This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Unknown
[{'content': 'A 32-year-old patient has decreased pain and temperature sensation in the upper extremities, atro¬phy of the intrinsic muscles of his hand, and brisk deep tendon reflexes in the upper extremity. Your diagnosis? \nSelect and explain. \nA. Amyotrophic lateral sclerosis, B. Multiple sclerosis, C. Syringomyelia, D. Subacute combined degeneration', 'role': 'user'}, {'content': "Answer: C \nExplanation: The patient is an adult with decreased pain and tem\xadperature sensation in the upper extremities, atrophy of the intrinsic muscles of his hand, and brisk deep tendon reflexes in the upper extremity. This constella\xadtion of clinical findings strongly suggests syringomye\xadlia, which most commonly affects the cervical spinal cord. Syringomyelia refers to a fluid-filled space within the cervical spinal cord that produces (1) cervical cord enlargement, best visualized with magnetic resonance imaging; (2) cape-like neurologic abnormalities in\xadvolving the shoulders and upper extremities; (3) de\xadcreased pain and temperature sensation from involve\xadment of the crossed lateral spinothalamic tracts, with preservation of light touch and proprioception; (4) atrophy of the small muscles of the hands from anterior horn cell involvement, simulating amyotrophic lateral sclerosis; (5) involvement of the lateral corticospinal tract with upper motor neuron findings; (6) Horner's syndrome, consisting of pupillary constriction, lid lag, and anhidrosis; (7) and associations with Arnold-Chi\xadari malformation and Dandy-Walker cysts.\nRegarding the other choices:\nAmyotrophic lateral sclerosis involves motor neurons producing upper and lower motor neuron disease. Sensory findings are not present. Multiple sclerosis has sensory and motor deficits.\xa0 Subacute combined degeneration occurs in vitamin B12 deficiency and involves the dorsal columns and the lateral corticospinal tract.\xa0 Guillain-Barre syndrome is an ascending paralysis without the type of sensory deficits described in this patient.", 'role': 'assistant'}]