Pre-eclampsia

Question 1

Definition of pre-eclampsia

Answer 1

A hypertensive syndrome unique to pregnancy (after 20 weeks’ gestation), characterised by:

• Hypertension >140/90 (new-onset)
• Proteinuria >0.3 g/24h

Question 2

Risk factors for pre-eclampsia

Answer 2

• Nulliparity
  
  • Development of immune tolerance with subsequent pregnancies
• Previous history
• Family history
• Long inter-pregnancy interval
• Advanced maternal age (>40 years)
• Obesity
• Microvascular disease
  
  • Hypertension
  • Renal disease
  • Diabetes
  • Autoimmune disease
    
    • Antiphospholipid syndrome (especially)
• Twin pregnancy

Question 3

Pathophysiology of pre-eclampsia

Answer 3

• Stage 1 (development of disease)
  
  • Incomplete trophoblastic invasion of spiral arteries (? immune modulated) →
  • ↓ uteroplacental blood flow → compensatory ↑ BP
• Stage 2 (manifestation of disease)
  
  • Ischaemic placenta → exaggerated maternal inflammatory response
    
    • Endothelial cell damage
      
      • ↑ vascular permeability
        
        • Oedema
        • Proteinuria
      • Vasoconstriction
        
        • Hypertension
        • Eclampsia (grand mal seizures)
        • Liver damage
      • Abnormal clotting

Question 4

Complications of pre-eclampsia

• Maternal
• Foetal

Answer 4

*↑ risk of maternal/foetal morbidity and mortality*

Maternal

• Eclampsia
  
  • Grand mal seizures resulting from cerebrovascular spasm
• Cerebrovascular accident (haemorrhage)
• HELLP syndrome (liver damage)
  
  • Haemolysis
  • Elevated Liver enzymes
  • Low Platelet count
• Disseminated intravascular coagulation (DIC)
• Liver failure
• Renal failure
• Pulmonary oedema → ARDS

Foetal

• Intrauterine growth restriction (IUGR)
  
  • ↓ placental blood flow
• Preterm birth
• Placental abruption
• Hypoxia

Question 5

Clinical features of HELLP syndrome

Answer 5

• Haemolysis
  
  • Dark urine
  • ↑ LDH
  • Anaemia
• Elevated Liver enzymes
  
  • Epigastric pain (ominous)
  • Liver failure
  • Abnormal clotting
• Low Platelets
  
  • Normally self-limiting

Question 6

Clinical features of pre-eclampsia

Answer 6

• Symptoms
  
  • Asymptomatic
  • Headache
  • Nausea/vomiting
  • Epigastric pain (severe)
• Signs
  
  • Hypertension (>140/90)
  • Oedema
  • Epigastric tenderness (severe)

Question 7

Investigations for pre-eclampsia

• Confirm diagnosis
• Monitor maternal complications
• Monitor foetal complications

Answer 7

To confirm diagnosis:

• BP >140/90
• Urinalysis (proteinuria)
  
  • Dipstick
  • Protein:creatinine ratio (PCR)
    
    • >30 mg/nmol
  • 24h collection
    
    • 0.3 g/24h

To monitor maternal complications:

• FBC
  
  • Low platelets
  • Anaemia (haemolysis)
• LFTs
  
  • ↑ ALT (liver damage)
  • ↑ LDH (haemolysis)
• U&E
  
  • ↑ creatinine (renal failure)

To monitor foetal complications:

• Ultrasound
  
  • Foetal weight, growth and wellbeing
• Umbilical artery Doppler +/- CTG
  
  • Foetal wellbeing

Question 8

Management of pre-eclampsia

• Delivery
  
  • Mild, moderate, severe
• Drugs
• Postnatal management
• Management of eclampsia

Answer 8

*Pre-eclampsia is cured only by delivery*

• Mild
  
  • Deliver by 37 weeks
• Moderate / Severe
  
  • Requires delivery if gestation exceeds 34-36 weeks
• Severe pre-eclampsia with complications or foetal distress
  
  • Requires delivery whatever the gestation
    
    • C-section before 34 weeks, induction thereafter

Drugs

• Antihypertensives (when >150/100)
  
  • Labetalol
  • Nifedipine
  • Hydralazine / methyldopa
• Low dose aspirin (prevention for women at risk)
  
  • Starting before 16 weeks
• Fluid restriction (severe)
• Furosemide + oxygen (pulmonary oedema)
• Corticosteroids (IM)
  
  • Promote foetal lung maturity if <34 weeks gestation
• Oxytocin (3rd stage of labour)
  
  • NOT ergometrine (↑ BP)

Postnatal management

• Fluid balance monitored closely
  
  • Pulmonary oedema and respiratory failure may follow uncontrolled administration of IV fluids during delivery
  • Furosemide if overload
• BP management

Eclampsia (grand mal seizures)

• Magnesium sulphate
  
  • ↑ cerebral perfusion
  • Calcium gluconate (in case of MgSO4 toxicity)