Hypertensive disorders of pregnancy

Question 1

What are the symptoms of pre-eclampsia?

Answer 1

Neurological symptoms: severe headache or visual disturbance

Epigastric pain - due to hepatic capsular stretching

Vomiting

Weight gain (excessive) – due to fluid retention

Facial & other non-dependent oedema

Question 2

Risk factors for preeclampsia include…

Answer 2

Nulliparity

Diabetes

Renal Insufficiency

Hypertension

Past Hx of Preeclampsia

FHx of Preeclampsia

Advanced maternal age (>35) - and young maternal age (<16y)

Obesity

Antiphospholipid antibody syndrome

Multiple gestation

Question 3

What is HELLP syndrome?

Answer 3

It is a multi-system variation of severe pre-eclampsia that includes:

1. Haemolysis
2. Elevated liver enzymes
3. Low platelet count

Question 4

How is pre-eclampsia diagnosed?

Answer 4

• BP >=140mm Hg on two separate readings taken at least 4-6 hours apart after 20 wks gestation in a person who has otherwise normal BP
• Proteinuria >=0.3g or more in a 24 hour urine sample or a urine protein to creatinine ratio >0.3
• If proteinuria is not present then also screen for other evidence of multi-system involvement, e.g.:
• neurological symptoms
• abnormal renal function (abnormal RFT)
• hepatic involvement (abnormal LFT)
• platelet consumption (low levels +/- coagulopathy)
• IUGR due to placental disease

Question 5

How does preeclampsia effect an unborn baby?

Answer 5

IUGR due to placental disease

Placental abruption is a recognised associated condition, especially if BP uncontrolled

Question 6

How is pre-eclampsia treated?

Answer 6

1. Symptomatic control - focused around lowering BP using anti-hypertensive medications: nifedipine, methyl-dopa & labetolol
2. For severe pre-eclampsia, primary prevention of seizures using magnesium sulphate; and
3. Definitive treatment - by delivering the baby

Question 7

What are complications of pre-eclampsia?

Answer 7

Eclampsia – Seizures caused by the increased BP (1%)

Severe hypertension leading to e.g. stroke

Renal failure, hepatic failure (usually temporary)

Placental abruption, stillbirth

Iatrogenic fetal prematurity

Question 8

What are some differentials of pre-eclampsia?

Answer 8

Chronic HTN

Chronic renal disease

Primary seizure disorder

Gallbladder and pancreatic disease

Thrombocytopaenia purpura

Antiphospholipid syndrome

Haemolytic Uraemic Syndrome

Thyrotoxicosis

Pheochromocytoma

Drug abuse

Question 9

What is Gestational Hypertension?

Answer 9

Hypertension arising after 20 weeks

No additional features of pre-eclampsia

Question 10

What are the initial investigations that you would do if a woman comes in with new-onset hypertension after 20 weeks gestation?

Answer 10

• BP measurement - to confirm
• Proteinuria assessment - protein:creatinine ratio on a single sample (>30) or 24h collection (>0.3g)
• Blood tests: FBC, Urea, creatinine, electrolytes and urate, LFT
• Fetal assessments with CTG if greater than 28 weeks gestation
• Ultrasound assessment of: fetal growth, amniotic fluid index, umbilical artery Doppler, and follow up to assess foetal growth velocity

Question 11

What is eclampsia?

Answer 11

It is defined as the occurrence of one or more seisures superimposed on preeclampsia: i.e. pre-eclampsia complicated by generalised tonic-clonic convulsions (in the absence of other structural or organic pathology to cause them)

Question 12

Describe the management of eclampsia.

Answer 12

• Protect the patient from harm
• Secure the airway: this is done in the left lateral position or via Guedel airway if seizure prolonged
• Administer oxygen
• Obtain IV access (if it is not in place already)
• Comence magnesium sulfate (4g loading dose, 1g/hr maintenance) to control seizures
• Consider other anti-seizure medication if seizure is prolonged: e.g diazepam
• Institute antihypertensives as needed to control blood pressure
• Arrange for delivery once the situation is stabilised

Question 13

What antihypertensive could you use for the treatment of pre-eclampsia?

Answer 13

Nidedipine - Calcium channel blocker with vasodilator effects

Labetolol- Combined alpha and beta blocker

Hydralazine-Directly relaxes smooth muscle

Contraindicated:

• ACE inhibitors
• Diuretics
• A2R antagonists

Question 14

What is the general pathophysiology of pre-eclampsia?

Answer 14

The placenta fails to invade properly to the level of the spiral arterioles leading to a high resistance placenta

This causes the release of vasculoendothelial substances from the placenta that causes multi-organ problems for the mother

The hormonal consequences result in generalised vasoconstriction. At the same time, endothelial cell damage causes interstitial leakage through which blood constituents, including platelets and fibrinogen, are deposited subendothelially

Question 15

What are the possible aetiologies for pre-eclampsia?

Answer 15

• Abnormal trophoblastic invasion of uterine vessels
• Immunological intolerance between maternal and fetoplacental tissues
• Maternal maladaptation to cardiovascular or inflammatory changes of normal pregnancy
• Dietary deficiencies
• Genetic influences

Question 16

Describe some of the serious consquences of eclampsia

Answer 16

• Placental abruption
• Perinatal death
• Maternal stroke
• Pulmonary oedema
• Cardiopulmonary arrest
• Acute renal failure
• Maternal death