Eclampsia

Quick links · seizure types & pathways
Seizure overviewStatus EpilepticusEclampsia (pregnancy)OB EmergenciesAlcohol withdrawalToxic ingestionFebrile seizure (peds)Hypoglycemia
New seizure in pregnancy ≥ 20 wk or ≤ 6 wk postpartum
Definition

Magnesium is first-line — NOT benzos. Benzos only if Mg fails or unavailable. Treat severe HTN (≥160/110) within 30–60 min. Definitive Rx is delivery.

Immediate priorities
  • ABCs · left lateral decubitus · O₂ NRB · suction · IV ×2 · monitor · fetal monitoring (if undelivered, > viability)
  • Call OB & anesthesia STAT · prepare for emergent delivery
  • Fingerstick glucose — D50 25 g IV if < 60
  • Labs: CBC, CMP, LFTs, LDH, uric acid, haptoglobin, smear, PT/PTT/fibrinogen, UA (protein/Cr ratio), type & screen, β-hCG (if undocumented gestation)
  • Rule out HELLP, abruption, ICH (if focal deficit, persistent AMS, or atypical features → CT head)
  • Foley to monitor UOP (Mg held if < 30 mL/hr · UOP guides toxicity risk)
  • DTRs and RR q15 min while loading Mg
≈ 154.3 lb
① Magnesium sulfate — first-line (start immediately)
  • Loading dose
    4–6 g IV over 15–20 min (mix in 100 mL NS)
  • Maintenance infusion
    1–2 g/hr IV continuous × 24 h after last seizure or delivery
  • No IV access — IM
    10 g IM (5 g each buttock); then 5 g IM q4h
  • Recurrent seizure on Mg
    Re-bolus 2 g IV over 5 min — then move to benzos if still seizing

Therapeutic Mg level 4.8–8.4 mg/dL. Loss of patellar reflex ≈ 9–12 · respiratory depression ≈ 12–16 · cardiac arrest > 25.

② Severe HTN — goal < 160/110 within 30–60 min
  • Labetalol (first-line)
    20 mg IV → 40 mg → 80 mg q10 min (max cumulative 300 mg) — avoid if asthma, HR < 60, decompensated HF
  • Hydralazine
    5–10 mg IV, repeat q20 min (max 30 mg) — risk of maternal hypotension → fetal distress
  • Nifedipine IR (PO option)
    10 mg PO, repeat q20 min × up to 3 doses (immediate-release only)

Avoid > 25% MAP drop — placental hypoperfusion. Avoid ACE-I/ARB, nitroprusside (cyanide accumulation), and esmolol (fetal bradycardia) when possible.

③ Refractory seizure (Mg ineffective) — benzo, then second-line
  • Lorazepam
    0.1 mg/kg IV (max 4 mg/dose), may repeat ×1
  • Midazolam (no IV)
    10 mg IM (≥40 kg) or 0.2 mg/kg IN (max 10 mg)
  • Diazepam (backup IV)
    0.2 mg/kg IV (max 10 mg/dose)
  • Levetiracetam (second-line load)
    60 mg/kg IV over 10 min (max 4500 mg) — preferred over fosphenytoin in pregnancy
  • Still seizing → intubate
    1–2 mg/kg IV + 1.2 mg/kg IV · then midazolam / propofol drip · OB for emergent delivery
④ Magnesium toxicity — rescue
  • Stop the magnesium infusion immediately
  • 1 g IV over 5–10 min (may repeat)
  • Support airway / ventilation · BVM · intubate if RR < 8 or apneic
  • Send Mg level; resume at lower rate once cleared and DTRs return

Toxicity signs: loss of DTRs (first), RR < 12, somnolence, flushing, UOP < 30 mL/hr, ECG changes, cardiac arrest.

Weight-based doses (auto-calculated)
Magnesium (fixed dosing — not weight-based)
Mg sulfate load
4–6 g IV / 15–20 min
Mg sulfate maintenance
× 24 h after last seizure or delivery
1–2 g/hr IV
Mg sulfate IM (no IV)
5 g each buttock; then 5 g q4h
10 g IM
Calcium gluconate (toxicity)
1 g IV / 5–10 min
Refractory benzos (if Mg fails)
Lorazepam 0.1 mg/kg IV
max 4 mg
4 mg
Midazolam 0.1 mg/kg IV
max 10 mg
7 mg
Midazolam IM
RAMPART weight band
10 mg
Diazepam 0.2 mg/kg IV
max 10 mg
10 mg
Second-line (after benzo)
Levetiracetam 60 mg/kg IV / 10 min
max 4500 mg · preferred in pregnancy
4,200 mg
Disposition
  • OB / MFM & anesthesia at bedside · admit L&D or OB-ICU
  • Definitive treatment is delivery — timing per OB (gestational age, fetal status, maternal stability)
  • Continue Mg × 24 h after delivery or last seizure; monitor DTRs, RR, UOP, Mg levels
  • Postpartum eclampsia can occur up to 6 weeks — counsel on warning signs (HA, vision changes, RUQ pain, edema)
Status Epilepticus PathwayFull OB Emergencies

Educational aid only — verify against ACOG and local OB / anesthesia protocols.