Hypertensive disorders of pregnancy — the spectrum and the magnesium sulphate

The spectrum:

• The gestational hypertension — the new HTN after 20 weeks, no proteinuria or the end-organ.
• The pre-eclampsia — the new HTN after 20 weeks PLUS the proteinuria or the end-organ. The severe features (the 160 over 110 or above, the thrombocytopenia, the creatinine, the transaminases, the pulmonary oedema, the cerebral or the visual) define the severe pre-eclampsia.
• The eclampsia — the seizure.
• The HELLP — the haemolysis, the elevated liver, the low platelets.
• The chronic hypertension and the superimposed pre-eclampsia.

The severe features (the trigger for the severe management and the delivery): the blood pressure 160 over 110 or above, the thrombocytopenia (the platelets below 100), the progressive renal insufficiency (the creatinine above 1.1), the impaired liver (the transaminases twice the normal), the pulmonary oedema, and the new-onset headache or the visual symptoms. ^[1][3]

The role of the magnesium sulphate: the cornerstone for the seizure prophylaxis in the severe pre-eclampsia and the treatment of the eclampsia. The loading 4 to 6 grams intravenously over 20 minutes, the infusion 1 to 2 grams per hour for the 24 hours or the 24 hours postpartum. The monitoring for the toxicity (the reflexes, the respiratory rate, the urine output), and the calcium gluconate as the antidote. The Cochrane review found magnesium sulphate more than halves the eclampsia risk versus placebo or no anticonvulsant, and the Collaborative Eclampsia Trial showed it is superior to diazepam and phenytoin for recurrent seizures. ^[3]

The principles: the magnesium sulphate for the seizures, the safe blood-pressure control (the labetalol, the hydralazine, the nifedipine — the ACE inhibitors contraindicated), and the delivery as the only cure.^[3]