7th Brazilian Guideline of Arterial Hypertension: Chapter 14 - Hypertensive Crisis

The terms HU and HE were proposed as an operational classification of HC in 1993 by the V Joint National Committee on Detection Evaluation and Treatment of High Blood Pressure. 1 The HUs are symptomatic clinical situations in which there is significant BP elevation (arbitrarily defined as DBP  120 mm Hg) without acute and progressive TOD. 2,3 The HEs are symptomatic clinical situations in which there is significant BP elevation (arbitrarily defined as DBP  120 mm Hg) with acute and progressive TOD. 2,3Patients complaining from headache, atypical chest pain, dyspnea, acute psychological stress, and panic syndrome associated with high BP levels characterize neither HU nor HE, but rather a pseudo hypertensive crisis. Treatment comprises the optimization of antihypertensive drugs and raising awareness about treatment adherence.ClassificationChart 1 shows the classification of HE, and Chart 2 differentiates HU from HE regarding diagnosis, prognosis and management.Major epidemiological, pathophysiological and prognostic aspects EpidemiologyHypertensive crisis accounts for 0.45-0.59% of all hospital emergency treatments, while HE accounts for 25% of all cases of HC, ischemic stroke and APE, which are the most frequent HEs. 4-6PathophysiologyIncreased intravascular volume and PVR, or reduced production of endogenous vasodilators seem to precipitate greater vascular reactivity, resulting in HC. 7 Self-regulation is compromised, particularly in the cerebral and renal vascular beds, resulting in local ischemia, which triggers a vicious circle of vasoconstriction, myointimal proliferation and target-organ ischemia. 8PrognosisSurvival up to 5 years is significantly higher in individuals with HU than with HE. 4,9 Absence of nocturnal dipping associates with higher risk for TOD and consequent endothelial dysfunction, a situation involved in acute BP elevation. 10

## General treatment of hypertensive crisis
The treatment of HU should begin after a period of clinical observation in a calm environment, which helps to rule out the cases of pseudocrisis (treated with only rest or use of painkillers or tranquilizers). Captopril, clonidine and BBs are oral antihypertensives used to gradually reduce BP in 24-48 hours. The use of drops of rapid-release nifedipine capsules to treat HU should be banned, because it is neither safe nor effective, and causes rapid and marked BP reductions, which can result in tissue ischemia. The use of nifedipine for preeclampsia is currently debatable. However, HEs should be approached considering the impaired system or target organ. Thus, each type of HE (CV, cerebral, renal or other) should be previously characterized before beginning specific antihypertensive therapy.

## Hypertensive emergency in special situations
Chart 3 shows the medications used for HE.

## Stroke
Arterial hypertension is the major risk factor for stroke, especially hemorrhagic stroke. The diagnosis is based on complete neurological exam. To assess the severity of the condition, the National Institute of Health Stroke Scale (NIHSS) should be used. Brain CT and MRI allow defining the type of stroke and territory involved, and, usually, 85% of the strokes are ischemic, and 15%, hemorrhagic. [bib_ref] Standard method for developing stroke registers in low-income and middle-income countries: experiences..., Truelsen [/bib_ref] For incipient infarctions, MRI is more sensitive than CT.

## Hemorrhagic stroke12
1 -For patients with SBP between 150 and 220 mm Hg and with no treatment contraindication, acute SBP reduction to 140 mm Hg is safe and can be effective to improve the functional outcome. (GR: IIa; LE: B) (in 1 hour with IV infusion of antihypertensives and BP monitoring 5/5 min) (GR: I; LE: A).
2 -For patients with SBP > 220 mm Hg, consider aggressive BP reduction with continuous IV infusion and frequent BP monitoring. (GR: IIb; LE: C).

## Ischemic stroke13
1-For patients with no indication for thrombolytic therapy and initial BP > 220/120 mm Hg, BP should not be reduced more than 15-20%, maintaining DBP as 100-110 mm Hg in the first 24 hours.

## 2-
The ideal BP level to be attained is not known, but there is consensus that no antihypertensive treatment should be instituted during the initial care, except if SBP is > 220 mm Hg or DBP is > 120 mm Hg. (GR: I; LE: C).
3-Consider the possibility of using thrombolytics after BP control. For patients with indication for thrombolytic therapy and initial BP > 185/110 mm Hg, BP should be reduced to < 185/105 mm Hg for, at least, the first 24 hours after the thrombolytic agent. (GR: I; LE: B).

## Acute coronary syndromes
Coronary syndromes can be accompanied by BP elevation, because of a reflex of the ischemic myocardium. The increased PVR increases myocardial oxygen demand because of the increased left ventricular wall tension.
The IV nitrates reduce PVR, improve coronary perfusion and have an important systemic vasodilator effect, reducing preload and myocardial oxygen consumption. SNP is not indicated because of the coronary flow steal mechanism caused by generalized coronary vasodilation. 2,3

## Unstable angina / non-st elevation mi / st elevation mi14,15
To treat AH, persistent ischemia and HF, IV nitroglycerin is indicated in the first 48 hours. Its use should not exclude other interventions that have proven to reduce mortality, such as BBs or ACEIs. Nitroglycerin is, however, contraindicated in the presence of recent use of phosphodiesterase inhibitors (previous 24 to 48 hours). (GR: I; LE: B).
The IV use of BBs is indicated for individuals with AH who have no signs of HF, clinical evidence of low cardiac output, increased risk for cardiogenic shock or other contraindications relating to beta blockade. (GR: IIa; LE: B).

## Acute pulmonary edema
Approximately one third of the patients admitted with APE and HE have preserved left ventricular function. Myocardial ischemia can also be involved in the pathophysiology of the APE associated with HE. [bib_ref] The pathogenesis of acute pulmonary edema associated with hypertension, Gandhi [/bib_ref] [bib_ref] Acute heart failure with preserved systolic function, Kumar [/bib_ref] The HE with APE findings should be controlled in an ICU setting, with parenteral medication, monitoring and gradual BP decrease. 18

## Acute aortic dissection
Acute aortic dissection should always be considered in patients with precordial pain and BP elevation. Progression of the dissection is related to the BP level and ventricular ejection velocity. [bib_ref] Clinical, diagnostic, and management perspectives of aortic dissection, Khan [/bib_ref] Target SBP (120 mm Hg) should be achieved in 20 minutes. The isolated use of SNP is not ideal, because it increases HR and the aortic ejection velocity, and can worsen the dissection. Thus, SNP should be associated with a BB. In case of intolerance to SNP or contraindication to BBs, trimethaphan should be used.

## Use of illicit substances
Illicit substances that raise BP, such as cocaine, crack, amphetamines and ecstasy, have sympathomimetic action. [bib_ref] Methamphetamine abuse: a review of the literature and case report in a..., Naidoo [/bib_ref] Crack and cocaine increase the risk for stroke and acute coronary insufficiency. [bib_ref] Cocaine use and risk of stroke: a systematic review, Sordo [/bib_ref] In addition to increasing HR and BP, ecstasy have other effects, mainly serotoninergic syndrome, and can cause rhabdomyolysis and AKI. [bib_ref] Club drugs: MDMA, gamma-hydroxybutyrate (GHB), Rohypnol, and ketamine, Gahlinger [/bib_ref] A complicator of those intoxications is the concomitant ingestion of high doses of caffeine, present in energetic beverages, nicotine and alcohol. Those intoxications have in common the high level of plasma noradrenaline. [bib_ref] Elevated norepinephrine may be a unifying etiological factor in the abuse of..., Fitzgerald [/bib_ref] The treatment includes the use of BBs, alpha-blockers and CCBs. [bib_ref] Experimental treatments for cocaine toxicity: a difficult transition to the bedside, Connors [/bib_ref] Rapidly progressive acute kidney injury Acute and progressive renal function impairment is observed in patients admitted to hospital emergency units. [bib_ref] Incidence and consequence of acute kidney injury in unselected emergency admissions to..., Challiner [/bib_ref] Individuals with greater renal function impairment have important cardiac dysfunction and greater loss of renal function during episodes of marked BP elevation, which is accompanied by high in-hospital mortality rates. [bib_ref] CKD Prognosis Consortium A meta-analysis of the association of estimated GFR, albuminuria,..., James [/bib_ref] Rapidly progressive AKI is defined as a sudden renal function worsening in 48 hours, with specific classification criteria: RIFLE (Risk, Injury, Failure, Loss, End-Stage Kidney Disease) and AKIN (The Acute Kidney Injury Network). [bib_ref] New biomarkers of acute kidney injury and the cardio-renal syndrome, Hawkins [/bib_ref] Treatment includes hydralazine, loop DIUs and BBs. In case of no result, SNP can be considered until dialysis is performed.
The management for preeclampsia and eclampsia is reported in Chapter 9.
[fig] Chart 2 -: Differences in the diagnosis, prognosis and management of hypertensive urgency and emergency [/fig]