipsychotics, mood stabilizers, and sedative/hypnotics can lead to hyponatremia. Age is a significant factor for drug induced hyponatremia. […] False hyponatremia is caused by a false lab measurement of sodium due to massive increases in blood triglyceride levels or extreme elevation of immunoglobulins as may occur in multiple myeloma. Hyponatremia with elevated tonicity can occur with high blood sugar, causing a shift of excess free water into the serum.

• #39 Azthena logo with the word Azthena

  https://www.news-medical.net/health/Hyponatremia-Causes.aspx

  Some examples of medications that can lead to hyponatremia include: Diuretics such as thiazides, and thiazide-like diuretics; Anti-epileptic drugs such as carbamazepine; Blood sugar reducing medications such as sulphonylureas (but not gliclazide); Proton pump inhibitors such as omeprazole and rabeprazole; Antidepressants, particularly selective serotonin reuptake inhibitors (SSRIs) such as fluoxetine, paroxetine; ACE inhibitors such as enalapril; Opiates such as morphine and codeine.

• #40 Hyponatremia causes – wikidoc

  https://www.wikidoc.org/index.php/Hyponatremia_causes

  Euvolemic Hyponatremia total body water total body sodium Drugs: Vasopressin, diuretics, antidepressants, opioids. SIAD: SIADH (Malignancy, central nervous system (CNS) disorders, pulmonary disease, or drugs, postoperative nausea, pain, stress, neoplasia (common), trauma, pregnancy), nephrogenic SIAD (Gain-of-function mutation of v2 receptors). High fluid intake: Physical activity, surgery, primary polydipsia, potomania, tea toast diet (caused by a low intake of solutes with relatively high fluid intake). Medical testing (excess fluid intake): Colonoscopy or cardiac catheterization. Hypothyroidism. Hormonal: Glucocorticoid deficiency, pituitary failure (secondary), hypothalamic failure (tertiary). […] Drugs which cause hyponatremia: Increase ADH secretion Antidepressants: Tricyclic antidepressants (Amitryptiline, Protriptyline, Desipramine), Selective serotonin reuptake inhibitors, Monoamine oxidase inhibitors. Antipsychotic drugs: Phenothiazines (Thioridazine, Trifluoperazine), Butyrophenones (Haloperidol). Antiepileptic drugs: Carbamazepine, Oxcarbazepine, Sodium valproate. Anticancer agents: Vinca alkaloids (Vincristine, Vinblastine), Platinum compounds (Cisplatin, Carboplatin). Alkylating agents: Intravenous Cyclophosphamide, Melphalan, Ifosfamide. Miscellaneous: Methotrexate, Interferon, Levamisole, Pentostatin, Monoclonal antibodies, MDMA, Nicotine.

• #41

  https://www.archivesofmedicalscience.com/Hyponatremia-in-patients-with-arterial-hypertension-pathophysiology-and-management,161578,0,2.html

  Hyponatremia is defined by a plasma sodium concentration lower than 135 mmol/l. […] In patients with arterial hypertension, the risk of hyponatremia is 1.5 times higher than in the general population. One of the causes of hyponatremia in patients with arterial hypertension is the use of thiazide or thiazide-like diuretics. […] The incidence of hyponatremia increases with age in patients using thiazide or thiazide-like diuretics. […] The use of diuretics significantly affects sodium homeostasis. […] Hyponatremia caused by the use of thiazide or thiazide-like diuretics (TIHs) was first described 35 years ago. […] The frequency of TIH has not yet been precisely defined. […] TIH was probably the cause of hyponatremia in some of the patients participating in the above-described epidemiological studies, who developed hyponatremia during the use of thiazide or thiazide-like diuretics. […] The pathogenesis of TIH is not fully understood.

• #42 Hyponatremia | Diagnosis & Disease Information – Renal and Urology News

  https://www.renalandurologynews.com/ddi/hyponatremia/

  Many conditions are associated with inappropriate ADH secretion and thus can result in hyponatremia. These include the following: Tumor-related conditions (cancers of the lung, pancreas, duodenum, ureter, bladder, and prostate, as well as lymphoma, thymoma, mesothelioma, and Ewing sarcoma); Lung problems (pneumonia, tuberculosis, aspergillosis, asthma, pneumothorax, cystic fibrosis, abscesses); Central nervous system problems (delirium tremens, seizures, Shy-Drager syndrome, Rocky Mountain spotted fever, lupus cerebritis, cavernous vein thrombosis, hydrocephalus, multiple sclerosis, schizophrenia, brain atrophy, encephalitis or meningitis, brain tumors or abscesses, head trauma, subdural hematoma, stroke, Guillain-Barr syndrome); Medication adverse effects (haloperidol, phenothiazines, opiates, selective serotonin reuptake inhibitors, tricyclic antidepressants, cyclophosphamide, vinca alkaloids, carbamazepine, clofibrate, sulfonylureas, arginine vasopressin); and Endocrine conditions (deficiency of glucocorticoids, myxedema).

• #43 Hyponatremia seizure overview – why does it happen?

  https://www.epsyhealth.com/seizure-epilepsy-blog/hyponatremia-seizure-overview—why-does-it-happen

  Hyponatremia is a common disorder, and can happen for several different reasons: […] Drinking lots of water, which dilutes salt levels […] Taking diuretics, which are medications and drugs which make you pee regularly […] Diarrhea […] Drinking too much alcohol (which makes you pee more than usual) […] Underlying kidney, heart or liver problems. […] Certain medications (including epilepsy medications like carbamazepine, oxcarbazepine, and eslicarbazepine) may also cause low sodium levels. […] Yes, low sodium seizures are one of the most severe symptoms of hyponatremia. […] Hyponatremia seizures are most likely to happen if sodium levels in the blood drop rapidly to below 115 mEg/L. […] Sodium helps to control the amount of water that enters the brain. […] When there isn’t enough sodium in the blood, then water flows into the brain and this causes the brain to swell.

• #44 Hyponatremia – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK470386/

  Causes of Hypervolemic Hyponatremia (TBW increases greater than an increase in total body sodium) include renal causes (acute renal failure, chronic renal failure, nephrotic syndrome), extrarenal causes (congestive heart failure, cirrhosis), and iatrogenic factors. […] Causes of Euvolemic Hyponatremia (TBW increase with stable total body sodium) include drugs, syndrome of inappropriate antidiuretic hormone (SIADH), Addison’s disease, hypothyroidism, high fluid intake in conditions like primary polydipsia, medical testing related to excessive fluids, and iatrogenic factors. […] Many drugs cause hyponatremia, and the most common include vasopressin analogs such as desmopressin and oxytocin, medications that stimulate vasopressin release or potentiate the effects of vasopressin, medications that impair urinary dilution, and illicit drugs such as methylenedioxymethamphetamine (MDMA or ecstasy).

• #45 Hyponatremia – PsychDB

  https://www.psychdb.com/cl/hyponatremia

  Syndrome of inappropriate antidiuretic hormone secretion (SIADH) can cause hyponatraemia. Many psychotropic medications can cause SIADH either by stimulating the release of vasopressin or by potentiating its action on the renal tubules. It is also thought that psychotropics may cause stimulation of central serotonin receptors as well. SIADH is a known side effect of antidepressants, especially in the elderly. […] In rare cases, antipsychotics can cause hyponatremia. Antipsychotics are thought to increase AVP release is increased despite normal plasma osmolality, resulting in syndrome of inappropriate antidiuretic hormone secretion (SIADH) causing hyponatremia.

• #46 Hyponatremia – Wikipedia

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

  The specific causes of hyponatremia are generally divided into those with low tonicity (lower than normal concentration of solutes), without low tonicity, and falsely low sodiums. Those with low tonicity are then grouped by whether the person has high fluid volume, normal fluid volume, or low fluid volume. […] Hypovolemia (extracellular volume loss) is due to total body sodium loss. Hyponatremia is caused by a relatively smaller loss in total body water. Any cause of hypovolemia such as prolonged vomiting, decreased oral intake, severe diarrhea. Diuretic use (due to the diuretic causing a volume depleted state and thence ADH release, and not a direct result of diuretic-induced urine sodium loss). Addison’s disease and congenital adrenal hyperplasia in which the adrenal glands do not produce enough steroid hormones (combined glucocorticoid and mineralocorticoid deficiency). Prolonged exercise and sweating, combined with drinking water without electrolytes is the cause of exercise-associated hyponatremia (EAH). It is common in marathon runners and participants of other endurance events. The use of MDMA (ecstasy) can result in hyponatremia.

• #47 Hyponatremia: Symptoms, Causes, and Treatments

  https://www.webmd.com/a-to-z-guides/what-is-hyponatremia

  Drinking too much water. It can dilute the amount of sodium in your blood. It usually happens when people drink too much during endurance events like marathons or triathlons and also lose sodium through their sweat. […] Drinking too much alcohol. Alcohol is a natural diuretic, which means it makes you pee more and lose sodium when you vomit. […] Ecstasy/molly (MDMA). This illegal amphetamine has been linked to serious cases of hyponatremia. […] Severe burns on a large part of the body. Loss of water from a burn wound can affect the balance of water in your body.

• #48 Hyponatremia – Symptoms and causes – Mayo Clinic

  https://www.mayoclinic.org/diseases-conditions/hyponatremia/symptoms-causes/syc-20373711

  Syndrome of inappropriate anti-diuretic hormone (SIADH). In this condition, high levels of the anti-diuretic hormone (ADH) are produced, causing your body to retain water instead of excreting it normally in your urine. […] Chronic, severe vomiting or diarrhea and other causes of dehydration. This causes your body to lose electrolytes, such as sodium, and also increases ADH levels. […] Drinking too much water. Drinking excessive amounts of water can cause low sodium by overwhelming the kidneys’ ability to excrete water. […] Hormonal changes. Adrenal gland insufficiency (Addison’s disease) affects your adrenal glands’ ability to produce hormones that help maintain your body’s balance of sodium, potassium and water. […] The recreational drug Ecstasy. This amphetamine increases the risk of severe and even fatal cases of hyponatremia.

• #49 Low sodium levels (hyponatremia): Symptoms and causes

  https://www.medicalnewstoday.com/articles/323831

  Hyponatremia is the most common electrolyte disorder. […] It can result from underlying conditions, such as kidney failure, or other factors, including drinking too much water or taking certain medications. […] Other medical conditions and factors that can cause sodium levels to fall include: gastrointestinal fluid loss from diarrhea or vomiting, pancreatitis, small bowel obstruction, certain medications, including diuretics or nonsteroidal anti-inflammatory drugs, renal causes, such as acute or chronic renal failure, congestive heart failure, syndrome of inappropriate antidiuretic hormone (SIADH), where the body makes excess antidiuretic hormone. […] Taking the recreational drug ecstasy or MDMA also increases the risk of severe hyponatremia in some cases. Hyponatremia resulting from ecstasy use can be fatal.

• #50 Hyponatremia and Addiction: Definition, Causes, Symptoms – Olympic Behavioral Health

  https://olympicbehavioralhealth.com/rehab-blog/hyponatremia-and-addiction/

  Excessive Diarrhea and Vomiting: Chronic diarrhea and vomiting result in excessive fluid and electrolyte loss. […] Excessive Alcohol Intake: Alcohol is a natural diuretic. It causes excessive urination and thus loss of electrolytes including sodium. […] Burns: Severe burns can result in hyponatremia. […] Hyponatremia does not have a direct causal relationship with addiction; however, there seem to be a few indirect connections. […] Yes, excessive alcohol or drug use contributes to dehydration, electrolyte imbalances, and conditions like SIADH, contributing to hyponatremia. […] Some medications for addiction or mental health affect sodium levels or cause electrolyte imbalances, influencing the risk of both conditions.

• #51 Hyponatremia: Practice Essentials, Pathophysiology, Etiology

  https://emedicine.medscape.com/article/242166-overview

  Although the differential diagnosis is quite broad, most hyponatremia can be classified as hypertonic, normotonic, or hypotonic in origin. […] Patients with hypertonic hyponatremia often have normal total body sodium levels but a dilutional drop in the measured serum sodium due to the presence of osmotically active molecules in the serum, which causes a water shift from the intracellular compartment to the extracellular compartment. […] Hypotonic hyponatremia always reflects the inability of the kidneys to handle the excretion of free water to match the intake. Hypotonic hyponatremia with a urinary osmolality 100 mOsm/kg (due to presence of inappropriate ADH) can be divided pathophysiologically into the following categories, according to the effective intravascular volume: hypervolemic, euvolemic, and hypovolemic.

• #52 Pseudohyponatremia

  https://acutecaretesting.org/en/articles/pseudohyponatremia

  Hyponatremia is a relatively common finding among surgical patients during the postoperative period and also among patients suffering a range of medical conditions. In fact, it is the single most common disturbance of blood chemistry, affecting 15 % of hospitalized patients in one UK survey. […] The concentration of plasma sodium is dependent on two variables: the amount of sodium in the ECF and the amount of water in the ECF (i.e. ECF volume). Although it might be supposed that hyponatremia is associated with sodium deficiency, this is not always the case. Indeed, hyponatremia is much more commonly due to an excess of water in the ECF than to a deficit of sodium. Depending on its cause, hyponatremia can be associated with a normal total amount of sodium, sodium deficit or even sodium excess.

• #53 Hyponatremia – Wikipedia

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

  Antipsychotics have been reported to cause hyponatremia in a review of medical articles from 1946 to 2016. Available evidence suggests that all classes of psychotropics, i.e., antidepressants, antipsychotics, mood stabilizers, and sedative/hypnotics can lead to hyponatremia. Age is a significant factor for drug induced hyponatremia. […] False hyponatremia is caused by a false lab measurement of sodium due to massive increases in blood triglyceride levels or extreme elevation of immunoglobulins as may occur in multiple myeloma. Hyponatremia with elevated tonicity can occur with high blood sugar, causing a shift of excess free water into the serum.

• #54 Hyponatremia – WikEM

  https://wikem.org/wiki/Hyponatremia

  Defined as sodium concentration 135meq/L[1] […] Patients often not symptomatic until 120meq/L, although this level varies by patients and may be higher if the change occurred abruptly[2] […] Thiazide diuretic use […] Na-wasting nephropathy (RTA, CKD) […] Osmotic diuresis (glucose, urea) […] Aldosterone deficiency […] GI loss […] 3rd space loss […] Burns […] Pancreatitis […] Peritonitis […] Urinary Na 20 […] Renal failure […] Urinary Na 20 […] Nephrotic syndrome […] Cirrhosis […] CHF […] SIADH […] Pain, stress, nausea […] Psychogenic polydipsia […] Hypothyroidism […] Drugs[4][5] […] H20 intoxication […] Glucocorticoid deficiency […] Sodium decreases by 2.4mEq/L for each 100mg/dL increase in glucose over 100mg/dL[6] […] Hyperlipidemia […] Hyperproteinemia

• #55 Hyponatremia in Infectious Diseases—A Literature Review

  https://www.mdpi.com/1660-4601/17/15/5320

  Hyponatremia is one of the most common water–electrolyte imbalances in the human organism. A serum sodium concentration threshold of less than 135 mmol/L is diagnostic for hyponatremia. The disorder is usually secondary to various diseases, including infections. […] The most common infections that were associated with hyponatremia were viral and bacterial infections, including COVID-19 (coronavirus disease 2019). The etiology varied according to the infection site, setting and patient cohort it concerned. […] Hyponatremia may occur as a result of numerous disorders. These include common infectious diseases as well as endocrine, nutritional, metabolic, cardiovascular, renal or hepatic pathologies. […] The primary purpose of this review was to perform a meta-analysis, which would elucidate the impact of hyponatremia on the prognosis, mortality, and outcomes among in-patients with an acute infective process.

• #56 Hyponatraemia – Causes – Management – TeachMeSurgery

  https://teachmesurgery.com/perioperative/endocrine/hyponatraemia/

  Hyponatraemia is defined as serum sodium 135mmol and is the most common post-operative electrolyte abnormality. […] Causes of hypo-osmotic hyponatraemia can be classified in terms of the patients extracellular fluid status and urine sodium concentration. […] Fluid retention is seen as part of stress response to surgery. There is an increase in hypothalamic-pituitary hormone secretion, resulting in increased cortisol and ADH release. The resulting free water reabsorption in excess of sodium results in a hyponatraemia. […] In addition, surgical patients receive significant volumes of intravenous fluid during the perioperative period. If the fluid used is dextrose solution (especially if excessive or prolonged use), this will cause a dilutional effect to the bodys serum sodium levels. […] In fact, the first step when investigating hyponatraemia should be to measure serum osmolality, to see whether it is hypo-osmotic, iso-osmotic or hyper-osmotic. However, in clinical practice, most cases of hyponatraemia encountered will be hypo-osmotic hyponatraemia, whereby there is either sodium depletion or water excess (or both).

• #57 Managing Hyponatremia in Heart Failure | USC Journal

  https://www.uscjournal.com/articles/managing-hyponatremia-heart-failure?language_content_entity=en

  The group most at risk for hyponatremia in heart failure is female geriatrics with low body mass. […] There is evidence that heart failure patients are more sensitive to low serum sodium levels than the general population. […] Therefore, it has been suggested that the definition of hyponatremia for patients with heart failure should be altered to a serum sodium level of 138mmol/l or lower. […] Hyponatremia may also be a causative factor in heart failure, although the clinical or pathophysiological effect on cardiac myocytes remains unclear. […] The determination of hyponatremia as a marker or pathogenic factor for heart failure will have a significant impact on therapeutic implications and therefore requires future investigation.

• #58 Hyponatremia | Endocrinology | Mercy Health

  https://www.mercy.com/health-care-services/endocrinology/conditions/hyponatremia

  Other risk factors for hyponatremia include: […] Those who eat a low-sodium diet also have an increased risk of hyponatremia because they don’t eat large amounts of sodium. […] Older people are more likely to take prescription drugs or have a chronic medical condition that causes hyponatremia. […] Female endurance athletes are more likely to develop hyponatremia than their male counterparts.

• #59 Diagnosis and Management of Sodium Disorders: Hyponatremia and Hypernatremia | AAFP

  https://www.aafp.org/pubs/afp/issues/2015/0301/p299.html

  Hyponatremia is a common electrolyte disorder defined as a serum sodium level of less than 135 mEq per L. A Dutch systematic review of 53 studies showed that the prevalence of mild hyponatremia was 22.2% in geriatric hospital wards, 6.0% in nongeriatric wards, and 17.2% in the intensive care unit. The prevalence of severe hyponatremia (serum sodium level less than 125 mEq per L) was 4.5%, 0.8%, and 10.3%, respectively. It is estimated that hyponatremia occurs in 4% to 7% of the ambulatory population, with rates of 18.8% in nursing homes. […] Hyponatremia is associated with increased morbidity and mortality. In patients with heart failure who undergo cardiac surgery, hyponatremia increases rates of postoperative complications, length of hospital stay, and mortality. Mild hyponatremia in the ambulatory setting is associated with increased mortality (hazard ratio = 1.94) compared with normal sodium levels. Patients who develop hyponatremia during hospitalization have increased mortality rates compared with those who have hyponatremia on admission. It is unclear if hyponatremia is a marker for poor prognostic outcomes or merely a reflection of disease severity. Its presence suggests a worse prognosis in patients with liver cirrhosis, pulmonary hypertension, myocardial infarction, chronic kidney disease, hip fractures, and pulmonary embolism.

• #60 Managing Hyponatremia in Heart Failure | USC Journal

  https://www.uscjournal.com/articles/managing-hyponatremia-heart-failure?language_content_entity=en

  Hyponatremia is the most common electrolytic abnormality in clinical practice and has a reported incidence of 15-30% in adults. […] It is particularly common in heart failure: the Organized Program to Initiate Life Saving Treatment in Patients Hospitalized for Heart Failure (OPTIMIZE-HF) registry recorded that 25.3% of 47,647 heart failure patients had hyponatremia on admission. […] Hyponatremia can be caused by either an excessive loss of sodium, known as depletional hyponatremia, or excessive retention of water, called dilutional hyponatremia. […] Depletional hyponatremia is caused by certain disorders or drugs that produce a decrease in extracellular fluid, leading to an excessive loss of renal salts. […] Hypervolemic hyponatremia is generally the result of fluid overload associated with raised AVP secretion, advanced liver cirrhosis, renal disease, or congestive heart failure.

• #61 What Causes Low Sodium? Hyponatremia, Explained.

  https://www.eatingwell.com/article/7969221/what-causes-low-sodium-hyponatremia/

  Electrolyte imbalances are common in patients with end-stage liver disease. As such, hyponatremia can occur. […] When you vomit or have diarrhea, your body loses fluid and electrolytes, including sodium. […] Sometimes, the medication you take can trigger another issue altogether. Certain diuretics, antidepressants and antiepileptics have all been linked to hyponatremia. In some cases, antihypertensive agents, antibiotics and proton pump inhibitors can also cause low levels of sodium in the blood. […] Having an underactive thyroid affects certain hormones that play a role in water balance in the body. This can result in more dilute blood levels and hyponatremia. […] Consuming excessive amounts of water, especially if you do so when sweating a lot (e.g., during a long endurance activity) can also dilute your body’s sodium levels and lead to hyponatremia. […] Hyponatremia is not caused by eating a low-sodium diet, but is often the result of certain health conditions.

• #62 Diagnosis and Management of Sodium Disorders: Hyponatremia and Hypernatremia | AAFP

  https://www.aafp.org/pubs/afp/issues/2015/0301/p299.html

  Hyponatremia is a common electrolyte disorder defined as a serum sodium level of less than 135 mEq per L. A Dutch systematic review of 53 studies showed that the prevalence of mild hyponatremia was 22.2% in geriatric hospital wards, 6.0% in nongeriatric wards, and 17.2% in the intensive care unit. The prevalence of severe hyponatremia (serum sodium level less than 125 mEq per L) was 4.5%, 0.8%, and 10.3%, respectively. It is estimated that hyponatremia occurs in 4% to 7% of the ambulatory population, with rates of 18.8% in nursing homes. […] Hyponatremia is associated with increased morbidity and mortality. In patients with heart failure who undergo cardiac surgery, hyponatremia increases rates of postoperative complications, length of hospital stay, and mortality. Mild hyponatremia in the ambulatory setting is associated with increased mortality (hazard ratio = 1.94) compared with normal sodium levels. Patients who develop hyponatremia during hospitalization have increased mortality rates compared with those who have hyponatremia on admission. It is unclear if hyponatremia is a marker for poor prognostic outcomes or merely a reflection of disease severity. Its presence suggests a worse prognosis in patients with liver cirrhosis, pulmonary hypertension, myocardial infarction, chronic kidney disease, hip fractures, and pulmonary embolism.

• #63 What Causes Low Sodium? Hyponatremia, Explained.

  https://www.eatingwell.com/article/7969221/what-causes-low-sodium-hyponatremia/

  Electrolyte imbalances are common in patients with end-stage liver disease. As such, hyponatremia can occur. […] When you vomit or have diarrhea, your body loses fluid and electrolytes, including sodium. […] Sometimes, the medication you take can trigger another issue altogether. Certain diuretics, antidepressants and antiepileptics have all been linked to hyponatremia. In some cases, antihypertensive agents, antibiotics and proton pump inhibitors can also cause low levels of sodium in the blood. […] Having an underactive thyroid affects certain hormones that play a role in water balance in the body. This can result in more dilute blood levels and hyponatremia. […] Consuming excessive amounts of water, especially if you do so when sweating a lot (e.g., during a long endurance activity) can also dilute your body’s sodium levels and lead to hyponatremia. […] Hyponatremia is not caused by eating a low-sodium diet, but is often the result of certain health conditions.

• #64 Hyponatremia – Endocrine and Metabolic Disorders – Merck Manual Professional Edition

  https://www.merckmanuals.com/professional/endocrine-and-metabolic-disorders/electrolyte-disorders/hyponatremia

  Euvolemic hyponatremia may also result from excessive water intake in the presence of Addison disease, hypothyroidism, or nonosmotic vasopressin release. […] The syndrome of inappropriate ADH secretion (SIADH) is another cause of euvolemic hyponatremia. […] Hypervolemic hyponatremia is characterized by an increase in both total body sodium (and thus ECF volume) and total body water with a relatively greater increase in TBW. […] Various edematous disorders, including heart failure and cirrhosis, cause hypervolemic hyponatremia. […] The syndrome of inappropriate ADH (vasopressin) secretion is attributed to excessive vasopressin release. […] Hyponatremia has been reported in 50% of hospitalized patients with AIDS. […] Hyponatremia frequently occurs in patients with brain pathology, including concussion, intracranial hemorrhage, encephalitis, meningitis, and CNS tumors.

• #65 Hyponatremia: Practice Essentials, Pathophysiology, Etiology

  https://emedicine.medscape.com/article/242166-overview

  Cerebral salt wasting (CSW) is seen with intracranial disorders, such as subarachnoid hemorrhage, carcinomatous or infectious meningitis, metastatic carcinoma, traumatic brain injury, and pituitary disorders, but especially after neurologic procedures. […] Plasma renin and aldosterone levels fail to rise appropriately in patients with CSW despite a reduced plasma volume because of disruption of the sympathetic nervous system. […] Diuretics may induce hypovolemic hyponatremia. Note that thiazide diuretics, in contrast to loop diuretics, impair the diluting mechanism without limiting the concentrating mechanism, thereby impairing the ability to excrete a free-water load.

• #66

  https://journals.lww.com/jasn/fulltext/2016/03000/chronic_hyponatremia_causes_neurologic_and.15.aspx

  Hyponatremia is the most common clinical electrolyte disorder. […] However, because underlying diseases such as adrenal insufficiency, heart failure, liver cirrhosis, and cancer may also affect brain function, the contribution of hyponatremia alone to neurologic manifestations and the underlying mechanisms remain unclear. […] Thus, these results suggest chronic hyponatremia in humans may cause gait disturbance and cognitive impairment, but these abnormalities are reversible and careful correction of this condition may improve quality of life and reduce mortality.

• #67 Hyponatremia: A practical approach

  https://pmc.ncbi.nlm.nih.gov/articles/PMC4192979/

  Hyponatremia is an important and common clinical problem. The etiology is multifactorial. […] Hyponatremia results from the inability of the kidney to excrete a water load or excess water intake. […] Hyponatremia occurs if there is persistent ADH stimulation which is seen in following situations. […] The causes of hypovolemic hyponatremia may be renal or non-renal. […] The commonest cause of euvolemic hyponatremia is Syndrome of inappropriate secretion of Anti diuretic hormone (SIADH). […] The causes of SIADH are shown in Tables 3 and 4. […] Plasma sodium concentration (PNa) is given by ratio of the body’s content of exchangeable sodium and potassium (NaE and KE) and total body water (TBW): PNa NaE + KE/TBW. […] Hyponatremia occurs commonly in both acute and chronic renal failure, because the kidneys cannot maximally excrete excess ingested water.

• #68

  https://link.springer.com/article/10.1007/s10157-025-02624-9

  Hyponatremia can result from various etiologies, ranging from the most common such as the syndrome of inappropriate antidiuresis (SIAD) and medication-induced hyponatremia, to the less common such as adrenal insufficiency and salt-losing nephropathy. […] Besides these causes, multiple additional factors can contribute to development of hyponatremia, making it more difficult to determine the root cause. […] The risk of developing hyponatremia is also increased in patients with chronic kidney disease (CKD). […] The difference in results between Japan and the U.S. suggests that hyponatremia is caused not only by impaired renal free water excretion resulting from CKD, but also by various other factors, including concomitant underlying diseases, diuretic use, and solute intake restriction.

• #69 Dilutional Hyponatremia & Mental Illness Symptoms, Causes, and Treatment

  https://www.therecoveryvillage.com/mental-health/dilutional-hyponatremia/

  Water intoxication is a potentially life-threatening condition resulting from low levels of sodium and excess fluids that can enter and swell the body’s cells. […] Dilutional hyponatremia, or water intoxication, occurs when an individual drinks an excessive amount of water without consuming enough electrolytes. This triggers an imbalance, as water enters the body’s cells and causes them to swell. […] Individuals with various mental health conditions such as schizophrenia, schizoaffective disorder and bipolar disorder are at higher risk for hyponatremia. […] Dilutional hyponatremia occurs when sodium levels fall in the blood, disrupting the regulation and balance of body fluids. Dilutional hyponatremia can result from medical conditions, certain medications or from drinking exorbitant amounts of water.

• #70 Dilutional Hyponatremia & Mental Illness Symptoms, Causes, and Treatment

  https://www.therecoveryvillage.com/mental-health/dilutional-hyponatremia/

  Psychogenic polydipsia hyponatremia is commonly seen in individuals with chronic schizophrenia. […] Other mental health conditions linked with psychogenic polydipsia include schizophrenia, affective disorders, personality disorders, and childhood-onset psychosis and more. […] Dilutional hyponatremia is frequently reported in individuals with chronic substance use disorders. […] Individuals may develop the condition from abusing stimulants, from drinking beer or from attempting to rapidly detoxify their body of drugs or alcohol.

• #71 Hyponatremia – PsychDB

  https://www.psychdb.com/cl/hyponatremia

  Hyponatremia is an electrolyte disturbance of low serum sodium that can result in neuropsychiatric symptoms. In psychiatric patients, the cause of hyponatremia is most commonly secondary to syndrome of inappropriate antidiuretic hormone secretion (SIADH) from psychotropics medications including antidepressants and antipsychotics. […] There are numerous etiologies of hyponatremia. The correct treatment and management of hyponatremia depends on identifying the etiology of the hyponatremia. For example, one must differentiate between iatrogenic hyponatremia (typically due to thiazide diuretics, carbamazepine, antidepressants, or antipsychotics), idiopathic hyponatremia, or other etiologies (like hypothyroidism or alcoholism). Generally speaking, the majority of hyponatremias in the psychiatric population are associated with physiologically inappropriate (but not necessarily elevated) levels of arginine vasopressin (AVP), leading to water retention and serum hypotonicity.

• #72 Hyponatremia – Knowledge @ AMBOSS

  https://www.amboss.com/us/knowledge/hyponatremia/

  Hyponatremia is typically caused by fluid imbalance; common causes are categorized as hypovolemic (e.g., dehydration), euvolemic (e.g., primary polydipsia, SIADH), or hypervolemic (e.g., CHF). […] Hyponatremia is classified according to serum osmolality and extracellular volume status. Multiple etiologies may be present. […] Causes: extrarenal and renal (see Causes of hypotonic hyponatremia). […] Thiazide diuretic use and SIADH are the most common causes of hyponatremia in the emergency department. […] Exercise-associated hyponatremia is most commonly associated with marathon running but has also been reported following other exertional activities such as football, cycling, fraternity hazing, and military training. […] Hyperglycemia, IV mannitol, and IV radiocontrast use are causes of hypertonic hyponatremia.

• #73 Hyponatremia – Wikipedia

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

  The specific causes of hyponatremia are generally divided into those with low tonicity (lower than normal concentration of solutes), without low tonicity, and falsely low sodiums. Those with low tonicity are then grouped by whether the person has high fluid volume, normal fluid volume, or low fluid volume. […] Hypovolemia (extracellular volume loss) is due to total body sodium loss. Hyponatremia is caused by a relatively smaller loss in total body water. Any cause of hypovolemia such as prolonged vomiting, decreased oral intake, severe diarrhea. Diuretic use (due to the diuretic causing a volume depleted state and thence ADH release, and not a direct result of diuretic-induced urine sodium loss). Addison’s disease and congenital adrenal hyperplasia in which the adrenal glands do not produce enough steroid hormones (combined glucocorticoid and mineralocorticoid deficiency). Prolonged exercise and sweating, combined with drinking water without electrolytes is the cause of exercise-associated hyponatremia (EAH). It is common in marathon runners and participants of other endurance events. The use of MDMA (ecstasy) can result in hyponatremia.

• #74 Hyponatremia | Endocrinology | Mercy Health

  https://www.mercy.com/health-care-services/endocrinology/conditions/hyponatremia

  Hyponatremia happens when your blood sodium levels fall below 135 mEq/L. This can happen for a variety of reasons. Certain medications can change the way your kidneys work. Medical conditions that affect your heart, liver, kidneys or endocrine system can cause water retention. They can also affect your body’s ability to produce hormones that balance your sodium and water levels. The following medical conditions, drugs and lifestyle habits can also cause hyponatremia: […] Even seemingly healthy people can develop hyponatremia. This condition can affect up to 30% of ultra-endurance athletes. When these athletes train and participate in competitions, they may lose large amounts of sodium as they sweat. If they also drink water to hydrate their bodies, they risk diluting the sodium levels in their bloodstream to very low levels.

• #75 Hyponatremia | Endocrinology | Mercy Health

  https://www.mercy.com/health-care-services/endocrinology/conditions/hyponatremia

  Other risk factors for hyponatremia include: […] Those who eat a low-sodium diet also have an increased risk of hyponatremia because they don’t eat large amounts of sodium. […] Older people are more likely to take prescription drugs or have a chronic medical condition that causes hyponatremia. […] Female endurance athletes are more likely to develop hyponatremia than their male counterparts.

• #76 Hyponatremia: A practical approach

  https://pmc.ncbi.nlm.nih.gov/articles/PMC4192979/

  Hyponatremia is an important and common clinical problem. The etiology is multifactorial. […] Hyponatremia results from the inability of the kidney to excrete a water load or excess water intake. […] Hyponatremia occurs if there is persistent ADH stimulation which is seen in following situations. […] The causes of hypovolemic hyponatremia may be renal or non-renal. […] The commonest cause of euvolemic hyponatremia is Syndrome of inappropriate secretion of Anti diuretic hormone (SIADH). […] The causes of SIADH are shown in Tables 3 and 4. […] Plasma sodium concentration (PNa) is given by ratio of the body’s content of exchangeable sodium and potassium (NaE and KE) and total body water (TBW): PNa NaE + KE/TBW. […] Hyponatremia occurs commonly in both acute and chronic renal failure, because the kidneys cannot maximally excrete excess ingested water.

• #77 Hyponatremia: Practice Essentials, Pathophysiology, Etiology

  https://emedicine.medscape.com/article/242166-overview

  Although the differential diagnosis is quite broad, most hyponatremia can be classified as hypertonic, normotonic, or hypotonic in origin. […] Patients with hypertonic hyponatremia often have normal total body sodium levels but a dilutional drop in the measured serum sodium due to the presence of osmotically active molecules in the serum, which causes a water shift from the intracellular compartment to the extracellular compartment. […] Hypotonic hyponatremia always reflects the inability of the kidneys to handle the excretion of free water to match the intake. Hypotonic hyponatremia with a urinary osmolality 100 mOsm/kg (due to presence of inappropriate ADH) can be divided pathophysiologically into the following categories, according to the effective intravascular volume: hypervolemic, euvolemic, and hypovolemic.

• #78 Diagnosis and Management of Sodium Disorders: Hyponatremia and Hypernatremia | AAFP

  https://www.aafp.org/pubs/afp/issues/2015/0301/p299.html

  The most common classification system for hyponatremia is based on volume status: hypovolemic (decreased total body water with greater decrease in sodium level), euvolemic (increased total body water with normal sodium level), and hypervolemic (increased total body water compared with sodium). Plasma osmolality has a role in the pathophysiology of hyponatremia. Osmolality refers to the total concentration of solutes in water. Effective osmolality is the osmotic gradient created by solutes that do not cross the cell membrane. Effective osmolality determines the osmotic pressure and the flow of water. Plasma osmolality is maintained by strict regulation of the arginine vasopressin (also called antidiuretic hormone [ADH]) system and thirst. If plasma osmolality increases, ADH is secreted and water is retained by the kidneys, thus decreasing serum osmolality. If plasma osmolality decreases, ADH also decreases, resulting in diuresis of free water and a return to homeostasis.

• #79 Diagnosis and Management of Sodium Disorders: Hyponatremia and Hypernatremia | AAFP

  https://www.aafp.org/pubs/afp/issues/2015/0301/p299.html

  The most common classification system for hyponatremia is based on volume status: hypovolemic (decreased total body water with greater decrease in sodium level), euvolemic (increased total body water with normal sodium level), and hypervolemic (increased total body water compared with sodium). Plasma osmolality has a role in the pathophysiology of hyponatremia. Osmolality refers to the total concentration of solutes in water. Effective osmolality is the osmotic gradient created by solutes that do not cross the cell membrane. Effective osmolality determines the osmotic pressure and the flow of water. Plasma osmolality is maintained by strict regulation of the arginine vasopressin (also called antidiuretic hormone [ADH]) system and thirst. If plasma osmolality increases, ADH is secreted and water is retained by the kidneys, thus decreasing serum osmolality. If plasma osmolality decreases, ADH also decreases, resulting in diuresis of free water and a return to homeostasis.

• #80

  https://link.springer.com/article/10.1007/s10157-025-02624-9

  AVP is said to be inappropriately secreted in the syndrome of inappropriate antidiuretic hormone secretion (SIADH) despite the absence of osmotic stimuli and normal EABV by clinical evaluation. […] More than half of SIAD cases, particularly in older patients, are reportedly diagnosed as idiopathic SIAD. […] Diagnosis of SIAD is usually challenging because it is a diagnosis of exclusion; however, many reports have shown that serum uric acid (UA) concentration and fractional excretion of UA (FEUA) help differentiate SIAD from other causes of hyponatremia. […] The pathogenesis of medication-induced hyponatremia can be classified into mechanisms involving the relative amounts of free water and Na+ in the body and the factors that regulate body water and Na+ homeostasis.

• #81 Hyponatremia: Practice Essentials, Pathophysiology, Etiology

  https://emedicine.medscape.com/article/242166-overview

  This is characterized by clinically detectable edema or ascites that signifies an increase in total body water and sodium. Paradoxically, however, a decrease in the effective circulating volume, critical for tissue perfusion, stimulates the same pathophysiologic mechanism of impaired water excretion by the kidney that is observed in hypovolemic hypotonic hyponatremia. […] Normovolemic (euvolemic) hypotonic hyponatremia is a very common cause of hyponatremia in hospitalized patients. It is associated with non-osmotic and nonvolume-related ADH secretion (ie, SIADH) secondary to a variety of clinical conditions. […] Hypovolemic hypotonic hyponatremia usually indicates concomitant solute depletion, with patients presenting with orthostatic symptoms. […] The pathophysiology underlying hypovolemic hypotonic hyponatremia is complex and involves the interplay of carotid baroreceptors, the sympathetic nervous system, the renin-angiotensin system, antidiuretic hormone (ADH; vasopressin) secretion, and renal tubular function.

• #82 Evaluation of hyponatremia – Differential diagnosis of symptoms | BMJ Best Practice US

  https://bestpractice.bmj.com/topics/en-us/57

  Failure to correct hyponatremia can lead to permanent neurologic damage, as can correcting sodium levels too rapidly. […] When hyponatremia is chronic and the serum sodium concentration increases too rapidly, osmotic demyelination syndrome (ODS; also known as central pontine myelinolysis) may develop.

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