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Magnesium sulphate in the Management of Eclampsia in

Malawi

Dr. Chisale Mhango FRCOG

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Objectives of Use of MgSO4 in the Eclampsia Management

1. To prevent severe pre-eclampsia progressing to eclampsia (life-threatening convulsions).

2. To stop the convulsions of eclampsia.

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Evidence of Effectiveness of Magnesium sulphate

1. In a series of 300 consecutive cases, of eclampsia, Pritchard in Texas USA achieved 100% survival

2. A 1998 review concluded that it is effective in preventing convulsions in women who have severe pre-eclampsia and in stopping convulsions in eclamptic women. (Obstetrics and Gynaecology, Vol. 92, pp. 883-889).

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Local guidelines on use of magnesium sulphate

Health Centre– All pre-eclampsia and eclampsia

patients shall be referred to the hospital immediately after admission.

– Give first dose (correct loading dose) to prevent progression of severe pre-eclampsia to eclampsia or stop fits and then refer to hospital.

– On the way to hospital patient must be accompanied by an experienced clinician to stabilise patient during transit.

Hospital– Give MgSO4 to prevent

progression of severe pre-eclampsia to eclampsia as per national guidelines depending on whether or not the patient already has a loading dose at source.

– Follow national protocol for the management of the eclamptic patientNPC Training in MNH

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Use of Valium

• NB MgSO4 is the drug of choice in all circumstances – it should always be available at both health centre and hospital levels

• Give diazepam 10 mg (2 ml) over 2 minutes if– Convulsions recur after giving MgSO4– Convulsions occur early in pregnancy– There is MgSO4 toxicity– MgSO4 is not available

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Administration of magnesium sulphate

Health Centre• Loading dose: 4 grams IV (over 5-15 min)

plus 10 grams IM,– 5 grams IM in each buttock: deep

intramuscular injection with 1ml 2% lignocaine or 2ml 1% lignocaine

• Rationale:– Pre-eclampsia can quickly develop

into eclampsia– Shaking during transport is a

convulsion stimulus– There is no risk of overdose after

loading dose even in a woman with anuria.

Hospital • Loading dose: 4grams IV plus

10 grams IM (5 grams IM in each buttock)

• Maintenance dose: 5 grams IM every 4 hrs.. in alternate buttock

NBa. Check for reflexes before

giving the maintenance doseb. At least 100ml urine /4 hrs.c. At least 16 breaths/minute

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Administration of MgSO4

20% MgSO4 SolutionRecommended for IV injection• 20% solution means

20g/100ml, i.e.. 4g/20ml.– i.e.. Give 20ml 20%

solution IV over 5-15 minutes

50% MgSO4 SolutionRecommended for IM injection• 50% solution means

50g/100ml, i.e. 5g/10ml.– i.e.. Give 10ml

solution IM

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Administration in Hospitals with High Dependency Wards

• IV MgSO4 is the initial drug administered to terminate seizures and lower BP.

• Seizures usually terminate after the loading dose of magnesium.

• A loading dose of 6 g (15-20 min)• and a maintenance dose of 2 g per hour as a

continuous IV solution (preferably using a pump to administer).

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1. Is Magnesium sulphate dangerous?• After administration, about 40% of plasma magnesium is

protein bound. • The clinical effect and toxicity of MgSO4 can be linked to its

concentration in plasma.– The unbound magnesium ion diffuses into the extravascular-

extracellular space, into bone, and across the placenta and foetal membranes and into the foetus and amniotic fluid.

• Magnesium is almost exclusively excreted in the urine, with 90% of the dose excreted during the first 24 hours after an intravenous infusion of MgSO4. Hence the need to monitor urine output in patients receiving the drug.

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2. Is Magnesium sulphate dangerous?

• MgSO4 toxicity is rare when it is carefully administered and monitored.

• Studies show that the benefits of MgSO4 may outweigh the risks to her and to her baby.

The answer to this question is NO!

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Do we need to control MgSO4 concentration in PIH management?

• In pregnant women, apparent volumes of distribution usually reach constant values between the third and fourth hours after administration, and range from 0.250 to 0.442 L/kg.

• A concentration of 1.8 to 3.0 mmol/L has been suggested for treatment of eclamptic convulsions.

The answer to this question is NO!NPC Training in MNH

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Why is Eclampsia still a major cause of maternal deaths in Malawi?

1. Fear of use of MgSO4 by clinicians1. Unjustified fear of fatal side-effects2. Lack of training/confidence in use of drug

2. Late initiation of drug1. Most patients develop eclampsia at home2. Health centres not using MgSO4

3. Inappropriate use of drug1. Lack of relating fluid balance to dosage of drug

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Antidote for MgSO4

In the rare situations when the patient is found to have no reflexes and not breathing

wells after MgSO4 the antidote is:

Calcium gluconate(10%) 10 mls. IV over 10 minutes, especially if there is < 16

breaths/minute or no reflexes.

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Can Magnesium be Administered in Combination with Other Drugs?

• Avoid the use of multiple agents to abate eclamptic seizures, unless necessary.

• Antihypertensive can be used together with MgSO4• Only where there is pulmonary oedema can a diuretic

be used – otherwise diuretics are contraindicated in management of eclampsia

• Steroids may be administered in anticipation of delivery when gestational age is < 34 weeks.– Betamethasone (12 mg IM q24h × 2 doses) or

dexamethasone (6 mg IM q12h × 4 doses) is recommended.

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