Clinical characteristics and associated comorbidities in diabetic patients with cranial nerve palsies

Background: Cranial mononeuropathy is one of the not so common forms of diabetic neuropathy that often appears to be a serious problem from a diagnostic and therapeutic point of view. Aim: Objective of this study was to determine the incidence, the clinical characteristics, and risk factors associated with cranial nerve palsies among persons with diabetes. Methods: We have performed a retrospective study of all diabetic patients with cranial nerve palsies who were hospitalized in a metabolic department over a 12-yr period. Results: During the period of the survey, a total of 8150 diabetic subjects were hospitalized and cranial nerve palsies were identified in 61 patients (0.75%). Isolated III nerve palsies accounted for the majority of patients (0.35%), with VII nerve palsies (0.21%) occurring more frequently than VI (0.15%) and multiple palsies (0.04%). Peripheral neuropathy was present in only 24% of patients. Patients with VII nerve palsies showed a tendency toward a lower coexistence of diabetic complications and cardiovascular risk factors than those with III and VI nerve palsies. Conclusions: Cranial nerve palsies are a not common problem among patients with diabetes; diagnosis of diabetic mononeuropathy should be considered even in the absence of peripheral neuropathy; the oculomotor nerve was most frequently affected in our case report. The coexistence of diabetic complications and cardiovascular risk factors was slightly lower in patients with VII nerve palsy: this fact is compatible with the hypotesis that this event is less closely related to diabetes and metabolic factors in its pathogenesis.