Snapshot A 35-year-old man presents to the emergency room for watery diarrhea. He reports that he feels as though he is always sick with sinusitis, upper respiratory infections, or diarrhea. He cannot recall when in the past year he has been free of symptoms. On physical exam, he is clinically dehydrated with poor skin turgor, sunken eyes, and dry mucous membranes. Lung exam reveals crackles bilaterally, and his abdomen is soft and tender to palpation. Bowel sounds are hyperactive. After reviewing his 10+ visits to his primary care physician and emergency room, the physician decides to evaluate this patient's immunoglobulin levels. Both his IgG and IgA levels come back low. He is started on intravenous immunoglobulin therapy. Introduction Clinical definition login to view 2 more bullets Epidemiology Demographics login to view 1 more bullet ETIOLOGY Pathogenesis login to view 4 more bullets Associated conditions login to view 4 more bullets Presentation Symptoms login to view 6 more bullets Physical exam login to view 2 more bullets Studies Diagnostic testing login to view 6 more bullets Differential X-linked agammaglobulinemia login to view 3 more bullets Severe combined immunodeficiency (SCID) login to view 4 more bullets DIAGNOSIS Diagnostic criteria login to view 4 more bullets Treatment Management approach login to view 1 more bullet First-line login to view 2 more bullets Second-line login to view 1 more bullet Complications Lymphoma is a common cause of death in these patients ~20% develop autoimmune disease