Correct Answer For :USMLE step 2 Mcq16:A 16yr old boy presented with chronic hepatitis and Parkinsonism like features of tremors and rigidity


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Correct Answer: A

Explanation:


Wilson's disease is autosomal recessive disorder copper metabolism. There is a genetic defect in chromosome 13. The initial steps of copper absorption and transport to liver are normal. But the copper fails to enter the circulation in form of ceruloplasmin. Thus there is progressive accumulation of copper in the liver leading to chronic liver injury and ultimate spill over of unbound copper into the blood. This unbound copper shows a predilection for deposition in the basal ganglia in the brain. Deposition in the basal ganglia results in Parkinsonism like features (tremors,rigidity) and a variety of other basal ganglia syndromes.The copper also gets deposited in the limbal area of the cornea causing a greenish-brown discoloration giving rise to the KAYSER FLIESCHER RINGS. These rings are diagnostic of Wilson's disease.So due to the presenting symptoms of chronic hepatitis, tremors, rigidity and greenish-brown corneal ring this is a case of Wilson's disease.

Hemochromatosis is a defect of iron metabolism. It also manifests with chronic hepatitis but there is never any central nervous system involvement. Also KAYSER FLIESCHER RINGS are diagnostic of Wilson's disease and not seen in hemochromatosis.

Indian childhood cirrhosis is a liver cirrhosis of unknown etiology seen in developing countries. This is not the correct answer because Indian childhood cirrhosis presents in early childhood and does not cause any nervous system or ocular manifestations.Chronic viral hepatitis is not possible because this also does not cause any nervous system or ocular manifestations.

Bantu's siderosis is an iron overload disease seen in south African black population who consume large amount alcohol brewed in iron utensils. There is no nervous system or ocular involvement and the history of consumption of alcohol brewed in iron utensils is present.


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