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Severe hypertension is characterized by diastolic blood pressure (BP) higher than 120 mmHg or systolic BP higher than 180 mmHg.
Clinical Evaluation of Hypertensive Syndromes
Hypertensive emergency is defined by a diastolic blood pressure >120 mmHg associated with ongoing vascular damage. Symptoms or signs of neurologic, cardiac, renal, or retinal dysfunction are present.
Hypertensive emergencies include severe hypertension in the following settings:
Aortic dissection
Acute left ventricular failure and pulmonary edema
Acute renal failure or worsening of chronic renal failure
Hypertensive encephalopathy
Focal neurologic damage indicating thrombotic or hemorrhagic stroke
Pheochromocytoma, cocaine overdose, or other hyperadrenergic states
Unstable angina or MI
Hypertensive urgency is defined as diastolic blood pressure >120 mmHg without evidence of vascular damage; the disorder is asymptomatic and no retinal lesions are present.
Causes of Secondary Hypertension include renovascular hypertension, pheochromocytoma, cocaine use, withdrawal from alpha2 stimulants, beta blockers or alcohol, and noncompliance with antihypertensive medications.
Initial Assessment of Severe Hypertension
When severe hypertension is noted, the measurement should be repeated in both arms to detect any significant differences.
Peripheral pulses should be assessed for absence or delay, which suggests a dissecting aortic dissection. Evidence of pulmonary edema should be sought. The initial assessment should also determine how ill the patient appears.
Target organ damage is evidenced by chest pain, neurologic signs, altered mental status, profound headache, dyspnea, abdominal pain, hematuria, focal neurologic signs (paralysis or paresthesia), or hypertensive retinopathy.
Prescription drug use should be assessed, including the possibility of a missed dose of antihypertensive therapy. Ask about recent cocaine or amphetamine use should be sought.
If focal neurologic signs are present, a CT scan may be required to differentiate hypertensive encephalopathy from a stroke syndrome. In stroke syndromes, hypertension may be secondary to the neurologic event; the neurologic deficits are fixed and follow a predictable neuroanatomic pattern. By contrast, in hypertensive encephalopathy, the neurologic signs follow no anatomic pattern, and there is diffuse alteration in mental function.
Laboratory Evaluation
Complete blood cell count, urinalysis for protein, glucose, and blood; urine sediment examination for cells, casts, and bacteria; chemistry panel (SMA-18).
If chest pain is present, cardiac enzymes are obtained.