Neurologic complications after surgery for obesity.

Bariatric surgical procedures are increasingly common. In this review, we characterize the neurologic complications of such procedures, including their mechanisms, frequency, and prognosis. Literature review yielded 50 case reports of 96 patients with neurologic symptoms after bariatric procedures. The most common presentations were peripheral neuropathy in 60 (62%) and encephalopathy in 30 (31%). Among the 60 patients with peripheral neuropathy, 40 (67%) had a polyneuropathy and 18 (30%) had mononeuropathies, which included 17 (94%) with meralgia paresthetica and 1 with foot drop. Neurologic emergencies including Wernicke's encephalopathy, rhabdomyolysis, and Guillain-Barré syndrome were also reported. In 18 surgical series reported between 1976 and 2004, 133 of 9996 patients (1.3%) were recognized to have neurologic complications (range: 0.08-16%). The only prospective study reported a neurologic complication rate of 4.6%, and a controlled retrospective study identified 16% of patients with peripheral neuropathy. There is evidence to suggest a role for inflammation or an immunologic mechanism in neuropathy after gastric bypass. Micronutrient deficiencies following gastric bypass were evaluated in 957 patients in 8 reports. A total of 236 (25%) had vitamin B(12) deficiency and 11 (1%) had thiamine deficiency. Routine monitoring of micronutrient levels and prompt recognition of neurological complications can reduce morbidity associated with these procedures.