Very severe thrombocytopenia and fragmentation hemolysis mimicking thrombotic thrombocytopenic purpura associated with a giant intracardiac vegetation infected with Staphylococcus epidermidis: Role of monocyte procoagulant activity induced by bacterial supernatant

Abstract

The pathogenesis of very severe thrombocytopenia in bacterial endocarditis is uncertain. We report a 50‐year‐old male with platelet counts < 10 × 109/l and fragmentation hemolysis complicating Staphyloccoccus epidermidis pacemaker endocarditis with a giant vegetation. Antibiotics, corticosteroids, high‐dose intravenous gammaglobulin, and plasmapheresis (for initially‐suspected thrombotic thrombocytopenic purpura) failed to produce significant platelet count increase. However, therapeutic‐dose heparin anticoagulation was associated with a platelet count increase from <10 to ∼40 × 109/l, with parallel reduction in thrombin‐antithrombin complexes (from 8.9 to 3.5 μg/l), facilitating surgical intervention. The thrombocytopenia promptly resolved following surgical removal of the vegetation. Culture supernatant from S. epidermidis isolated from the patient's blood induced monocytes to express procoagulant activity (assessed by factor Xa generation) equivalent to lipopolysaccharide (1 μg/ml), with half‐maximal activation seen with culture supernatant diluted to 1:12,800. These data are consistent with previous animal models of endocarditis demonstrating staphylococci‐induced procoagulant changes in monocytes. This case demonstrates that heparin anticoagulation can be therapeutic in infective endocarditis‐associated severe thrombocytopenia in a non‐bleeding patient, and that such therapy may ameliorate the platelet count enough to permit surgical intervention. Am. J. Hematol 2007. © 2006 Wiley‐Liss, Inc.

Microangiopatias trombóticas: púrpura trombocitopênica trombótica e síndrome hemolítico-urêmica

“…The systemic diseases include disseminated malignant neoplasias, 59,60 systemic infections, [61][62][63] malignant hypertension, 64,69 systemic lupus erythematosus, and other kidney diseases. 69 In addition, physicians should maintain continued vigilance regarding the existence of possible alternative diseases, even after establishing the diagnosis of TTP, and starting treatment with PE.…”

Ten patient stories illustrating the extraordinarily diverse clinical features of patients with thrombotic thrombocytopenic purpura and severe ADAMTS13 deficiency

“…This patient's presentation was perfectly typical of bacterial endocarditis and bacterial endocarditis can mimic TTP [7]. Undetectable ADAMTS13 activity was unexpected; however, there are previous reports of severe ADAMTS13 deficiency associated with sepsis and disseminated intravascular coagulation [8].…”

Systemic infections mimicking thrombotic thrombocytopenic purpura

“…For some infections, the pathogenesis of microangiopathic hemolytic anemia has been described. Examples are bacterial endocarditis, [62] bacterial infections associated with microvascular injury such as brucellosis [32,33] streptococcal infections resulting in acute glomerulonephritis, [66] angioinvasive fungi such as aspergillosis, [83], and viruses and rickettsiae that cause endothelial injury such as CMV, [71][72][73] HIV, [16] erlichiosis, [44] and Rocky Mountain spotted fever [56]. However for other infections the mechanisms of microangiopathic hemolytic anemia are unclear.…”