Snapshot A 2-month-old boy presents with a 2-day history of fever and a painful bump on his rear-end. On exam, there is a fluctuant, erythematous bump with purulent material draining. The abscess is drained and cultured, and the patient is started on antibiotics. The cultures come back positive for S. aureus. This is his second episode of a S. aureus-induced abscess. A nitroblue tetrazolium test is negative. Introduction Chronic granulomatous disease (CGD) is a rare primary immunodeficiency of phagocytes Genetics X-linked recessive results in deficiency in NADPH oxidase Epidemiology males > females due to inheritance pattern Pathogenesis recall normal physiology NADPH oxidase is important in respiratory or oxidative burst results in rapid release of reactive oxygen species such as superoxide CGD patients lack the oxidative burst can only use peroxide from microorganisms to make reactive oxygen species ↑ risk of catalase-positive species (S. aureus, E. coli, Aspergillus, Candida, etc.) Leads to granulomas Presentation Symptoms often appear in first year of life with recurrent pyogenic infections recurrent infection with catalase-positive organisms pneumonias aspergillosis skin abscesses pulmonary abscesses chronic diarrhea failure to thrive Physical exam short stature eczematoid dermatitis hepatomegaly Evaluation Flow cytometry reduction of dihydrorhodamine abnormal can detect X-linked carrier status cannot differentiate oxidase-positive from oxidase-negative phagocyte subpopulations in CGD carriers Nitroblue tetrazolium dye reduction test negative finding = incubated leukocytes do not turn the plate blue Cytochrome c reduction assay measures production of reactive oxygen species Differential Diagnosis IgA deficiency HIV/AIDs Other primary immunodeficiencies Treatment INF-γ Antibacterial and antifungal prophylaxis Only curative therapy hematopoietic stem cell transplant Prognosis, Prevention, and Complications Prognosis improving with treatment 50% survival rate to age 30-40 Prevention antifungals and antibiotics Complications severe fungal infections are often determinant of survival