Preeclampsia: Pathophysiology

General Features

• Preeclampsia is classically defined as the new onset of hypertension and proteinuria after 20 weeks of gestation.

  • New onset hypertension with significant end-organ dysfunction (with or without proteinuria) after 20 weeks of gestation also satisfies the diagnosis of preeclampsia.

    • Severe headache, epigastric or right upper quadrant pain, visual disturbances, thrombocytopenia, impaired liver function, renal insufficiency, pulmonary edema

    • HELLP syndrome: Hemolysis, Elevated Liver enzymes, Low Platelets

  • Edema may or may not be present.

• Eclampsia = preeclampsia + seizures

• Risk factors include nulliparity, past history of preeclampsia, preexisting hypertension or renal disease, autoimmune disease, very young or advanced maternal age, diabetes, and obesity.

• Curative treatment is delivery

Pathophysiology

• Genetic and immunological factors

• Defective spiral artery remodeling during pregnancy

  • During a normal pregnancy trophoblast cells invade the myometrial segment of the spiral arteries to cause transformation and dilation of the arteries.

  • In preeclampsia there is insufficient trophoblast cell invasion, which causes the spiral arteries to remain narrow and leads to placental hypoperfusion.

• Diseased placenta releases proinflammatory proteins

  • Hypertension

  • Vasoconstriction

  • Endothelial cell dysfunction

    • Formation of thrombi

  • End-organ damage