Rosen & Barkin's 5-Minute Emergency Medicine Consult (97 page)

969.6 Poisoning by psychodysleptics (hallucinogens)

BASICS

• Acute,
  idiopathic
  peripheral CN VII (facial nerve) palsy
  
• Complete recovery in 85% of cases without treatment
  
• Degree of deficit correlates with prognosis:
  
  • Complete lesions have poorest prognosis
    
  • Partial lesions often have excellent results
    
• Recovery usually begins within 2 wk (often taste returns 1st) and is complete by 2–3 mo:
  
  • Advanced age and slow recovery are poor prognosticators
    
• Affects men and women equally
  
• Age predominance between the 3rd and 5th decade (may occur at any age)
  
• Diabetes and pregnancy increase risk
  
• Incidence 15–40 per 100,000 per year
  
• The most common cause of facial nerve palsy in children
  

• Idiopathic by definition, but viral cause (particularly herpes simplex) suspected
  
• Lyme disease, infectious mononucleosis (Epstein–Barr virus [EBV] infection), varicella-zoster infections, and others may cause peripheral 7th nerve palsy
  
• Mechanism: Edema and nerve degeneration within stylomastoid foramen
  
• Innervation to each side of forehead is from both motor cortices:
  
  • Unilateral cortical processes do
    not
    completely disrupt motor activity of forehead
    
• Only peripheral or brainstem lesion can interrupt motor function of just 1 side of forehead
  

DIAGNOSIS

Sudden onset of unilateral facial droop, incomplete eyelid closure, and loss of forehead muscle tone:

• Maximal deficit by 5 days in almost all cases (2 days in 50%)
  
• Tearing (68%) or dryness of eye (16%) and less frequent blinking on affected side
  
• Subjective “numbness” of the affected side
  
• Abnormal taste, drooling
  
• Hyperacusis (sensitivity to loud sounds)
  
• Fullness or pain behind mastoid
  
• Viral prodrome frequently reported
  

• Unilateral facial palsy including the forehead
  
• If forehead muscle tone is
  not
  lost, a central lesion is strongly implied (i.e., this is
  not
  Bell's palsy)
  
• Motor weakness isolated to 7th nerve distribution:
  
  • Involves both upper and lower face
    
• An otherwise normal neurologic exam including all cranial nerves and extremity motor function
  
• The Bell phenomenon (upward rolling of the eye on attempted lid closure) may be seen
  

Diagnosis is clinical and based on history and physical exam

• Not helpful in diagnosis of Bell's palsy
  
• Lyme titers are useful when Lyme disease is suspected or in endemic area
  
• Tests for mononucleosis (CBC, monospot) if EBV infection suspected
  

• Not helpful in diagnosis of Bell's palsy unless a parotid tumor, mastoiditis, etc. are suspected
  

• Brainstem events (mass, bleed, infarct) affecting CN VII almost always involve CN VI (abnormal EOM) and may affect long motor tracts:
  
  • There have been (
    rare
    ) case reports of
    isolated
    CN VII palsy from brainstem disease.
    
• Lyme disease: History of tick bite, erythema migrans rash, or endemic area
  
• Zoster (Ramsay Hunt syndrome): Look for herpetic vesicles, inquire about tinnitus or vertigo
  
• Infectious mononucleosis: Look for pharyngitis, posterior cervical adenopathy
  
• Tumors: Parotid, bone, or metastatic masses, acoustic neuroma (deafness)
  
• Trauma: Skull fracture or penetrating facial injury may damage CN VII
  
• Middle ear or mastoid surgery or infection, cholesteatoma
  
• Meningeal infection
  
• Guillain–Barré syndrome: Other neurologic deficits are present (e.g., ascending motor weakness or diminished deep tendon reflexes [DTRs])
  
• Basilar artery aneurysm; other CN deficits should be present
  
• Bilateral peripheral CN VII palsy: Consider multiple sclerosis, sarcoidosis, leukemia, and Guillain–Barré. Idiopathic (Bell's) palsy may be bilateral in rare cases
  
• Early HIV infection
  
• Bell's palsy may reoccur; treatment is unchanged
  

TREATMENT

None

Patients with an isolated peripheral CN VII palsy are stable.

• Corneal damage may result from incomplete eyelid closure:
  
  • Lubricating and hydrating ophthalmic preparations are often needed
    
  • Eye patching at night
    
• Oral steroids may hasten recovery if started within 1 wk of onset (preferably w/in 72 hr):
  
  • Complications of therapy are rare
    
• Antiviral therapy (acyclovir or valacyclovir) with steroids may be effective in improving functional nerve recovery:
  
  • Initiate within 72 hr of symptom onset
    
  • No clear proven benefit
    
  • May be indicated for severe palsy
    
• Suspected Lyme disease should be treated with doxycycline or amoxicillin
  
• Surgical decompression may be indicated for complete lesions that do not improve; this is controversial
  

• Lacri-Lube or artificial tears: At bedtime and PRN; dryness/irritation in affected eye (or equivalent)
  
• Prednisone: 30–40 mg PO BID for 7 days, (peds: 2 mg/kg/d PO [max. 60 mg])
  

Valacyclovir 1 g PO TID for 7 days (peds: 20 mg/kg TID) may be useful in severe cases.

FOLLOW-UP

Isolated peripheral CN VII palsy does not require admission.

Isolated peripheral CN VII palsy may be treated on outpatient basis.

Follow-up should be within 1 wk.

• Motor weakness isolated to 7th nerve distribution:
  
  • Involves both upper and lower face
    
  • If tone is NOT lost on the forehead, it is
    not
    Bell's palsy.
    
• Otherwise normal neurologic exam including all cranial nerves and extremity motor function
  
• Protect the eye
  
• Steroids beneficial, antivirals controversial
  

• de Almeida JR, Al Khabori M, Guyatt GH, et al. Combined corticosteroid and antiviral treatment for Bell's palsy: A systematic review and meta-analysis.
  JAMA
  . 2009;302:985–993.
  
• Engström M, Berg T, Stjernquist-Desatnik A, et al. Prednisolone and valaciclovir in Bell’s palsy: A randomised, double-blind, placebo-controlled, multicentre trial.
  Lancet Neurol
  . 2008;7:993–1000.
  
• Gilden DH. Bell’s palsy.
  N Engl J Med
  . 2004;351:1323–1331.
  
• Gilden DH, Tyler KL. Bell’s palsy—Is glucocorticoid treatment enough?
  N Engl J Med
  . 2007;357:1653–1655.
  
• Hato N, Yamada H, Kohno H, et al. Valacyclovir and prednisolone treatment for Bell’s palsy: A multicenter, randomized, placebo-controlled study.
  Otol Neurotol
  . 2007;28:408–413.
  
• Sullivan FM, Swan IR, Donnan PT, et al. Early treatment with prednisolone or acyclovir in Bell’s palsy.
  N Engl J Med
  . 2007;357:1598–1607.
  
• Wang CH, Chang YC, Shih HM, et al. Facial palsy in children: Emergency department management and outcome.
  Pediatr Emerg Care
  . 2010;26:121–125.
  

CODES

351.0 Bell’s palsy

BASICS