Over the years, the AMA has run dozens of example questions from Kaplan Medical. If you’re preparing for the United States Medical Licensing Examination® (USMLE®) Step 1 exam, you might want to know which questions are most often missed by test-prep takers. We’ve compiled three cases from Kaplan Medical involving infant patients. Each question comes with an expert explanation of the answer. You can check out all posts in this series.
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Think you can answer these questions involving infant patients? Find out now.
- A 6-month-old boy is brought to the physician by his parents, who are first cousins, for a well-child examination. The boy appears thin, small and lethargic. Physical examination shows slightly misshapen long bones. Joint movements are restricted, the corneas are clouded, and the gums are hyperplastic. Laboratory studies of serum show elevated levels of acid hydrolases and glycosylases. Which metabolic activity is most likely defective in this patient?
- A 7-week-old girl is brought to the physician by her mother because of a one-day history of labored breathing. Her birth was uneventful, but her mother says the infant developed conjunctivitis on the fifth day of life. The infant’s temperature is 98.6 °F (37 °C), and her respiratory rate is 40 beats per minute. Bilateral inspiratory crackles and a slight wheeze are heard on auscultation of the chest. A chest X-ray shows bilateral interstitial infiltrates with hyperinflation. Laboratory studies show a leukocyte count of 15,000/mm³ with 40% eosinophils. What is most likely to be seen on a Pap smear preparation from the mother?
- A male newborn born at 37 weeks' gestation has a large mass over the lumbar region. Examination of the mass shows cerebrospinal fluid (CSF)-filled meningeal tissue that has herniated through a vertebral defect. The newborn is able to move all extremities and responds normally to external stimuli. What is the most likely diagnosis?
For more prep questions on USMLE Steps 1, 2 and 3, view other posts in this series.