Malignant hypertension: Difference between revisions
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Revision as of 17:56, 22 February 2013
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] ; Associate Editor(s)-in-Chief: Aditya Govindavarjhulla, M.B.B.S. [2]
Overview
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.
Causes
- Cocaine
- Monoamine oxidase inhibitors (MAOIs)
- Withdrawal of beta-blockers
- Alpha-stimulants (such as clonidine)
- Renal disease
Natural history , Complications and Prognosis
Prior to effective therapy, life expectancy was less than 2 years, with most deaths resulting from stroke, renal failure, orheart 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.
Diagnosis
Symptoms
The most common presentations of hypertensive emergencies at an emergency department are
- Chest pain (27%)
- Dyspnea (22%)
- Neurologic deficit (21%)
The primary cardiac symptoms are
Physical examination
Vital Signs
- Blood pressure must be checked in both arms to screen for aortic dissection or coarctation.
- Orthostatic vital signs
Eyes
- 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)
Head and Neck
- Examination of jugular veins
- Carotid bruits
Heart
- Third or fourth heart sound or murmurs.
Lungs
Abdomen
- Renal bruits
- Assessment of liver size
Extremities
Neurologic
- Focal neurologic signs
- Focal signs of subarachnoid hemorrhage, infarct, or the presence of a mass.
Laboratory Findings
- Coagulation profile
- urinary catecholamines
- 24-hour urine collection for vanillylmandelic acid (VMA) and catecholamines.
- BUN, creatinine
Urinalysis may reveal
- Microscopic hematuria
- RBC or hyaline casts.
In patients with hyperaldosteronism (a secondary cause of hypertension), aldosterone promotes renal potassium wasting, resulting in low serum potassium.
Electrocardiogram
The ECG is necessary to screen for ischemia, infarct, or evidence of electrolyte abnormalities or drug overdose.
Chest X ray
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.
Treatment
The most commonly used intravenous drug is nitroprusside. An alternative for patients with renal insufficiency is intravenous 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 be used with caution as it can cause a rapid uncontrollable drop in blood pressure.
References
Related Chapters