Clinical reasoning: a 62-year-old man with right wrist drop.

SECTION 1 A 62-year-old man presented to our neurology outpatient clinic with a 3-week history of progressive right wrist drop. He had been complaining of generalized asthenia, numbness, and tingling involving the soles of both feet for the last year. He had a history of chronic renal failure due to type 2 diabetes, for which he was on maintenance hemodialysis. He had hypertension and hyperlipidemia, treated respectively with propranolol and simvastatin. He denied smoking and alcohol abuse. Family history was unremarkable. General examination was normal, heart rate was 80 bpm, and orthostatism was not observed. Neurologic examination revealed mild ataxic gait with negative Romberg sign; right mild ptosis, which did not fluctuate after 60 seconds of upward gaze; equally sized pupils, briskly reacting to light and accommodation; full range and no clinical evidence of extraocular movement fatigability. Medical Research Council strength score was 4/5 in distal muscles of upper and lower limbs, with the exception of 1/5 score in wrist and finger extensors (extensor carpi ulnaris and radialis, extensor digitorum, extensor indicis); there was no evidence of fatigability. Deep tendon reflexes (DTRs) were symmetrically reduced. Sensory examination showed increased thermo-nociceptive and vibration threshold at distal lower limbs bilaterally.