WCS17 Hypertension And Pregnancy

Question 1

Hypertension in pregnancy

Answer 1

Leading cause of Maternal mortality:
- ***Eclampsia
- Cerebrovascular accident (CVA)

Perinatal mortality:
- Preterm
- ***Intrauterine growth restriction (IUGR)
- Placental abruption

Heterogenous conditions:
1. Gestational hypertension / Pre-eclampsia (pregnancy specific syndrome)
2. Chronic hypertension / Renal disease

Question 2

Pre-eclampsia

Answer 2

2.5-3% of women

Potentially dangerous complication of 2nd half of pregnancy, labour, early period after delivery

New onset of hypertension **>20 weeks with one of the following:
1. **Proteinuria (>= 300 mg/day)

2. Other **maternal organ dysfunction
   —> Renal: Cr >= 90 mmol/L
   —> Hepatic: Elevated ALT/AST +/- RUQ / Epigastric pain
   —> Neurological: Eclampsia, altered mental status, blindness, stroke, clonus, severe headache, visual disturbance
   —> Haematological: thrombocytopenia (Plt < 150), DIC, haemolysis, **HELLP
3. Uteroplacental dysfunction
   - IUGR
   - Stillbirth

***Characterised by:
1. Hypertension
2. Proteinuria
3. Other systemic disturbances

Eclampsia: End stage of disease characterised by ***generalised seizures

Question 3

Classification of pregnancy hypertension

Answer 3

1. Gestational hypertension / Proteinuria (normal baseline BP, present > 20 weeks)
   - Gestational hypertension
   - Gestational proteinuria
   - Gestational proteinuric hypertension (aka Pre-eclampsia)
2. Chronic hypertension / Renal disease (present < 20 weeks)
   - Chronic hypertension
   - Chronic renal disease
   - Chronic hypertension with superimposed Pre-eclampsia (develop proteinuria later)
3. Unclassified
   - Presents > 20 weeks / insufficient information

Question 4

Pathophysiology of Pre-eclampsia

Answer 4

1. Placental pre-eclampsia:
   **Poor placentation
   —> Lack of endovascular **cytotrophoblastic invasion in maternal spiral artery in 2nd trimester
   —> poor remodelling
   —> **high resistance in uteroplacental circulation (too small)
   —> Hypoxic placenta suffers **oxidative stress
   —> ↑ release of Trophoblast debris
   —> ***Generalised systemic inflammatory response (Endothelial dysfunction)

Result:
1. Endothelial dysfunction: Vasospasm, Microthrombi
2. ↓ Perfusion to all organs
3. ↓ Vasodilator Prostacyclin
4. ↑ Vasoconstrictive TXA
5. Platelet aggregation
6. Hypertension + Proteinuria
7. Systemic disease

2. Maternal pre-eclampsia
   - Interaction between **normal placenta and **maternal constitution that is susceptible to ***microvascular disease, e.g. chronic hypertension, DM
   - Abnormal maternal response —> Abnormal pregnancy
   - Pregnancy: Metabolic + Vascular stress test to a woman
3. Mixed

Question 5

Risks of Pre-elampsia

Answer 5

Maternal:
1. **Eclampsia
2. **Pulmonary edema
3. DIC
4. **Placental abruption
5. **Acute renal failure
6. **Liver failure / haemorrhage
7. **HELLP (Haemolysis, Elevated Liver enzymes, Low Platelet)
8. Long term CVS morbidity
9. Death (rare)

Fetal:
1. **Preterm delivery
2. **IUGR
3. ***Hypoxia-neurologic injury
4. Perinatal death
5. Long term CVS morbidity associated with low birth weight

Magnitude of risk depends on gestational age at diagnosis, delivery, severity, presence of associated medical disorders

Question 6

Predisposing factors of Pre-eclampsia

Answer 6

1. ***Primigravida
2. ***Advanced maternal age (>35 at expected date of confinement)
3. Past obstetric history (***History of pre-eclampsia (self notes))
4. Pre-existing diseases e.g. **DM, **HT, **Renal disease, **Antiphospholipid syndrome
5. Obstetric conditions: ***Multiple pregnancy, Hydatidiform mole, Hydrops fetalis

Question 7

Diagnosis of Pre-clampsia

Answer 7

Usually ***asymptomatic —> regular antenatal visit for early detection

Classical triad:
1. Hypertension
2. Proteinuria
3. Edema (sudden onset + severe)

Presentation is variable:
- Normal BP (16%) and no proteinuria (14%) prior to eclampsia
- Late postpartum eclampsia
- > 48 hours after delivery

Question 8

Hypertension

Answer 8

Sitting, Appropriate cuff, at level of heart

• BP >= 140/90 mmHg
• **2 consecutive readings **4 hours apart with rest
  OR
• **1 reading of DBP **>=110 mmHg

Use Korotkoff 5 sound to define DBP (disappearance of sound, more identified and agreement, but may at / near zero —> ***K4 (muffling sound))

Mercury sphygmomanometer: Errors, White coat HT
Automated: Reduce errors, Measures K5

Question 9

Proteinuria

Answer 9

• Dipstick: ***>= 1+
• 24 hour urine protein >= ***300 mg/day
• Heavy proteinuria >= ***1 g/day
• ***Spot urine for protein / Cr ratio

Question 10

Edema

Answer 10

• Common
• Now ***omitted from all definitions of PET
• Widespread severe edema of sudden onset is of clinical importance

Pathophysiology:
1. Endothelial damage —> ↑ Vascular permeability
2. Loss of protein through kidney
—> Edema

Question 11

Pathophysiology of 3 classic symptoms

Answer 11

1. Frontal headache
   - cerebral edema + ↑ ICP
2. Visual disturbance
   - impeded blow flow + ischaemic injury secondary to vasospasm of retinal arteries
3. Epigastric pain
   - Periportal fibrin deposition —> ***Hepatic sinusoid obstruction —> stretching liver capsule + haemorrhage

Question 12

Steps of diagnosis

Answer 12

BP 140/90
—> Rest and Recheck
—> Still high
—> ***Admit for BP monitoring

1. BP normal + No proteinuria before 20 weeks
   - HT alone —> Gestational HT
   - HT + Proteinuria afterwards —> Pre-eclampsia
2. HT / Proteinuria before 20 weeks
   —> likely to be Chronic HT / Renal disease
   —> Rule out secondary causes: Renal, CVS, Endocrine, Autoimmune

Question 13

Management of ***Mild non-proteinuria hypertension

Answer 13

Day case / ***Outpatient
- reduces inpatient stay, convenient

Monitor:
- S/S of ***Severe pre-eclampsia (e.g. headache, visual disturbance), proteinuria
- CBC, LFT, RFT, urate, clotting profile
- Fetal growth by USG
- +/- Antihypertensive
- Induction of labour before 40 weeks

Question 14

Management of ***Pre-clampsia

Answer 14

1. Stabilisation of maternal condition
   - Hypertension: ***BP control (beware of sudden BP drop: damage Uteroplacental, Cerebral perfusion)
2. ***Fluid balance
   - watch out for fluid overload e.g. Pulmonary edema
3. Prevention of eclampsia (for S/S of pending eclampsia / severe pre-eclamptic toxaemia)
   - ***MgSO4 (10% risk of second seizure)
4. ***Screening + Manage associated complication
   - HELLP
   - Coagulopathy
   - Pulmonary edema
   - Renal failure
   - Stroke (ischaemic / haemorrhagic)
   - Fetal growth
5. Planning for delivery (**Definitive treatment)
   - timing is balance between severity of **Pre-eclampsia and risk of ***Prematurity

Question 15

***Severe Pre-eclampsia / Imminent Eclampsia

Answer 15

Symptoms:
1. Headache
2. Visual disturbance
3. Epigastric / RUQ pain
4. N+V

**Signs:
1. BP **>= 160/110
2. Proteinuria: **3/4+ or **>3 g/day
3. Gross + rapidly progressive edema
4. ***Oliguria: <30 ml/hr
5. Brisk jerks / clonus

Laboratory results:
1. Thrombocytopenia
2. Impaired LFT, RFT
3. Impaired clotting profile

Management:
1. BP Control
- ↓ risk of Cerebral haemorrhage (>= 160/110 mmHg)
- avoid sudden drop of BP —> **Fetal distress
- keep DBP 90-100
- Antihypertensive: IV **Labetalol / ***Hydralazine

Question 16

Conduct of delivery

Answer 16

Timing + Mode (balance risk to mother, fetus)
- If extreme prematurity —> conservative treatment (to improve neonatal outcome)
—> **Betamethasone to promote fetal lung maturity (if gestation **<34 weeks)
—> Close monitoring of maternal well-being
- Vaginal vs **C-section (for more severe Pre-eclampsia)
- **Epidural anaesthesia preferred for vaginal delivery (provided no coagulopathy)

Monitor
- Fetus: Continuous fetal heart monitoring
- Maternal: BP, Maternal symptoms
—> if on MgSO4: monitor **Jerks, **RR, ***Urine output (Mg toxicity)
—> avoid fluid overload

Postpartum
- watch out for Convulsion, Pulmonary edema

Question 17

Eclampsia

Answer 17

Occurrence of **convulsion in pregnancy (unless known epilepsy / cause)
- **Generalised tonic-clonic type
- High index of suspicion
- Eclampsia until proven otherwise

Occur up to ***10 days post delivery

1.8% mortality

Question 18

Management of ***Eclampsia

Answer 18

1. ABC
2. Prevention of injury / aspiration
3. Stabilisation of maternal condition
   - **MgSO4 (10% risk of second seizure)
   - **Fluid balance
   - ***BP control (uteroplacental, cerebral perfusion)
   - Secondary / associated complication
   —> HELLP
   —> Coagulopathy, Pulmonary edema, Renal failure
   —> Stroke
4. Planning for delivery
   - Mode of delivery (non reassuring fetal heart rate)

Question 19

MgSO4: Anticonvulsant

Answer 19

• Low therapeutic-toxic range
• Excreted in urine
• Toxicity: **Respiratory depression + **Cardiac arrest (Prolonged AV conduction)
• Monitor: **Loss of patellar reflex, **Urine output (> 30 ml/h), ***RR (> 12 / min), Blood Mg level
• Continue MgSO4 infusion till ***24 hours after delivery
• Antidote: Ca gluconate (SpC OG)

Question 20

Post-natal counselling

Answer 20

Hypertension + Proteinuria should resolve by ***6 weeks after delivery —> if not then suspect chronic HT / renal disease

Recurrence of PET: 1 in 10, 1 in 4 (if eclampsia)

Long term risk of CVS disease after PET
- HT
- IHD
- Stroke

Contraception
- if BP normal, no contraindication to use oral combined contraceptive pills

Question 21

Prevention of Pre-eclampsia

Answer 21

**Antiplatelet agents (Low dose Aspirin 75mg)
- start before **16 weeks (SpC OG: until 36 weeks, stop before giving birth to prevent bleeding tendency)
(Indications of Aspirin (SpC OG):
1. Pre-existing renal disease
2. Pre-existing DM
3. APLS
4. AMA
5. Multiple pregnancy)

Primary:
- Early detection + control of Gestational HT / Pre-eclampsia

Secondary:
- ***Prophylactic use of MgSO4 (to prevent eclampsia in women with severe pre-eclampsia)

Tertiary:
- Prevent subsequent convulsions with MgSO4

Others (weak evidence):
- advise on rest at home / bed rest
- corticosteroids for HELLP

***Vitamin C, D, E, Diuretics NOT recommended

Question 22

Chronic HT in pregnancy

Answer 22

Are antihypertensive agents for chronic HT safe in pregnancy?
- BP may fall slightly in 2nd trimester
- Methyldopa (1st line), Labetalol, Ca blocker

Chronic HT:
- Prognosis depends on whether there is superimposed Pre-eclampsia, Deterioration of renal function, Progression of underlying disorder e.g. SLE

Question 23

Chronic HT with superimposed PET

Answer 23

When to suspect superimposed PET:
- **Sudden ↑ BP
- **↑ / Development of proteinuria
- ***IUGR
- Features of multi-system disorders

Question 24

Antihypertensive in superimposed PET

Answer 24

• ↓ risk of severe HT but ***not risk of superimposed PET
• consider if BP ***>=150/100 mmHg

1. Methyldopa:
   - α-agonist
   - widely used, safe, well-tolerated
   - SE: dizziness, postural hypotension, nightmare, ***depression, abnormal LFT
2. Labetalol:
   - combined α + β blocker
   - vasodilatation
   - SE: flushing, light head, palpitations, scalp tingling
3. Nifedipine M/R:
   - Ca channel blocker
   - SE: headache, tachycardia, flushing, N+V
4. Hydralazine:
   - vasodilator
   - ***↑ HR, CO
   - SE: tachyphylaxis, headache, flushing, light head, nausea, palpitation

Avoid:
- Propranolol —> IUGR, Neonatal depression
- ACE inhibitors —> Fetal death, Neonatal renal failure

Question 25

Summary: General management of Pre-eclampsia

Answer 25

1. Monitor maternal well-being
   - BP
   - Blood tests: CBP, L/RFT, Urate, Coagulation profile
   - Urine: **Protein / Cr ratio or **24-hour urine for protein
   - Symptoms
2. Monitor fetal well-being
   - **Cardiotocogram (CTG)
   - **USG for growth, ***liquor volume, Doppler study
   - Fetal movement
3. ***Steroid prophylaxis < 34 weeks
4. BP control
5. Thromboprophylaxis
   - ***Pressure stocking +/- LMWH
6. ***MgSO4 for severe Pre-eclampsia
7. Timing of delivery
   - depend on gestation and severity of condition