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Hypertension, hypertensive crisis, and hypertensive emergency: approaches to emergency department care

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Training accredited REVIEW ARTICLE Hypertension, hypertensive crisis, and hypertensive emergency: approaches to emergency department care ELISENDA GÓMEZ ANGELATS, ERNESTO BRAGULAT BAUR Sección de Urgencias
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Training accredited REVIEW ARTICLE Hypertension, hypertensive crisis, and hypertensive emergency: approaches to emergency department care ELISENDA GÓMEZ ANGELATS, ERNESTO BRAGULAT BAUR Sección de Urgencias Medicina. Área de Urgencias. Hospital Clínic. Barcelona, Spain. CORRESPONDENCE: Dra. Elisenda Gómez Angelats Sección de Urgencias Medicina Área de Urgencias Hospital Clínic C/Villarroel, Barcelona. Spain RECEIVED: ACCEPTED: CONFLICT OF INTEREST: None Elevated arterial blood pressure is a frequent reason for seeking emergency care. It is important to remember that pressure elevation alone does not define whether the situation should be considered a life-threatening emergency or denotes only a need for urgent attention. Rather, it is the signs and symptoms accompanying the elevation that will reveal which patients are in need of emergency treatment. A hypertensive emergency is characterized by clear signs of acute injury to a target organ, presenting as hypertensive encephalopathy, intracranial bleeding, acute coronary syndrome, heart failure with acute pulmonary edema, aortic dissection, eclampsia or preeclampsia, or accelerated hypertension. These situations require the immediate but not abrupt reduction of arterial pressures by means of parenteral administration of drugs. A hypertensive patient in need of urgent care, but not in an emergency situation, on the other hand, has seriously elevated pressures but no signs of acute or progressive target organ injury. Such a patient requires gradual reduction of pressures over a period of 24 hours to several days and can receive oral treatment. A large number of drugs are available for managing hypertension. No single drug has been reliably shown to be better than others at reducing pressures, whether administered parenterally or not. However, recommendations can be made based on the accompanying clinical picture and individual patient characteristics. This review will outline such recommendations. [Emergencias 2010;22: ] Key words: Hypertension. Hypertensive crisis. Hypertensive emergency. Introduction Hypertensive crises are a frequent cause of emergency department (ED) visits. An isolated reading of blood pressure (BP) alone does not define the clinical picture as a hypertensive crisis. In other words, there are many clinical situations that are accompanied by an elevation of BP, which may generate confusion as to whether high BP (hypertension: HT) in a particular context is the cause or the consequence of the picture giving rise to the visit. Although hypertensive crises usually occur in HT patients who are untreated or inadequately treated, its definition and clinical course should not be confined to the magnitude of the rise in BP value, but also the existence of specific clinical symptoms that will be discussed below. Similarly, it should be noted that moderately high BP values can lead to emergency situations in a previously normotensive person 1. In this review we discuss those emergency situations that require special treatment to achieve rapid and optimal BP control, and the new criteria for treatment based primarily on pathophysiological mechanisms causing BP elevation. Definitions A hypertensive crisis is considered to be any increase of BP generally above 180/120 mmhg. Depending on the magnitude and the presence or absence of target organ damage (TOD) and the presence of associated symptoms, it is subdivided into HT emergency (life-threatening), urgent attention HT or pseudocrisis 2. Hypertensive emergency This refers to intense elevation of BP associated with acute injury to vulnerable organs. Pronounced increases in BP accompanied by obvious TOD should be treated immediately (without necessarily waiting for high values to return to nor- Emergencias 2010; 22: E. Gómez Angelats et al. mal BP) to prevent or limit organ damage 3. Examples of hypertensive emergencies: hypertensive encephalopathy, intracranial hemorrhage, acute coronary syndrome (ACS), heart failure with acute pulmonary edema, dissecting aorta, eclampsiaeclampsia and accelerated hypertension. A patient with a hypertensive emergency usually presents grade III-IV retinopathy. It is therefore a process that is identified by the symptoms experienced by the patient and not by the values of BP. Urgent attention HT This denotes elevated BP not accompanied by progressive TOD, and therefore requires gradual normalization of BP values in a period of time ranging from 24 hours to several days with orally administered drugs. It is therefore important to note that the difference between urgent attention HT and hypertensive emergency is not in the values of BP but rather the existence of TOD. Thus, patients with long-standing HT may have diastolic BP between mmhg and be asymptomatic, while patients with preeclampsia, cocaine users or patients with acute glomerulonephritis presenting DHT of mmhg may constitute a hypertensive emergency. Hypertensive pseudocrisis or false hypertensive crisis This refers to transient elevation of BP appearing in different situations and diseases, and BP elevation is a secondary phenomenon associated with them. We may see this in situations of pain, emotional stress, peripheral vertigo, spinal cord injury, acute urinary retention, hypoxia, brain damage with intracranial hypertension, etc. In these cases the treatment should be directed toward the underlying disease, since the BP values usually normalize once the cause of elevation is resolved. Clinical Manifestations There are many and varied main reasons for ED visits or referral among patients with a HT crisis. They range from the asymptomatic patient referred after an incidental finding of high BP to a patient with acute pulmonary edema. As mentioned, BP values per se do not determine case severity, but the accompanying symptoms do, in which case severity depends on the target organ affected. However, this does not mean that a patient with nephritic colic and BP 180/120 mmhg constitutes hypertensive emergency with renal impairment. Conversely, a patient with rapidly progressive dyspnea and BP 150/105 mmhg constitutes a hypertensive emergency with cardiac involvement and acute lung edema, which requires immediate lowering of BP. It is therefore very important to assess the patient's clinical context when classifying cases as hypertensive crisis or urgent attention HT, since the approach and therapeutic implications are going to be very different. It should also be noted that patients with chronic hypertension may tolerate BP levels of 150/100 mmhg well and without symptoms, while the same levels in younger patients with acute glomerulonephritis, or after cocaine consumption, may generate severe symptoms. In the case of a possible hypertensive emergency, the symptoms and physical findings guide us to the diagnosis. Thus, a patient may consult for visual disturbances, headache, confusion and vomiting as a manifestation of hypertensive encephalopathy or with reduced level of consciousness in the case of intracerebral hematoma or subarachnoid hemorrhage. Cardiovascular disorders include ACS, rapidly progressive dyspnea in the case of acute pulmonary edema and chest pain and/or abdominal pain in the case of aortic dissection. In the case of pregnant women with preeclampsia, the appearance of severe renal impairment with oliguria, anuria and microangiopathic anemia indicates eclampsia (Table 1). The most common presentation of accelerated-malignant hypertension is headache with visual alterations, which appear in up to 50% of patients with this type of hypertensive emergency 4. It is characterized pathologically by fibrinoid necrosis of the arterioles and myointimal proliferation of small arteries, manifesting in the form of retinopathy (hypertensive grade III-IV) and renal disease evidenced by impaired renal function and/or hematuria and/or proteinuria. The patient requiring urgent attention for hypertension is one who, despite high BP, does not exhibit any BP-related symptoms, as shown in Table 1. Initial assessment Patients attending an emergency department for elevated BP are usually referred or attend spontaneously due to the appearance of a symptom accompanied by the elevation. So, initially, 210 Emergencias 2010; 22: HYPERTENSION, HYPERTENSIVE CRISIS, AND HYPERTENSIVE EMERGENCY: APPROACHES TO EMERGENCY DEPARTMENT CARE Table 1. Main forms of presentation of hypertensive emergencies in the emergency department Hypertensive emergencies Symptoms Hypertensive encephalopathy Headache, visual disturbances, vomiting, altered level of consciousness. Severe hypertension with ischemic stroke/cerebral hemorrhage Neurological deficit, altered level of consciousness. Hypertensive left ventricular failure Cough, dyspnea, orthopnea, rapidly progressive dyspnea. Accelerated-malignant hypertension Visual changes, headache. Renal failure, oliguria, hematuria. Hypertension and aortic dissection Chest pain and/or intense abdominal pain. Vegetatism, signs of poor perfusion. Hypertension with acute coronary syndrome Chest pain. Use of drugs such as amphetamines, LSD, cocaine or ecstasy Tachycardia, sweating, altered mood and / or level of consciousness. Severe preeclampsia or eclampsia Oliguria, anuria, microangiopathic anemia. rapid triage should assess whether this elevation involves the possibility of TOD, at least incipient, and therefore makes the case a hypertensive emergency. It is important to establish whether the patient is known to be hypertensive or not, the regular medication and adherence to treatment, as well as their usual BP values. Many patients with chronic hypertension have BP values which range between 150/ mmhg and are asymptomatic. It is also important, especially in younger people, to inquire about the possibility of drug use, such as amphetamines or cocaine. It is also important to collect information about possible consumption of medication such as ergot, non-steroidal anti-inflammatory agents, nasal decongestants, and failure to adhere to normal hypertensive medication or abrupt termination of beta-blockers. BP must be measured in both arms, if possible, and take into account that in obese patients the use of BP arm bands that are not adapted to the arm circumference causes falsely high readings 4. Relevant information should include BP values before the ED visit, previous or only current causes for concern, and prescribed medication being taken. The physical examination should focus on identifying or excluding evidence of acute TOD. It is important to check peripheral pulse symmetry. Auscultation of crackles in a dyspneic patient with orthopnea and cough as an atypical symptom should arouse suspicion of acute lung edema, and the presence of angina suggests ACS. A neurological deficit is suggestive of either ischemic or hemorrhagic stroke, and not hypertensive encephalopathy, which manifests in the form of headache and altered level of consciousness. Fundus examination, mandatory in all hypertensive crises, may reveal the presence of exudate and hemorrhage (grade III retinopathy), and/or papilledema (grade IV retinopathy), in which case the rise in BP should be treated as a hypertensive emergency (Table 2). Based on this assessment we should be able to distinguish between cases requiring urgent attention and an emergency, with a view to establishing the most appropriate diagnostic and therapeutic strategy. Are complementary tests necessary in the asymptomatic patient? This is often asked in the ED. A proper history and complete physical examination, including fundus examination, can allow one to detect signs and symptoms of TOD that were initially not apparent. Thus, in asymptomatic patients, one may detect grade III-IV retinopathy, or the patient may present mild confusion, previously not known, dyspnea or oliguria. The performance of complementary tests in a patient attending for BP elevation should be evaluated individually, taking into account the patient s symptoms and clinical findings. In a recent study 6, an electrocardiogram and a chest radiograph changed the diagnostic and therapeutic decision in only 2 out of 116 patients, and the authors concluded that it is not necessary to perform such additional examinations in this type of patients if they show no symptoms suggestive of TOD. Generally, in all patients with symptoms and/or signs of hypertensive emergency, and while treatment is initiated, the following are necessary: complete blood count and biochemistry, urine strip test for proteinuria, and electrocardiogram that will help detect signs of left ventricular hypertrophy and electrical changes in case of chest pain, as well as chest X-ray to assess the mediastinum, the cardiothoracic ratio and signs of Table 2. Keith-Wagener-Barker classification of hypotensive retinal changes Grade I Mild generalized retinal arteriolar narrowing. Grade II Definite focal narrowing and aretriovenous nipping. Grade III The above and retinal hemorrhages, exudates, and cotton wool spots. Many of these patients present cardiac, brain or kidney compromise. Grade IV Severe grade III and papilloedema. Cardiac, brain and kidney compromise is more severe. Emergencias 2010; 22: E. Gómez Angelats et al. heart failure. In addition, we should proceed to determine troponin I levels in cases of suspected ACS or heart failure. In hypertensive emergency patients with neurological deficit or altered level of consciousness, CT scan should be requested. Suspected aortic dissection must be confirmed by contrast CT scan or chest MRI. If accelerated BP is suspected, schistocyte count must be requested to rule out microangiopathic hemolytic anemia. Considerations in the initial management of PA The asymptomatic patient To date, no studies clearly demonstrate the most appropriate ED approach to the asymptomatic patient with a hypertensive crisis. Despite this lack of evidence, it is very common for the attending physician to choose to initiate treatment in the ED 6. In this case, and before starting, we should be aware that at least one third of patients with DBP increase 95 mmhg in the ED show spontaneous decrease before they begin follow up 7. BP elevation in the absence of symptoms or signs of TOD rarely requires urgent treatment but does require deferred monitoring/treatment 3,4. Most patients attending the emergency department with elevated BP do not present acute TOD in the initial evaluation. They are usually patients attending for many different diseases, and therefore the elevated BP should be evaluated in the context of chronic hypertension. In these patients, either because the finding is coincidental or because they are asymptomatic and without evidence of acute TOD, treatment should be aimed at achieving a progressive decrease in BP with oral drugs within hours 8, and it is not recommended that one should wait for BP values to normalize pharmacologically in the ED itself. Rapid BP reduction, especially in patients with chronic hypertension, is accompanied by a shift to the right in the selfregulation pressure/perfusion curve (Figure 1), in the brain, heart and kidney 9, which may lead to cerebral, myocardial or renal ischemia and infarction, respectively, so this approach is formally disallowed in hypertensive emergencies. Hypertensive emergency Given that hypertensive emergency patients present TOD, a rapid but controlled correction of BP is necessary. It should be noted that extremely fast reduction is associated with complications such as cerebral, myocardial or renal hypoperfusion 2. That is why the management of these patients is based on the use of easily titrated drugs with short half-life in continuous infusion. For the same reason, the sublingual and intramuscular injection routes should be avoided. In a hypertensive emergency, the immediate objective is to reduce DBP by 10-15% or to 110 mmhg over a period of 30 to 60 minutes. In patients with suspected or confirmed aortic dissection, the BP must be reduced quickly, in 5-10 min, until achieving and SBP 120 mmhg, as tolerated 10,11. Once BP has been controlled and accompanying organ damage has ceased, oral antihypertensive drugs should be started, and the dose of the continuous infusion progressively reduced. Drugs used in hypertensive crises Habitually, intravenous drugs are used in hypertensive emergencies and oral drugs in cases of urgent attention 12. A great variety of antihypertensive agents are used in hypertensive crisis. The choice of drug depends on the patient's clinical condition and symptom presentation. The most commonly used in emergencies are: labetalol, fenoldopam, nitroglycerin and nitroprusside, because they are easily titratable, and their effect is rapid. Cases requiring urgent attention Normotensive Hypertensive Figure 1. Diagram showing the limits of cerebral blood flow self-regulation in relation to changes in blood pressure. X axis: cerebral blood flow (ml/100 g per min) and Y axis: values of blood pressure in mmhg (Adapted from Strangaard et al, Br Med J.). It is important to remember that sublingual nifedipine is not recommended in any type of hypertensive crisis 3. The recommended drugs are those with long half-life (Table 3), since the aim is to normalize BP values in about hours 3. Angiotensin converting enzyme inhibitors (ACEI) are most commonly used in cases requiring urgent at- 212 Emergencias 2010; 22: HYPERTENSION, HYPERTENSIVE CRISIS, AND HYPERTENSIVE EMERGENCY: APPROACHES TO EMERGENCY DEPARTMENT CARE Table 3. Main drugs used in the treatment of hypertensive patients requiring urgent attention Drug Calcium antagonists (long-acting dihydropyridines) Amlodipine Lacidipine Betablockers Bisoprolol Carvedilol Atenolol Diuretics Furosemide Torasemide Angiotensin-converting enzyme inhibitors Captopril Enalapril Angiotensin II receptor antagonists Losartan Irbesartan Candesartan Alpha blockers Doxazosin Initial Dose 5-10 mg 4 mg 2,5-5 mg 12,5-25 mg mg mg 5-10 mg 12,5-25 mg 5-20 mg 50 mg mg 8-16 mg 1-4 mg tention, especially captopril, which has faster onset of action (between 30 and 60 minutes) 13, although, as said, BP should not be reduced too rapidly. Any drug with a relatively fast onset of action can be used, including loop diuretics, β- blockers, α 2 -adrenergic agonists or calcium antagonists (except short-acting nifedipine). The most significant change in recent years in pharmacologic management of hypertension has been the development of type 1 angiotensin II receptor antagonists (ARA II), of which Losartan is the most used. The use of these drugs in hypertensive crises is poorly documented but possibly the decrease in BP is comparable to that obtained with ACE inhibitors, although the onset of its action may be slower. Hypertensive Emergencies Labetalol This is a combined selective blocker of α 1 and non-selective blocker of β-adrenergic receptors, with an α-β blocker ratio of 1:7. Its hypotensive action begins at 2-5 minutes after intravenous administration, reaching a peak at 5-15 minutes, with a duration of between 2 and 4 hours 14. Unlike selective beta-blockers, it does not have a negative inotropic effect 15. It decreases peripheral resistance without reducing peripheral flow, whereas renal, cerebral and coronary blood flow remain constant. It can be used in cases of eclampsia and preeclampsia because passage through the placental barrier is minimal It is administered with an initial loading dose of 20 mg, followed by progreesively larger doses of 20 to 80 mg in 10 minute intervals. After the loading dose, one can start infusion of 1-2 mg/min titrated on the basis of the hypotensive effect desired. A bolus of 1-2 mg/kg should be avoided because of the risk of sudden hypotension (Table 4). Esmolol This is a cardioselective blocker with extremely short-acting effect. Onset of action occurs in 1 minute, with a duration of minutes. A bolus of 0.5 mg/kg is recommended followed by continuous infusion of mg/kg/min. This
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