HIV RELATED HEMOLYTIC UREMIC SYNDROME. Physical exam in the ER showed a distressed lady with tachycardia and tachypnea. She had petechiae over the legs, 3+ bilateral pedal edema and a right pleural effusion. Labs revealed severe anemia (hematocrit 21); normal platelet count (227k/ml), increased BUN and creatinine (81/5.3); increased LDH (579) and near normal PT and PTT (14.8/28.6) . Peripheral smear showed schistocytes. Factor V and VIII were normal. Hospital stay was initially represented by persistent anemia, worsening thrombocytopenia (down to 29k/ml), bleeding from multiple sites, worsening renal and pulmonary function. Neurological exam remained normal. LDH remained high whereas PT and PTT remained mostly unchanged. CD4 count and viral load sent at this time came back as 89 (Â106/L) and 42 (k copies/ml) respectively. A diagnosis of HUS was made on clinical and laboratory parameters. No known risk factors were identified. Patient underwent plasmapheresis and hemodialysis. Her condition however continued to deteriorate and she died seven weeks post admission. Autopsy confirmed HUS and ARDS. DISCUSSION: HUS has been seen mostly in terminal AIDS patients and thrombotic microangiopathy in AIDS patients is increasingly being considered a consequence of direct pathogenic effect of the virus over glomerular capillaries and arterioles. We were unable to identify any other risk factor for HUS in our patient as well. Prior to this admission our patient did not have any AIDS defining illness. We concur with others that HUS may be considered as an AIDS defining illness. Plasmaphersis was not associated with survival in our patient. The role of this mode of therapy in HIV patients needs to be studied further. MRI showed mild periventricular white matter disease and audiometric testing showed severe bilateral vestibular defects. In late 1997 she presented with recurrent pulmonary infections and was diagnosed with common variable immunodeficiency (CVID). In October 1998 she began having 10 ± 15 minute episodes of ascending right or left hand tingling and weakness followed by slurred speech and a reported mild facial droop that resolved with verapamil in December. In April 2000 she presented with declining memory, concentration problems and diarrhea. Workup revealed secondary adrenal insufficiency, hyperprolactinemia and decreased insulin-like growth factor 1 (IGF-). Extensive testing over six years included three head MRIs, two lumbar punctures, audiology testing, psychosocial evaluation, bronchoscopy, muscle biopsy, abdominal CT and numerous blood tests. Positive studies included high CSF protein of 64, oligoclonal bands, cortisol base 3.2 "g/dL (6 ± 25) after stimulation 14.6 "g/dL (!18 at 60 minutes after injection) and ACTH 5, prolactin 109ng/mL (1 ± 24) , and IGF1 50 ng/mL (71 ± 240). The lack of linear plaques and atrophy of the corpus callosum on the MRI scans were inconsistent with MS and neurology and otolaryngology consultants concluded that her progression of symptoms, imaging studies, and lab testing were most consistent with a diagnosis of Susac Syndrome. DISCUSSION: There have been less than 50 reported cases of Susac syndrome in the literature. This is the first reported case of immune deficiency and endocrine abnormalities accompanying Susac's syndrome which is described as a clinical course of hearing loss, encephalopathy, and visual changes consistent with a microangiopathy of the cochlea, brain and retina. High suspicion and extensive testing is required to rule out other etiologies of this triad of symptoms.