WBR0262

Author	PageAuthor::Vendhan Ramanujam
Exam Type	ExamType::USMLE Step 3
Main Category	MainCategory::Community Medical Health Center, MainCategory::Primary Care Office, MainCategory::Inpatient Facilities
Sub Category	SubCategory::Hematology, SubCategory::Genetics
Prompt	[[Prompt::A 56 year old man complains of impotence. On physical examination, he looks obese with has an elevated jugular venous pressure, S3 gallop, hepatomegaly and a gray opaque ring in corneal margin of both the eyes. He also appears tanned, with pigmentation along joint folds. His left knee is swollen and tender. His blood pressure is 150/98 with a heart rate of 98/min. The liver enzymes are elevated and the plasma glucose is found to be 250 mg/dL. The next best investigation to establish the diagnosis will be]]
Answer A	AnswerA::Slit lamp examination of the eye
Answer A Explanation	[[AnswerAExp::Incorrect-Slit lamp examination will only be needed when Wilson’s disease is the probable cause of hepatic abnormalities. The clinical picture here is inconsistent with that diagnosis and the bilateral gray corneal margin is arcus senilis and not Kayser-Fleischer ring, which is found within the cornea due to copper deposition in the descemet membrane of cornea.]]
Answer B	AnswerB::Echocardiography
Answer B Explanation	AnswerBExp::'''Incorrect'''-Echocardiogram can only confirm the cardiomyopathy, but will not help to establish the diagnosis.
Answer C	AnswerC::Determination of serum copper
Answer C Explanation	AnswerCExp::'''Incorrect'''-Determination of serum copper will only be needed when Wilson’s disease is the probable cause of hepatic abnormalities.
Answer D	AnswerD::24 hours urine cortisol
Answer D Explanation	[[AnswerDExp::Incorrect-The constellation of clinical findings does not suggest Cushing’s disease and the 24 hours urine cortisol screening test will not be be helpful.]]
Answer E	AnswerE::Determination of iron saturation
Answer E Explanation	[[AnswerEExp::Correct-The most frequent cause of iron overload is a common genetic disorder (C282Y mutation of HFE gene) known as (idiopathic) hemochromatosis. Secondary iron storage problems can occur in a variety of anemias. The most practical screening test is the determination of serum iron, transferrin saturation, and plasma ferritin. Serum iron will be elevated and so will the plasma ferritin level. But increased ferritin value is less sensitive than increased transferrin saturation value, since they require greater degree of iron overload to increase the iron stores. So transferrin saturation >45% along with increased serum iron will be the most sensitive screening test.]]
Right Answer	RightAnswer::E
Explanation	[[Explanation::Iron overload should be considered among patients who present with any one or a combination of the following: hepatomegaly, weakness, pigmentation, atypical arthritis, diabetes, impotence, unexplained chronic abdominal pain or cardiomyopathy. Diagnostic suspicions should be particularly high when the family history is positive for similar clinical findings. The most frequent cause of iron overload is a common genetic disorder (C282Y mutation of HFE gene) known as (idiopathic) hemochromatosis. Secondary iron storage problems can occur in a variety of anemias. The most practical screening test is the determination of serum iron, transferrin saturation, and plasma ferritin. Serum iron will be elevated and so will the plasma ferritin level. But increased ferritin value is less sensitive than increased transferrin saturation value, since they require greater degree of iron overload to increase the iron stores. So transferrin saturation >45% along with increased serum iron will be the most sensitive screening test. Genetic screening is now used to assess which patients are at risk for severe fibrosis of the liver. Definitive diagnosis can be established by liver biopsy. Educational objective: Iron overload is the cause of suspicion when a patient presents with a constellation of clinical signs like hepatomegaly, weakness, pigmentation, atypical arthritis, diabetes, impotence, unexplained chronic abdominal pain, and cardiomyopathy. Screening test will involve serum iron, transferrin saturation, and plasma ferritin. Live biopsy will confirm the diagnosis and a genetic testing will help to find out a hereditary cause. Educational Objective: References: ]]
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