Malignant hypertension

Malignant hypertension is a complication of hypertension characterized by very elevated blood pressure, and organ damage in the eyes, brain, lung and/or kidneys. It differs from other complications of hypertension in that it is accompanied by papilledema. Systolic and diastolic blood pressures are usually greater than 200 and 140, respectively.

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History

The most common presentations of hypertensive emergencies at an emergency department are chest pain (27%), dyspnea (22%), and neurologic deficit (21%). The primary cardiac symptoms are angina, myocardial infarction, and pulmonary edema. Orthostatic symptoms may be prominent. Neurologic presentations are occipital headache, cerebral infarction or hemorrhage, visual disturbance, or hypertensive encephalopathy (a symptom complex of severe hypertension, headache, vomiting, visual disturbance, mental status changes, seizure, and retinopathy with papilledema). Medications or drugs that may cause a hypertensive emergency include cocaine, monoamine oxidase inhibitors (MAOIs), and oral contraceptives; the withdrawal of beta-blockers, alpha-stimulants (such as clonidine), or alcohol, steroids also may cause hypertensive emergency. Renal disease may present as oliguria (renal failure) or any of the typical features of renal failure. Gastrointestinal symptoms are nausea and vomiting.

Physical

Cardiovascular system

Blood pressure must be checked in both arms to screen for aortic dissection or coarctation. If coarctation is suspected, blood pressure also should be measured in the legs. Screen for carotid or renal bruits. Listen for a third or fourth heart sound or murmurs. Volume status should be assessed, with orthostatic vital signs, examination of jugular veins, assessment of liver size, and investigation for peripheral edema and pulmonary rales.

Central nervous system

A complete neurologic examination is needed to screen for localizing signs. Focal neurologic signs might not be attributable to encephalopathy. Focal signs mandate screening for subarachnoid hemorrhage, infarct, or the presence of a mass. A funduscopic examination may reveal silver wiring (Grade I retinopathy), AV nipping (Grade II) flame-shaped retinal hemorrhages, soft exudates (Grade III), or papilledema (Grade IV).

Lab studies

Lab studies include a complete blood count and electrolytes, coagulation profile, and urinalysis, cardiac enzymes, urinary catecholamines, thyroid-stimulating hormone (TSH), and 24-hour urine collection for vanillylmandelic acid (VMA) and catecholamines.

Renal function should be evaluated through a urinalysis, complete chemistry profile, and complete blood count. Expected findings include elevated BUN and creatinine, hyperphosphatemia, hyperkalemia or hypokalemia, glucose abnormalities, acidosis, hypernatremia, and evidence of microangiopathic hemolytic anemia. Urinalysis may reveal proteinuria, microscopic hematuria, and RBC or hyaline casts. In patients with hyperaldosteronism (a secondary cause of hypertension), aldosterone promotes renal potassium wasting, resulting in low serum potassium.

The chest radiograph is useful for assessment of cardiac enlargement, pulmonary edema, or involvement of other thoracic structures, such as rib notching with aortic coarctation or a widened mediastinum with aortic dissection. Other tests, such as head CT scan, transesophageal echocardiogram, and renal angiography, are indicated only as directed by the initial workup. The ECG is necessary to screen for ischemia, infarct, or evidence of electrolyte abnormalities or drug overdose.

Treatment

A commonly used drug is IV fenoldopam. Labetalol is another common alternative, providing easy transition from IV to oral (PO) dosing. Beta-blockade can be accomplished intravenously with esmolol or metoprolol. Hydralazine is reserved for use in pregnant patients, while phentolamine is the drug of choice for a pheochromocytoma crisis. iv sodium nitroprusside should never be used as it can cause a rapid uncontrollable drop in blood pressure.

Prognosis

Prior to effective therapy, life expectancy was less than 2 years, with most deaths resulting from stroke, renal failure, or heart failure. The survival rate at 1 year was less than 25% and at 5 years was less than 1%. With current therapy, including dialysis, the survival rate at 1 year is greater than 90% and at 5 years is 80%. The most common cause of death is cardiac, with stroke and renal failure also common. The single greatest prognostic factor in malignant hypertension is renal function, with renal insufficiency secondary to malignant nephrosclerosis being strongly associated with poorer outcomes.

References

1. ^ http://medaphase.net/Newsletter/ViewArticle.asp?ArticleID=20

See also

• Hypertensive emergency
• Hypertension
• Hypertensive retinopathy