Materiały źródłowe

• #1 The etiology of Bell’s palsy: a review

  https://pmc.ncbi.nlm.nih.gov/articles/PMC7320932/

  Bells palsy is the most common condition involving a rapid and unilateral onset of peripheral paresis/paralysis of the seventh cranial nerve. […] However, the etiology of Bells palsy is unclear, and this affects its treatment. Thus, it is critical to determine the causes of Bells palsy so that targeted treatment approaches can be developed and employed. […] Despite its severe effects, the exact etiology of BP remains unclear. […] The GDG has also recognized the acute or rapid onset nature of BP and that the occurrence of paralysis/paresis usually reaches its maximum severity in less than 72 h of paralysis/paresis onset. But the current literature similarly lacks a precise etiology for the acute onset of facial palsy. […] There are five major theories regarding the causes of BP including anatomical, viral infection, ischemia, inflammation, and cold stimulation.

• #2 Bell’s palsy: Pathogenesis, clinical features, and diagnosis in adults – UpToDate

  https://www.uptodate.com/contents/bells-palsy-pathogenesis-clinical-features-and-diagnosis-in-adults

  Idiopathic facial nerve palsy, also referred to as Bell’s palsy, is the most common type of spontaneous peripheral facial paralysis. A viral etiology (ie, activation of the herpes simplex virus) is suspected in most cases of Bell’s palsy, although there is no established or widely available method of confirming a viral mechanism in clinical practice. […] This review will discuss the pathogenesis, clinical features, and diagnosis of Bell’s palsy.

• #3 Bell Palsy – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK482290/

  Bell palsy, which is a unilateral hemifacial palsy of rapid onset, results from inflammation of the facial nerve, typically originating in the labyrinthine segment. The narrowness of this portion of the facial nerve’s canal through the temporal bone of the skull predisposes it to dysfunction, potentially due to edema and subsequent impairment of perfusion when inflammation occurs, with Bell palsy more likely to occur in patients who have narrow labyrinthine segments of the facial canal. […] Bell palsy is thought to result from compression of the seventh cranial nerve within the labyrinthine segment of the Fallopian canal. Not only is this segment the narrowest along the nerve’s course within the temporal bone, but it also appears to have the most tenuous blood supply, with very fine arterioles connecting the angiosomes supplied by the internal auditory branch of the anterior inferior cerebellar artery proximally and the petrosal branch of the middle meningeal artery distally.

• #4 Bell Palsy: Practice Essentials, Background, Anatomy

  https://emedicine.medscape.com/article/1146903-overview

  The precise pathophysiology of Bell palsy remains an area of debate. The facial nerve courses through a portion of the temporal bone commonly referred to as the facial canal. A popular theory proposes that edema and ischemia result in compression of the facial nerve within this bony canal. The cause of the edema and ischemia has not yet been established. This compression has been seen in MRI scans with facial nerve enhancement. […] The first portion of the facial canal, the labyrinthine segment, is the narrowest; the meatal foramen in this segment has a diameter of only about 0.66 mm. This is the location that is thought to be the most common site of compression of the facial nerve in Bell palsy. Given the tight confines of the facial canal, it seems logical that inflammatory, demyelinating, ischemic, or compressive processes may impair neural conduction at this site.

• #5 Bell Palsy | Treatment & Management | Point of Care

  https://www.statpearls.com/point-of-care/18195

  Bell palsy, which is a unilateral hemifacial palsy of rapid onset, results from inflammation of the facial nerve, typically originating in the labyrinthine segment. The labyrinthine segment is the second intratemporal segment of the facial nerve and the narrowest, with an average diameter of 0.7 mm and a length of 3 to 5 mm. The narrowness of this portion of the facial nerve’s canal through the temporal bone of the skull (the Fallopian canal) predisposes it to dysfunction, potentially due to edema and subsequent impairment of perfusion when inflammation occurs, with Bell palsy more likely to occur in patients who have narrow labyrinthine segments of the facial canal. […] Bell palsy is thought to result from compression of the seventh cranial nerve within the labyrinthine segment of the Fallopian canal. Not only is this segment the narrowest along the nerve’s course within the temporal bone, but it also appears to have the most tenuous blood supply, with very fine arterioles connecting the angiosomes supplied by the internal auditory branch of the anterior inferior cerebellar artery proximally and the petrosal branch of the middle meningeal artery distally. The final segment of the intratemporal facial nerve is perfused by the stylomastoid artery, a branch of the posterior auricular artery. Further implicating the labyrinthine segment as the primary site of Bell palsy inflammation is the appearance of the nerve on magnetic resonance imaging (MRI): 59% of patients with acute Bell palsy have asymmetric enhancement of the labyrinthine segment, and a further 33% have enhancement of both the labyrinthine segment and the geniculate ganglion.

• #6 Bell Palsy – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK482290/

  The severity of this inflammation may depend upon several factors, including the patient’s immune status, blood glucose level, blood pressure, and age. There is a hypothesis that edema of the nerve within the Fallopian canal compromises perfusion, leading to nerve dysfunction. The extent of the dysfunction and the prognosis for recovery depend on the degree of disruption of the internal architecture of the facial nerve, in which each axon has a myelin sheath and an endoneurial membrane surrounding it, with the axons grouped together into fascicles surrounded by perineurial membranes, and the fascicles together constituting the nerve itself, which is invested in epineurium.

• #7 Bell Palsy | Treatment & Management | Point of Care

  https://www.statpearls.com/point-of-care/18195

  The severity of this inflammation may depend upon several factors, including the patient’s immune status, blood glucose level, blood pressure, and age. There is a hypothesis that edema of the nerve within the Fallopian canal compromises perfusion, leading to nerve dysfunction. The extent of the dysfunction and the prognosis for recovery depend on the degree of disruption of the internal architecture of the facial nerve, in which each axon has a myelin sheath and an endoneurial membrane surrounding it, with the axons grouped together into fascicles surrounded by perineurial membranes, and the fascicles together constituting the nerve itself, which is invested in epineurium. […] A mild injury may only cause a temporary conduction block with or without focal demyelination, known as neuropraxia in the Seddon grading system, or a Sunderland class I injury. Actual axonal damage occurs in a Sunderland class II injury, but all of the internal architecture of the nerve is otherwise preserved, virtually ensuring that the axons regrow correctly along their original paths. In the case of a Sunderland class III injury, the axons undergo Wallerian degeneration as they do in a class II injury. However, the endoneurial membranes that surround the damaged axons are violated, which permits mild misdirection of the regenerating axons that may result in discoordinated movements and spasms (synkinesis). A Sunderland class IV injury adds perineurial damage to the class III injury, which results in disruption of the fascicular organization of the nerve and greater potential for synkinesis. Sunderland class II to IV injuries are collectively known as axonotmesis in the Seddon grading system, and a Sunderland class V injury is known as neuronotmesis. Neuronotmesis is a complete transection of the nerve, including the epineurium, guaranteeing severe synkinesis even if the nerve is repaired microsurgically.

• #8 To explore the pathogenesis of Bell’s palsy using diffusion tensor image | Scientific Reports

  https://www.nature.com/articles/s41598-023-42570-8

  To explore the pathogenesis of Bell’s palsy using the diffusion tensor image on 3.0 T MR. […] This study showed that the myelin sheath injury of the intratemporal facial nerve is the main cause of Bell’s palsy. […] The results showed that there was no significant difference in DTI indexes between the bilateral nerves of healthy people. There was a significant difference in FA, MD, and RD between the affected nerve and healthy nerve; there was no significant difference in AD. The decrease in FA and the increase in MD suggest that the integrity of the affected facial nerve is damaged. There was no significant difference in AD between affected and healthy facial nerves, suggesting that the axon of the facial nerve was not damaged. The increase in RD suggests that the cause of facial nerve damage is myelin injury. […] This study may explain why most of Bell’s palsy is self-limited.

• #9

  https://consensus.app/questions/causes-of-bells-palsy/

  One of the most widely accepted causes of Bell’s palsy is viral infection. Herpes simplex virus (HSV) is frequently implicated, with evidence suggesting that HSV may reside within the peripheral nerve cells and reactivate, leading to inflammation and compression of the facial nerve. […] Autoimmune responses have also been proposed as a potential cause of Bell’s palsy. It is suggested that an autoimmune reaction against myelin components of the facial nerve could lead to demyelination and subsequent paralysis. This mechanism is similar to that seen in Guillain-Barr syndrome, where a viral infection or reactivation may provoke an autoimmune response. […] Ischemia, or reduced blood flow, and inflammation are additional factors that may contribute to Bell’s palsy. Inflammation of the facial nerve, possibly due to viral infection or autoimmune responses, can lead to swelling and compression within the narrow confines of the bony fallopian canal, resulting in nerve damage and paralysis.

• #10 The etiology of Bell’s palsy: a review

  https://pmc.ncbi.nlm.nih.gov/articles/PMC7320932/

  Another possible etiology of BP that has been suggested is infection by reactivated viruses, such as the varicella zoster virus (VZV), herpes simplex virus type 1 (HSV-1), human herpes virus 6, and the Usutu virus. […] A possible cause of HSV-1-mediated neural dysfunction is the activation of apoptotic pathways and intra-axonal degradation, which are driven by the axons local indirect and direct responses to the viruses themselves in susceptible phenotypes. […] Studies have suggested that viruses use abnormal expressions of p53 upregulated modulator of apoptosis (PUMA) and/or innate immunity signaling molecule (SARM1) to trigger axon degeneration. […] BP, an acute idiopathic lower motor neuron palsy, is commonly a unilateral and self-limiting inflammatory condition. […] Among those cases that do not resolve, studies have implicated secondary ischemia, tertiary ischemia, or their sequelae, and this in turn, can result in thickening of the facial nerve sheath, forming one or more fibrous bands that cause nerve strangulation and compression, thereby hampering recovery.

• #11

  https://link.springer.com/article/10.1007/s00415-019-09282-4

  Another possible etiology of BP that has been suggested is infection by reactivated viruses, such as the varicella zoster virus (VZV), herpes simplex virus type 1 (HSV-1), human herpes virus 6, and the Usutu virus. […] Studies have suggested that viruses use abnormal expressions of p53 upregulated modulator of apoptosis (PUMA) and/or innate immunity signaling molecule (SARM1) to trigger axon degeneration. […] BP, an acute idiopathic lower motor neuron palsy, is commonly a unilateral and self-limiting inflammatory condition. […] Most cases of BP remit within 46 months and almost always resolve completely within 1 year. […] Numerous lines of evidence have suggested that BP results from acute, inflammation-caused demyelination. […] It has also been suggested that BP is actually a polyneuropathy, with facial paralysis often involving other cranial nerves.

• #12 Bell’s palsy – Wikipedia

  https://en.wikipedia.org/wiki/Bell%27s_palsy

  Bell’s palsy is the result of a malfunction of the facial nerve (cranial nerve VII), which controls the muscles of the face. Facial palsy is typified by an inability to move the muscles of facial expression. The paralysis is of the infranuclear/lower motor neuron type. […] It is thought that as a result of inflammation of the facial nerve, pressure is produced on the nerve where it exits the skull within its bony canal (the stylomastoid foramen), blocking the transmission of neural signals or damaging the nerve. […] In some research, the herpes simplex virus type 1 (HSV-1) has been identified in a majority of cases diagnosed as Bell’s palsy through endoneurial fluid sampling. […] In addition, HSV-1 infection is associated with demyelination of nerves. This nerve damage mechanism is different from the above-mentioned that edema, swelling, and compression of the nerve in the narrow bone canal are responsible for nerve damage. Demyelination may not even be directly caused by the virus but by an unknown immune response.

• #13 Bell’s Palsy: To Treat or Not to Treat

  https://www.uspharmacist.com/article/bells-palsy-to-treat-or-not-to-treat

  Bells palsy is often described as idiopathic. However, current evidence suggests a possible viral pathogenesis with herpes simplex virus type 1 (HSV-1). Recent molecular analyses by means of polymerase chain reaction have shown latent HSV genome in the geniculate ganglia, as well as active HSV segments in the endoneural fluid of the facial nerve. Therefore, it is believed that patients experience inflammation because of reactivated HSV causing mechanical compression and possible demyelination and ischemia of the facial (seventh cranial) nerve in the geniculate ganglion. This results in paralysis of all the muscles involved in facial expression on the affected side of the face. […] Corticosteroids work by suppressing inflammation and the bodys natural immune response found in the facial nerve responsible for facial paralysis. The practice parameter issued by the Quality Standards Subcommittee of the AAN in 2001 concludes that oral steroids are safe and probably effective in improving facial functional outcomes in patients with Bells palsy(level B recommendation).

• #14 Bell’s Palsy (Facial Nerve Problems) Symptoms, Treatment, Causes

  https://www.medicinenet.com/facial_nerve_problems/article.htm

  One proposed mechanism of injury includes: […] The virus lives in the nerve (geniculate ganglion) for months to years. […] The virus becomes reactivated at a later date. […] The virus reproduces and travels along the nerve. […] The virus infects the cells surrounding the nerve (Schwann cells) resulting in inflammation. […] The immune system responds to the damaged Schwann cells, which causes inflammation of the nerve and subsequent weakness or paralysis of the face. […] The course of the paralysis and the recovery will depend upon the degree and amount of damage to the nerve.

• #15 Azthena logo with the word Azthena

  https://www.news-medical.net/health/Bells-Palsy-Pathology.aspx

  The hypothesis that HSV-1 is the etiologic agent in Bell’s palsy was proposed in 1972 by McCormick. After causing primary infection in the form of cold sores (clusters of small fluid-filled blisters on the lips, mouth or nose), the virus travels along the neuron (in a process called retrograde transport) to the geniculate ganglion. There a lifelong silent infection is established, and autopsy studies showed the presence of HSV-1 in the ganglions of affected patients. The virus can be reactivated when the immune defenses are low, causing local damage to the nerve.

• #16 The etiology of Bell’s palsy: a review

  https://pmc.ncbi.nlm.nih.gov/articles/PMC7320932/

  Numerous lines of evidence have suggested that BP results from acute, inflammation-caused demyelination. […] The myelin sheath is a layer that wraps the axons of nerve cells and is mainly composed of Schwann cells. […] BP, as GuillainBarr syndrome, may be an acute demyelinating disease of the peripheral nervous system. […] Collectively, these studies and those discussed above demonstrate that the incidence of BP increases with acute cold exposure and in places with large diurnal temperature differences, indicating that sharp temperature changes may be a risk factor for facial nerve palsy.

• #17

  https://link.springer.com/article/10.1007/s00415-019-09282-4

  The presence of small round lymphatic cells and the breakdown of myelin sheaths are common histologic features of autoimmune responses, with viral infection prompting an autoimmune reaction against a component of peripheral myelin and resulting in the cranial nerves demyelination and especially facial nerve demyelination. […] Collectively, these studies and those discussed above demonstrate that the incidence of BP increases with acute cold exposure and in places with large diurnal temperature differences, indicating that sharp temperature changes may be a risk factor for facial nerve palsy.

• #18 Virus-Associated Demyelination in the Pathogenesis of Bell’s Palsy

  https://www.jstage.jst.go.jp/article/internalmedicine1992/31/11/31_11_1250/_article

  We examined the cerebrospinal fluid findings, including the activity of the myelin-associated enzyme 2′, 3′-cyclic nucleotide 3′-phosphohydrolase (CNP), and virus serology in patients with Bell’s palsy. […] The activity of CNP was significantly elevated in the patient group (15.53.8nmol/h/ml) as compared with the control (13.21.3nmol/h/ml) (p 0.01), suggesting the presence of intrathecal myelin breakdown. […] Furthermore, there was an association between antibodies against herpes simplex virus (HSV) and elevated CNP activity. […] The inflammatory alterations and accompanying spinal fluid abnormalities, together with the high frequency of HSV antibodies suggest that HSV-associated demyelination may play a pathogenetic role in Bell’s palsy.

• #19 Current management of idiopathic facial palsy (Bell’s …

  https://otorhinolaryngologypl.com/seo/article/01.3001.0010.1027/en?language=pl

  According to some authors, the pathogenesis of Bell’s palsy is further complicated by varicella-zoster infections that do not produce skin lesions (i.e., zoster sine herpete). […] It has long been postulated that disorders of microcirculation within the vessels that supply the nerves (i.e., vasa nervorum) can be implicated in the pathogenesis of idiopathic facial palsy. […] Based on the above-described studies, one can think that more studies on the role of viruses in the pathogenesis of idiopathic facial palsy and improvements in the diagnostic methods of detecting viruses will appear in the near future.

• #20

  https://link.springer.com/article/10.1007/BF00313837

  The frequency of diabetes mellitus reported in subjects affected by Bell’s palsy varies widely. In this investigation, a case-control study, we encountered a frequency of 24.8%. […] These findings appear to suggest a primarily ischaemic pathogenesis for most cases of idiopathic peripheral facial paralysis. […] Furthermore, the finding of significantly lower taste impairment in diabetics than in non-diabetics with Bell’s palsy may support the hypothesis of a vascular rather than a metabolic pathogenesis in these cases also. […] In fact, the vessels supplying the distal portion of the facial nerve, probably more affected in the diabetic patients in order to preserve taste sensation, have such a particular anatomical configuration that this might favour the onset of a diabetic small vessel disease which, in turn, would represent a factor of easier decompensation.

• #21 Bell’s Palsy: Causes, Treatment & Nutrients – Life Extension

  https://www.lifeextension.com/protocols/neurological/bells-palsy?srsltid=AfmBOoqlppI8I7askOQwV5lmWIHV4MGfaNE-2iCssP3zFKwr4Fv_9jDa

  Inflammation and anatomical factors can result in blood vessel compression and ischemia (decreased blood flow and poor oxygenation) of the facial nerve. Ischemia, which can cause thickening of connective tissue and further nerve compression, has been proposed to be a factor in cases of Bells palsy that do not resolve. […] It is widely thought that reactivation of latent viral infection triggers the onset of Bells palsy in many cases. Herpes simplex virus-type 1 (HSV-1) is the most studied with regard to its relationship with Bells palsy. HSV-1 and other herpes viruses generally manifest in two distinct stages: during the first stage, there is active symptomatic infection and viral replication, whereas during the second stage, the virus is dormant (or latent), residing in the nervous system. The dormant virus may become reactivated and give rise to another active infection. […] Another possible underlying mechanism involves an autoimmune process in which immune cells become activated against the myelin proteins specific to the facial nerve. This type of immune reaction may be triggered by an infection or, in rare cases, certain vaccines.

• #22 Facial Palsy – Causes – Differential Diagnosis – Management – TeachMeSurgery

  https://teachmesurgery.com/ent/presentations/facial-palsy/

  Bell’s palsy remains a poorly understood condition. Many causative associations have been proposed, the most universally accepted theory suggests a viral origin, yet no conclusive evidence is available at present. […] The main risk factor for developing Bell’s palsy is known concurrent viral infection, such as HSV-1, CMV, and EBV, whilst less common risk factors include diabetes mellitus and pregnancy.

• #23 Bell’s Palsy: Pearls and Pitfalls in Evaluation and Management – emDocs

  https://www.emdocs.net/bells-palsy-pearls-and-pitfalls-in-evaluation-and-management/

  Bell’s palsy (BP) is a unilateral facial paralysis resulting from lower motor neuron involvement of Cranial Nerve VII. […] While the exact pathogenesis is unclear, BP is thought to occur from inflammation and swelling of the facial nerve at the geniculate ganglion, which can cause compression and ischemia or demyelination of the nerve. […] The exact etiology of BP is controversial; reactivated herpes simplex virus is thought to be the most probable cause followed by herpes zoster virus. […] The risk of developing BP increases threefold during pregnancy, especially the third trimester, which is thought to occur due to swelling of the facial nerve. […] The classic presentation of BP is a patient with partial or complete weakness of the muscles on one half of the face. […] An important distinction to make during the exam is involvement of the forehead.

• #24 What Doctors Know About Bell’s Palsy

  https://www.brainandlife.org/articles/what-doctors-know-about-bells-palsy

  Lyme disease also can be a cause of the nerve inflammation that leads to Bell’s palsy, says Dr. Gronseth. […] Bell’s palsy is not life-threatening, but it’s still important to see a medical provider urgently when this symptom occurs, says Dr. Lewis. […] The steroid prednisone seems to work better the sooner it’s given, Dr. Gronseth says. […] Antiviral medications added to the steroid may give some small additional benefit, says Dr. Gronseth. […] Hearing also may be affected because Bell’s palsy can affect a tiny branch of the facial nerve involved in the mechanism of hearing, says Dr. Lewis. […] Pregnancy, diabetes, and high blood pressure increase the risk for Bell’s palsy, and the latter two may contribute to a slower or incomplete recovery, says Dr. Gronseth. […] There’s a lot of fluid retention [in the third trimester of pregnancy], so the nerves tend to swell up during that time. […] Bell’s palsy sometimes results in synkinesis, a miswiring of nerves when they regrow that causes an involuntary movement to accompany an unrelated voluntary movementan eye tearing up while a person is eating, for example, or squinting when smiling.

• #25 Refractory Bell’s palsy responding to late treatment with high-dose intravenous steroids

  https://www.e-acn.org/journal/view.php?doi=10.14253/acn.2021.23.2.121

  Bells palsy is an acute peripheral facial paralysis with no detectable cause. […] The reactivation of latent herpes simplex virus or varicella zoster virus within geniculate ganglia causes neuropathy with cytotoxic edema induced by neuronal inflammation in Bells palsy. […] This pathogenesis has led to corticosteroids and antiviral agents being used to treat Bells palsy. […] The prognosis of Bells palsy can be predicted most accurately from the degree of facial nerve degeneration. […] The mechanisms underlying abnormal contrast enhancement in cranial nerves are not yet fully understood. […] This enhancement is thought to be related either to hypervascularity of perineural structures or to actual disruption of the blood-nerve barrier resulting from inflammation. […] Glucocorticoids can be used to accelerate the recovery from this inflammation due to their anti-inflammatory effects, which are mainly attributable to the action of glucocorticoid receptors that alter the transcription of numerous genes in cells. […] Therefore, it can be assumed that high-dose IV steroid treatment might be a useful therapy for Bells palsy that has not recovered with the standard regimen of an antiviral plus oral steroid.

• #26 An In-Depth Look at Bell’s Palsy Facts and Myths

  https://facialparalysisinstitute.com/blog/3-myths-about-living-with-bells-palsy/

  Bells palsy is a medical condition that results in immediate facial paralysis on one side of the face. […] NIH defines Bells palsy as a form of temporary facial paralysis that is caused by damage or trauma to the facial nerve. […] With Bells palsy, the facial nerve that directs muscles on one side of the face is disrupted. This interferes with the messages that the brain sends to facial muscles, resulting in temporary facial paralysis. […] In 85 percent of Bells palsy cases, facial paralysis goes away on its own. However, in approximately 15 percent of patients, the facial nerve function does not return to normal. […] The exact cause of Bells palsy remains unknown. But, Bells palsy is commonly viewed as a viral infection. […] To date, research has linked Bells palsy has been linked to the herpes simplex virus, which can cause cold sores and genital herpes.

• #27 An In-Depth Look at Bell’s Palsy Facts and Myths

  https://facialparalysisinstitute.com/blog/3-myths-about-living-with-bells-palsy/

  It has also been connected to the herpes zoster virus, cytomegalovirus, and Epstein-Barr virus. […] If Bells palsy symptoms linger for more than a month, they can cause serious health issues. […] For some Bells palsy patients, partial or complete blindness in the eye on the paralyzed side of the face can occur. […] These patients are also susceptible to irreversible damage to the facial nerve and/or abnormal regrowth of nerve fibers.

• #28 Facial Palsy and the Ear – Facial Palsy UK

  https://www.facialpalsy.org.uk/support/patient-guides/facial-palsy-and-the-ear/

  When a diagnosis of Bells palsy is made, this means that only the facial nerve is injured/inflamed. […] Stapedial synkinesis causes a distortion of hearing due to abnormal regeneration of some of the nerve fibres (axons) originally supplying the muscles of facial expression. These axons have regrown along the nerve to the stapedius muscle. The synkinesis is experienced as an abnormal sound and or pressure in the ear during facial expressions and/or when speaking. It can be described as a crackling/rumbling sound or muffled hearing. […] Stapedial synkinesis: this is a distortion of hearing which only occurs during facial movement. For example, a crackling sound in the ear when smiling or when blinking or closing the eye.

• #29 A general practice approach to Bell’s palsy

  https://www.racgp.org.au/afp/2016/november/a-general-practice-approach-to-bell-s-palsy

  Bells palsy is characterised by an acute onset of unilateral, lower motor neuron weakness of the facial nerve in the absence of an identifiable cause. […] The exact mechanism of Bells palsy is unknown, although a viral aetiology is suspected. […] The unilateral facial weakness associated with Bells palsy is thought to result from facial nerve inflammation and oedema induced by reactivation of Herpes simplex or Varicella zoster virus. […] In the temporal bone, the facial nerve travels in a narrow canal; swelling of the nerve may result in compression and subsequent damage. […] Bells palsy is thought to result from facial nerve inflammation and oedema; thus, corticosteroids are the mainstay of treatment and their use has been supported by a number of well-designed, randomised controlled trials.

• #30 A general practice approach to Bell’s palsy

  https://www.racgp.org.au/afp/2016/november/a-general-practice-approach-to-bell-s-palsy

  Meta-analyses have shown that the rate of residual facial dysfunction at six months is 23% in patients who received corticosteroid treatment, compared with 33% in the control group. […] Oral steroids should be initiated within 72 hours of symptom onset. […] To date, there is no evidence to suggest that oral antiviral therapy alone is effective for the management of Bells palsy. […] Well-designed clinical trials have shown that antiviral therapy in combination with corticosteroid therapy is of no additional benefit, compared with corticosteroid therapy alone; however, a small benefit cannot be completely excluded. […] Management of Ramsay Hunt syndrome entails antiviral therapy, often given intravenously, in addition to corticosteroids.

• #31

  https://journals.lww.com/otology-neurotology/Fulltext/2011/01000/Prednisolone_in_Bell_s_Palsy_Related_to_Treatment.25.aspx?generateEpub=Article%7Cotology-neurotology:2011:01000:00025%7C%7C

  To evaluate if treatment start and age are related to the outcome in Bell’s palsy patients treated with prednisolone. […] Patients treated with prednisolone within 24 hours and 25 to 48 hours had significantly higher complete recovery rates, 66% (103/156) and 76% (128/168), than patients given no prednisolone, 51% (77/152) and 58% (102/177) (p = 0.008 and p = 0.0003, respectively). […] Treatment with prednisolone within 48 hours of onset of palsy resulted in significantly higher complete recovery rates and less synkinesis compared with no prednisolone.

• #32 Bell’s Palsy: To Treat or Not to Treat

  https://www.uspharmacist.com/article/bells-palsy-to-treat-or-not-to-treat

  Because of the suspected causative viral etiology of HSV-1, antivirals such as acyclovir, valacyclovir, and famciclovir theoretically should be of benefit. Antivirals work by inhibiting viral DNA polymerase, ultimately leading to inhibition of viral DNA synthesis. The use of these medications as monotherapy is not recommended, according to the Cochrane Review: High quality evidence from randomized controlled trials of herpes simplex antivirals for the treatment of Bells palsy showed no significant benefit from antivirals compared to placebo. […] The use of antivirals and corticosteroids has been highly controversial in the past because of conflicting evidence. The two most common antivirals studied are acyclovir and valacyclovir. According to the AANs practice guidelines, Early treatment with acyclovir in combination with prednisone is recommended as possibly effective to improve facial functional outcomes (level C recommendation).

• #33 The Role of Acupuncture in the Management of Bell’s Palsy: A Review of the Evidence and Perspectives in Emergency Care

  https://www.mdpi.com/2813-7914/1/3/24

  Bell’s Palsy, a sudden onset of facial paralysis of unknown etiology, poses a significant challenge in emergency care settings due to its acute presentation and potential long-term sequelae. […] Emerging evidence suggests a potential role for complementary therapies, such as acupuncture, in optimizing outcomes for patients with Bell’s Palsy. […] Despite the growing interest in acupuncture as a complementary therapy for Bell’s Palsy, the exact mechanisms underlying its therapeutic effects remain incompletely understood. Recent studies have proposed several potential mechanisms of action, shedding light on the multifaceted nature of acupuncture’s impact on the pathophysiology of Bell’s Palsy. […] Acupuncture’s ability to modulate inflammation is of particular interest, as evidenced by its regulatory effects on cytokine levels and immune responses. By attenuating the inflammatory cascade implicated in the pathogenesis of Bell’s Palsy, acupuncture may help alleviate facial paralysis and associated symptoms.

• #34 The Role of Acupuncture in the Management of Bell’s Palsy: A Review of the Evidence and Perspectives in Emergency Care

  https://www.mdpi.com/2813-7914/1/3/24

  Furthermore, acupuncture-induced neuroplastic changes within the central nervous system offer insights into its capacity to facilitate functional recovery of the facial nerve and associated musculature. […] Acupuncture in Bell’s Palsy operates through several proposed mechanisms, each addressing different aspects of the condition’s pathophysiology. One such mechanism involves its anti-inflammatory properties. By regulating pro-inflammatory cytokines and mediators, acupuncture mitigates inflammation, reducing tissue damage and creating a conducive environment for nerve regeneration. […] Moreover, acupuncture fosters neuroplasticity, promoting synaptic remodeling and neuronal connectivity in the central nervous system, crucial for functional recovery. […] Another significant facet of acupuncture’s efficacy lies in its ability to enhance blood flow and microcirculation at the affected site. This improvement facilitates the delivery of essential nutrients, oxygen, and immune cells, expediting tissue healing and regeneration.

• #35 The Role of Acupuncture in the Management of Bell’s Palsy: A Review of the Evidence and Perspectives in Emergency Care

  https://www.mdpi.com/2813-7914/1/3/24

  By both addressing the underlying inflammation and promoting neuroregeneration, acupuncture plays a vital role in alleviating symptoms and enhancing the overall quality of life for Bell’s Palsy patients. […] Through these multifaceted mechanisms, acupuncture offers comprehensive and effective treatment for Bell’s Palsy, warranting its consideration as an adjunctive therapy in clinical practice.

• #36 A meta-analysis uncovers the first sequence variant conferring risk of Bell’s palsy | Scientific Reports

  https://www.nature.com/articles/s41598-021-82736-w

  Bells palsy is still idiopathic since we do not know what causes it; there are no biomarkers to support the diagnosis and the diagnosis requires exclusion of any other cause of facial paralysis. In Bells palsy, a viral infection is considered one of the possible causes. The main treatment is corticosteroids, which supports the theory of edema induced entrapment neuropathy. The facial nerve traverses through the temporal bone (the facial canal) and branches to innervate the facial muscles. The narrowest part of the canal, the labyrinthine segment, is where most cases of compression occur, which may result in ischemic neuropathy of the facial nerve. […] We were unable to determine a gene at 6p21.1 involved in Bells palsy pathology. However, the association of rs9357446-A with IDD brings up the possibility that the variant may confer risk of Bells palsy through an effect on cartilage and bone development. Alternatively, the association between Bells palsy, IDD, and reduced lung function may be a result of a true pleiotropy. Although more studies are needed, the identification of this variant contributes to the limited understanding of Bells palsy.

• #37

  https://consensus.app/questions/causes-of-bells-palsy/

  In summary, the etiology of Bell’s palsy is multifactorial, involving viral infections, genetic predisposition, autoimmune mechanisms, ischemic and inflammatory factors, and environmental triggers. Understanding these diverse causes is crucial for developing targeted treatment strategies and improving patient outcomes. […] The first sequence variant identified is associated with Bell’s palsy and also increases the risk of intervertebral disc disorders, suggesting a common pathogenesis or true pleiotropy. […] Bell’s palsy may be caused by viral infection or autoimmune disease, and combination therapy with acyclovir, valacyclovir, and short-course oral corticosteroids may be effective in treating symptoms. […] Bell’s palsy is an acute benign cranial polyneuritis caused by reactivation of the herpes-simplex virus, and early prednisone treatment can restore facial function and avoid facial nerve decompression. […] Viral DNA from herpes simplex virus type 1, varicella-zoster virus, and Epstein-Barr virus was found in facial nerve endoneurial fluid and posterior auricular muscle tissue, suggesting a potential link between viral infection and facial paralysis.

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