Bell Palsy

Bell Palsy is a topic covered in the 5-Minute Clinical Consult.

To view the entire topic, please or .

Medicine Central™ is a quick-consult mobile and web resource that includes diagnosis, treatment, medications, and follow-up information on over 700 diseases and disorders, providing fast answers—anytime, anywhere. Explore these free sample topics:

-- The first section of this topic is shown below --

Basics

Description

An acute, usually unilateral peripheral facial nerve palsy. The etiology is largely idiopathic; however, many cases have been attributable to herpes simplex virus (HSV) type 1. An ischemic process involving the facial nerve has also been posited as a likely cause for Bell palsy.

Epidemiology

  • Affects 0.002% of the population annually
  • No geographic or gender predominance
  • Affects all ages with a median age of onset of 40 years but with highest incidence in persons over 70 years
  • Occurs with equal frequency on the left and right sides of the face

Incidence
Most population studies have shown an annual incidence of 15–30 per 100,000.

Etiology and Pathophysiology

  • Inflammation of cranial nerve VII causes edema of perineurium and subsequent compression and possibly degeneration of both the nerve and the associated vasa nervorum.
  • Infectious, immune, and ischemic mechanisms suggested, with activation of latent herpes virus (HSV type 1 and herpes zoster virus) in cranial nerve ganglia as the most likely infectious etiology.

Risk Factors

  • Pregnancy, with increased risk seen in patients with chronic hypertension, maternal obesity, and severe preeclampsia
  • Immunocompromised status
  • Diabetes mellitus
  • Age >30 years
  • Upper respiratory infection
  • Chronic hypertension
  • Obesity

-- To view the remaining sections of this topic, please or --

Basics

Description

An acute, usually unilateral peripheral facial nerve palsy. The etiology is largely idiopathic; however, many cases have been attributable to herpes simplex virus (HSV) type 1. An ischemic process involving the facial nerve has also been posited as a likely cause for Bell palsy.

Epidemiology

  • Affects 0.002% of the population annually
  • No geographic or gender predominance
  • Affects all ages with a median age of onset of 40 years but with highest incidence in persons over 70 years
  • Occurs with equal frequency on the left and right sides of the face

Incidence
Most population studies have shown an annual incidence of 15–30 per 100,000.

Etiology and Pathophysiology

  • Inflammation of cranial nerve VII causes edema of perineurium and subsequent compression and possibly degeneration of both the nerve and the associated vasa nervorum.
  • Infectious, immune, and ischemic mechanisms suggested, with activation of latent herpes virus (HSV type 1 and herpes zoster virus) in cranial nerve ganglia as the most likely infectious etiology.

Risk Factors

  • Pregnancy, with increased risk seen in patients with chronic hypertension, maternal obesity, and severe preeclampsia
  • Immunocompromised status
  • Diabetes mellitus
  • Age >30 years
  • Upper respiratory infection
  • Chronic hypertension
  • Obesity

There's more to see -- the rest of this topic is available only to subscribers.