When bronchiolitis doesn't make sense: Alveolar hemorrhage in an infant with undiagnosed wiskott-aldrich syndrome

ABSTRACT

Case Report Wiskott-Aldrich Syndrome (WAS) is a recessive Xlinked syndrome characterized by atopic dermatitis, impaired humoral immunity, thrombocytopenia, and autoimmune disease. We present a case of diffuse alveolar hemorrhage initially thought to be bronchiolitis. A 4-month-old late preterm male with history of congenital thrombocytopenia and eczema presented with respiratory distress, hypoxia, cough, petechiae, and painful rash on day of illness (DOI) 5. He had no fever, congestion, or rhinorrhea. Rapid RSV was positive, but viral PCR including RSV and SARS-CoV-2 was negative. Admission labs were notable for thrombocytopenia (54 K/mm3), and otherwise normal leukocytes (9.8 K/mm3), hemoglobin (11.4 g/dL), and CRP (4.9 mg/L). Chest radiograph showed interstitial changes suggesting chronic lung disease. Hypoxia worsened on DOI 6 requiring critical care admission and escalation of oxygen to high flow nasal cannula. Dermatology diagnosed his rash as eczema with viral exanthem. His clinical course and radiographic finding of interstitial changes were not consistent with bronchiolitis and prompted a chest CT on DOI 8 that demonstrated extensive patchy bilateral ground glass opacities consistent with diffuse alveolar hemorrhage. PT, PTT, D-dimer, and Factor VIII activity were normal. Peripheral smear showed small scant platelets. Immunoglobulins were mildly elevated. Oxygen was weaned off by DOI 23. PJP prophylaxis was started due to mild neutropenia with presumed WAS diagnosis. Genetic testing confirmed the diagnosis of WAS. The WAS gene mutation results in a spectrum of syndromes including Wiskott-Aldrich syndrome, X-linked thrombocytopenia and X-linked neutropenia. WAS includes thrombocytopenia, atopic dermatitis, recurrent infections, and autoimmune diseases which rarely can include pulmonary capillaritis leading to diffuse alveolar hemorrhage. Here the initial diagnosis of RSV bronchiolitis was misleading, but a high index of suspicion with an atypical course lead to diagnosis and appropriate treatment and follow-up for WAS.