Mycobacterium tuberculosis presenting as immune mediated thrombocytopenia purpura

Introduction: Many hematologic abnormalities have been reported in association with tuberculosis, isolated thrombocytopenia is an uncommon complication. Tuberculosis presenting as immune mediated thrombocytopenia purpura is extremely rare with an incidence estimated at approximately 1%. Case Presentation: A 53 year old cross country truck driver presented to an outside hospital with a several day history of epistaxis. He also complained of malaise, intermittent fevers, dyspnea and a 30 lb. weight loss over the past three months. He attributed his symptoms to a "cold" he developed after a work related trip to Ohio. Pertinent history included cocaine and marijuana use and a 50 pack year tobacco abuse. On admission to the outside hospital, significant findings included active epistaxis, buccal and palatal petechia, bibasilar crackles and hepatosplenomegaly. Laboratory data on admission revealed a white blood cell count of 4,600 with a left shift; hematocrit - 23%; platelet count - 3,000; mildly elevated liver enzymes; room air arterial blood gas: pH - 7.48/PaCO2 - 31/PaO2 - 79; creatinine - 1.6. The chest radiograph was interpreted as bilateral interstitial infiltrates. At the outside hospital prior to transfer, he received antibiotics to cover community acquired organisms and transfusions of packed red blood cells and platelets. Over the next 36 hours, he developed a massive upper gastrointestinal bleed, massive hemoptysis, and seizures related to an intracranial hemorrhage. He was transferred to our institution for further evaluation. On arrival, he was lethargic but followed commands. Vital signs on admission: heart rate - 72, blood pressure - 140/56, respiratory rate - 26, oxygen saturation of 96% on 60% face mask. His exam was as described previously with no focal neurologic deficit. Other pertinent laboratory data included normal coagulation parameters; platelet count of 7,000 despite aggressive platelet transfusions, lactate dehydrogenase - 979 IU/l. Chest radiograph revealed diffuse interstitial opacities. He was placed into respiratory isolation, pancultured for routine bacteria, mycobacteria, fungi, and atypical organisms; and initiated on broad spectrum antibiotics. Workup included a bronchoscopy with bronchoalveolar lavage which revealed diffuse large airway edema with no active bleeding. All special stains and smears for organisms, fungi, and mycobacteria were negative. Bone marrow aspirate and biopsy was performed and demonstrated no granulomes, an increased number of megakaryocytes and an elevated number of plasma cells. Again all special stains were negative. Antiplatelet antibodies revealed a markedly elevated IgG of 2556 (>800-abnormal) and an IgM of 31% consistent with immune mediated thrombocytopenia. Other data included: a negative HIV antibody, urine histoplasmosis antigen, serum cryptococcal antigen, serum and urine protein electrophoresis and an anergic purified protein derivative and control panel. Despite steroids, intravenous immunoglobulin and vincristine, he persisted with significant, transfusion-requiring bleeding. An abdominal computed tomography demonstrated massive hepatosplenomegaly with retroperitoneal adenopathy and bilateral adrenal enlargement. A splenectomy was performed for refractory thrombocytopenia. Histopathology of the spleen and lymph nodes revealed diffuse necrotizing granulomatous inflammation with a positive acid fast bacilli smear. He was initiated on anti-tuberculous therapy. Platelet count normalized by postoperation day 2. Cultures of his initial sputum, spleen, and lymph nodes eventually grew Mycobacterium tuberculosis. On four month follow-up he is doing quite well with a platelet count of 250,000 and has returned to work. Discussion: Mycobacterium tuberculosis (Mtb) is a significant worldwide problem. While most patients do not manifest major hematologic abnormalities, some patients will demonstrate minor hematologic abnormalities including anemia, monocytosis, leukocytosis, and pancytopenia. Isolated thrombocytopenia associated with Mtb is rare. Immune mediated thrombocytopenia (ITP) as the presenting sign of Mtb is extremely rare with only a few case reports in the literature.^1-4 This is a case of Mtb presenting as ITP with life threatening bleeding. Radiographs and histopathologic specimens are available for review.