Back
ditki Logo
medical & biological sciences

Pre-eclampsia & Eclampsia for ABIM

Start your One-Week Free Trial
Already subscribed? Log in »
Pre-eclampsia & Eclampsia for the American Board of Internal Medicine Exam
Overview of Pre-eclampsia and Eclampsia
  • Definition and Classification:
    • Pre-eclampsia: A hypertensive disorder occurring after 20 weeks of gestation characterized by new-onset hypertension (≥140/90 mmHg) and proteinuria (≥300 mg/24 hours) or systemic organ dysfunction.
    • Eclampsia: A severe complication of pre-eclampsia marked by new-onset generalized tonic-clonic seizures not attributable to other causes.
    • Classifications of Pre-eclampsia:
    • Mild Pre-eclampsia: Hypertension without severe end-organ damage or significant laboratory abnormalities.
    • Severe Pre-eclampsia: Defined by blood pressure ≥160/110 mmHg, or presence of symptoms such as severe headache, visual changes, elevated liver enzymes, thrombocytopenia, or pulmonary edema.
  • Epidemiology:
    • Pre-eclampsia affects 2–8% of pregnancies globally and is a leading cause of maternal and neonatal morbidity and mortality.
    • Eclampsia is rarer, occurring in about 0.5% of women with pre-eclampsia if untreated or poorly managed.
Pathophysiology
  • Vascular Dysfunction and Placental Abnormalities:
    • Abnormal placental implantation leads to shallow invasion of trophoblasts and impaired spiral artery remodeling.
    • Placental ischemia triggers the release of antiangiogenic factors like soluble fms-like tyrosine kinase-1 (sFlt-1), which antagonizes vascular endothelial growth factor (VEGF) and promotes endothelial dysfunction.
  • Systemic Inflammation:
    • An imbalance in immune regulation causes excessive systemic inflammatory responses and oxidative stress, further contributing to vascular and endothelial dysfunction.
  • Endothelial Injury and Increased Vascular Permeability:
    • Endothelial damage from circulating factors disrupts nitric oxide synthesis, resulting in vasoconstriction, increased vascular permeability, and hypertension.
    • Proteinuria results from damage to glomerular endothelium, leading to leakage of protein into the urine.
  • Coagulopathy:
    • Endothelial injury promotes a pro-coagulant state, with an increased risk of thrombotic events and complications such as HELLP (hemolysis, elevated liver enzymes, low platelets) syndrome.
Clinical Presentation
  • Symptoms of Pre-eclampsia:
    • Mild Pre-eclampsia: May be asymptomatic or present with mild edema and headache.
    • Severe Pre-eclampsia: Patients may experience:
    • Severe headaches
    • Blurred vision or scotomata
    • Right upper quadrant or epigastric pain
    • Nausea and vomiting
    • Dyspnea due to pulmonary edema
  • Signs of Eclampsia:
    • Onset of seizures in the presence of pre-eclampsia symptoms.
    • Symptoms may precede seizures, such as severe headache, visual disturbances, and hyperreflexia.
  • Differential Diagnosis:
    • Consideration of other causes of seizures and hypertension in pregnancy, such as epilepsy, cerebrovascular events, and systemic lupus erythematosus, is critical in the diagnostic process.
Diagnostic Evaluation
  • Laboratory Tests:
    • Urinary Protein: ≥300 mg in a 24-hour urine collection confirms proteinuria; alternatively, urine protein-to-creatinine ratio ≥0.3 is diagnostic.
    • Complete Blood Count (CBC): Thrombocytopenia (platelets <100,000/mcL) is a marker of severity.
    • Liver Function Tests (LFTs): Elevated liver enzymes (AST/ALT >2 times the upper limit of normal) indicate liver involvement.
    • Renal Function Tests: Elevated serum creatinine (>1.1 mg/dL) or doubling of baseline indicates renal impairment.
    • Uric Acid Levels: Often elevated in pre-eclampsia and may correlate with disease severity.
  • Imaging:
    • Obstetric Ultrasound: Used to assess fetal growth restriction (common in pre-eclampsia) and amniotic fluid volume.
    • Doppler Ultrasound: Abnormal flow in uterine arteries can suggest impaired placental perfusion.
Management and Treatment
  • General Management:
    • Close maternal and fetal monitoring is essential for both pre-eclampsia and eclampsia to assess worsening symptoms or complications.
    • Delivery is the definitive treatment, often pursued if the disease is severe or if gestational age is beyond 37 weeks.
  • Blood Pressure Control:
    • Target BP: Typically <160/110 mmHg to prevent further complications.
    • First-line Medications: Labetalol, nifedipine, and hydralazine are preferred due to their safety profile in pregnancy.
    • Monitoring: Regular blood pressure monitoring and adjustment of antihypertensive therapy based on BP readings.
  • Seizure Prophylaxis and Treatment:
    • Magnesium Sulfate: Administered as prophylaxis for severe pre-eclampsia and as first-line treatment for eclamptic seizures.
    • Dosage: Loading dose of 4–6 g IV, followed by maintenance infusion (1–2 g/hr).
    • Monitoring: Magnesium levels, reflexes, and respiratory rate to avoid toxicity.
    • Alternative Agents: If magnesium is contraindicated or seizures persist, benzodiazepines or phenytoin may be used.
  • Fetal Management:
    • Steroid Administration: For pregnancies between 24–34 weeks of gestation to accelerate fetal lung maturity in anticipation of preterm delivery.
    • Continuous Fetal Monitoring: Essential in severe pre-eclampsia to detect signs of fetal distress.
    • Delivery Planning: Timing and mode of delivery depend on disease severity, gestational age, and fetal status.
Complications
  • Maternal Complications:
    • Cerebral Edema and Stroke: Eclampsia increases the risk of cerebral edema, seizures, and stroke.
    • HELLP Syndrome: A severe variant characterized by hemolysis, elevated liver enzymes, and low platelet count, with increased risks of hepatic rupture and renal failure.
    • Pulmonary Edema: Resulting from endothelial injury, leading to fluid leakage and respiratory distress.
  • Fetal Complications:
    • Intrauterine Growth Restriction (IUGR): Impaired placental perfusion can cause restricted fetal growth.
    • Prematurity: Often necessitated by early delivery due to maternal or fetal compromise, with associated neonatal complications.
    • Stillbirth: Severe pre-eclampsia and eclampsia increase the risk of intrauterine fetal demise.
Prevention
  • Low-Dose Aspirin:
    • Initiating low-dose aspirin (81 mg/day) between 12 and 28 weeks gestation reduces the risk of pre-eclampsia in high-risk individuals.
    • Recommended for women with a history of pre-eclampsia, chronic hypertension, or other predisposing factors.
  • Lifestyle and Dietary Adjustments:
    • Although not definitive in prevention, maintaining a healthy lifestyle, adequate calcium intake, and smoking cessation are generally advised.
  • Follow-up After Delivery:
    • Blood pressure monitoring is essential in the postpartum period, as pre-eclampsia can worsen or emerge after delivery.
    • Long-term cardiovascular risk is elevated in women with a history of pre-eclampsia, necessitating regular follow-up and lifestyle modifications to mitigate cardiovascular risk factors.
Key Points
  • Pre-eclampsia is characterized by new-onset hypertension and proteinuria after 20 weeks gestation, while eclampsia involves seizures.
  • The underlying mechanism involves abnormal placentation, vascular dysfunction, and systemic inflammation leading to endothelial injury.
  • Severe pre-eclampsia is diagnosed by high BP (>160/110 mmHg) or symptoms such as headache, visual changes, and organ dysfunction.
  • Management includes blood pressure control with antihypertensives and seizure prophylaxis with magnesium sulfate.
  • Delivery is the only definitive treatment; timing depends on severity, gestational age, and maternal/fetal status.
  • Major maternal complications include cerebral edema, HELLP syndrome, and pulmonary edema; fetal complications include IUGR and preterm delivery.
  • Low-dose aspirin is recommended for high-risk women to reduce the incidence of pre-eclampsia.

Related Tutorials