About 20% to 30% of adults in developed countries have hypertension.1 Because of the high prevalence of this condition, it is not uncommon to encounter patients with elevated blood pressure (BP) in the primary care setting. Although the greatest impact of hypertension on health results from its long-term effects, some patients present with markedly elevated BP that requires emergent intervention.
Thus, the challenge is to distinguish nonurgent BP elevations from those that demand immediate attention. Here we discuss the clues that signal target organ damage, and we provide a detailed road map for the workup.
DEFINITIONS
The National Heart, Lung, and Blood Institute's Joint National Committee recently defined hypertensive emergencies and urgencies in their most recent guidelines (JNC 7).2 A hypertensive emergency requires immediate BP reduction (although not necessarily to the reference range) with parenteral antihypertensives to limit target organ damage (namely, damage to the brain, heart, kidneys, or eyes). In a patient with a hypertensive urgency, the marked elevation in BP is not associated with target organ damage; however, the risk of such damage is very high.3 Combination oral antihypertensive therapy should be started when a hypertensive urgency is diagnosed.2
CLINICAL EVALUATION
The clinical presentation of a hypertensive emergency reflects the consequences of elevated BP on the target organs. The extent of such consequences depends on how high and how quickly the BP has risen, whether the patient has a history of hypertension, and whether comorbid conditions are present.
The evaluation of a patient in whom a hypertensive emergency or urgency is suspected has 2 chief aims (Table 1):
- Assessment of target organ damage and/or risk of such damage.
- Determination of the cause of the acute elevation in BP (if possible).
History. A primary purpose of the history taking is to assess the severity of symptoms-which can help gauge the extent of target organ damage. Symptoms that suggest a cardiovascular problem include:
- Chest pain and/or syncope (suggests myocardial ischemia/unstable angina or aortic dissection).
- Back pain (suggests aortic dissection).
- Dyspnea (suggests pulmonary edema or congestive heart failure).
Symptoms that suggest a neurologic problem include:
- Seizure/altered mental status (suggests hypertensive encephalopathy).
- Focal weakness and/or speech change (suggests cerebrovascular accident or transient ischemic attack).
- Headache and/or visual disturbance (suggests CNS compromise).
Symptoms that suggest a renal problem include:
If the patient has a history of hypertension, find out when BP elevations began, how the hypertension has been treated, what degree of BP control was achieved, and whether there has been any previous target organ damage. This information can help assess risk and guide treatment. For example, patients with chronic hypertension in whom a hypertensive emergency develops are more likely to experience cerebral ischemia and other negative consequences if BP is reduced abruptly. Hypertensive patients may have poor outcomes even if their BP is reduced to a range tolerated by most normotensive persons.4
A thorough history taking also attempts to uncover the cause of acutely elevated BP (Table 2). To investigate possible toxicologic causes, ask about:
- Recent illicit drug use (eg, cocaine, methamphetamine).
- Recent sympathomimetic use.
- Concurrent use of monoamine oxidase inhibitors and ingestion of foods that contain tyramine (eg, wine, aged cheese, and canned meats).
To investigate possible iatrogenic causes, inquire about:
- Use of exogenous glucocorticoid therapy (which can precipitate Cushing syndrome).
- Use of weight loss medications (either prescription or over-the-counter).
- Discontinuation of antihypertensive medications (especially clonidine(Drug information on clonidine) and β-blockers).
