Your answer Was Correct
NEUROSAE 2018 ANNUAL MEETING EDITION (VOLUME 10, ISSUE 3)
QUESTION 57 OF 100
A 48-year-old man with history of diabetes mellitus, hypertension and sleep apnea, presents with a history of progressive gait imbalance and multiple falls. Four months ago, he underwent a gastric bypass and has lost a 100 lbs. in the past 8 months. Since the surgery, his insulin requirements have decreased and he no longer requires blood pressure medication. Examination reveals loss of proprioception and vibration in the distal lower extremities with mild weakness. Reflexes are absent at the ankles but notably increased at the knees. He has no dysmetria or tremor but has a positive Rhomberg sign. EMG/nerve conduction studies show a demyelinating sensory dominant neuropathy. An MRI scan of the spine and brain is shown. Which of the following mechanisms is most likely implicated as the source of the patient’s symptoms?
A. Rapid improvement of serum glucose with associated polyneuritis and myelitis
B. Impaired absorption of vitamin B12 due to gastric bypass surgery and lack of vitamin supplementation **
C. Compressive myelopathy related to persistent epidural lipomatosis
D. Ischemic myelopathy due to surgery-associated dural spinal arteriovenous fistula
E. Acquired cerebellar ataxia due to malabsorption of vitamin E
** = Your answer
The rising rates of bariatric surgery are accompanied by neurologic complications related primarily to nutrient deficiencies, commonly vitamin B12, thiamine, and copper. Early neurologic complications following bariatric surgery may be related to thiamine deficiency, whereas delayed complications are often due to copper or vitamin B12 deficiency. Mechanical or inflammatory mechanisms also are responsible for early neurologic manifestations following bariatric surgery. The early postoperative period is associated with compressive or stretch peripheral nerve injury, rhabdomyolysis, Wernicke encephalopathy, and inflammatory polyradiculoneuropathies. Late complications include peripheral neuropathy, myelopathy, and less commonly optic neuropathy or myopathy. The MRI scan of the cervical cord shows T2 signal changes in the posterior column, which support a diagnosis of a subacute combined degeneration associated with vitamin B12 deficiency related to the patient’s gastric bypass surgery.
* Kumar N. Nutrients and neurology. Continuum Lifelong Learning Neurol. 2017;23(3):822-861.
* Kumar N. Overview of the interface of neurology and medicine. Neurologic Complications of Medical Disease C13 AAN Annual Meeting 2017.