A 20-day-old newborn is brought to the physician because of poor feeding and lethargy for one week. The child was delivered at term at home and has not yet been evaluated by a physician. He is at the 90th percentile for head circumference, 50th percentile for length, and 60th percentile for weight. Vital signs are within normal limits. Serum TSH above the normal range and serum thyroxine (T4) below the normal range for his age. Examination shows scleral icterus and an enlarged tongue. Which of the following is the most likely cause of these findings?

Question

Quizplus · Accepted Answer

Eductional Objective: The most common cause of congenital hypothyroidism is thyroid dysgenesis (i.e., thyroid hypoplasia, dysplasia, or aplasia). Early initiation of thyroxine supplementation is essential to prevent the patient from developing permanent intellectual disability.   In this condition, TSH is elevated and thyroxine (T4) is low.

A 20-Day-Old Newborn Is Brought to the Physician Because of Poor