HIV-Associated Thrombotic Thrombocytopenic Purpura in a Virally Suppressed Patient With Normal CD4 Count: A Rare Presentation

Thrombotic thrombocytopenic purpura (TTP) is a thrombotic process characterized by multiorgan failure secondary to microvascular thrombi comprising platelets and von Willebrand factor. HIV is a known risk factor for TTP. However, patients generally have low CD4+ count during initial presentation or subsequent flare-ups. This case report describes a 69-year-old man with HIV who presented with an initial presentation of TTP while having a prior history of HIV with a normal CD4 count and undetectable viral load on presentation. A 69-year-old Caucasian male with a previous history of HIV on antiretroviral therapy (ART), a history of recurrent deep vein thrombosis maintained on Coumadin, and no previous history of tobacco dependence or substance use presented to the emergency department with symptoms of fatigue and dyspnea worsening on exertion. The patient had stable vital signs on arrival. The initial lab workup was remarkable for hemoglobin of 9.3 g/dL, hematocrit 29%, platelets 22 x 10⁹/L, prothrombin time (PT) 51 seconds, activated partial thromboplastin time (PTT) 41 seconds, international normalized ratio (INR) 4.3 (on warfarin), blood urea nitrogen (BUN) 29 mg/dL, creatinine 2.0 mg/dL, total bilirubin 1.8 mg/dL, lactate dehydrogenase (LDH) 1229 U/L, haptoglobin less than 10 mg/dL, reticulocyte count 6.21%, fibrinogen 519 mg/dL, and D-dimer within normal limits. A clinical diagnosis of TTP was made with a peripheral blood smear showing schistocytes, as well as evidence of hemolytic anemia and thrombocytopenia. Prompt initiation of treatment with plasma exchange therapy was started. The patient was also given high-dose steroids and prednisone 1 mg/kg with a prolonged taper. Due to the delay in improvement in platelet count, the patient was also given concurrent rituximab therapy. TTP in HIV is rare, primarily seen in HIV patients who have a high viral load, low CD4 count, or if there is a delay in starting ART. In HIV-induced TTP patients, the relationship between CD4 count and viral load is complex and not fully elucidated. Further research is needed to understand better the interplay between HIV parameters (such as CD4 count and viral load) and the development of TTP in HIV-infected individuals who are already on treatment. This understanding could aid in identifying high-risk patients and developing targeted interventions to prevent or manage TTP in this population.