Review Question - QID 110028

A 12-year-old boy presents to the pediatrician for a routine checkup. He and his family immigrated from Pakistan to the United States when he was 9 years of age. Per his mother, he had measles when he was 4 years of age and a high fever following a sore throat at the age 7. He received all appropriate vaccinations when he arrived in the United States. He takes no medications. He does well academically and plays soccer in a recreational league. He was born at 38 weeks gestation. His temperature is 98.4°F (36.9°C), blood pressure is 115/65 mmHg, pulse is 80/min, and respirations are 18/min. On exam, he is a healthy boy in no apparent distress. Breath sounds are equal bilaterally with good aeration. Fixed splitting of the second heart sound is noted on auscultation. Without adequate treatment, this patient will be at increased risk for developing which of the following?