Two cases of unilateral wasting and weakness of distal upper limb: Similar onset and different diagnosis in young patients

A 20-years-old woman (patient 1) and a 16-years-old man (patient 2) developed weakness and wasting of left distal upper limb, subsequently spreading to forearms. Clinical, laboratory, neurophysiological and MRI assessment were performed. Results Both patients exhibited weakness and hypotrophy of forearms and hands muscles on neurological examination, unremarkable laboratory and cerebrospinal fluid work-up, including anti-gangliosides antibodies, and brain MRI. Patient 1: upper and lower limb motor evoked potentials (MEPs) were absent bilaterally. Somatosensory evoked potentials (SSEPs) and nerve conduction study (NCS) were normal. Electromiography showed chronic denervation signs in upper limbs muscles. Cervical spine MRI was normal. Patient 2: SSEPs detected prolonged latencies in lower limbs; upper and lower limb MEPs were absent bilaterally. Electromiography showed …