michigan hypertension core curriculum - State of Michigan
michigan hypertension core curriculum - State of Michigan
michigan hypertension core curriculum - State of Michigan
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ACUTE KIDNEY INJURY (AKI)<br />
In addition to papilledema, acute renal failure/ AKI were the earliest described TOD caused<br />
by severely elevated BP (“malignant <strong>hypertension</strong>”). The endothelial damage and arteriolar fibrinoid<br />
necrosis mirrors that seen in the heart, brain, and other organs. The syndrome is recognized by<br />
the combination <strong>of</strong> acutely decreased GFR, proteinuria, anemia, thrombocytopenia, and presence<br />
<strong>of</strong> schistocytes and other red cell fragments. It can be confused with hemolytic uremic syndrome<br />
or TTP, although the thrombocytopenia is generally less severe than in these other thrombotic<br />
microangiopathies while the BP elevation is usually more severe. Treatment principles are the same<br />
as in other types <strong>of</strong> TOD – rapid reduction <strong>of</strong> BP to levels that stop further vascular damage while<br />
maintaining perfusion <strong>of</strong> organs that generally have impaired autoregulation. Nitroprusside is commonly<br />
used although the dose and duration <strong>of</strong> use must be monitored and to avoid cyanide or thiacyanate<br />
toxicity. The simultaneous infusion <strong>of</strong> thiosulate can reduce but not eliminate the threat <strong>of</strong> this toxicity.<br />
Some advocate the use <strong>of</strong> the dopamine-1 receptor antagonist fenoldopam mesylate in this setting, not<br />
only to avoid toxicity but because it may increase renal blood flow and sodium excretion.<br />
PREECLAMPSIA AND ECLAMPSIA<br />
The treatment <strong>of</strong> pre-eclampsia and eclampsia is governed by the need to protect the health<br />
<strong>of</strong> both the mother and fetus. The role <strong>of</strong> medical management, discussed in a later section <strong>of</strong> this<br />
chapter, is only a temporizing measure until the fetus can be safely delivered. The choice <strong>of</strong> drugs is<br />
dictated both by efficacy and avoidance <strong>of</strong> fetal toxicity or harm. Drugs accepted as safe in this setting<br />
primarily include labetolol, nifedipine, nicardipine, and hydralazine. 17 Magnesium sulfate, generally<br />
indicated when a diagnosis <strong>of</strong> eclampsia or severe pre-eclampsia is entertained, is used primarily for<br />
prophylaxis against seizures, not management <strong>of</strong> <strong>hypertension</strong> per se.<br />
.<br />
CONCLUSIONS:<br />
The mortality and morbidity associated with hypertensive emergency and urgency is<br />
considerable in untreated patients. At the same time, there is potential for serious adverse effects <strong>of</strong><br />
treatment and specific recommendations remain opinion based at this time. There are no definitive<br />
studies establishing the ideal levels or rates <strong>of</strong> blood pressure lowering. In hypertensive emergencies,<br />
a compromise must be reached between preventing additional target organ damage while maintaining<br />
perfusion. In each case choice <strong>of</strong> anti-hypertensive medications needs to be individualized.<br />
1. Zampaglione B, Pascale C, Marchisio M, Cavallo-Perin P. Hypertensive urgencies and<br />
emergencies. Prevalence and clinical presentation. Hypertension 1996; 27(1): 144-147.<br />
2. Bennett NM, Shea S. Hypertensive emergency: case criteria, sociodemographic pr<strong>of</strong>ile, and<br />
previous care <strong>of</strong> 100 cases. Am J Public Health 1988; 78(6): 636-640.<br />
244 Hypertension Core Curriculum