HISTORY OF PRESENT ILLNESS The patient was a 38-year-old man with a long history of common variable immunodeficiency (CVID) who was admitted to the hospital with a 3-day history of progressive obtundation followed by lethargy and coma. Fever, swelling, and pain of the left ankle were also noted on admission. Very little additional history was obtainable because the patient lived alone and his family was unable to provide further information. One month earlier, the patient was hospitalized for peritonitis, pneumonia, right-sided empyema, possible splenic abscesses, chronic anemia, and arthralgias of the right wrist and shoulder. All the routine bacterial cultures of blood, peritoneal, and empyema fluids were negative, and he was treated with broad-spectrum antibiotics (ampicillin, gentamicin, metronidazole, ciprofloxacin) and pleural decortication. During that hospitalization, he complained of arthralgias (wrists and right shoulder) that were interpreted as being tenosynovitis. The patient had not received intravenous Ig treatment for 3 years before this hospitalization. During the hospitalization, he received a dose of intravenous immunoglobulin (IVIG; 200 mg/kg), and his symptoms of tenosynovitis improved.