Hypertension and Pre-eclampsia

Question 1

Definition

Answer 1

New high blood pressure (hypertension) in pregnancy with end-organ dysfunction, notably with proteinuria
= Occurs after 20 weeks gestation, when the spiral arteries of the placenta form abnormally, leading to a high vascular resistance in these vessels.

Question 2

Pre-eclampsia triad

Answer 2

• Hypertension
• Proteinuria
• Oedema

Question 3

Chronic HTN definition

Answer 3

High blood pressure that exists before 20 weeks gestation and is longstanding.
- This is not caused by dysfunction in the placenta and is not classed as pre-eclampsia.

Question 4

Pregnancy-induced hypertension/ gestational hypertension

Answer 4

Hypertension occurring after 20 weeks gestation, without proteinuria.

Question 5

Eclampsia

Answer 5

When seizures occur as a result of pre-eclampsia.

Question 6

High Risk factors

Answer 6

• Pre-existing hypertension
• Previous hypertension in pregnancy
• Existing autoimmune conditions (e.g. systemic lupus erythematosus)
• Diabetes
• Chronic kidney disease

Question 7

Moderate Risk Factors

Answer 7

• Older than 40
• BMI > 35
• More than 10 years since previous pregnancy
• Multiple pregnancy
• First pregnancy
• Family history of pre-eclampsia

Question 8

Pathophysiology

Answer 8

• Poorly understood
• When blastocyst implants on the outermost layer of endometrium (syncytiotrophoblast), and grows into it forming finger-like projections called chorionic villi containing fetal blood vessels.
• Trophoblast invasion of the endometrium sends signals to the spiral arteries in the area of the endometrium, reducing their vascular resistance + making them more fragile = blood flow to these arteries increases = eventually breakdown leaving pools of blood (lacunae). Maternal blood flows from the uterine arteries into lacunae and back out through the uterine veins. lacunae form at around 20 weeks gestation.
  When the process of forming lacunae is inadequate, the women can develop pre-eclampsia.

Question 9

Effects on placenta due to pre-eclampsia

Answer 9

Poor perfusion of the placenta. This causes oxidative stress in the placenta, and the release of inflammatory chemicals into the systemic circulation, leading to systemic inflammation and impaired endothelial function in the blood vessels.

Question 10

Symptoms

Answer 10

• Headache
• Visual disturbance or blurriness
• Nausea and vomiting
• Upper abdominal or epigastric pain (this is due to liver swelling)
• Oedema
• Reduced urine output
• Brisk reflexes

Question 11

Diagnosis

Answer 11

• Systolic blood pressure above 140 mmHg
• Diastolic blood pressure above 90 mmHg
  + any of:
  = Proteinuria (1+ or more on urine dipstick)
  = Organ dysfunction (e.g. raised creatinine, elevated liver enzymes, seizures, thrombocytopenia or haemolytic anaemia)
  = Placental dysfunction (e.g. fetal growth restriction or abnormal Doppler studies)
• Proteinuria can be quantified using:
  = Urine protein:creatinine ratio (above 30mg/mmol is significant)
  = Urine albumin:creatinine ratio (above 8mg/mmol is significant)

Placental growth factor (PGIF) completed between 20 -35 weeks gestation = low

Question 12

Prophylactic Treatment

Answer 12

Aspirin - given 12 weeks of gestation until birth to women with:
- A single high-risk factor
- Two or more moderate-risk factors

Question 13

Routine check up to check for pre-eclampsia

Answer 13

Blood pressure
Symptoms
Urine dipstick for proteinuria

Question 14

Gestational hypertension (without proteinuria) management

Answer 14

• Treating to aim for a blood pressure below 135/85 mmHg
• Admission when BP < 160/110 mmHg
• Urine dipstick testing at least weekly
• Blood tests weekly (FBC, LFT and renal profile)
• Monitoring fetal growth by serial growth scans
• PlGF testing on one occasion

Question 15

Pre-eclampsia monitoring

Answer 15

Similar to GH +
- Scoring systems used to determine whether to admit woemn (fullPIERS or PREP-S)
- Blood pressure is monitored closely (at least 48 hours)
- Urine dipstick weekly not necessary (Dx already made)
- USS. amniotic fluid and dopplers = two weekly to monitor fetus

Question 16

Medical management

Answer 16

FIRST LINE = LABETOLOL (Anti hypertensive)
Second line = Nifedipine (modified-release)
Third line = Methyldopa (MUST be stopped within 48hrs of birth

Question 17

Acute treatment in critical care in severe pre-eclampsia or eclampsia

Answer 17

Intravenous hydralazine

Question 18

Medication given during labour and in the 24 hours afterwards to prevent seizures

Answer 18

• IV magnesium sulphate
• Fluid restriction is used during labour in severe pre-eclampsia or eclampsia, to avoid fluid overload

Question 19

Planned early birth

Answer 19

May be necessary if the blood pressure cannot be controlled or complications occur.
- Corticosteroids should be given to women having a premature birth to help mature the fetal lungs.

Question 20

After delivery care

Answer 20

Blood pressure is monitored closely = should return to normal after placenta removed
Medication:
- FIRST LINE = Enalapril
- SECOND LINE (FL IN BLACK AFRICAN OR CARIBEAN Px) = Nifedipine
THIRD LINE = Labetolol

Question 21

Eclampsia treatment

Answer 21

Magnesium sulphate IV bolus of 4g over 5-10 minutes should be given followed by an infusion of 1g / hour used to manage seizures associated with pre-eclampsia.
- Continued for 24 hours after last seizure or delivery which ever is longer

Question 22

HELLP Syndrome

Answer 22

Complications of pre-eclampsia:
- Haemolysis
- Elevated Liver enzymes
- Low Platelets

Question 23

Complications

Answer 23

Significant cause of maternal and fetal morbidity and mortality.
- Without Tx can lead to:
= maternal organ damage,
= fetal growth restriction,
= seizures,
= early labour
= small proportion is death.