Bench-to-bedside review: thrombocytopenia-associated multiple organ failure--a newly appreciated syndrome in the critically ill

Abstract

New onset thrombocytopenia and multiple organ failure (TAMOF) presages poor outcome in critical illness. Patients who resolve thrombocytopenia by day 14 are more likely to survive than those who do not. Patients with TAMOF have a spectrum of microangiopathic disorders that includes thrombotic thrombocytopenic purpura (TTP), disseminated intravascular coagulation (DIC) and secondary thrombotic microanigiopathy (TMA). Activated protein C is effective in resolving fibrin-mediated thrombosis (DIC); however, daily plasma exchange is the therapy of choice for removing ADAMTS 13 inhibitors and replenishing ADAMTS 13 activity which in turn resolves platelet: von Willebrand Factor mediated thrombosis (TTP/secondary TMA).

Figure 1

Systemic inflammation results in systemic coagulation. Thrombotic thrombocytopenuc purpura (TTP) is a microangiopathy phenotype characterized by ADAMTS 13 deficiency. Left: Platelets attach to ultra large vWF multimers. Because vWF-CP (ADAMTS 13) is inhibited this leads to massive vWF:platelet thrombosis (right). Ab, antibody; CP, cleaving protease; vWF, von Willebrand factor.

Figure 2

Disseminated intravascular coagulation (DIC) is a microangiopathy phenotype characterized by increased tissue factor (TF) and plasminogen activator inhibitor type I (PAI-1), unopposed by the anticoagulant proteins TFPI, protein C, antithrombin III, and prostacyclin. The severest forms also have an ADAMTS 13 deficiency. Tissue factor activates factor VII (left), leading to massive consumptive fibrin thrombosis (right). VII, factor VII; vWF, von Willebrand factor.

Figure 3

Secondary thrombotic microangiopathy (TMA) has a phenotype characterized by decreased ADAMTS 13, and increased plasminogen activator inhibitor type I (PAI-1) and von Willebrand factor (vWF) levels with normal or high fibrinogen levels. Platelets attach to increased large vWF multimers and form thrombi in the presence of decreased PAI-I activity (left), leading to systemic platelet thrombi with delayed fibrinolysis (right). CP, cleaving protease; TF, tissue factor; TFPI, tissue factor pathway inhibitor; vWF-CP, ADAMTS 13.

Figure 4

Specific therapies used to reverse or promote thrombosis and promote or stop fibrinolysis. Therapies used to reverse thrombosis include protein C concentrate (prot C), activated protein C (APC), tissue factor pathway inhibitor (TFPI), antithrombin III, heparin, and thrombin inhibitors such as argatroban and hyarudin. Therapies used to promote thrombosis include activated factor VII. Therapies used to promote fibrinolysis include tissue plasminogen activator (TPA), streptokinase, urokinase, and defibrinopeptide. Therapies used to stop fibrinolysis include aminocaproic acid, tranexamine, and aprotinin. PAI, plasminogen activator inhibitor type I.