WBR0745

Author	[[PageAuthor::Rim Halaby, M.D. [1]]]
Exam Type	ExamType::USMLE Step 1
Main Category	MainCategory::Pathology
Sub Category	SubCategory::Hematology
Prompt	[[Prompt::A 4 year old boy is brought by his mother to the emergency department for a yellow skin color and excessive fatigue. Physical examination is remarkable for skin jaundice and palpable spleen on abdominal exam. Blood work-up shows low hemoglobin levels, elevated levels of mean corpuscular hemoglobin concentration (MCHC), and increased bilirubin. Blood smear of the patient is shown in the image below. Which of the following findings during history-taking is most consistent with the patient's condition? ]]
Answer A	AnswerA::Family history positive for cholecystectomy
Answer A Explanation	[[AnswerAExp::Hereditary spherocytosis (HS) is an autosomal dominant genetic disorder characterized by the hemolysis and increased bilirubin that prediposes affected patients to gallbladder stones. Since the disease is autosomal dominant, a positive family history of HS is typical and thus a positive family history of cholecystectomy should raise the suspicion of HS in young patients presenting with jaundice and anemia.]]
Answer B	AnswerB::Personal history of macrosomia at birth
Answer B Explanation	AnswerBExp::Macrosomia is not associated with hereditary spherocytosis. The latter is a hereditary disorder.
Answer C	AnswerC::Maternal history of pre-eclampsia during pregnancy
Answer C Explanation	AnswerCExp::Pre-eclampsia does not predispose patients to hereditary spherocytosis. The latter is a hereditary disorder.
Answer D	AnswerD::Maternal use of amoxicillin during pregnancy
Answer D Explanation	AnswerDExp::Amoxicillin in considered safe in pregnancy.
Answer E	AnswerE::Recent history of fava bean intake
Answer E Explanation	AnswerEExp::Fava bean intake is associated with hemolysis in patients with G6PD deficiency.
Right Answer	RightAnswer::A
Explanation	[[Explanation::Hereditary spherocytosis (HS) is an autosomal dominant genetic disorder characterized by the elastic deformity of red blood cells (RBC) due to red cell membrane defect. As such, the RBC will lose its biconcave shape and have a spherical shape that predisposes it to rupture. When RBCs rupture, patients have clinical manifestations of the disease that are mostly: anemia, jaundice, and splenomegaly. On blood work-up, the patients typically have low hemoglobin with elevated MCHC, and elevated levels of bilirubin due to hemolysis. Diagnosis of HS is by peripheral smear that shows spherically-shaped RBCs. For most patients with HS, splenectomy is curative. Because HS is an autosomal dominant disorder, patients have a positive family history of the disease. In these patients, elevated bilirubin due to hemolysis predisposes to gallbladder stones that increase the risk of cholecystitis. As such, patients typically present with a very positive family history of cholecystectomies. Educational Objective: Young patients presenting with jaundice, splenomegaly, and anemia with a positive family history of cholecystectomy should raise the suspicion of hereditary spherocytosis. Educational Objective: References: ]]
Approved	Approved::No
Keyword	WBRKeyword::family, WBRKeyword::history, WBRKeyword::cholecystectomy, WBRKeyword::hereditary, WBRKeyword::spherocytosis, WBRKeyword::anemia, WBRKeyword::jaundice, WBRKeyword::bilirubin, WBRKeyword::MCHC, WBRKeyword::splenomegaly, WBRKeyword::splenectomy, WBRKeyword::curative, WBRKeyword::cell, WBRKeyword::membrane, WBRKeyword::defect, WBRKeyword::autosomal, WBRKeyword::dominant, WBRKeyword::hemolysis, WBRKeyword::hemolytic, WBRKeyword::gallbladder, WBRKeyword::stones
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