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Hypertension and Pre-eclampsia


Eclampsia

  • Grand mal convulsions occurring with features of pre-eclampsia
  • May occur before, during or after delivery

Physiological changes to blood pressure in pregnancy

  • BP directly proportional to systemic vascular resistance and cardiac output
  • Vasodilatation is primary change in pregnancy
  • BP falls in early pregnancy, nadir about week 22-24
  • May be low if woman supine due to diminished venous return
  • falls after delivery, then rises to peak 3-4 days later
    • ?return of normal vascular tone
    • ? vasomotor instability
  • Epidemiology
    •  hypertension 10-15% pregnancies
    • mild pre-eclampsia 10% primips
    • Severe pre-eclampsia 1%
    • Eclampsia 0.05%
    • Death from eclampsia 2%

Essential Hypertension

  • Likely to be pre-existing problem if first appears during 1st trimester
  • If require treatment before pregnancy risk of pre-eclampsia doubled
  • exclude secondary causes of hypertension

Pregnancy induced hypertension

  • Appears in 2nd half pregnancy and resolves in 6 weeks (may take up to 3 months)
  • Without proteinuria

Pre-eclampsia

  • pregnancy-specific multi-system disorder
  • diffuse vascular endothelial dysfunction
  • involving
    • renal
    • hepatic
    • cardiovascular
    • CNS
    • coagulation

History

  • headache
  • flashing lights
  • epigastric / right upper quadrant pain
  • nausea / vomiting
  • rapidly increasing / severe swelling of face, fingers or legs

Examination

  • pregnancy induced hypertension
  • proteinuria
  • rapidly progressive oedema
  • convulsions /  mental disorientation
  • intrauterine growth retardation / intrauterine death
  • placental abruption

Investigations

  • 24h urinary protein >0.3 g
  • increased serum uric acid
  • thrombocytopenia
  • increased clotting time
  • increased creatinine, urea
  • increased haematocrit, haemoglobin
  • Abnormal LFTs
  • Reduced fetal growth / oligohydramnios
  • abnormal / umbilical / uterine artery on Doppler

Crises

Causes of death

Pathogenesis

  • Abnormal placentation and trophoblast invasion
  • lack of vascular adaptation
  • decrease in prostacyclin and increase in thromboxane A2

Risk Factors

Management

  • Screening for pre-eclampsia
    • serum urea, creatinine, uric acid, haemoglobin, platelet count, coagulation screen, LFTs
    • urinalysis
    • uterine artery Doppler at 20-24 weeks - good negative predictive value
  • Treatment of blood pressure
  • Fetal surveillance
  • Decision of timing of delivery
  • Acute severe hypertension
  • Eclampsia
    • magnesium sulphate
  • Delivery
  • Prophylaxis
 

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