Current Diagnosis and Management of Hypertensive Emergency

1 CRITICAL CARE ISSUES FOR THE NEPHROLOGISTC urrent Diagnosis and Management of HypertensiveEmergencyAndrew R. Haas and Paul E. MarikDivision of Critical Care, Pulmonary, Allergy and Immunologic Disease, Jefferson Medical College ofThomas Jefferson University, Philadelphia, PennsylvaniaABSTRACTThe appropriate and timely evaluation and treatment ofpatients with severely elevated blood pressure is essential toavoid serious adverse outcomes. Most importantly, the distinc-tion between a Hypertensive Emergency (crisis) and urgencyneeds to be made. A sudden elevation in systolic (SBP) and/ordiastolic blood pressure (DBP) that is associated with acuteend organ damage (cardiovascular, cerebrovascular, or renal)is defined as a Hypertensive crisis or Emergency . In contrast,acute elevation in SBP and/or DBP not associated with evi-dence of end organ damage is defined as Hypertensive patients with a Hypertensive Emergency , blood pressurecontrol should be attained as expeditiously as possible withparenteral medications to prevent ongoing and potentially per-manent end organ damage.

2 In contrast, with hypertensiveurgency, blood pressure control can be achieved with the useof oral medications within 24 48 hours. This paper reviews themanagement of Hypertensive is one of the most common chronicmedical conditions in the United States affecting close to30% of the population over the age of 20 years (1,2).While chronic hypertension isanestablishedriskfactorfor cardiovascular and cerebrovascular mortality andend-stage renal disease, accelerated elevations in bloodpressure from various etiologies can result in acute endorgan damage and dysfunction. These acute blood pres-sure elevations are likely to be encountered by a widevariety of clinicians and recognition and prompt evalua-tion and treatment are crucial to prevent permanent endorgan damage. Unfortunately, the impact of these clin-ical situations is often underappreciated such that appro-priate and timely evaluation and treatment is delayedleading to potentially serious adverse terminology applied to the clinical situationsassociated with acute elevations in blood pressure hasbeen confusing and often misused.

3 Most authorities con-cur that a sudden elevation in systolic (SBP) and/or dia-stolic blood pressure (DBP) that is associated with acuteend organ damage (cardiovascular, cerebrovascular, orrenal) is defined as Hypertensive crisis or Emergency (3 11). In contrast, acute elevation in SBP or DBP not asso-ciated with evidence of end organ damage is defined ashypertensive urgency (7,8,11). To simplify the categor-ization of acute elevations in blood pressure, the term malignant hypertension, used to describe a syndromecharacterized by elevated blood pressure with encephal-opathy or acute nephropathy, has been removed by theNational and International Blood Pressure ControlGuidelines and should be referred to as hypertensiveemergency or crisis instead (1,12).Several points should be considered when distin-guishing Hypertensive Emergency from hypertensiveurgency. The presence of end organ damage, not theabsolute blood pressure, isthe differentiating factorbetween Hypertensive Emergency and urgency.

4 Thisdifferentiation is critical, as how quickly and aggres-sively the quest for blood control is pursued is dictatedby the presence of end organ damage. Specifically, inhypertensive Emergency , blood pressure control shouldbe attained as expeditiously as possible with parenteralmedications to prevent ongoing and potentially per-manent end organ damage. In contrast, with hyperten-sive urgency, blood pressure control can be achievedwith the use of oral medications within 24 48 hours(7,8,11). This review will focus on the Management ofhypertensive 1 lists those clinicalconditions regarded as a Hypertensive classification and approach to hypertensionundergoes periodic review by the Joint NationalCommittee (JNC) on Prevention, Detection, Eval-uation, and Treatment of High Blood Pressure with themost recent report (JNC VII) having been released in2003 (see Table 2) (1,12). Within this report, the classifi-cation of blood pressure was simplified compared withprevious JNC reports with the recognition of two stagesAddress correspondence to: Paul E.

5 Marik, MD, Division ofPulmonary and Critical Care Medicine, 834 Walnut Street,Suite 650, Philadelphia, PA 19107, or e-mail: in Dialysis Vol 19, No 6 (November December)2006 pp. 502 512502of hypertension (compared with the previous four stagesin JNC VI), but a new category called prehypertensionwas added (13). Addition of this category was deemedimportant to recognize that progression from this cate-gory to hypertension is often encountered, which subse-quently puts patients at increased risk for the variouscomplications associated with chronic mentioned previously, hypertension is an extre-mely common medical problem in the United Stateswith an ever-increasing incidence given increasingobesity rates and the metabolic syndrome affecting thenation (14 16). A striking increaseinhypertensioninyoung adults and children because of obesity and sed-entary lifestyles is also occurring (17,18). Most of thesepatients have essential hypertension; however, were reported to be aware of their blood pres-sure problem, only were under pharmacologictreatment, and adequate blood pressure control wasachieved in only 30 50% of patients depending on thepopulation studied (2,19 25).

6 Interestingly, even withthese poor statistics on blood pressure recognition,treatment, and control, only 1% of these patients willdevelop a true Hypertensive Emergency (26,27). Aswould be expected, most patients who present withhypertensive Emergency have previously received adiagnosis of hypertension with many of them havinginadequate blood pressure control on oral therapy. Ofnote, because of many factors including access tohealthcare, economic demographics, and age and eth-nic responses to various medications, the elderly andAfrican Americans are at higher risk of developing ahypertensive Emergency (11,28 30).PathophysiologyThe pathophysiology of Hypertensive Emergency ismultifactorial and includes such factors as mechanicalstress and injury, endothelial damage, renin angiotensinsystem activation, and oxidative stress. The initial insultis often difficult to ascertain, but abrupt release ofhumoral vasoconstrictors increase systemic vascularresistance (31,32). The subsequent increase in bloodpressure generates mechanical stress and endothelialinjury leading to increasedpermeability, activation ofthe coagulation cascade and platelets, and deposition offibrin.

7 This process results in ischemia and the releaseof additional vaso-active mediators generating a viciouscycle of ongoing injury. The renin angiotensin system isoften activated leading to further vasoconstriction andthe production of proinflammatory cytokines such asIL-6 (33,34). Furthermore, NADPH oxidase activity isincreased and generates reactive oxygen species (35).These collective mechanisms can culminate in end organhypoperfusion, ischemia, and dysfunction that manifestas Hypertensive Diagnostic EvaluationPatients with Hypertensive Emergency usually presentfor evaluation as a result of a new symptom complexrelated to their elevated blood pressure. Patient triageand physician evaluation should proceed expeditiouslyto prevent ongoing end organ damage. A focused med-ical history that includes the use of any prescribed orover-the-counter medications should be obtained. Ifthe patient is known to have hypertension, their hyper-tensive history, previous control, Current antihyperten-sive medications with dosing, compliance, and timefrom last dose are important facts to know as subse-quent treatment decisions are made.

8 Inquiry into useof recreational drugs (amphetamines, cocaine, andphencyclidine) or monoamine oxidase inhibitorsshould be made. Confirmation of the blood pressureshould be obtained in both arms by a physician usinga blood pressure cuff of appropriate size. The appro-priate size cuff is particularly important as the use of acuff too small for the arm size has been shown to arti-ficially elevate blood pressure readings in obesepatients (36,37). As mentioned previously, it is import-ant to note that the rate of blood pressure elevationmay be more important than the absolute value (38 41). Patients with long-standing hypertension maytolerate SBP > 200 mmHg or DBP > 150 mmHgwithout developing clinicalsignsorsymptomsofendorgan damage; however, in postoperative or pregnancypatients a much lower but more rapidly progressiveincrease in blood pressure may result in end physical examination should attempt to identifyevidence of end organ damageby assessing pulses in allextremities, auscultatingthe lungs for evidence of pul-monary edema, the heart for murmurs or gallops, therenal arteries for bruits, and performing a focused neur-ologic and fundoscopic examination.

9 Headache andaltered levels of consciousness are the usual manifesta-tions of Hypertensive encephalopathy (38,42). Focalneurological findings, especially lateralizing signs, areuncommon in Hypertensive encephalopathy, being moresuggestive of a cerebrovascular accident. Subarachnoidhemorrhage should be considered in patients with asudden onset of a severe headache. The ocular examina-tion may show evidence of advanced retinopathy withTABLE 1. Hypertensive emergenciesHypertensive encephalopathyAcute aortic dissectionAcute myocardial infarctionAcute coronary syndromePulmonary edema with respiratory failureSevere pre-eclampsia, HELLP syndrome, eclampsiaAcute renal failureMicroangiopathic hemolytic anemiaHELLP, Hemolysis, elevated liver enzymes, low 2. Joint National Committee on Prevention, Detection,Evaluation, and Treatment of High Blood Pressure categorizationof blood pressure (JNC VII) (1,12)Blood Pressure Class Systolic BP (mmHg) Diastolic BP (mmHg)Normal<120<80 Prehypertension121 13980 89 Stage I140 15990 99 Stage II>160>100 Hypertensive EMERGENCY503arteriolar changes, exudates, hemorrhages, or papille-dema assisting in the identification of Hypertensive en-cephalopathy.

10 Cardiac evaluation should aim to identifyangina or myocardial infarction with the focus on clar-ifying any atypical symptoms such as dyspnea, cough, orfatigue that may be overlooked (28,43). Severe renalinjury may result in hematuria or oliguria. On the basisof this evaluation, the clinician should be able to distin-guish between a Hypertensive Emergency and an urgencyand to formulate the subsequent plan for further diag-nostic tests and objective evaluation should include a meta-bolic panel to assess electrolytes, creatinine, and bloodurea nitrogen; a complete blood count (and smear ifmicroangiopathic hemolytic anemia is suspected); aurinalysis to look for proteinuria or microscopichematuria;andanelectrocardiog ram to assess forcardiac ischemia (27). Supportive radiographic studiessuch as a chest radiograph ina patient with dyspnea orchest pain or a head computed tomography scan in apatient with neurologic symptoms should be obtainedin the appropriate clinical scenario.