Localized brucellosis: popliteal artery aneurysm, mediastinitis, dementia, and pneumonia.

Four patients with unusual manifestations of brucellosis presented to two tertiary-care teaching hospitals over a 15-year period. These cases posed difficult diagnostic problems. Each patient presented with signs and symptoms suggestive of a localized disease process: ischemic limb, mediastinal mass, dementia, and pneumonia. Two were afebrile, and two were acutely ill with high fever. Three patients had normal agglutination titers on admission, although in one patient the titer rose to 1:5,120 during therapy. During this same 15-year period only 10 cases of acute uncomplicated brucellosis were diagnosed at the two hospitals. The rarity of focal manifestations of brucellosis and general inexperience with brucellosis led to delays in diagnosis of 5-14 days. In view of the protean clinical presentations of localized brucellosis, careful inquiries about possible exposure to livestock and repeated serologic tests for brucellosis are important in the management of any diagnostically difficult clinical problem.