BP normally decreases initially (nadir at 16-20wks) then increases in pregnancy. Baseline 5-10% preeclampsia risk in primips.
Most common complication in pregnancy (2-3%)
Definitions
- Hypertension: blood pressure exceeding 140/90 mm Hg
- Hypertension with onset >20 weeks GA – PIH
- Mild pre-eclampsia: PIH, proteinuria, no end organ damage
- Severe pre-eclampsia: PIH, proteinuria, end organ damage
- Eclampsia: pre-eclampsia plus convulsions
- Hypertension with onset < 20 weeks, w/o proteinuria – CHRONIC HTN
- Transient hypertension of pregnancy or chronic hypertension identified in the latter half of pregnancy – GESTATIONAL HTN
- Preeclampsia superimposed on chronic hypertension
- HELLP: haemolytic anemia, elevated liver enzymes, low platelets
Pathogenesis
Failure of the second wave of trophoblastic invasion of spiral vessels (normally will get rid of surrounding muscle) – leads to tight spiral vessels, decreased prostacyclin (vasodilator), increased thromboxane (vasoconstrictor) – the placenta releases cytokines, free radicals and complement fixation – inflammatory response, endothelial cell damage, fibrin deposition, HTN – vasoconstriction – vascular bed most affected = presentation (kidney – pre-eclampsia; liver – fatty liver; reticuloendothelial – HELLP)
* VASOSPASM
Symptoms: Signs:
Headaches HTN
Visual disturbances Retinal vsaospasm
Epigastric or RUP pain Hepatic tenderness
Edema Hyperreflexia/clonus
Treatment
- Delivery!
- Continuous fetal monitoring
- Magnesium sulphate for prevention of seizures (4g IV bolus over 20 minutes, then 2-4g/hr) à continue for 12-24 hr post partum and must monitor for toxicity (↓DTR, ↓RR, anuria, hypotonia, CNS/cardiac depression) à antagonist calcium gluconate (10%), 1g or 10mL IV over 2 minutes
- Antihypertensives
- Hydralazine 2-10mg IV bolus over 5 minutes, then q15-30minutes prn
- Labetolol 50-100mg IV q10minutes (contraindicated if poor liver function)
- Methyldopa 250mg bid – 1g tid
- Nifedipine 10mg PO q4-8h
- Admission orders
- NPO
- Bedrest
- Vitals and DTR q1h
- Fetal monitor
- IV NS
- Foley
- I/O q1h
- Urine dip d12h
- Labs – Hgb, PLT, Cr, AST/ALT, Uric acid, urine protein
- Consider peripheral smear, PT/PTT, LDH
- NST qdaily
- BPP
- MgSO4 4g IV push then 2g IV q1h (continue until 24 hr postpartum)
- Hydralazine 5mg IV push over 5 minutes q15minutes until BP <140/90, repeat 6 hr later if BP >140/90