Tl;dr: (1) Don’t forget to order a uric acid with the labs as it increases the specificity in diagnosing preeclampsia. (2) If the pt is preeclamptic with severe features (see below), then give 4g IV Mg followed by 1-2gr/hr infusion for 24hrs. (3) Unlike other hypertensive emergencies, start with push dose meds rather than our usual drips, either IV push 10-20 mg labetalol or 5-10 mg hydralazine. (4) Prompt ob consultation and/or transfer to an appropriate facility.
We often don’t manage hypertension in pregnancy as we generally send stable late term pregnancies straight to L&D. However, many of us will end up working in practice environments where we won’t be so lucky. Also be on your guard with postpartum patients (up to 6wks out), you need to consider preeclampsia (preE) prior to discharge. Here is a little review…
Recall there is spectrum of disease including cHTN in pregnancy, gHTN, preE without severe features (SF), preE with SF, cHTN with superimposed preE and HELLP. A few definitions before jumping in:
Mild Preeclampsia
- SBP > 140 or DBP > 90, 2+ protein on udip, gestational age >20wks, & asymptomatic
Severe Preeclampsia
- SBP > 160 or DBP > 110
- Mild preE + concerning sign / sx: headache, visual changes, persist RUQ pain, SOB, significant edema
- Mild preE + concerning labs: plt < 100, LFTs 2x upper limit of nml, AKI
If you concerned about preE, then critical labs include Hct, Plt, Cr, AST/ALT, Uric Acid, and UA/Urine Protein Creatinine ratio (important to send straight catheter urine sample if the patient labored during delivery course). Uric acid is not included in the definition of preE but it does increase specificity for the diagnosis so don’t forget to send it (your consultants will appreciate it).
Severe preE should be treated with IV magnesium and aggressive blood pressure management. Start with 4g IV Mg bolus followed by a 1-2gr/hr infusion. Monitor closely for respiratory depression. You can do serial reflex exams as absent deep tendon reflexes are one of the earliest signs of magnesium toxicity. Give IV calcium if the patient develops depressed reflexes or a decreased respiratory drive.
Unlike other hypertensive emergencies where we turn to a cardene or esmolol gtt, you should start with IV pushes of either labetalol (10-20mg, generally first line) or hydralazine (5-10mg). Repeat doses may be required with a max dose of 300mg labetalol. You may consider a labetalol infusion or nitroprusside infusion in refractory cases. Nitroprusside does run the risk of fetal cyanide toxicity if used >4hrs, so use it judiciously.
Finally get Ob involved early or transfer to an appropriate facility as delivery is the definitive treatment for preeclampsia.
Thank you Brindha (my ob friend), who helped put this together!
Sources:
Hypertension in Pregnancy. The American College of Obstetricians and Gynecologists. Available at: https://www.acog.org/~/media/Task%20Force%20and%20Work%20Group%20Reports/public/HypertensioninPregnancy.pdf. Accessed Aug 2018.
