Pre-eclampsia
Definition
A multisystem vascular disease characterised by hypertension and proteinuria
Epidemiology
Pretty common. 10% of primiparous women (first time delivering) and there is a 12% recurrence rate in multiparous women (not first delivery). However, if a multip has new partner, her risk then goes up again.
Pathophysiology
The best theory that anybody's come with is that the placenta doesn't implant properly. As such, in order for the foetus to get enough blood, the mother's blood pressure needs to rise.
That's the theory, anyway. Nobody's really sure if it's true but it might help you remember it.
Risk Factors
- Previous history (12% recurrence risk)
- Primiparous (10%)
- Proteinuria at booking
- Diastolic BP > 80mmHg at booking
- Multiple pregnancy
- Underlying medical conditions affecting blood pressure
It's also a big cause of IUGR and can lead to eclampsia which is a potentially fatal condition.
Clinical Features
Basically, the two big things are new hypertension (>90mmHg diastolic measured on 2 separate occasions) or new proteinuria (>0.3g on 24h urine collection).
There are also a tonne of other things but these present in severe disease:
- Headache
- Visual disturbance or papilloedema
- Epigastric pain or liver tenderness
- Clonus
- Vomiting
- Foetal distress
It is split into three basic levels of severity, like a lot of things in medicine: mild, moderate and severe:
- Mild - BP <100mmHg, no proteinuria
- Moderate - BP ≥100mmHg, no proteinuria OR BP <100mmHg with proteinuria
- Severe - BP ≥100mmHg with proteinuria OR any complications
Complications
Essentially, the image on the right covers the main problems that can come of pre-eclampsia. (The management of eclampsia is detailed below.) Just for completeness, I've also listed them here with some extra ones which didn't really fit onto the image:
- Eclampsia
- Cerebrovascular haemorrhage
- Pulmonary oedema
- Liver failure
- Renal failure
- Placental abruption
- DIC
- HELLP syndrome - Haemolysis, Elevated LFT's and Low Platelets.
Any of these complications are indicative of severe pre-eclampsia - essentially, this is potentially life-threatening for the mother. Maternal death is the most important and most rubbish complication of pre-eclampsia. Avoid it like the plague.
Investigations
- 24h urine - proteinuria
- FBC - anaemia, low platelets both in HELLP syndrome
- LFTs - elevated in liver failure
- U&Es - renal failure
- CTG - foetal distress
- USS - IUGR