Obs Emergencies - Pre-eclampsia

Question 1

What is pre-eclampsia?

Answer 1

Combination of:

*Hypertension during pregnancy (Sustained BP of 140/90 after 20 weeks gestation)

*Significant Proteinuria (≥ 300mg of protein in 24h or ≥0.3 on spot urine protein creatinine ratio)

It is a placental disease and occurs in 5% of first pregnancies. In its worst form it can result in catastrophic maternal and fetal compromise.

Question 2

What is the pathophysiology of pre-eclampsia?

Answer 2

The exact mechanism of pre-eclampsia is unclear. However, most current theories attribute pre-eclampsia to poor placental perfusion, secondary to abnormal placentation.

In normal placentation, the trophoblast invades the myometrium and the spiral arteries of the uterus, destroying the tunica muscularis media. This renders the spiral arteries dilated and unable to constrict, providing the pregnancy with a high flow, low resistance circulation.

In pre-eclampsia, the remodelling of spiral arteries is incomplete. A high resistance, low-flow uteroplacental circulation develops, as the constrictive muscular walls of the spiral arterioles are maintained.

The resultant increase in blood pressure, combined with hypoxia and oxidative stress from inadequate uteroplacental perfusion, leads to a systemic inflammatory response and endothelial cell dysfunction (resulting in leaky blood vessels).

Question 3

What are the risk factors for pre-eclampsia?

Answer 3

Risk factors for PET can be divided into high and moderate risk factors.

High Risk Factors:
1. Chronic HTN
2. Past Hx HTN, pre-eclampsia, or eclampsia in past pregnancy
3. Pre existing chronic kidney disease
4. Diabetes Mellitus
5. Autoimmune disease e.g. SLE

Moderate Risk Factors:
1. Nuliparity
2. Advanced maternal age >40
3. Advanced BMI >35 at initial presentation
4. FHx of pre-eclampsia
5. Pregnancy interval >10 years
6. Multiple pregnancy

Question 4

When and what prophylaxis is recommended?

Answer 4

In the UK, prophylaxis with aspirin 75mg a day is recommended for women with 1 high risk factor or ≥ 2 moderate risk factors. This should be continued from 12 weeks’ gestation until birth.

Question 5

What are the clinical features of pre-eclampsia?

Answer 5

Hypertension (systolic BP >140 mmHg or diastolic BP >90 mmHg), on two occasions at least 4 hours apart.
Significant proteinuria – >300 mg protein in a 24-hour urine sample or >30 mg/mmol urinary protein:creatinine.
In a woman greater than 20 weeks’ gestation.
The exact clinical presentation of pre-eclampsia varies between individuals. Patients may be asymptomatic – therefore blood pressure and a urine dipstick to check for proteinuria should be performed at each antenatal clinic. In addition to the above, the clinical features of pre-eclampsia include:

Headaches (usually frontal).
Visual disturbances e.g. blurred or double vision, halos, flashing lights.
Epigastric pain (due to hepatic capsule distension/infarction).
Sudden onset non-dependent oedema.
Hyper-reflexia.

Question 6

How do you classify pre-eclampsia?

Answer 6

In the UK, pre-eclampsia is classified as mild, moderate or severe. This is based on the degrees of hypertension, proteinuria and symptoms:

Mild BP 140/90-149/99 mmHg

Moderate BP 150/100 – 159/109 mmHg

Severe BP > 160/110 + proteinuria > 0.5 g/ day
or BP > 140/90 mmHg + proteinuria + symptoms.

Question 7

What are you thinking RE pre-eclampsia complications?

Answer 7

Pre-eclampsia is a multi-system disorder, associated with a number of potentially serious maternal and fetal complications.

Whilst it is not possible to predict which individuals will develop complications, the onset of pre-eclampsia before 34 weeks’ gestation is associated with a poorer prognosis.

Question 8

What are the complications of pre-eclampsia?

Answer 8

Maternal:
1. HELLP syndrome
2. Eclampsia
3. Acute Kidney Injury
4. Disseminated Intravascular Coagulation
5. Adult Respiratory Distress Syndrome
6. Hypertension 4x risk post partum
7. Cerebrovascular haemorrhage 1-2%
8. Death

Fetal:
1. prematurity
2. intrauterine growth restriction
3. placental abruption
4. intrauterine fetal death

Question 9

What is your differential diagnosis of pre-eclampsia?

Answer 9

1. Essential hypertension - existing before 20 weeks gestation
2. Pregnancy induced hypertension - HTN after 20 weeks without significant proteinuria
3. Eclampsia - obstetric emergency

Question 10

What investigations and findings would you expect in pre-eclampsia?

Answer 10

Pre-eclampsia is diagnosed by the presence of hypertension and proteinuria. Protein in the urine can be detected by a urine dipstick, and then quantified through a 24-hour urinary collection.

Other investigations are used to monitor for signs of organ dysfunction. The following blood test results may be observed in patients with pre-eclampsia:

Full blood count: ↓ Hb, ↓ platelets.
Urea and electrolytes: ↑ urea, ↑ creatinine, ↑ urate, ↓ urine output.
Liver function tests: ↑ ALT, ↑ AST.

Fetal health –CTG for FHR, Obstetric US (x4

Question 11

What is the management of preeclampsia?

Answer 11

Cure is delivering the baby and placenta
Based on gestational age, severity, and fetal status

> 37 weeks –deliver
Admission and IV line +/- urinary catheter, 4hrly BP, daily CTG, twice weekly bloods, fetal wellbeing

Deliver if severe PET or fetal compromise

Commence on Labetalol (IV/PO) or nifedipine (PO short/long acting)

VTE prevention - LMWH
antenatal steroids if needed
Mgso4 if indicated

Postpartum - monitor still at risk of seizure

Question 12

Why are antihypertensives important?

Answer 12

used to reduce the risk of maternal haemorrhagic stroke, but they do not alter the disease course itself.

One of the main interventions in the management of pre-eclampsia is to achieve adequate blood pressure control.

The severity of hypertension correlates to the risk of stroke; and thus it is important to maintain the blood pressure at a level that minimises this risk.

Question 13

What are the 3 main antihypertensives used in pregnancy?

Answer 13

Medication: Drug Class: Common Side-Effects:

Labetalol (1st line) = Beta-blocker.
SEs: Postural hypotension, fatigue, headache, nausea and vomiting, epigastric pain.

Nifedipine = Calcium channel blocker.
SEs: Peripheral oedema, dizziness, flushing, headache, constipation.

Methyldopa = Alpha-agonist.
SEs: Drowsiness, headache, oedema, GI disturbances, dry mouth, postural hypotension, bradycardia, hepatotoxicity.

Question 14

Can you give an ACE-inhibitor?

Answer 14

ACE-inhibitors are contra-indicated in pregnancy due to their association with congenital abnormalities.

Question 15

When is labetalol not first line?

Answer 15

Avoid Labetalol if the women has asthma or diabetes

Question 16

Post natal care of pre-eclampsia?

Answer 16

Pre-eclampsia resolves following delivery of the placenta. However, it is important to monitor the mother for at least 24 hours post-partum – as they are still at risk of having eclamptic seizures. Generally speaking, by day 5 they can be considered ‘safe’.

Blood pressure should be monitored daily for the first 2 days post-partum, and at least once 3-5 days post-partum. The need for antihypertensives should then be reassessed.

Women should be advised about their risk of developing pregnancy-induced hypertension and pre-eclampsia in subsequent pregnancies.

Question 17

What might you find on examination of a lady with pre-eclampsia?

Answer 17

IMEWS –specifically BP
SFH consistent with gestation … <dates –IUGR
RUQ /epigastric tenderness

Cerebral irritation
* Jitteriness
* Hyperreflexia of the knee
* Clonus of ankle

Oedema of face, hands, feet
Urinalysis –protein
Triad –proteinuria, hypertension, oedema

Question 18

What is eclampsia?

Answer 18

Eclampsia is defined as the occurrence of one or more convulsions in a pre-eclamptic woman in the absence of any other neurological or metabolic causes.

It is an obstetric emergency affecting approximately 5/10,000 pregnancies, with a maternal mortality rate of 1.8% and a fetal mortality rate of up to 30%.

The majority of seizures occur in the post-natal period (44%), but they can also occur in the antepartum (38%) or intrapartum (18%) settings.

Question 19

What are the clinical features of Eclampsia?

Answer 19

The hallmark feature of eclampsia is a new onset tonic-clonic type seizure, in the presence of pre-eclampsia (new onset hypertension and proteinuria after 20 weeks’ gestation).

The seizures typically last around 60 to 75 seconds, followed by a variable lasting post-ictal phase. Maternal convulsions may cause fetal distress and bradycardia.

Aside from the presence of seizures, the clinical presentation is much the same as that of pre-eclampsia, and often includes signs and symptoms relating to end-organ dysfunction:

Headache (usually frontal).
Hyper-reflexia.
Nausea and vomiting.
Generalised oedema.
Right upper quadrant pain +/- jaundice.
Visual disturbances e.g. flashing lights, blurred or double vision.
Change in mental stage.

Question 20

What would your differential diagnosis of eclampsia be?

Answer 20

Other seizures:

Hypoglycaemia. Medication-induced.
Pre-existing epilepsy. Brain tumour.
Head trauma. Cerebral aneurysm.
Haemorrhagic stroke. Septic shock.
Meningitis. Ischaemic stroke.

Question 21

What is the management of Eclampsia?

Answer 21

1. Resuscitation
   - Call for help, ABCDE, resuscitation
   - Patient should lie in the left lateral position, with secured airway and oxygen therapy.
2. Cessation of seizures:
   - Magnesium Sulfate
3. Blood pressure control
   - IV labetalol or IV hydralazine
4. Prompt delivery
   - must be stable
   - Caesarean section is the ideal mode of delivery. However, intrapartum seizures in established labour may be managed by vaginal delivery.

After delivery, the patient will require HDU care until she is stable – well controlled blood pressure, adequate urine output, and discontinuation of MgSO4. This usually takes a minimum of 24 hours.

5. Monitoring
   - Fluid balance monitoring is important to prevent pulmonary oedema and detect acute kidney injury.

Indicators of complications of eclampsia should also be monitored – such as platelets, transaminases and creatinine levels.