Ischemic necrosis of both lower extremities as a result of the microembolism syndrome complicating the adult respiratory distress syndrome caused by Escherichia coli pneumonia and septicemia.

Extensive gangrene of both lower extremities necessitating bilateral above-the-knee amputations complicated the adult respiratory distress syndrome (ARDS) caused by Escherichia coli pneumonia and septicemia in a 52-yr-old man. Concurrent with the evolution of tissue necrosis, peripheral blood leukocyte and platelet counts fell, and pulmonary vascular resistance increased. Adequacy of the cardiac output was confirmed by repeated thermodilution cardiac output measurements, and major vascular occlusion was excluded surgically. Fibrin degradation products and thrombocytopenia were present, but the other usual criteria for disseminated intravascular coagulation were absent. Small vessel thrombosis by fibrin and leukocytes was observed histologically in the amputated extremities. These findings suggest that gangrene was due to the "microembolism syndrome"--diffuse small vessel occlusion by fibrin thrombi complicating ARDS. This unusual complication of ARDS may occur without abnormalities suggestive of diffuse intravascular coagulation in routine laboratory tests of blood coagulation. It should be suspected and treated promptly to avoid severe disability in survivors.