Snapshot A 6-year-old boy presents to the hospital with a severe upper respiratory infection requiring hospitalization. Chart review reveals that he has presented multiple times to the emergency room and primary care physician’s office for a variety of infections, including otitis media, upper respiratory infections, pneumonia, and sinusitis. When detailing family history, it is found that his maternal uncle died of an infection as a child. Lab findings include decreased levels of IgG, IgM, and IgA. Introduction Primary humoral immunodeficiency characterized by decreased immunoglobulins Genetics login to view 2 more bullets Pathogenesis login to view 6 more bullets Presentation Symptoms login to view 5 more bullets Physical exam login to view 1 more bullet Evaluation Diagnosis based on family history, clinical history, and exam Serologies login to view 3 more bullets Diagnosis confirmed with DNA, mRNA, or protein analysis showing mutation in BTK Differential Diagnosis Common variable immunodeficiency Severe combined immunodeficiency Transient hypogammaglobulinemia of infancy Treatment Antibiotics for infections Regular IVIG infusions Prognosis, Prevention, and Complications Prognosis login to view 1 more bullet Prevention login to view 2 more bullets Complications login to view 1 more bullet