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ERCAST


Welcome to ERCast, a focused discussion on the questions, quagmires and known unknowns we face everyday in the emergency department.

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Jun 7, 2011

HTN should be straightforward, so why is it confusing? Part of the problem is terminology. Shane and Pitts got it right in 2003 when they made sense of classifying different hypertensive scenarios. What in the world do accelerated, malignant, urgent and malignant HTN mean? I have no idea either. Here's the Shane and Pitts BP breakdown....

Severely elevated blood pressure can be thought of in three ways:

Hypertensive emergency: end organ damage because of severely increased blood pressure. In this scenario, BP should be lowered in the next 1 to 2 hours.

Hypertensive urgency: severely elevated blood pressure in patients at high risk for acute end organ damage but without evidence of new injury. This includes a history of prior end organ disease like CHF, unstable angina, renal failure, CVA, etc. Do these patients need to be admitted or have immediate BP reduction in the ED? Your decision will be physician comfort level based rather than evidence based, because there's no evidence so say what's the right thing to do. However, you should have increased vigilance. If the patient is discharged, set up a plan for BP reduction and follow-up in a day or two.

Everyone else is in the third group: Uncontrolled Severe HTN.  The most important management piece here is good follow up. You may end up starting these patients on antihypertensives in the ED, or maybe they’ll be referred for a BP recheck in a week because this was a first reading of high BP or they had an acute painful condition that confounded to the picture.

In the old system, where everyone with really high blood pressure but without end organ dysfunction was classified as an urgency, it was hard to organize treatment and disposition. With this grouping: emergency, urgency and uncontrolled severe HTN, I find it easier to organize my treamtent and disposition.

And now for some shownote goodness from my man, Justin Arambassick, MD...

What lab tests should you think about before starting or changing BP meds?
Urine
o   PROTEIN IN URINE = KIDNEY DAMAGE
o   This may be due to the hypertension itself or another disease process such
as diabetes.
o   Either way, the drugs of choice in the setting of proteinuria are ACE
inhibitors (e.g. lisinopril) or ARB angiotensin receptor blockers (e.g.
losartan).
In general, no benefit to giving a combination of an ACE and an ARB.
Blood
Creatinine, if elevated:
o   ACE or ARB first line treatment, though start at low dose and monitor Cr
o   These medications may cause kidney injury by reducing GFR (glomerular
filtration rate)
o   Contraindicated in bilateral renal stenosis
o   Monitor that the patient is not dehydrated or on other medications that may
stress the kidney
o   If these meds are started, the patient must have good follow-up for
creatinine and potassium monitoring.

Sodium
o   If low, avoid thiazide diuretics
o   Furosemide and loop diuretics do not affect as much, though you probably do not
want to start loop diuretics either

ALLHAT study conclusions

o   No significant difference in all-cause mortality, fatal heart disease, or
non-fatal myocardial infarction when chlorthalidone was compared with lisinopril
or amlodipine

o   Decrease rate of heart failure after 6 years in chlorthalidone group compared with amlodipine

o   Study conclusion: thiazide-type diuretics are preferred first-step in antihypertensive therapy.

ACCOMPLISH trial
o    ACE and a CCB are a more effective combination than ACE plus a diuretic.
o   Among the patients taking the ACEI/CCB combination, 81.7% had their BP
controlled to < 140/90 mm Hg compared with 78.5% of the ACEI/HCTZ group.o   Approximately 50% of patients still on only the designated study medication(no add-ons) at 30 months.

General rules:

First line treatment is a thiazide diuretic (chlorthalidone was the medication originally studied, not hydrochlorothiazide.) Chlorthalidone is more potent, though has more side effects than hydrocholorthiazide.

If a patient has severe asthma don’t start a beta blocker

If a patient has coronary artery disease,  ACE and a
beta blocker
If a young healthy patient: ACE-I
If African American: thiazide diuretic or calcium channel blocker

Algorithmic approach to starting antihypertensive meds