Obstetrics - Pre-Eclampsia and HELLP Syndrome

Question 1

Can you define pre-eclampsia?

Answer 1

Pre-eclampsia (PET) is pregnancy-induced hypertension (>140/90 mmHg) presenting after 20 weeks’ gestation in the presence of proteinuria (≥0.3 g/day), with or without peripheral oedema.

Question 2

What is the pathophysiology of Pre-eclampsia?

Answer 2

The pathophysiology is yet to be fully elucidated, but is thought to be due to abnormal placentation:
– Impaired maternal spiral artery relaxation with failure of trophoblastic invasion results in placental hypoperfusion and ischaemia
– This causes widespread maternal endothelial dysfunction with excess thromboxane A2 (TXA2) and deficient prostacyclin, causing platelet aggregation and vasoconstriction

Question 3

How does pre-eclampsia present?

Answer 3

Cardiovascular
– Vasoconstriction causes hypertension with reduced plasma volume

Neurological
– Headache, visual disturbance, irritability (due to cerebral hypoperfusion and
oedema)

Renal
– Proteinuria, reduced GFR leads to AKI and hyperuricaemia
– Renal blood flow (RBF) is maintained due to activation of the RAA system

Gastrointestinal
– Nausea and vomiting, epigastric pain (due to stretching of liver capsule),
transaminitis

Haematological
– Decrease plasma oncotic pressure leads to oedema formation
– Platelet aggregation causes microthrombi
– There is haemoconcentration (due to reduced plasma volume) and coagulopathy

Question 4

How do you diagnose severe pre-eclampsia?

Answer 4

The NICE definition of severe pre-eclampsia is the presence of severe hypertension (>160/110mmHg) with symptoms and/or biochemical or haematological derangement

Question 5

How is pre-eclampsia managed?

Answer 5

Mild disease may be managed with oral antihypertensives such as labetalol or nifedipine. Severe disease necessitates close monitoring, preferably in an HDU environment with MDT input and IV antihypertensive therapy. Pre-eclampsia should be managed with an ABCDE approach, treating abnormalities as they are found.

The specific management of pre-eclampsia is:

1 Oral antihypertensives
– Nifedipine
– Labetolol

2 Intravenous antihypertensive therapy, aiming BP <150/80–100 mmHg:
– Labetalol – bolus and/or infusion
– Hydralazine – bolus and/or infusion

3 Magnesium sulphate
– Used in severe pre-eclampsia (specific criteria) and eclampsia
– The Magpie trial (2002) showed that magnesium therapy halved the risk of
eclamptic seizures in mothers with pre-eclampsia (see page 283)
– 4 g bolus over 5 minutes followed by an infusion of 1 g/hour for 24 hours
– Aim for serum Mg2+ 2–3 mmol/l (there is loss of deep tendon reflexes at
Mg2+ 4–6 mmol/l)

4 Restrictive fluid management
– Patients are at risk of pulmonary oedema (leaky capillaries, low oncotic
pressure due to renal protein wasting)
– Follow protocol on each labour ward, usually use 0.5 ml/kg/hour, target
urine output 0.5 ml/kg/hour

5 The definitive treatment of pre-eclampsia is delivery of the placenta (and baby!)
– Steroids should be given to aid maturation of the fetal lungs before
34 weeks’ gestation (delivery is then ideally delayed for 48 hours for maximum
benefit)

Question 6

What are the complications of pre-eclampsia?

Answer 6

The complications of pre-eclampsia can be divided into maternal and fetal.
Maternal
1 Eclampsia
2 Renal failure
3 VTE (due to intravascular volume depletion, renal loss of antithrombin III)
4 HELLP syndrome
5 Intracranial haemorrhage
6 Acute fatty liver of pregnancy – contentious, but thought to be part of the
spectrum
7 Placental abruption

Fetal
1 Utero-placental insufficiency and intra-uterine growth retardation (IUGR)
2 Pre-term delivery
3 Fetal death

Question 7

What is HELLP syndrome?

Answer 7

HELLP syndrome is a triad of:
1 Haemolysis
2 Elevated liver enzymes
3 Low platelets

It is considered to represent the extreme end of the pre-eclampsia spectrum of disease, although this is controversial. It complicates 0.1–0.6% of all pregnancies and 4–12% of cases of pre-eclampsia. The associated maternal mortality is 24% (ICH is the most common finding at post-mortem examination), and morbidity is significant (DIC in 20%, abruption in 16%, AKI in 7%, pulmonary oedema in 6%).

It presents with:
– Malaise (90%)
– Epigastric/RUQ pain (90%)
– Nausea and vomiting (50%)
– Headache (up to 68%)
– Visual disturbance (10–20%)
– Jaundice (5%)

The disease can be classified using the Mississippi Classification according to
severity on the basis of platelet count, ALT/AST and LDH levels

Question 8

How would you manage a patient with HELLP syndrome?

Answer 8

The management involves admission to HDU, treatment of hypertension and seizure prophylaxis, repletion of blood products as indicated, and cautious IV fluid therapy. Delivery of the fetus arranged as soon and as safely as possible; collaboration with obstetric, anaesthetic and haematology colleagues is essential. There has been no convincing evidence that the use of steroids is beneficial to maternal outcome in HELLP syndrome, and current guidelines do not recommend their use.