Bell's palsy--revisited.

Bell’s palsy shows no gender predilection. Female teenagers suffer in large number. It is familial in 10% of the patients. Diabetics and pregnant are predisposed. Infections, immunologic and genetic factors have been suggested to play roles in the aetio-pathogenesis of the disease. Herpes Simplex virus has been demonstrated in the geniculate ganglion by using molecular techniques supported by raised antiviral antibody titres. Entrapment of the nerve at the meatal foramen is the principle pathology. MRI enhancement favours invoviement of the albyrinthine, geniculate and the proximal tympanic segments of the facial nerve. Poor vasculature of the labyrinthine segment makes it a vulnerable site. Evaluation ‘of Bells’ palsy needs a careful history, head and neck examination. Topographic diagnosis is not very useful. Electrophysiological studies are useful when the paralysis is complete. Electroneuronography (Enog) informs about the degree of degeneration in facial nerve fibers. Transcranial magnetic stimulation (TMS) is a new, cheap and non-invasive tool to assess facial nerve’s intracranial segment close to the internal meatus. Presence of acoustic reflex is a favourable prognostic indicator. Interferon induced enzyme 2’ -5’ Oligoadenylate synthetase is a supplementary diagnostic tool. Gadolinium enhanced MM is helpful as a diagnostic and prognostic instrument in selected cases. Bell’s palsy can be a manifestation of neuroborrel iosis, multiple sclerosis, diabetes, HIV infection and Burkitt’s lymphoma. Oral steroids should be started in all the cases of Bell’s palsy immediately irrespective of the clinical status. Parenteral steroids, combination of steroids and Acylovir has produced better results. The role of stellate ganglion block to improve the circulation in Bell’s palsy is hypothetical. Middle cranial fossa approach to decompress the facial nerve has proved to be the choicest of the surgical procedures in selected group of refractory Bell’s palsy. Care of the eye is very important in Bell’s palsy and tarsorraphy may be required in cases of corneal abrasions. Old age, post-auricular pain, dysgeusia, hyperacusis, dry eye and delayed onset of recovery affect a bad prognosis. Enog, TMS and eye blink reflex response are the other useful prognostic indices.