Hypertensive Disorders

Pregnancy-induced hypertension

This is defined as having a raised blood pressure which occurs after the 20th week of pregnancy without proteinuria.

– If a woman has hypertension before, then this is counted as pre-existing hypertension. Whereas, if she develops other symptoms like proteinuria and oedema, this points to a diagnosis of pre-eclampsia

– Gestational hypertension resolves after birth, but women have higher risk of pre-eclampsia in the next pregnancy

– The major risk to watch out for is progression to pre-eclampsia (High BP with proteinuria)

The hypertension is defined as two separate readings confirming either:

– Systolic >140mmHg or diastolic >90mmHg

– Or Increase above booking readings of >30mmHg systolic or >15mmHg diastolic

Tests:

These are done to monitor the blood pressure and check for progression to pre-eclampsia:

– Urine dipstick + 24hr urine collection                            

– Blood tests –> FBC, LFTs, U&Es

Management:

– Antihypertensive medication –> 1st line is labetalol, 2nd line nifedipine, 3rd methyldopa

– Maternal monitoring –> Monitor BP weekly (aim for <135/85) and monitor urine dipstick for proteinuria

– Foetal monitoring –> Foetal heart auscultation at every antenatal appointment + US from 28 weeks 

Pre-eclampsia

This is a condition in pregnancy which is characterised by pregnancy induced hypertension with proteinuria

– In normal placentation, trophoblast cells invade the spiral arteries of the uterus

– Remodelling occurs resulting in spiral arteries that are dilated giving high flow, low resistance circulation

– In pre-eclampsia, there is poor remodelling of the spiral arteries giving low-flow and high-resistance

– The increase in blood pressure leads to a systemic inflammatory response and endothelial cell dysfunction 

Symptoms:

– Can be asymptomatic

– Headache with visual disturbances

– Papilledema

– Sudden onset non-dependent oedema

– Hyperreflexia

– RUQ/epigastric pain (due to hepatic capsule distension/infarction)

– Can lead to HELLP syndrome

Complications:

– Mother –>  Eclampsia (seizures), HELLP syndrome and uncontrolled hypertension

– Fetus –> Prematurity, intrauterine growth restriction, placental abruption

Tests:

– BP measurement and urine dipstick with 24hr collection

– FBC –> may show low Hb, low platelets (progression to HELLP syndrome)

– U&Es –> elevated urea and creatinine (different ranges from normal population as plasma is diluted)

– LFTs –> elevated ALT and AST (used to assess for HELLP syndrome)

Diagnosis:

– For a diagnosis of pre-eclampsia, three criteria should be met:

i) Gestation >20 weeks

ii) Hypertension: systolic >140 or diastolic >90 on two occasions 4 hour apart

iii) Proteinuria: Protein: creatinine ratio >30mg/mmol

Management:

– It is important monitor maternal BP and urine and fetus regularly

– Antihypertensive medication –>  1st line is labetalol, then nifedipine or hydralazine

– Delivery of baby –> This is the only definitive cure for pre-eclampsia

– Induce delivery by latest 37-37 weeks (or 34 weeks if severe symptoms)

– Must monitor post-delivery as mother has highest risk of seizures 24hrs post-partum

Before the baby can be delivered, you will need to stabalise the mother before she goes into labour

– This is because unstable mothers who develop eclampsia will require general anaesthetic to terminate seizures

– This gives a significant risk of rebound hypertension

– It also increases the risk of haemorrhagic stroke and makes intubation very difficult

Therefore, activate severe pre-eclamptic protocol –> 1st give oral labetalol, 2nd line is IV infusion

– Also give magnesium sulphate (prevents development of seizures).

– Then you should deliver the baby

Prevention:

– To mitigate the risk of pre-eclampsia, give prophylaxis if 1 high risk or 2+ moderate factors:

– Give aspirin 75mg/day from 12 weeks to 36 weeks

Eclampsia

This is the development of seizures in association with pre-eclampsia.

– It occurs due to the failure of cerebral autoregulation leading to seizures and haemorrhagic stroke.

– The biggest complication is AKI which leads to pulmonary oedema (leading cause of eclampsia death)

– It can occur any time after the 20th week of pregnancy but the highest risk if 24 hours post delivery

Symptoms:

– Background of Pre-eclampsia –> Pregnancy induced hypertension and proteinuria

– Failure of cerebral autoregulation –> seizures and haemorrhagic stroke

Management:

This involves stabilising the mother followed by immediate delivery of the fetus (if not yet born)

– Give magnesium sulphate (used to prevent and treat seizures)

– Mother is given an IV bolus, followed by a continuous infusion

– This infusion is continued for 24 hours after last seizure or delivery (whichever is later)

– It can lead to respiratory depression, but this can be reversed with calcium gluconate

– Fluid restrict to prevent pulmonary oedema

– One mother is stabilised, attempt delivery (continue magnesium sulphate infusion for 24 hours after)

HELLP syndrome

This is a condition which stands for Haemolysis, Elevated Liver enzymes and Low Platelet count.

– It shares features with pre-eclampsia but is separate condition

– Pre-eclampsia is a risk factor for the development of HELLP syndrome, which is an obstetric emergency

Risk factors:

– Pre-eclampsia/eclampsia

– Mother >25 ages

– Previous history

– Being Caucasian

Symptoms:

– Haemolysis –> gives low Hb and lethargy

– Elevated liver enzymes –> Gives raised LFTs, RUQ pain and nausea/vomiting

– Low platelet count –> Bleeding (e.g. haematuria)

– Can lead to DIC, placental abruption and kidney failure

Diagnosis:

– Blood tests –> Shows high LFTs, low platelet, low Hb, raised LDH and bilirubin

– Blood smear –> Shows schistocytes

Management:

Delivery of the baby as soon as possible