El Diagnostico y Manejo de Las Crisis Hipertensivas

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Transcript of El Diagnostico y Manejo de Las Crisis Hipertensivas

  • DOI: 10.1378/chest.118.1.214 2000;118;214-227 Chest

    Joseph Varon and Paul E. Marik The Diagnosis and Management of Hypertensive Crises

    This information is current as of August 20, 2006

    http://www.chestjournal.org/cgi/content/full/118/1/214located on the World Wide Web at:

    The online version of this article, along with updated information and services, is

    ISSN: 0012-3692. may be reproduced or distributed without the prior written permission of the copyright holder. 3300 Dundee Road, Northbrook IL 60062. All rights reserved. No part of this article or PDFpublished monthly since 1935. Copyright 2005 by the American College of Chest Physicians, CHEST is the official journal of the American College of Chest Physicians. It has been

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  • The Diagnosis and Management ofHypertensive Crises*

    Joseph Varon, MD, FCCP; and Paul E. Marik, MD, FCCP

    Severe hypertension is a common clinical problem in the United States, encountered in variousclinical settings. Although various terms have been applied to severe hypertension, such ashypertensive crises, emergencies, or urgencies, they are all characterized by acute elevations inBP that may be associated with end-organ damage (hypertensive crisis). The immediate reductionof BP is only required in patients with acute end-organ damage. Hypertension associated withcerebral infarction or intracerebral hemorrhage only rarely requires treatment. While nitroprus-side is commonly used to treat severe hypertension, it is an extremely toxic drug that should onlybe used in rare circumstances. Furthermore, the short-acting calcium channel blocker nifedipineis associated with significant morbidity and should be avoided. Today, a wide range ofpharmacologic alternatives are available to the practitioner to control severe hypertension. Thisarticle reviews some of the current concepts and common misconceptions in the management ofpatients with acutely elevated BP. (CHEST 2000; 118:214227)

    Key words: aortic dissection; b-blockers; calcium channel blockers; fenoldopam; hypertension; hypertensive crises;hypertensive encephalopathy; labetalol; nicardipine; nitroprusside; pregnancy

    Abbreviations: ACE 5 angiotensin-converting enzyme; CBF 5 cerebral blood flow; DA 5 dopamine

    H ypertension is a common clinical problem in theUnited States, and physicians of all types arelikely to encounter patients with hypertensive urgen-cies and emergencies. Although various terms havebeen applied to these conditions, they are all char-acterized by acute elevations in BP.18 Prompt butcarefully considered therapy is necessary to limitmorbidity and mortality.9,10 Unfortunately, acceler-ated hypertension is among the most misunderstoodand mismanaged of acute medical problems seenin clinical practice. Many physicians have an urgentneed to rapidly lower an elevated BP without con-sidering the pathophysiologic principles involved.

    Definitions

    The Joint National Committee on Prevention,Detection, Evaluation, and Treatment of High BloodPressure has classified hypertension according to thedegree of BP elevation.1 Stage 1 patients have asystolic BP of 140 to 159 mm Hg or a diastolic BP of90 to 99 mm Hg. Stage 2 individuals have a systolicBP of 160 to 179 mm Hg or a diastolic BP of 100 to109 mm Hg, whereas stage 3 includes a systolic BPpressure $ 180 mm Hg or a diastolic BP $ 110 mmHg. Stage 3 hypertension has also been called severehypertension or accelerated hypertension. The fea-tures and classification and of pregnancy-inducedhypertension are included in Table 1.11

    A number of different terms have been applied tosevere acute elevations of BP. However, most au-thors have defined hypertensive crises or emergen-cies as a sudden increase in systolic and diastolic BPassociated with end-organ damage of the CNS, theheart, or the kidneys; the term hypertensive urgen-cies has been used for patients with severely elevatedBP without acute end-organ damage.25,8,12,13 Table2 lists those clinical conditions that meet the diag-

    *From the Department of Medicine (Dr. Varon), Baylor Collegeof Medicine, Houston TX; and the Department of InternalMedicine, Section of Critical Care (Dr. Marik), WashingtonHospital Center, Washington, DC.Manuscript received July 9, 1999; revision accepted December 3,1999.Correspondence to: Joseph Varon, MD, FCCP, Research Direc-tor, Department of Emergency Services, The Methodist Hospital,6565 Fannin M 196, Houston, TX 77030; e-mail:jvaron@bcm.tmc.edu

    review

    214 Review

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  • nostic criteria of hypertensive crises. It is importantto note that the clinical differentiation betweenhypertensive emergencies and hypertensive urgen-cies depends on the presence of target organ dam-age, rather than the level of BP.

    Another frequently encountered term, malignanthypertension, is defined as a syndrome characterizedby elevated BP accompanied by encephalopathy ornephropathy.1,14 Postoperative hypertension has ar-bitrarily been defined as systolic BP . 190 mm Hgand/or diastolic BP $ 100 mm Hg on two consecu-tive readings following surgery.15,16 The transientnature of postoperative hypertension and the uniqueclinical factors present in the postoperative periodrequire that this clinical syndrome be given individ-ual consideration. A systolic pressure . 169 mm Hgor a diastolic . 109 mm Hg in a pregnant woman isconsidered a hypertensive emergency requiring im-mediate pharmacologic management.17

    Epidemiology, Etiology, Pathogenesis

    Hypertension is extremely common in the Amer-ican population. Sixty million US inhabitants sufferfrom hypertension.1 The vast majority of these pa-tients have essential hypertension. Moreover, a largenumber of affected individuals are unaware of their

    hypertension. Three quarters of those affected donot have their BP well controlled. Fewer than 1% ofthese patients will develop one or multiple episodesof hypertensive crises.18,19

    The incidence of hypertensive crises is higheramong African Americans and the elderly.10,13,20,21The majority of patients presenting with hyperten-sive crises have previously received a diagnosis ofhypertension, and many have been prescribed anti-hypertensive therapy with inadequate BP con-trol.10,13,20 The incidence of postoperative hyperten-sive crises varies depending on the populationexamined, being reported in 4 to 35% of patientsshortly after the surgical procedure.16,22,23 Like otherforms of accelerated hypertension, a history of hy-pertension is common.

    Preeclampsia (pregnancy-related hypertension) isa form of hypertension that deserves mention. Theincidence of preeclampsia varies according to thepatient characteristics. It occurs in 7% of all preg-nancies. Of them, 70% are null-gravidas and 30% aremulti-gravidas. In molar pregnancies, preeclampsiahas been described in up to 70% of cases.24

    The pathophysiology of hypertensive crises isthought to be due to abrupt increases in systemicvascular resistance that are likely related to humoralvasoconstrictors.25,26 With severe elevations of BP,endothelial injury occurs and fibrinoid necrosis ofthe arterioles ensues.25,26 This vascular injury leadsto deposition of platelets and fibrin, and a break-down of the normal autoregulatory function. Theresulting ischemia prompts further release of vaso-active substances, completing a vicious cycle.26

    It should be appreciated that most patients whopresent to hospital with an elevated BP are chron-ically hypertensive, with a rightward shift of thepressure/flow (cerebral and renal) autoregulation

    Table 2Hypertensive Emergencies

    Hypertensive encephalopathyAcute aortic dissectionAcute pulmonary edema with respiratory failureAcute myocardial infarction/unstable anginaEclampsiaAcute renal failureMicroangiopathic hemolytic anemia

    Table 1Classification of Preeclampsia*

    Variables Mild Severe

    BP 130/80 to 140/95 mm Hg . 160/110 mm HgAbsolute Systolic $ 140 mm Hg

    Diastolic $ 90 mm HgRelative Systolic increased . 30 mm Hg

    Diastolic increased . 15 mm HgWeight , 5 lb/wk . 5 lb/wkLaboratory

    Proteinuria 300 mg/24 h $ 5 g/d; 3 1 /4 1 semiquantitativePlatelets Normal May be , 150,000 3 109/LLiver function Normal Elevated AST/ALTClotting studies Normal May be prolongedBilirubin Normal May be elevated

    *AST/ALT 5 aspartate transaminase/alanine transaminase.HELLP syndrome characterized by hemolysis, elevated liver enzymes, and low platelet count reflects those patients with the greatest risk formortality and morbidity.

    CHEST / 118 / 1 / JULY, 2000 215

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  • curve (Fig 1).27 Furthermore, most patients withsevere hypertension (diastolic pressure $ 110 mmHg) have no acute, end-organ damage. Rapid anti-hypertensive therapy in this setting may be associ-ated with significant morbidity.2830 There are, how-ever, true hypertensive emergencies in which therapid (controlled) lowering of BP is indicated (seebelow).18,19,31

    Clinical Manifestations

    The manifestations of hypertensive crises arethose of end-organ dysfunction. Table 2 lists thoseconditions that, when associated with severely ele-vated BP, are referred to as hypertensive crises/emergencies. Organ dysfunction is uncommon withdiastolic BPs , 130 mm Hg, although it may occur.

    It is important to recognize that the absolute levelof BP may not be as important as the rate ofincrease.7,9,32,33 For example, patients with long-standing hypertension may tolerate systolic BPs of200 mm Hg or diastolic increases up to 150 mm Hgwithout developing hypertensive encephalopathy,while children or pregnant women may developencephalopathy with diastolic BP . 100 mm Hg.17

    Headache, altered level of consciousness, andless-severe