Reproductive · Hypertensive Disorders of Pregnancy
The facts most likely to be tested
Preeclampsia is defined as new-onset hypertension (systolic ≥140 or diastolic ≥90) after 20 weeks gestation accompanied by proteinuria or end-organ dysfunction.
The presence of severe features includes a systolic BP ≥160, diastolic BP ≥110, thrombocytopenia, impaired liver function, progressive renal insufficiency, pulmonary edema, or new-onset cerebral/visual disturbances.
Magnesium sulfate is the first-line agent for the prevention of eclamptic seizures in patients with preeclampsia with severe features.
Delivery is the only definitive treatment for preeclampsia, with timing determined by gestational age and the presence of severe features.
Low-dose aspirin (81 mg/day) is indicated for high-risk patients starting between 12 and 28 weeks gestation to reduce the risk of developing preeclampsia.
HELLP syndrome is a severe variant of preeclampsia characterized by hemolysis, elevated liver enzymes, and low platelets.
Eclampsia is defined as the development of tonic-clonic seizures in a patient with preeclampsia that cannot be attributed to other neurological conditions.
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A 28-year-old G1P0 woman at 34 weeks gestation presents for a routine prenatal visit. She reports a mild persistent headache and blurred vision over the last two days. Physical examination reveals a blood pressure of 165/105 mmHg and 2+ pitting edema of the lower extremities. Laboratory studies demonstrate a platelet count of 90,000/µL and an elevated AST/ALT.
What is the most appropriate next step in management to prevent a life-threatening complication?
Intravenous magnesium sulfate administration
The patient exhibits preeclampsia with severe features (hypertension, visual disturbances, thrombocytopenia, and elevated liver enzymes); magnesium sulfate is required for seizure prophylaxis.
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High yield triage
Etiology / Epidemiology
Occurs >20 weeks gestation. Nulliparity, advanced maternal age, and chronic hypertension are primary risk factors.
Clinical Manifestations
New-onset hypertension and proteinuria or end-organ dysfunction. HELLP syndrome is a severe variant.
Diagnosis
BP ≥140/90 mmHg on two occasions + proteinuria (≥300mg/24hr or protein/creatinine ratio ≥0.3).
Treatment
Magnesium sulfate for seizure prophylaxis; delivery is the only definitive cure.
Prognosis
Risk of eclampsia (seizures) and placental abruption. Monitor for postpartum resolution.
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Epidemiology & Etiology
Primarily affects nulliparous women or those with a history of preeclampsia. Other high-risk factors include multiple gestations, diabetes mellitus, and renal disease. It is considered a disease of the placenta, typically resolving after delivery.
Pertinent Anatomy
The placenta is the primary organ of pathology. Abnormal trophoblastic invasion leads to inadequate remodeling of the spiral arteries, causing placental ischemia.
Pathophysiology
Placental ischemia triggers the release of anti-angiogenic factors into maternal circulation. This causes systemic endothelial dysfunction, leading to increased vascular permeability and vasoconstriction. The resulting hypertension and end-organ damage define the clinical syndrome.
Clinical Manifestations
Patients present with new-onset hypertension and signs of end-organ damage such as headache, visual disturbances (scotomata), or epigastric/RUQ pain. Eclampsia is defined by the onset of tonic-clonic seizures. HELLP syndrome (Hemolysis, Elevated Liver enzymes, Low Platelets) is a life-threatening complication.
Diagnosis
Diagnosis requires BP ≥140/90 mmHg on two occasions at least 4 hours apart after 20 weeks gestation. Proteinuria is confirmed via 24-hour urine collection (≥300mg) or a protein/creatinine ratio ≥0.3. In the absence of proteinuria, diagnosis is confirmed by thrombocytopenia, impaired liver function, renal insufficiency, or pulmonary edema.
Treatment
For severe features, magnesium sulfate is the first-line agent for seizure prophylaxis. Antihypertensive therapy (e.g., labetalol or hydralazine) is indicated for BP ≥160/110 mmHg. Do not use ACE inhibitors or ARBs due to fetal renal failure. Delivery is the definitive treatment, with timing dependent on gestational age and maternal stability.
Prognosis
Complications include placental abruption, DIC, and stroke. Patients require close monitoring for postpartum hypertension, which can persist for weeks. Long-term, these patients have an increased risk of cardiovascular disease later in life.
Differential Diagnosis
Chronic hypertension: elevated BP present before 20 weeks gestation
Gestational hypertension: elevated BP without proteinuria or end-organ damage
Chronic kidney disease: elevated creatinine and proteinuria present prior to pregnancy
Acute fatty liver of pregnancy: associated with hypoglycemia and jaundice
Thrombotic thrombocytopenic purpura: characterized by fever and neurological deficits