Index of Suspicion

Case 1 Presentation

A 15-year-old adolescent was well until 1 week ago, when he began experiencing shortness of breath (SOB) upon mild exertion. He now experiences significant SOB, even while walking a few steps. He denies chest pain or palpitations, but has experienced diaphoresis and worsening cough. He denies fever, rhinorrhea, sore throat, joint pain, or swelling of the legs or back, but does recall having mild cold symptoms 2 weeks ago.

The boy has been well; takes no medications; and denies using tobacco, alcohol, or other substances. His family has no known history of early heart disease or sudden death.

On physical examination, the boy’s heart rate is 125 beats/min, respiratory rate is 16 breaths/min, blood pressure is 86/43 mm Hg, and oxygen saturation is 92%. He looks pale and diaphoretic and is in moderate respiratory distress. Cardiac examination reveals a gallop rhythm, but no murmur. He has substernal and subcostal retractions, even though his lungs are clear to auscultation. His liver is not enlarged. His distal pulses are normal. The arms are warm, but both legs are cool.

The white blood cell (WBC) count is 10×10³/mcL (10×10⁹/L), with 62% neutrophils and 29% lymphocytes. His hemoglobin is 14 g/dL (140 g/L), platelet count is 140×10³/mcL (140×10⁹/L), and erythrocyte sedimentation rate (ESR) is 1 mm/h. His serum chemistry panel demonstrates normal electrolytes, blood urea nitrogen, creatinine, ionized calcium, liver enzymes, total protein, albumin, and antithrombin III. Prothrombin time and partial thromboplastin time are normal, as are findings on urinalysis. An imaging test leads to the correct diagnosis.

Case 2 Presentation

A healthy 2-month-old boy is found to have an abdominal mass on routine examination. He was delivered at term after an uncomplicated pregnancy. His parents are first-degree relatives, and the family history is unremarkable.

Physical examination reveals an …