Bell's palsy overview
|
Bell's palsy Microchapters |
|
Diagnosis |
|---|
|
Treatment |
|
Case Studies |
|
Bell's palsy overview On the Web |
|
American Roentgen Ray Society Images of Bell's palsy overview |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Mohamadmostafa Jahansouz M.D.[2]
Historical Perspective
The first comprehensive description of Bell's palsy was first discovered by Abū Bakr Muhammad ibn Zakariyyā al-Rāzī, a Persian polymath, physician, alchemist, philosopher, in 9th century, although Sir Charles Bell, a Scottish surgeon, was the first to provide the anatomic basis for the condition that bears his name in 1821. For the fiest time, Razi provided accurate descriptions of facial muscles disorders. Razi describes a clinical method for distinguishing spasm and paralysis for the first time. In 9th century, the therapy of Bell's palsy was developed by Abū Bakr Muhammad ibn Zakariyyā al-Rāzī. In 1821, Sir Charles Bell described the lesions of the seventh cranial nerve produce facial paralysis. Bell described the Bell's palsy is caused by problem of 7th cranial nerve(facial nerve).
Classification
Bell's palsy may be classified into five categories according to laterality and recurrence and alternating of the palsy include: unilateral nonrecurrent, unilateral recurrent, simultaneous bilateral, alternating bilateral and recurrent bilateral type.
Pathophysiology
The exact pathophysiology of Bell' palsy is not known. Bell's palsy occurs due to failure to function in a normal manner of the facial nerve (VII cranial nerve). The malfunction of the facial nerve caused involuntary spasm in the facial muscles which called facial palsy. Bell's palsy causes the lower motor neuron type paralysis. Although the exact etiology of Bell's palsy is unknown, there is some evidences that implies there may be some relation between vasospasm, from any cause, along any facial nerve branch, with Bell's palsy. There is no established association between genetic factors and Bell's palsy. Hereditary components may play a role in familial recurrent Bell's palsy. On microscopic histopathological analysis, thickened perineurium, infiltrates of inflammatory cells between nerve bundles and around blood vessels are characteristic findings of Bell’s palsy. It appears that the histology of the facial nerve in Bell's palsy is similar to Herpes Zoster infection, suggestive of an infectious cause.