Eclampsia

Eclampsia is one or more generalised seizures in a woman with preeclampsia, not caused by epilepsy or other brain disease. It results from cerebral vasospasm, oedema and loss of autoregulation. It is far more common where antenatal care is limited, and carries a high maternal and perinatal mortality.

• It may follow severe preeclampsia or occur with only mild hypertension.
• Magnesium sulphate is the drug of choice and is better than diazepam or phenytoin.
• Delivery follows stabilisation.

The woman has a tonic clonic seizure lasting 1 to 3 minutes, followed by a postictal state with drowsiness or confusion. Warning signs include headache, visual change, epigastric pain and hyperreflexia, but may be absent.

• Hypertension and proteinuria are usual.
• Tongue biting, incontinence and hypoxia during the fit.
• Differential diagnosis: epilepsy, cerebral malaria, meningitis, cerebral venous thrombosis, intracranial haemorrhage, hypoglycaemia, hypertensive encephalopathy, hyponatraemia, thrombotic thrombocytopenic purpura, space occupying lesion.
• Complications: aspiration, hypoxia, stroke, cerebral oedema, pulmonary oedema, abruption, HELLP syndrome, acute kidney injury, fetal bradycardia, maternal and perinatal death.

The diagnosis is clinical, made by a seizure in a woman with new hypertension after 20 weeks or up to 6 weeks after birth.

• Blood pressure, urine protein, reflexes, temperature, glucose; malaria test.
• Full blood count and film, creatinine, electrolytes, liver enzymes, lactate dehydrogenase, coagulation screen, group and cross-match.
• CT or MRI of the brain if seizures are atypical, focal deficit, persistent coma, onset after 48 hours postpartum, or no response to magnesium.
• Cardiotocography after the mother is stable.

The principle is to protect the airway, stop and prevent seizures with magnesium sulphate, control blood pressure and deliver once stable.

• Supportive: call for help; place on the left side on a flat surface; protect from injury; clear the airway; give oxygen 10 to 15 L/minute by mask; two cannulae; urinary catheter with hourly output; restrict total fluids to 80 mL per hour; continuous pulse oximetry; avoid restraint.
• Pharmacological: magnesium sulphate 4 g IV over 20 minutes then 1 g per hour for 24 hours after the last seizure or delivery, whichever is later, or where infusion is not possible give 4 g IV plus 10 g IM (5 g in each buttock) then 5 g IM 4-hourly; for a repeat seizure give 2 g IV over 5 minutes; stop magnesium for absent patellar reflexes, respiratory rate below 12 per minute or urine below 30 mL per hour, and give calcium gluconate 1 g IV over 10 minutes for toxicity; if magnesium is unavailable give diazepam 10 mg IV over 2 minutes, repeated once after 10 minutes, with airway support; labetalol 20 mg IV over 2 minutes then 40 mg, 80 mg and 80 mg at 10 minute intervals (maximum 220 mg) or nifedipine immediate release 10 mg oral repeated after 30 minutes or hydralazine 5 mg IV then 5 to 10 mg every 20 to 30 minutes (maximum 20 mg) to bring blood pressure to 140 to 150/90 to 100 mmHg; dextrose 50 percent 50 mL IV if glucose is below 3.5 mmol/L; betamethasone 12 mg IM twice, 24 hours apart, before 34 weeks if time allows; oxytocin 10 IU IM after birth and no ergometrine.
• Procedures: delivery within 12 hours of the first seizure after stabilisation; induction with misoprostol 25 micrograms vaginal 6-hourly (maximum 4 doses) or Foley catheter with oxytocin if vaginal birth is expected, otherwise caesarean section; assisted second stage with forceps or vacuum; intubation for coma or aspiration.
• Special groups: kidney disease reduces magnesium sulphate to 0.5 g per hour with level monitoring; asthma uses nifedipine instead of labetalol.
• Red flags: repeated seizures, coma, blood pressure 160/110 mmHg or more, oxygen saturation below 94 percent, oliguria, bleeding, fetal bradycardia.
• Follow-up: high dependency care for 24 to 48 hours after birth; blood pressure at 6 hours, daily for 5 days, then at 2 and 6 weeks; neurological review at 6 weeks, with imaging if deficits persist; counsel on recurrence and aspirin from 12 weeks in future pregnancy.