Obstetrics and Gynecology/Hypertensive Disorders including Pre-Eclampsia

Definition

 * Diastolic blood pressure greater than 90mmHg on two recordings on the same arm greater than five minutes apart.
 * Gestational hypertension must be new onset after the 20th week of gestation.

Epidemiology

 * Affects 5% of pregnancies.
 * Along with bleeding, the leading cause of maternal mortality in Canada.
 * 35% risk of developing preeclampsia

Definition

 * Hypertension in pregnant women diagnosed prior to the 20th week of gestation.

Epidemiology

 * 25% risk of developing preeclampsia, with a 25% recurrence.

Definition

 * Gestational hypertension with proteinuria or end organ dysfunction.
 * Preexisting hypertension with resistant hypertension with new or worsening proteinuria or one or more adverse conditions.
 * Resistant hypertension requires 3 or more drugs for control after 20 weeks of gestation.
 * Proteinuria is suspected at a urine dipstick result >2. If this result is positive, a 24h protein collection should be done and the result will be >300mg/day. The latter test is performed to account for orthostatic proteinuria which may confound the dipstick test.
 * Adverse conditions are defined as
 * BP >160/110
 * HELLP syndrome: Hemolysis, Elevated Liver enzymes, Low Platelets. Leads to placental abruption, hepatic and or renal dysfunction, preterm delivery, and death.
 * Proteinuria >5g per day
 * CNS symptoms
 * Pulmonary edema
 * Fetal growth restriction
 * Severe preeclampsia is pre-eclampsia beginning before 34 weeks with 5g proteinuria per day. 20% of these women develop HELLP

Etiology

 * Etiology unknown, but may involve vascular endothelial damage and widespread coagulation.
 * Risk factors include nulliparity, >35 or <18 years of age in the mother, past history of preeclampsia or hypertension, connective tissue disease, diabetes, black, thrombophilia, antiphospholipid antibody syndrome, and mulitfetal gestation.

Pathophysiology

 * The primary factor is vasospasm to separate end organs.
 * Hematologic abnormalities include hemolysis, thrombocytopenia, and coaglulopathy secondary to hepatic dysfunction.
 * Decreased renal blood flow leads to increased blood urea nitrate concentration.
 * Neurological sequelae ensue: headache, visual changes, seizures from intracranial bleeding.
 * Decreased blood flow to the fetus creates hypoxia, growth restriction, and oligohydramnios.

Clinical Presentation

 * Eclampsia

Management

 * The primary treatment for gestational hypertension and pre-eclampsia is delivery.
 * If term gestation (>37 weeks), deliver the baby.
 * If preterm (<34 weeks), only deliver if membranes have ruptured, if the fetal status is questionable, intrauterine growth retardation, and the fetal lungs appear mature.
 * Patients should be sent to a tertiary center with high-level neonatal care.
 * If adverse conditions are present
 * Antihypertensive medications should be administered (target less than 160/110, but with the diastolic pressure no lower than 90 acutely)
 * MgSO4
 * Anesthesia
 * Delivery
 * MgSO4 IV bolus and infusion for eclampsia, antihypertensives, and delivery. The mother is the first priority in this circumstance.
 * Delivery independent of gestational age for HELLP syndrome.
 * Prevention: baby aspirin once every day; calcium 1g per day, every day.