Malignant hypertension (MH) is a type of hypertension which results in the impairment of one or more systems, especially the central nervous system, the cardiovascular system, and the renal system . It is also commonly known as hypertensive emergency.
The presentation of MH underlines a condition of elevated blood pressure, like the appearance of exudates on pores and wounds of the body. Optic discs begin to swell, in a condition known as papilledema, frequently coupled with signs of retinal hemorrhage. The subjects also show signs of increased intracranial pressure, like headache and vomiting, which are frequently followed by faintness or vertigo, anxiety, or agitation in a general altered mental status. The damage in kidneys usually results in hematuria, proteinuria, and acute renal failure.
Other classical signs of MH include chest pain, arrhythmias, epistaxis, dyspnea, and paresthesias. Sometime, chest pain might be so severe to require immediate use of antihypertensive drugs such as nifedipine and calcium channel blockers.
As MH is a dangerous condition, its evaluation should be rapid. Medical history can be useful for a correct diagnosis of MH, especially when it indicates previous cases of hypertension. Anyway, all the examples of previous damage to the central nervous system, cardiovascular system, and renal system can support the diagnosis of MH. The neurological damages include blurry vision, dizziness, and loss of movement or sensation. Cardiovascular damages include chest pain, orthopnea, paroxysmal nocturnal dyspnea, or edema. The most important sign of renal damage, instead, is the decrease in urine output. It should be noted that many of these clinical manifestations might be caused by sympathomimetic drugs such as cocaine and LSD. Therefore, an investigation on the use of these drugs by the patients is paramount.
The most important physical examination to diagnose MH is blood pressure measurement, which should be performed on both arms. If a marked difference in blood pressure between the two arms is noted, aortic dissection should be taken into consideration as alternative diagnosis. Fundoscopic examination is particularly useful to detect ocular signs such as retinal edema and papilledema, while bedside neurologic exam cab be used to measure nerve functions. Clinicians are also advised to perform an assessment of the cardiopulmonary status, to detect the presence of additional signs such as murmurs, hearts sounds, or jugular venous distension, which might help them reach the final diagnosis.
Laboratory evaluation includes complete blood count, blood biochemical panel, and analysis of urine, but sometime also plasma rennin activity and aldosterone or metanephrine levels, if aldosterone or pheochromocytoma are suspected to have caused hypertension. Imaging studies, instead, can be used when hypertension is suspected to have been caused by other conditions such as aortic dissection, ischemic stroke or intracranial hemorrhage.
The use of antihypertensive drugs is the most important treatment for MH. There are many classes of antihypertensive drugs and their choice should be based on the etiology of the hypertensive crisis, the severity of the condition, and the usual blood pressure of the patient before the hypertensive crisis itself, as the patient can have a history of chronic hypertension and might not tolerate normal blood pressure. Sodium nitroprusside, injected intravenously, is especially used in the most urgent cases requiring immediate treatment, because of its prompt effect. Oral agents like captopril, clonidine, or prazosin are used instead in less urgent cases, because their action is much slower than that of sodium nitroprusside, even though it remains effective. If sodium nitroprusside is unavailable and the action of oral agents is not began yet, controlled bloodletting can be used as effective alternative measure.
MH might turn out to be particularly resistant when end stage renal failure occurs. In these cases the clinicians can consider non-pharmaceutical treatments such as surgical nephrectomy and laparoscopic nephrectomy. There is also a therapy under investigation based on the electrical stimulation of the carotid sinus which is showing promising results for the treatment of MH .
It should be remembered that blood pressure reduction should be smooth and limited to a certain range, otherwise it might precipitate coronary, cerebral, and renal ischemia as well as infarction .
If patients are treated in a proper manner with the appropriate antihypertensive therapy, the prognosis of MH is good, with a survival rate after 5 years from the MH episode of 70%. However, if treatment is neglected the prognosis of MH becomes bad, and patients have just a 10% to 20% survival rate after 1 year from the MH event. Mortality rate increases substantially when the MH is accompanied by renal failure  .
Many are the causes of MH, the most common of which is essential hypertension frequently undiagnosed or not properly treated . Very common are also clinical conditions secondary to renal diseases and procedures, such as kidney transplant, renal artery stenosis, or acute glomerulonephritis  . Other causes of MH include pregnancy-related eclampsia, hyperaldosteronism, and the conditions triggering excess circulating catecholamines like sympathomimetic drug intake or autonomic dysfunction after spinal cord injury .
The prevalence of hypertension is very high. In USA, 30% of the population suffer from hypertension  , while worldwide it has been estimated that around 26% of the population is affected by this cardiovascular condition. Statistical data show that 1% to 2% of these people will experience a hypertensive crisis at some point of their life  .
MH is much more frequent in men than women, and many studies reveal that it is more common in elderly and black people   . The prevalence of hypertension and MH is expected to increase substantially over the next few decades, due to aging of the global population. MH prevalence is also substantially favored by the lack of incurrence, absence of primary care and noncompliance with prescribed treatments  .
The factors underlying the development of hypertension and MH are still unclear and poorly understood. However, it is believed that the starting point of this process is the rise of systemic vascular resistance which increases blood pressure. This in turn brings about a mechanical stress and an endothelial injury which increases permeability, activates coagulation cascade and platelets, and causes fibrin deposition. In this condition, ischemia begins to develop and additional vasoactive mediators are released, which foster the ongoing injury. The systemic vasoconstriction caused by the volume depletion due to pressure natriuresis and the renin-angiotensin system activation brings about a decrease in blood flow towards vital organs, which then leads to the final consequent injury of the organs concerned.
Damages mainly regard the central nervous system with injuries like encephalopathy and seizures, the cardiovascular system with injuries like chest pain and aortic dissection, and the renal system with like oliguria and azotemia    .
Close outpatient follow-up for hypertension is the most important measure to avoid future episodes of MH. Therefore, patients are highly recommended to refer to a specialist to organize an effective preventive plan. The plan should also include a diet low in fat and daily physical activity, both well known to have beneficial effects on the entire cardiovascular system.
Malignant hypertension (MH) is defined by a systolic blood pressure greater than 210 mmHg and a diastolic blood pressure greater than 130 mmHg. It implies a rapid deterioration of vital organ function which brings about some severe clinical consequences such as encephalopathy, retinopathy, renal failure, and myocardial ischemia. MH is very similar to accelerated hypertension, both in terms of clinical outcomes and therapies involved, even though MH is characterized by the typical sign of papilledema, that is the swelling of the optic disc.
Malignant hypertension (MH) is a type of high blood pressure (hypertension) which results in the impairment of one or more organ systems, especially the central nervous system, the heart and vessels, and the kidneys. MH is defined by a systolic blood pressure greater than 210 mmHg and a diastolic blood pressure greater than 130 mmHg. There are many causes of MH, the most common of which is essential hypertension frequently undiagnosed or not properly treated. Very common are also clinical conditions secondary to kidney diseases and procedures, such as kidney transplant, artery stenosis, or acute glomerulonephritis.
Common signs and symptoms of MH are:
The use of antihypertensive drugs is the most important treatment for MH. There are many classes of antihypertensive drugs and their choice is based on the cause of the hypertensive crisis, the severity of the condition, and the usual blood pressure before the hypertensive crisis itself.
Close follow-up for hypertension is the most important measure to avoid future episodes of MH. Therefore, patients are highly recommended to refer to a specialist to organize an effective preventive plan. The plan should also include a diet low in fat and daily physical activity, both well known to have beneficial effects on the entire cardiovascular system.