Bell's palsy: etiologic and prognostic factors

A series of over 200 patients with Bell's Palsy (BP) is reviewed, and the epidemiology of this nosological entity discussed. In a search for the causes of BP, the glucose tolerance of a large group of patients was tested. Diabetes was found in a high percentage of cases, although in the majority it was not overt. Signs of atherosclerosis and hypertension were present in a small group of patients, usually diabetics. Based on capillaroscopy and other diagnostic procedures, the assumption was made that in most cases BP is caused by diabetic microangiopathy, and not as a direct result of the metabolic abnormalities of diabetes mellitus. Several patients reported a 'viral' illness preceding the appearance of facial paresis. Clinical and laboratory examinations confirmed the presence of a transient inflammatory process in some patients, but efforts to identify the responsible virus have failed. The relationship of the preceding illness to BP therfore remains uncertain. Eleven patients developed BP while pregnant. This figure is greater than that expected by chance distribution alone. Two other patients with BP were found to have monoclonal gammopathy. The prognosis of BP is more favorable in the young, but is not affected by the presence of diabetes, or a history of a preceding 'viral' illness. Retroauricular pain diminishes the chances for recovery, particulary in older patients, but the presence of abnormalities in taste sensation is not important