A 12-Year-Old Girl With Dyspnea and Unilateral Interlobular Septal Thickening

CASE PRESENTATION: A 12-year-old girl was admitted to the hospital for exercise intolerance and radiographic abnormalities. She presented with a 5-year history of shortness of breath during intense exercise and did not undergo any medical evaluation. She felt that her symptoms had progressed with fever and right chest pain 2 months prior to admission. She was diagnosed with pneumonia by her chest CT scan, which revealed a small right hemithorax, interlobular septal thickening, and ground-glass opacity of the right lung (Fig 1A), and was treated with antibiotics. She soon became afebrile, but still felt shortness of breath during intense exercise. Then, a contrast-enhanced CT scan of the chest (not shown) showed the right lung still had interlobular septal thickening, and the right pulmonary artery was smaller than the left. There were no systemic symptoms, including skin rash and arthralgia. Family history showed her grandparents were cousins and her father had congenital dysarthria.