O&G · Critical care — maternal resuscitation
Hypertensive crisis and refractory eclampsia
Also known as Severe hypertension in pregnancy · Hypertensive emergency in pregnancy · Refractory eclampsia · Recurrent eclampsia · Magnesium-resistant eclampsia · Pre-eclampsia with severe features
Exam-exhaustive FRANZCOG fellowship reference on the hypertensive crisis and refractory eclampsia — the severe-range blood pressure treatment targets and the three first-line agents (labetalol, hydralazine, nifedipine) with doses and titration, the magnesium sulfate loading, maintenance and antidote with doses, the refractory-eclampsia escalation ladder, and the delivery decision. RANZCOG-primary, globally tagged to MRCOG and ABOG.
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Red flags
- Severe-range blood pressure — systolic 160 or diastolic 110 or more — is an emergency needing treatment within hours, not observation
- Sublingual nifedipine causes precipitate cerebral and coronary hypoperfusion — give it oral, never sublingual
- Over-rapid or excessive blood pressure reduction causes stroke — the target is controlled, not normal
- Disappearing reflexes, a respiratory rate under 12, or a falling conscious level — suspect magnesium toxicity and give calcium gluconate now
- Recurrent seizure despite magnesium is refractory eclampsia — escalate to a second agent, do not simply reload
- A normal blood pressure after birth does not mean the crisis is over — postpartum pre-eclampsia and eclampsia peak in the first 48 hours
It is 04:15 on labour ward. A woman at 37 weeks with known pre-eclampsia has just had a tonic-clonic seizure. Her blood pressure is 188/118. You have three jobs in the first ten minutes — protect her airway, control her blood pressure, and stop the seizures with magnesium — and one job that decides everything: deliver her, once she is stable. Eclampsia and the hypertensive crisis reward the registrar who has the doses on the tip of the tongue and punishes the one who reaches for the wrong drug. This topic is that rehearsal.[1][3]
Overview and definition
A hypertensive crisis in pregnancy is severe-range blood pressure — a systolic of 160 mmHg or more, or a diastolic of 110 mmHg or more, sustained — that threatens cerebral autoregulation and demands urgent treatment. The threshold is set because cerebral haemorrhage, the leading cause of pre-eclampsia-related death, tracks the uncontrolled high pressure.[5][8]
Eclampsia is a tonic-clonic seizure in a woman with pre-eclampsia where no alternative cause is found. Refractory (recurrent) eclampsia is a seizure that recurs despite an adequate loading dose of magnesium sulfate — the condition that forces the escalation ladder. Status epilepticus in pregnancy is rarer still but overlaps with the refractory-eclampsia pathway.[1][6]
Two facts frame the whole topic. First, magnesium sulfate halves the risk of eclampsia in pre-eclampsia and is superior to both diazepam and phenytoin for treating it — the clearest evidence-based win in obstetric critical care.[1][3] Second, the single biggest error is not the choice of drug but the timing: a severe-range pressure left untreated, or a magnesium infusion started too late.[8][9]
References10ShowHide
- [1]Which anticonvulsant for women with eclampsia? Evidence from the Collaborative Eclampsia Trial Lancet, 1995.PMID 7769899
- [2]Altman D, Carroli G, Duley L, et al. Do women with pre-eclampsia, and their babies, benefit from magnesium sulphate? The Magpie Trial: a randomised placebo-controlled trial Lancet, 2002.PMID 12057549
- [3]Duley L, Gülmezoglu AM, Henderson-Smart DJ, et al. Magnesium sulphate and other anticonvulsants for women with pre-eclampsia Cochrane Database Syst Rev, 2010.PMID 21069663
- [4]Duley L, Meher S, Jones L Drugs for treatment of very high blood pressure during pregnancy Cochrane Database Syst Rev, 2013.PMID 23900968
- [5]Gestational Hypertension and Preeclampsia: ACOG Practice Bulletin, Number 222 Obstet Gynecol, 2020.PMID 32443079
- [6]Roberti R, Rocca M, Iannone LF, et al. Status epilepticus in pregnancy: a literature review and a protocol proposal Expert Rev Neurother, 2022.PMID 35317697
- [7]Vossler DG, Bainbridge JL, Boggs JG, et al. Treatment of Refractory Convulsive Status Epilepticus: A Comprehensive Review by the American Epilepsy Society Epilepsy Curr, 2020.PMID 32822230
- [8]Nair M, Kurinczuk JJ, Brocklehurst P, et al. Factors associated with maternal death from direct pregnancy complications: a UK national case-control study BJOG, 2015.PMID 25573167
- [9]Schaap TP, Knight M, Zwart JJ, et al. Eclampsia, a comparison within the International Network of Obstetric Survey Systems BJOG, 2014.PMID 24636369
- [10]Smith JM, Lowe RF, Fullerton J, et al. An integrative review of the side effects related to the use of magnesium sulfate for pre-eclampsia and eclampsia management BMC Pregnancy Childbirth, 2013.PMID 23383864