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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