Contents
Introduction
Pre-eclampsia and eclampsia are different stages of the same condition. Pre-eclampsia is often asymptomatic, but can be detected with a combination of hypertension and proteinuria (or thrombocytopenia – low platelets) and it can result in eclampsia at any time. Eclampsia is immediately life-threatening and often symptomatic.
Pre-eclampsia is a condition characterised by increased blood pressure, proteinuria and often oedema during pregnancy. It is typically asymptomatic, and occurs after 20 weeks, although it rarely presents before 32 weeks – but when it does, it is associated with a worse prognosis.
- Without prompt treatment eclampsia is deadly
- Due to its asymptomatic onset, screening is very important
Suspect pre-eclampsia in any pregnant women after 20 week gestation with:
- Neurological features:
- Headaches
- Nausea or vomiting
- Visual disturbance
- Pain
- Epigastric, RUQ or retro-sternal
- Oedema
- Including face, hands or feet
- Proteinuria or thombocytopenia
Epidemiology and Aetiology
- Occurs in 1 in 2000 pregnancies (0.05%)
- Risk factors include:
- Primgravida, or >10 years since last pregnancy
- FH of pre-eclampsia
- Previous history of pre-eclampsia
- <155cm maternal height
- Obesity / overweight mother – especially BMI >30
- Maternal age <20 or >35
- Past Hx of migraine
- Hypertension at onset of pregnancy
- Underlying renal disease
- History of autoimmune disease – e.g. SLE or antiphospholipid syndrome
- Smoking reduces the risk(!)
Signs & Symptoms
Most commonly asymptomatic, but can cause:
- Flu-like symptoms
- Vomiting
- ↑pulse
- Hyperreflexia and Clonus (>3 beats)
- Seizures – indicates eclampsia
- Headache
- Visual disturbance
- Bruising (Platelets <100)
- Epigastric pain – HELLP – difficult to differentiate pain from that of reflux (common in pregnancy). HELLP does not respond to antacids, and may radiate to the back
- Urea and creatinine – normal at first, may rise later
Pathology
It is a multisystemic disorder, resulting from a defect in the placenta. It is thought that placental factors that usually control blood flow to the fetus invade the mothers tissues, and affect arterial contractility.
- These factors usually prevent vasodilation – thus providing a constant stream of blood to the fetus. In pre-eclampsia, they also affect the maternal tissues.
- In the maternal endothelium, the factors have a similar effect, and maternal BP rises in an attempt to compensate for this
As well as the maternal endothelium, the liver, kidneys and platelet count are often affected.
The organ damage seen in eclampsia is a mostly result of the hypertension, and controlling the hypertension can reduce the risk of progression from pre-eclampsia to eclampsia.
Some risks are not reduced by controlling the hypertension, these include:
- Fetal growth restriction
- Placental abruption
- Pre-term birth
- Stillbirth
Diagnosis
There are several different criteria that can constitue a diagnosis:
- Scenario One
- Proteinuria (+1)
- BP >140/90 – on two separate occasions > 6 hours apart
- Scenario Two
- BP >160/100 alone
- Scenario three
- BP rise > 30/20 over the booking BP
If pre-eclampsia is suspected – urgent referral to hospital is required.
Investigation
If hypertension is discovered in pregnancy, arrange:
- Urine dip for proteinuria
- Also send for a formal albumin:creatinine ratio (ACR)
- FBC
- UEC
- LFT
- Uric acid
Prevention
- Regular screening of BP and urine – especially after 20 weeks
- For mothers at risk, prophylactic aspirin reduces the risk
- Consider Doppler ultrasound of the umbilical artery identify at risk mothers, or can just go off risk factors (above)
- Consider referral of all at-risk mother to obstetrics at 16 weeks gestation
- 100mg aspirin OD from 12 until 36 weeks
- Calcium supplementation 1.5g daily
- In mothers with pre-existing hypertension
- Stop any existing anti-hypertensives and monitor the BP
Death usually results from:
- Stroke – most common
- Hepatic failure
- Renal failure
- Liver failure
- Women with pre-eclampsia can deteriorate extremely quickly! Within 24 hours…
Management
Management depends on the stage:
- Pre-eclampsia
- Eclampsia during pregnancy
- Post-partum care
Delivery is the only cure – but – risk of pre-eclampsia progressing to eclampsia still exists for around a week after delivery, and pre-eclampsia can take up to 3 months to resolve.
- About 50% of eclamptic seizures occur after delivery
- ½ of these are in the first 48hours
- Management is possible up until and around delivery, but delivery should be planned as soon as the diagnosis is made
Pre-eclampsia
The aim is control hypertension.
- Aim for BP <150/100 mmHg
- Stricter BP control can result in fetal growth restriction
- Labetalol 100-200mg BD is first line
- Contraindicated in asthma
- Max dose 200mg TDS – increase the dose weekly as required
- Methyldopa 250mg BD or TDS
- Increase ever two days as required – max dose 500mg TDS
- Can depress mood – especially if history of depression
- After delivery, can change to a more traditional antihypertensive
Counsel about the signs and symptoms of eclampsia and advise to present to hospital if these occur
Eclampsia
Eclampsia is a medical emergency and requires inpatient hospital treatment.
Antihypertensives
- Give hydralazine IV in 5mg/20 mins until 20mg given
- Give prophylactic H2-antagonists until after delivery
- Catheterise and measure urine output
- Restrict fluid intake to 80ml/hour (unless haemorrhage)
- Avoid diuretics at all costs! – they reduce plasma volume
- Antihypertensives reduce the risk of stroke but not the risk of death
Seizures
- Seizures indicate the presence of eclampsia (i.e. it has progressed from pre-eclampsia)
- Patients with seizures require ICU admission
- Treat with magnesium sulphate 4g IV – with 100ml 0.9% saline.
- Beware of respiratory depression!
- If not successful, other anti-epileptics may be used but require specialist consultation
- After the initial dose, give a further 1g/24hours
- Check resp rate and reflexes every 15 mins. Stop if <14/min or loss of reflexes
- Calcium gluconate can reverse the effects of magnesium, if necessary
Delivery
- Deliver as appropriate for gestation:
- >34 weeks consider normal delivery
- <34 weeks by caesarian
- If <34 weeks give steroids before delivery
- After the third stage of delivery, give 5U oxytocin IM or IV
Postpartum
Pre-eclampsia can take 3 months to resolve
- Review BP weekly with GP
- Try to avoid hypotension
- Aim for BP in the normal range, and definitely below 160/100
- If BP remains elevated longer than 3 months, consider a diagnosis of essential (primary) hypertension
- Can use traditional antihypertensives, except for dietetics – which are contraindicated in breast-feeding
- e.g. ACE-i or ARB, then add calcium channel blocker if required
- Consider thrombophlebitis screen at 3 months postpartum
- Advise to patient
- Increased lifetime risk of cardiovascular disease
- Increased risk of pre-eclampsia in future pregnancies
- Consider low-dose prophylactic aspirin in future pregnancies (as above)
Complications
HELLP syndrome (Haemolysis, Elevated Liver enzymes, Low Platelets) is seen in severe cases of eclampsia. Debate exists as to whether or not it is a truly distinct syndrome, or just a part of severe cases of eclampsia.
In HELLP syndrome, the physiological changes seen in the mother also affect the placenta.
It occurs in 10-20% of cases of severe eclampsia – and thus about 0.5% of all pregnancies.
In severe cases, liver transplantation many be needed or death may occur.
References
- Murtagh’s General Practice. 6th Ed. (2015) John Murtagh, Jill Rosenblatt
- Oxford Handbook of General Practice. 3rd Ed. (2010) Simon, C., Everitt, H., van Drop, F.
- Beers, MH., Porter RS., Jones, TV., Kaplan JL., Berkwits, M. The Merck Manual of Diagnosis and Therapy