Abstract

An 85-year-old man presented with a 1 month history of jerks affecting his trunk and lower limbs. He reported severe subacute low back pain and gradually progressive weakness in both lower limbs over 4 months. His history included type 2 diabetes mellitus, chronic kidney disease, AF, prostate cancer and lumbar canal stenosis.

Examination revealed frequent brief, sudden, jerks affecting his trunk and lower limbs. There was mild weakness in both lower limbs, left worse than right, with absent reflexes and flexor plantars. Pinprick sensation was absent below both ankles.

CSF analysis showed significantly elevated protein at 5.79 g/L, with otherwise normal constituents. MRI spine reported degenerative changes and lumbar canal stenosis. Neurophysiology was consistent with diabetic polyradiculoneuropathy. An EEG was in-keeping with encephalopathy.

A brief period of clinical encephalopathy, which developed after admission, resolved with opiate withdrawal.

He was treated with sodium valproate 600 mg BD, levetiracetam 500 mg BD and a tapering course of prednisolone. Within a few weeks, the myoclonus resolved. There was modest improvement in limb power, although the clinical picture was complicated by multiple comorbidities.

Diabetic polyradiculoneuropathy, also known as diabetic amyotrophy, is rare, particularly with myoclonus, and its recognition relies on clinical suspicion and electrophysiological findings.