Pediatric Hospital Medicine Curriculum
The Anatomy of a Didactic Question
A 10-month-old boy is admitted for hydration in the setting of emesis and poor oral intake. His illness began with fever and a maculopapular rash on the distal extremities, as well as watery, foul-smelling stools. His rash and diarrhea have resolved, but he continues to have a low-grade fever and poor energy. Since yesterday, he has had four episodes of emesis and is feeding poorly, taking a maximum of 2 ounces of liquid at a time. He received 20 cc/kg of isotonic fluid resuscitation prior to admission. On examination, the infant is sleepy with a low-grade fever, heart rate of 130 bpm, respiratory rate of 30 breaths per minute, normal blood pressure, and normal oxygen saturation. Extremities are cool. An additional 20 cc/kg of normal saline is ordered. Halfway through the bolus, his nurse calls with concern that his heart rate and respiratory rate have both increased, and his oxygen saturation has begun briefly dropping to 88% on room air. On repeat examination, perfusion remains poor, and blood pressure is 66/37 mm Hg. Crackles are present in both lung bases, and a liver edge is palpated 3 centimeters below the costal margin. Which of the following tests is most likely to be abnormal?
Answer choice options
- A. Blood culture.
- C. Liver function tests.
- D. Stool culture.
- B. Echocardiogram.
The incorrect options (distractors) are not totally wrong. These options can be diagramed as follows:
- B.Echocardiogram.Will show decreased systolic function of the myocardium.
- A.Blood culture.Obtained for suspected sepsis, however given worsening clinical status after fluid administration, less likely to be sepsis.
- C.Liver function tests. The liver may be enlarged, but is likely functioning normally.
- D.Stool culture.Indicated in suspected bacterial gastroenteritis. Clinical presentation more consistent with cardiogenic shock.