Clinical spectrum of pre-eclampsia

Pre-eclampsia is a unique disorder found only in human pregnancies. Historically, pre-eclampsia has been defined as the triad of hypertension, proteinuria and edema in a pregnant woman. Eclampsia is the occurrence of seizures that cannot be attributed to another cause in a patient with pre-eclampsia. Pre-eclampsia typically occurs in the third trimester of pregnancy, although some cases manifest earlier. Although many patients with pre-eclampsia demonstrate the classic triad, it is now clear that the disorder is really a spectrum of clinical signs and symptoms that accompany microvascular changes in multiple organ systems (Fig. 38.1). The disorder has so many presentations that it has been called the “great imitator.” Central nervous system involvement can result in severe headaches, visual changes, seizures, stroke and blindness. Renal involvement is almost always present and can manifest as proteinuria, oliguria or renal failure. Edema can accumulate in many sites, including the feet, hands, face and lungs. Hemoconcentration, thrombocytopenia and intravascular hemolysis are common signs of hematologic involvement. Hepatic dysfunction often accompanies hematologic changes and produces a group of clinical findings known as HELLP syndrome (hemolysis, elevated liver function tests, low platelets). Patients with HELLP will often develop vague epigastric pain resulting from liver involvement which may be mistaken for heartburn, gallbladder disease or the flu by an unsuspecting health care provider.

The overall incidence of pre-eclampsia in the obstetric population is 5–8%; the absolute number depends on the proportion of patients at increased risk. Risk factors for developing pre-eclampsia include the primigravid state (first pregnancy), multiple gestation, diabetes, pre-existing hypertension, a long interval between pregnancies, pre-eclampsia in a previous pregnancy, a family history of pre-eclampsia, hydatidiform mole, and inherited and acquired clotting disorders (e.g., protein S and protein C deficiencies and antiphospholipid antibodies). There is considerable overlap between the risk factors for pre-eclampsia and those for fetal growth restriction (FGR). Indeed, the presence of FGR may be the first sign of impending pre-eclampsia and women with pre-eclampsia are at risk for delivering a growth-restricted baby.

Left untreated, pre-eclampsia can be a highly morbid and even fatal disease. The ultimate treatment for the condition is delivery of the pregnancy. This is so effective a therapy that all deranged physiology will revert to normal after delivery provided that no permanent tissue damage has occurred. If the mother is medically supported through a timely delivery and postpartum recovery, her kidneys will begin to make urine again, blood will clot and seizures will stop. In spite of its potential for a 100% cure with proper diagnosis and treatment, pre-eclampsia remains one of the leading causes of maternal death in both developed and developing countries.