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USMLE Q Bank Step 1- 214




A 1-year-old boy is brought to the clinic by his mother due to recurrent upper respiratory tract infections and oral fungal infections. Physical examination reveals low set ears and fish-like mouth. Laboratory tests reveal hypocalcemia and chest x-ray shows no thymus shadow.

What is the most likely etiology of hypocalcemia in this case?

A-Decreased secretion of parathyroid hormone

B-End-organ hyposensitivity to parathyroid hormone

C-End-organ hyposensitivity to calcitonin

D-Increased secretion of calcitonin

E-Increased secretion of parathyroid hormone

Answer




This case is most likely Di George syndrome. It is characterized by a defect in the third pharyngeal pouch which gives rise to inferior parathyroid and thymus. The fourth pharyngeal pouch gives rise to superior parathyroid.

The correct answer is A



2 thoughts on “USMLE Q Bank Step 1- 214”

  1. Thank you so much. I really appreciate your wonderful feedback.

    God bless you too Dear Dr MUNYENSANGA

  2. I really appreciate your work. As a medical doctor in Subsahara African Hospital, with lifelong learning, I dairly lean from you through all these review questions and I’m very thankful for your dairly help.

    God bless you!

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