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A 30-year-old woman presents with complaints of weakness and headaches. Her friends say she has been
irritable and depressed lately. On physical examination, the patient is jaundiced, and her liver is small and firm. Neurologic examination is remarkable for choreoathetotic movements and a fine tremor that, when her upper limbs are extended, resembles a bird flapping its wings. Which of the following tests would most likely lead to to correct diagnosis?
A. Nerve conduction studies
B. Prussian blue stain of liver biopsy specimen
C. Serum alkaline phosphatase
D. Serum transaminases
E. Slit-lamp examination of the eyes
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The correct answer is E. This patient is exhibiting symptoms of Wilson's disease, which is due to inadequate
copper excretion by the biliary system. Mutations in a copper-transporting ATPase, coded for by the ATP7B
gene on chromosome 13, appear to underlie this autosomal recessive disorder. Accumulation of copper in the
liver initially produces fatty change, followed by hepatocellular necrosis, inflammation, bile duct proliferation,
and cirrhosis. Eventually, the copper spills out of the liver to deposit in other tissues, notably the brain. The
caudate nucleus and putamen are generally most affected; injury to these structures produces an
extrapyramidal movement disorder that most commonly presents with choreoathetosis and tremor but which
may produce cerebellar signs or parkinsonism. Various psychiatric symptoms can accompany neurological
involvement. Copper deposition in Descemet's membrane in the cornea produces the nearly pathognomonic
Kayser-Fleischer ring, which can be seen with slit-lamp examination of the eyes. Failure to demonstrate a
Kayser-Fleischer ring in a patient with hepatic disease and neurological impairment virtually excludes the
diagnosis of Wilson's disease. Low serum ceruloplasmin and increased urinary copper, or increased copper
levels on liver biopsy, are diagnostic.
Nerve conduction studies (choice A) would be of little value in the diagnosis of Wilson's disease, although they
are valuable in detecting dysfunction of peripheral nerves that result, for example, from demyelination, loss of
nerve axons, failure of conduction, or neuromuscular junction failure.
A Prussian blue stain performed on a liver biopsy (choice B) would demonstrate increased iron stores in a
patient's liver secondary to hemochromatosis.
Serum alkaline phosphatase (choice C) would be elevated in patients with biliary tract disease, although other
types of liver disease, bone disease, or pregnancy can produce elevations as well.
Serum transaminases (choice D) would be increased in patients with a variety of diseases causing
hepatocellular injury, including hepatitis and cirrhosis, but this finding is not particularly specific
