Amniotic fluid embolism is sudden, with the vascular collapse of the woman soon after delivery. Due to the presence of procoagulant rich fluid in the circulatory system, there is often overwhelming DIC. Therapy is directed at both supporting blood volume and correcting hemostatic defects.
HELLP
The acronym HELLP (hemolysis, elevated liver tests, low platelets) describes a variant of preeclampsia.90 Classically, HELLP syndrome occurs after 28 weeks of gestation in a patient with preeclampsia, but can occur as early as 22 weeks in patients with antiphospholipid antibody syndrome.91–93 The preeclampsia need not be severe. The first sign of HELLP is a decrease in the platelet count followed by abnormal liver function tests. Signs of hemolysis are present with abundant schistocytes on the smear and a high lactate dehydrogenase level. HELLP can progress to liver failure, and deaths are also reported due to hepatic rupture. Unlike TTP, fetal involvement is present in the HELLP syndrome, with fetal thrombocytopenia reported in 30% of cases. In severe cases, elevated D-dimers consistent with DIC are also found. Delivery of the child will most often result in cessation of the HELLP syndrome, but refractory cases will require dexamethasone and plasma exchange.94 Patients should be closely observed for 1 to 2 days after delivery as the hematologic picture can transiently worsen before improving.95
Acute Fatty Liver of Pregnancy
Fatty liver of pregnancy also occurs late in pregnancy and is only associated with preeclampsia in 50% of cases.96,97 Patients first present with nonspecific symptoms of nausea and vomiting but can progress to fulminant liver failure. Patients develop thrombocytopenia early in the course, but in the later stages can develop DIC and very low fibrinogen levels. Mortality rates without therapy can be as high as 90%. Low blood glucose and high ammonia levels can help distinguish fatty liver from other pregnancy complications.98 Treatment consists of prompt delivery of the child and aggressive blood product support.
Retained Dead Fetus Syndrome
Becoming rarer in modern practices, the presence of a dead fetus for many weeks (usually ≥ 5) can result in a chronic DIC state with fibrinogen depletion and coagulopathy. In some women, this is worsened at delivery. In a stable patient, a short trial of heparin prior to planning delivery can control the DIC to allow the coagulopathy to stabilize.
DRUG-INDUCED HEMOLYTIC-DIC SYNDROMES
A severe variant of the drug-induced immune complex hemolysis associated with DIC has been recognized. Rare patients who receive certain second- and third-generation cephalosporins (especially cefotetan and ceftriaxone) have developed this syndrome.99–104 The clinical syndrome starts 7 to 10 days after the drug is administered. Often the patient has only received the antibiotic for surgical prophylaxis. The patient will develop severe Coombs’-positive hemolysis with hypotension and DIC. The patients are often believed to have sepsis and in the management of the supposed sepsis often are re-exposed to the cephalosporin, resulting in worsening of the clinical picture. The outcome is often fatal due to massive hemolysis and thrombosis.101,105–107
Quinine is associated with a unique syndrome of drug-induced DIC.108–111 Approximately 24 to 96 hours after quinine exposure, the patient becomes acutely ill with nausea and vomiting. The patient then develops a microangiopathic hemolytic anemia, DIC, and renal failure. Some patients, besides having antiplatelet antibodies, also have antibodies binding to red cells and neutrophils, which may lead to the more severe syndrome. Despite therapy, patients with quinine-induced TTP have a high incidence of chronic renal failure.
Treatment of the drug-induced hemolytic-DIC syndrome is anecdotal. Patients have responded to aggressive therapy, including plasma exchange, dialysis, and prednisone. Early recognition of the hemolytic anemia and the suspicion it is drug related is important for early diagnosis so that the incriminated drug can be discontinued.
CANCER
Cancers, primarily adenocarcinomas, can result in DIC. The classic Trousseau syndrome referred to the association of migratory superficial thrombophlebitis with cancer112 but now refers to cancer associated with thrombotic DIC.113,114 Highly vascular tumor cells are known to express tissue factor.114,115 In addition, some tumor cells can express a direct activator of factor X (“cancer procoagulant”). Unlike many DIC states, cancer presents with thrombosis instead of bleeding. This may be due to the inflammatory state which accompanies cancer, or it may be a unique part of the chronic nature of cancer DIC biology that allows time for the body to compensate for loss of coagulation factors. In some patients, thrombosis is the first sign of an underlying cancer, sometimes predating the cancer diagnosis by months.115 Rarely, the DIC can result in nonthrombotic endocarditis with micro-emboli leading to widespread small-vessel thrombosis.113