Neurology Book


Bell's Palsy

Aka: Bell's Palsy, Bells Palsy, Bell Palsy, Facial Nerve Paralysis, Facial Nerve Palsy, CN 7 Palsy
  1. See Also
    1. Facial Nerve Injury from Birth Trauma
    2. Facial Nerve Paralysis Causes
  2. Definitions
    1. Bell's Palsy (Facial Nerve Palsy)
      1. Idiopathic, acute Facial Nerve Paralysis
  3. Background: History
    1. Named for Sir Charles Bell (1774-1842) who first described the syndrome
  4. Epidemiology
    1. Incidence: 15-30 per 100,000 per year (45,000 per year in U.S.)
    2. No gender predominance
    3. Incidence peaks at age 40-49 years
  5. Pathophysiology
    1. Facial Nerve inflammation typically at Geniculate Ganglion (risk of ischemia, demyelination)
    2. Associated with Herpesvirus infection in 30% of cases
  6. Risk Factors
    1. Diabetes Mellitus (comorbid in 10% of cases)
    2. Pregnancy (associated with 3 fold increased risk)
    3. Herpesvirus infection (comorbid in 30% of cases)
      1. Herpes Simplex Virus
      2. Varicella Zoster Virus
      3. Epstein-Barr Virus
  7. History: Red Flags suggestive of other Facial Nerve Paralysis Cause
    1. Gradual onset over >2 weeks
      1. Suggests mass lesion
    2. Forehead not involved
      1. Suggests Central Nervous System cause (supranuclear lesion)
      2. Facial Nerve motor nucleus is divided
        1. Dorsal aspect (forehead innervation) and ventral aspect (lower facial innervation)
        2. Both sides of the brain provide input to the dorsal aspect (forehead)
          1. Hence lack of forehead involvement implies an Upper Motor Neuron Lesion
        3. Only one side of the brain provides input to the ventral aspect (lower face)
    3. Bilateral involvement
      1. Suggests autoimmune Polyneuropathy
      2. Lyme Disease
    4. Recent new medications (e.g. Influenza Vaccine)
    5. Lyme Disease Risk Factors (Tick Bite, endemic Lyme Disease region during peak season)
      1. Lyme Disease
    6. Fever
      1. Consider infectious cause such as Otitis Media
    7. Rash
      1. Vesicular rash (Herpes Zoster, Ramsay Hunt Syndrome)
      2. Erythema Migrans (Lyme Disease)
    8. Hearing Loss and Vestibular Symptoms or Ataxia
      1. Acoustic Neuroma
    9. Children (esp. children age <5 years)
      1. Otitis Media
      2. Trauma
      3. Herpes Simplex Virus
      4. Varicella Zoster Virus
      5. Lyme Disease
      6. Malignancy (esp. Leukemia, Lymphoma, Brain Tumor)
        1. Associated with a 0.7% risk in children age <5 years (contrast with 0.3% overall)
        2. Evaluate for Hepatosplenomegaly and Lymphadenopathy, and ensure close follow-up
      7. References
        1. Claudius and Walsh (2022) EM:Rap 22(9): 8-9
        2. Walsh (2022) Am J Emerg Med 53:63-7 +PMID:34992025 [PubMed]
  8. Exam
    1. Head and neck
      1. External Ear and ear canal (e.g. Otitis Externa, Herpes Zoster, Ramsay Hunt Syndrome)
      2. Tympanic Membrane (e.g. Otitis Media)
      3. Mouth and pharynx (e.g. Herpes Simplex Virus)
      4. Parotid Gland
    2. Neurologic Exam
      1. Perform complete Neurologic Exam including gait
      2. Cranial Nerve Exam
        1. Test Cranial Nerve 7 bilaterally on lower face and forehead
      3. Extremity Motor Exam and Sensory Exam
    3. Skin
      1. Vesicular rash (Herpes Zoster, Ramsay Hunt Syndrome)
      2. Erythema Migrans (Lyme Disease)
  9. Symptoms
    1. Idiopathic Facial Nerve Paralysis
      1. Hypoesthesia or dysesthesia (80%)
        1. Glossopharyngeal Nerve dysfunction
        2. Trigeminal Nerve dysfunction
      2. Facial or retroauricular pain (60%)
      3. Dysgeusia (57%)
      4. Hyperacusis (30%)
      5. Vagal nerve motor weakness (20%)
      6. Decreased Lacrimation (17%)
      7. Trigeminal Nerve motor weakness (3%)
      8. Synkinesis (e.g. mouth twitching while blinking, or winking while smiling)
    2. References
      1. Adour (1982) N Engl J Med 307: 348-51 [PubMed]
  10. Signs: General
    1. Preserved facial Sensation
      1. However hypoesthesia or dysesthesia is common (see above)
    2. Mouth and nasolabial changes
      1. Loss of facial creases and nasolabial fold
      2. Corner of mouth droops
    3. Eye changes
      1. No closure or decreased closure of upper Eyelid
      2. Lower Eyelid sag
      3. Decreased tear production
    4. No furrow over forehead (forehead appears flattened)
      1. Critical to recognize when the forehead and Eyelid are not involved
      2. Lack of forehead and Eyelid involvement suggests an Upper Motor Neuron Lesion such as a CVA
  11. Signs: Facial Nerve Grading (House-Brackman)
    1. Grade 1: Normal Facial Nerve Function
    2. Grade 2: Mild Facial Nerve Dysfunction
      1. Gross
        1. Slight weakness on close examination
        2. Synkinesis slight
      2. Rest: Normal symmetry and tone
      3. Motor Exam
        1. Forehead: Moderate to good function
        2. Eyes: Complete closure with minimum effort
        3. Mouth: Slight asymmetry
    3. Grade 3: Moderate Facial Nerve Dysfunction
      1. Gross:
        1. Obvious difference between sides (not disfiguring)
        2. Synkinesis noticeable
      2. Rest: Normal symmetry and tone
      3. Motor Exam
        1. Forehead: slight to Moderate movement
        2. Eyes: Complete closure with effort
        3. Mouth: Slightly weak with maximal effort
    4. Grade 4: Moderately Severe Facial Nerve Dysfunction
      1. Gross
        1. Obvious weakness
        2. Disfiguring asymmetry
      2. Rest: Normal symmetry and tone
      3. Motor Exam
        1. Forehead: No motor function
        2. Eyes: Incomplete closure
        3. Mouth: Asymmetric with maximal effort
    5. Grade 5: Severe Facial Nerve Dysfunction
      1. Gross: Barely perceptible motion
      2. Rest: Asymmetry
      3. Motor Exam
        1. Forehead: No motor function
        2. Eyes: Incomplete closure
        3. Mouth: Slight movement
    6. Grade 6: Total Facial Nerve Paralysis
    7. References
      1. House (1985) Otolaryngol Head Neck Surg 93:146-7 [PubMed]
  12. Differential Diagnosis
    1. See Facial Nerve Paralysis Causes
  13. Labs
    1. Labs are not indicated in isolated peripheral Facial Nerve Paralysis
    2. Serum Glucose is not routinely recommended
      1. Diabetes Mellitus does not cause Bell's Palsy, and is simply a predisposing factor
    3. Lyme Antibody titer is not routinely recommended
      1. Lyme peripheral facial palsy is almost always associated with other findings (e.g. Arthritis, facial swelling, rash)
      2. Isolated Facial Nerve Palsy is not typically due to Lyme Disease
      3. However, consider empiric therapy for Lyme Disease and lyme test with risk factors
        1. Bilateral Facial Nerve involvement (high risk, treat as Lyme Disease while testing)
        2. Known recent deer Tick Bite
        3. Erythema Migrans (diagnostic without Lyme Titer)
        4. Peak season in endemic Lyme Disease region
      4. References
        1. Kuiper (1992) Arch Neurol 49(9): 940-3 [PubMed]
  14. Imaging: MRI Head
    1. Benefits
      1. MRI Identifies central causes (Schwannoma, Hemangioma, meningioma and Cholesteatoma)
      2. MRI offers prognostic information based on nerve contrast enhancement
    2. Indications
      1. Suspected central cause (see Red Flags above)
      2. Persistent or progressive peripheral Facial Nerve Palsy lasting >2 months
      3. Facial twitching or spasm
  15. Management: Loss of Blink Reflex
    1. Rewetting the eye
      1. Frequent use of preservative-free artificial tears (every 15 to 30 minutes)
      2. Refresh PM ointment six times daily
    2. Protective glasses with side pieces
      1. Use in outdoors, drafty, dusty areas
      2. Alternatively can use eye shield or cup
    3. Avoid grinding, sanding, or sawing
    4. At night:
      1. Apply bland ointment (Refresh PM, Lacri-Lube)
      2. Tape eye shut
    5. Ophthalmology Consultation indicated for incomplete Eyelid closure persisting for weeks
      1. Risk of permanent ocular injury from drying
  16. Management: Corticosteroids and Antimicrobials
    1. Approach
      1. Start Corticosteroid within 72 hours of onset
      2. Antiviral may be considered in moderate to severe cases (House-Brackman Grade 4 and above)
      3. Consider Lyme Disease management if suggested by history or exam
        1. Doxycycline (preferred) 100 mg bid or Amoxicillin 500 mg tid for 14-21 days
    2. High dose Corticosteroids: Prednisone or Prednisolone (primary intervention)
      1. Adult: 60-80 mg orally daily for 7 days
      2. Child: 2 mg/kg/day (up to adult dosing) for 7 days
      3. Salinas (2010) Cochrane Database Syst Rev (3):CD001942 +PMID:20238317 [PubMed]
    3. Antiviral agents (optional)
      1. Mechanism
        1. Based on reactivated HSV hypothesis
      2. Indications
        1. Findings consistent with Herpes Zoster, herpes simplex or Ramsay Hunt Syndrome (e.g. vesicular rash)
        2. Antiviral may be considered in moderate to severe cases (House-Brackman Grade 4 and above)
      3. Efficacy of empiric antiviral use (excluding cases of herpetic, vesicular rashes which should be treated)
        1. Original studies showed synergistic benefit with antivirals in combination with Corticosteroids
          1. More recent studies show primary improvement with Corticosteroids
          2. Only marginal added benefit with antivirals
        2. Reasonable to offer antivirals in moderate to severe cases
          1. However patients should be counseled on low efficacy of antivirals
      4. Agents
        1. Acyclovir
          1. Adult: 400 mg five times per day for 7 days
          2. Child (>2 years): 80 mg/kg daily (max: 3200 mg/day) divided every 6 hours for 5 days
        2. Valacyclovir
          1. Age >12 years: 1 gram orally three times daily for 7 days
      5. References
        1. Gronseth (2012) Neurology 79(22): 2209-13 [PubMed]
        2. Adour (1996) Ann Otol Rhinol Laryngol 105:371-8 [PubMed]
        3. Hato (2007) Otol Neurotol 28: 408-13 [PubMed]
        4. Hato (2003) Otol Neurotol 24: 948-51 [PubMed]
    4. Other antimcrobial considerations
      1. Consider empiric Doxycycline in Lyme Disease endemic regions (esp. bilateral, peak tick season, known Tick Bite)
  17. Management: Associated Conditions
    1. Otitis Media or Mastoiditis Complications
      1. IV antibiotics
      2. Otolaryngology Consultation for possible wide incision of Tympanic Membrane
    2. Herpes Zoster Oticus (Ramsay Hunt Syndrome)
      1. See Herpes Zoster for antiviral agents
      2. May be associated with Tinnitus and Hearing Loss
      3. High dose Corticosteroids (1 mg/kg/day)
        1. Avoid in Diabetes Mellitus, peptic ulcer, Glaucoma
  18. Management: Referral Indications
    1. Otitis Media complications
    2. Mastoiditis complications
    3. Signs of secondary cause
      1. Intracranial lesion or nerve impingement
    4. Incomplete Eyelid closure persisting for weeks
      1. Risk of permanent ocular injury from drying
      2. Referral to ophthalmology for management beyond artificial tears
    5. Other procedure referrals not routinely recommended
      1. Facial Nerve decompression surgery (may rarely be indicated)
      2. Physical Therapy (no evidence of benefit in Bell's Palsy)
  19. Prognosis: Factors associated with poor prognosis
    1. Worse Prognosis with time needed for recovery
      1. No recovery by 3 weeks suggests worse prognosis (15% of cases)
      2. Further recovery occurs over 3-5 months
    2. Hyperacusis
    3. Diabetes Mellitus
    4. Hypertension
    5. Pregnancy
    6. Facial Nerve with severe degeneration by EMG
    7. Decreased tearing
    8. Age over 60 years
    9. Ramsay Hunt Syndrome (Herpes ZosterVirus)
    10. Severe pain
      1. Aural pain
      2. Anterior facial pain
      3. Radicular pain
  20. Complications
    1. Corneal Ulceration
    2. Permanent Eyelid weakness
    3. Permanent facial asymmetry
  21. Prognosis
    1. Early recovery (85%) within 3 weeks
    2. Prolonged recovery (15%) over 3-5 months
      1. Slight residual deficit: 12%
      2. Mild residual deficit: 13%
      3. Severe residual deficit: 4%
        1. Facial weakness
        2. Contracture or spasm
    3. Recurrence: 8% of cases
      1. Higher risk of recurrence in Diabetes Mellitus
  22. Course
    1. Maximal weakness at 3-7 days after onset
    2. Most cases (85%) improve within 3 weeks even without treatment
      1. Additional improvement may require up to 5 months
      2. Prolonged recovery duration required for nerve regeneration
  23. References
    1. Herbert et al in Herbert (2015) EM:Rap 15(11): 3-4
    2. Zalvan (1999) Consultant 39(1):39-48
    3. Zvonar and Welsh (2021) Crit Dec Emerg Med 35(2): 25
    4. Albers (2014) Am Fam Physician 89(3): 209-12 [PubMed]
    5. Gilden (2004) N Engl J Med 351:1323-31 [PubMed]
    6. Holland (2004) BMJ 329:553-7 [PubMed]
    7. Tiemstra (2007) Am Fam Physician 76:997-1002 [PubMed]

Facial paralysis (C0015469)

Definition (NCI) Partial or complete paralysis of the facial muscles of one side of a person's face. It is caused by damage to the seventh cranial nerve. It is usually temporary but it may recur.
Definition (MSH) Severe or complete loss of facial muscle motor function. This condition may result from central or peripheral lesions. Damage to CNS motor pathways from the cerebral cortex to the facial nuclei in the pons leads to facial weakness that generally spares the forehead muscles. FACIAL NERVE DISEASES generally results in generalized hemifacial weakness. NEUROMUSCULAR JUNCTION DISEASES and MUSCULAR DISEASES may also cause facial paralysis or paresis.
Definition (CSP) severe or complete loss of facial muscle motor function; this condition may result from central or peripheral lesions; damage to CNS motor pathways from the cerebral cortex to the facial nuclei in the pons leads to facial weakness that generally spares the forehead muscles; facial nerve diseases generally results in generalized hemifacial weakness; neuromuscular junction diseases and muscular diseases may also cause facial paralysis.
Concepts Disease or Syndrome (T047)
MSH D005158
ICD10 G51.0
SnomedCT 280816001, 267703001, 90039006, 155070005, 46382007, 330021000009104, 79359001
LNC LP145905-8, MTHU043316
English Facial Paralysis, Paralyses, Facial, PARALYSIS FACIAL, Paralysis, Facial, Facial paralysis, Facial Palsies, Facial Palsy, Palsies, Facial, Palsy, Facial, Bell's Palsy, Facial Paralysis [Disease/Finding], Paralysis facial, cranial nerve vii diseases, facial nerve diseases, facial nerve palsies, nerve disorders facial, palsy facial, paralysis facial nerve, seventh nerve palsy, facial nerve paralysis, facial nerve disorder, seventh nerve paralysis, Palsy;facial, facial nerve disorders, facial nerve disease, facial neuropathy, facial palsy, palsy facial nerve, facial paralysis, facial nerve palsy, facial paralyses, Facial nerve paralysis, Facial nerve palsy, Facial nerve palsy (cranial nerve VII), Seventh nerve palsy, VII nerve palsy, Seventh nerve paralysis, Facial nerve paralysis (disorder), Facial nerve palsies, PARALYSIS OF FACIAL NERVE, FACIAL NERVE PARALYSIS, NERVE PARALYSIS, FACIAL, Facial palsy, Facial palsy (disorder), facial; paralysis, paralysis; facial nerve, paralysis; facial, Facial nerve paralysis, NOS, Facial Nerve Paralysis, VII th nerve palsy, Palsy;VII nerve
French PARALYSIE FACIALE, Paralysie faciale
Portuguese PARALISIA FACIAL, Paralisia facial, Paralisia Facial, Paresia Facial
Spanish PARALISIS FACIAL, Parálisis facial, parálisis del nervio facial, parálisis del séptimo par craneal, parálisis facial (trastorno), parálisis facial, Parálisis Facial
Swedish Ansiktsförlamning
Czech faciální paralýza, Obrna lícního nervu
Finnish Kasvohermohalvaus
German FACIALISLAEHMUNG, Fazialislaehmung, Gesichtslaehmung, Laehmung des Gesichts, Faziale Lähmung, Gesichtslähmung
Japanese 顔面筋麻痺, 顔面神経麻痺, ガンメンマヒ, ガンメンシンケイマヒ, 顔面神経麻痺-末梢性, 顔面麻痺, 顔面運動麻痺, 末梢性顔面神経麻痺
Dutch facialis verlamming, gelaatsparalyse, paralyse faciaal, facialis; paralyse, paralyse; facialis, paralyse; nervus facialis, Facialisparalyse, Facialisparese, Paralyse, facialis-
Polish Porażenie nerwu twarzowego
Hungarian Facialis bénulás, Facialis paralysis
Norwegian Ansiktslammelse, Facialisparalyse, Facialisparese
Italian Paralisi facciale
Derived from the NIH UMLS (Unified Medical Language System)

Bell Palsy (C0376175)

Definition (CHV) temporary facial paralysis resulting from damage
Definition (CHV) temporary facial paralysis resulting from damage
Definition (CHV) temporary facial paralysis resulting from damage
Definition (CHV) temporary facial paralysis resulting from damage
Definition (CHV) temporary facial paralysis resulting from damage
Definition (CHV) temporary facial paralysis resulting from damage
Definition (CHV) temporary facial paralysis resulting from damage
Definition (MEDLINEPLUS)

Bell's palsy is the most common cause of facial paralysis. It usually affects just one side of the face. Symptoms appear suddenly and are at their worst about 48 hours after they start. They can range from mild to severe and include

  • Twitching
  • Weakness
  • Paralysis
  • Drooping eyelid or corner of mouth
  • Drooling
  • Dry eye or mouth
  • Excessive tearing in the eye
  • Impaired ability to taste

Scientists think that a viral infection makes the facial nerve swell or become inflamed. You are most likely to get Bell's palsy if you are pregnant, diabetic or sick with a cold or flu.

Three out of four patients improve without treatment. With or without treatment, most people begin to get better within 2 weeks and recover completely within 3 to 6 months.

NIH: National Institute of Neurological Disorders and Stroke

Definition (MSHCZE) Bellova paréza – izolovaná jednostranná obrna lícního nervu (n. facialis). Vzniká náhle, někdy jí předchází prochlazení či virové onemocnění. (cit. Velký lékařský slovník online, 2013 )
Definition (MSH) A syndrome characterized by the acute onset of unilateral FACIAL PARALYSIS which progresses over a 2-5 day period. Weakness of the orbicularis oculi muscle and resulting incomplete eye closure may be associated with corneal injury. Pain behind the ear often precedes the onset of paralysis. This condition may be associated with HERPESVIRUS 1, HUMAN infection of the facial nerve. (Adams et al., Principles of Neurology, 6th ed, p1376)
Concepts Disease or Syndrome (T047)
MSH D020330
ICD9 351.0
ICD10 G51.0
SnomedCT 193093009, 267703001, 155070005, 79359001
English Bell Palsy, Bell's Palsies, Bell's Palsy, Bells Palsy, Palsies, Bell's, Palsy, Bell's, Idiopath acute facial nrve pal, ACUTE INFLAMM FACIAL NEUROPATHY, FACIAL NEUROPATHY INFLAMM ACUTE, INFLAMM FACIAL NEUROPATHY ACUTE, Bell's palsy (diagnosis), Acute Idiopathic Facial Neuropathy, Facial Neuropathy, Idiopathic Acute, Idiopathic Acute Facial Neuropathy, Acute Inflammatory Facial Neuropathy, Facial Neuropathy, Inflammatory, Acute, Inflammatory Facial Neuropathy, Acute, Bell Palsies, Palsies, Bell, Palsy, Bell, Facial Paralyses, Idiopathic, Facial Paralysis, Idiopathic, Idiopathic Facial Paralyses, Idiopathic Facial Paralysis, Paralyses, Idiopathic Facial, Paralysis, Idiopathic Facial, Bell palsy, Bell Palsy [Disease/Finding], Palsy Bells, facial paralysis bell's palsy, Palsy;Bells, bell's palsy facial paralysis, bells's palsy, bell's palsy, bell palsy, palsy bells, Bells palsy, Palsy - Bell's, Bell's (facial) palsy, Bell's palsy, Idiopathic acute facial nerve palsy, Bell's palsy (disorder), Facial paralysis/bell's palsy, Bell's palsy; paralysis, Bell; palsy, Bell; paralysis, palsy; Bell, paralysis; Bell's palsy, paralysis; Bell, Bell's palsy (disorder) [Ambiguous], bells palsy
Swedish Bells pares
Czech nervus facialis - paralýza idiopatická, Bellova paralýza, nervus facialis - neuropatie zánětlivá akutní, Bellova obrna, Bellova paréza, lícní obrna
Finnish Bellin pareesi
Japanese ヘルペス性顔面神経麻痺, 顔面神経障害-炎症性-急性, 顔面神経麻痺-特発性, 顔面神経麻痺-特発, 顔面ニューロパシー-炎症性-急性, 急性炎症性顔面神経障害, 炎症性顔面ニューロパシー-急性, 顔面神経麻痺-ヘルペス性, 顔面神経麻痺眼球症状, 急性炎症性顔面ニューロパシー, 特発顔面神経麻痺, Bell麻痺, 特発性顔面神経麻痺, ベル麻痺, 炎症性顔面神経障害-急性, ベルマヒ
Italian Neuropatia facciale infiammatoria acuta, Neuropatia facciale acuta idiopatica, Paralisi facciale idiopatica, Paralisi di Bell
Korean 벨마비
Dutch facialis paralyse, verlamming van Bell, Facialisparalyse/Bell's palsy, Bell's palsy; verlamming, Bell; palsy, Bell; paralyse, palsy; Bell, paralyse; Bell, verlamming; Bell's palsy, Bell's palsy, Bell-verlamming, Cerlamming, Bell-, Faciale neuropathie, inflammatoire, acute, Faciale paralyse, idiopathische
German Parese, Bell, Bell-Parese, Fazialisparese, Fazialisparalyse, idiopathische, Bell-Lähmung, Fazialisneuropathie, entzündliche, akute
Polish Porażenie Bella, Porażenie obwodowe nerwu twarzowego, Porażenie twarzy idiopatyczne, Porażenie twarzy herpeswirusowe, Porażenie jednostronne mięśni twarzy
Hungarian Bell-paresis, Bell-féle paresis
Norwegian Akutt idiopatisk facialisparese, Ansiktslammelse, akutt idiopatisk, Akutt idiopatisk ansiktslammelse, Bells parese, Facialisparese, akutt idiopatisk
Spanish parálisis idiopática aguda del nervio facial (trastorno), parálisis idiopática aguda del nervio facial, parálisis a frigore, parálisis de Bell, parálisis de Bell (trastorno), parálisis facial, parálisis de Bell (concepto no activo), Neuropatía Facial Inflamatoria Aguda, Parálisis de Bell, Parálisis Facial Idiopática
Croatian Idiopatska akutna facijalna neuropatija, Bellova pareza, Bellova paraliza
French Paralysie faciale a frigore, Paralysie faciale idiopathique, Maladie de Bell, Paralysie de Bell, Paralysie faciale de Bell
Portuguese Neuropatia Facial Aguda Inflamatória, Paralisia de Bell, Paralisia Facial Idiopática
Derived from the NIH UMLS (Unified Medical Language System)

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