A 46‐year‐old man with diabetes meHitus, hypertension, and hyperlipidemia was admitted with history of myalgias, cough with sputum, emesis, chills, abdominal pain, and diarrhea. Examination was significant for an ill‐appearing male, normolensive, and tachypneic with bilateral basal crackles. His CBC revealed leukocytosis with hemoglobin and platelet count being normal. Chest x‐ray showed bilateral lower‐lobe infiltrates, and a chest CT confirmed the x‐ray findings. The patient was promptly started on antibiotics. Over a week, he clinically deteriorated with worsening dyspnea and the development of thrombocytopenia, anemia, and acute renal failure, and he was transferred to the ICU. He was noted 1c have high LDH and low haptoglobin, with a peripheral blood smear showing numerous schistocytes, and a presumptive diagnosis of TTP was made. His PT, PTT, fibrinogen level, vasculitis screen including complement levels was normal and his hepatitis panel and HIV testing were negative. The patient was initiated on plasmapheresis and systemic steroids; his platelet count failed to improve after 14 sessions of plasmapheresis. He was started on Rituxan and with continued pheresis his platelet count stabilized, LDH decreased, and his renal function gradually improved. There was no evidence of relapse on frequent monitoring of his LDH, hemoglobin/hematocrit, and platelet count thereafter.
The exact cause of TTP is unclear, although several precipitating factors including pregnancy, drugs, infections, and malignancies have been identified. It is characterized by multiorgan ischemia and dysfunction resulting from the formation of occlusive platelet thrombi in microcirculation. These in turn result from The incomplete processing of ulTralarge von Willebrand factor multimers (ULvWFs) released from damaged endothelial cells by a metalloproteinase called ADAMTS‐13. Congenital severe deficiency or toxin‐mediated endothelial injury or cross reactivity with antibodies, as in the case of Legionella infections, leading to reduction in ADAMTS‐13 levels, have been proposed to induce TTP. However, the utility of measuring ADAMTS‐13 levels To guide TTP management is still uncertain. In this case, detection of a microangiopathic process in The peripheral smear helped to ascertain TTP Review of appropriate laboratory data including normal coagulation, autoimmune, and vasculitic panels ruled out the possibility of imitating clinical phenomena.
The current case emphasizes the rare association of TTP with Legionella pneumonia. It also exemplifies the complex interplay of various pathogenetic mechanisms and importance of accurate diagnosis, given the varied management strategies and outcomes involved. Periphera smears should be routinely reviewed in patients with thrombocytopenia because potentially fatal but easily treatable causes could be ignored.
I. Al‐Howaidi, none; W. Gonsalves, none; T. Tashi, none; A. Ganta, none: I. Aldoss, none; M. Kalaiah, none; A. Sama, none; P. Hurley, none; P. Silberstein, none; S. Subbiah, none
To cite this abstract:Al‐Howaidi I, Gonsalves W, Tashi T, Ganta A, Aldoss I, Kalaiah M, Sama A, Hurley P, Silberstein P, Subbiah S. An Unlikely But Potentially Fatal Association — TTP and Legionella Pneumonia. Abstract published at Hospital Medicine 2010, April 8-11, Washington, D.C. Abstract 208. Journal of Hospital Medicine. 2010; 5 (suppl 1). https://www.shmabstracts.com/abstract/an-unlikely-but-potentially-fatal-association-ttp-and-legionella-pneumonia/. Accessed May 26, 2019.