Acquired Thrombotic Thrombocytopenic Thrombocytopenia Presenting As Urinary Tract Infection and Perianal Abscess: A Case Review.

Thrombotic thrombocytopenic purpura (TTP) is a rare but potentially life-threatening hematologic disorder characterized by hemolytic anemia, thrombocytopenia, renal failure, fever, and neurologic dysfunction. While cases often do not present with all five characteristics (<5%), TTP can be hereditary or acquired, often due to a deficiency or dysfunction of the ADAMST13 enzyme. Here, we describe a case of infection-induced acquired TTP in a middle-aged male with urinary tract infection (UTI) and perianal abscess. Suspicion arose from hematologic abnormalities, fever, thrombocytopenia, acute renal failure, and the presence of an underlying infection. A PLASMIC score of 6 (indicating a 72% probability of ADAMTS13 deficiency) prompted ADAMTS13 level testing, revealing levels <5% with the presence of an inhibitor, confirming TTP diagnosis. Treatment with high-dose steroids and daily plasma exchange yielded a swift platelet response, necessitating only two to three days of plasma exchange. In addition, incision and drainage of the perianal abscess were performed. The patient was discharged on daily prednisone and initiated on four doses of weekly Rituximab to mitigate recurrence risk. This case underscores the importance of early suspicion and treatment in infectious triggers such as UTI/perianal abscess, offering crucial diagnostic and prognostic insights.