Atrofia monomiélica distal de extremidad superior. Caso clínico / Monomelic amyotrophy. Report of one case

Monomelic amyotrophy, also known as Hirayama disease, is a rare lower motor neuron syndrome due to localized lower motor neuron loss in the spinal cord at the cervical level. Clinically, monomelic amyotrophy is defined by the insidious onset of unilateral atrophy and weakness involving the hand and forearm, typically beginning in the second or third decade of life. We report 19-year-old man with a two years history of slowly progressive unilateral weakness and atrophy of his right-hand muscles. Neurological examination revealed weakness and atrophy in his intrinsic hand muscles, with sparing of the abductor pollicis brevis muscle. Also, mild atrophy of the ulnar aspect of the forearm was detected with sparing of the brachioradialis muscle. Electromyography showed active and chronic neurogenic changes affecting C8 and T1 myotomes, with mild chronic neurogenic changes on C7 myotome. Magnetic resonance imaging of his cervical spine revealed spinal cord atrophy involving C5 to C7 segments, associated with forward displacement of the posterior wall of the dura in cervical spine flexion. The clinical features associated with the imaging and electrophysiological findings support the diagnosis of monomelic amyotrophy.

Xantomatosis cerebrotendinosa sin xantomas tendíneos: caso clínico / Cerebrotendinous xanthomatosis: report of one case

Cerebrotendinous xanthomatosis (CTX) is an uncommon autosomal recessive disease caused by deficiency of 27-sterol-hydroxylase that results in an accumulation of cholestanol in the central nervous system, eyes, tendons, and blood vessels. We report a 22-year-old woman with a history of cataract surgery at the age of 14, cholecystectomy due to cholelithiasis at the age of 17 and chronic diarrhea, who presented with a six months period of gait instability and frequent falls. Physical examination revealed a bilateral pyramidal and cerebellar syndrome, with no visible tendon xanthomas. Cerebral magnetic resonance imaging showed an increase of the signal intensity on the T2-weighted images in periventricular cerebral white matter, dentate nuclei and spinal cord. With a high suspicion of CXT, a genetic study was conducted identifying a pathogenic variant in the CYP27A1 gene. There is considerable variation in clinical characteristics and age of onset of this disease, including absence of tendon xanthomas, delaying the diagnosis. Early recognition and chronic chenodeoxycholic acid therapy can improve outcome and quality of life.