Malignant arterial hypertension

Malignant arterial hypertension is severe arterial hypertension with edema of the papilla of the optic nerve or extensive exudates (often hemorrhages) on the fundus, early and rapidly increasing damage to the kidneys, heart, and brain. Blood pressure usually persistently exceeds 220/130 mm Hg.

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Epidemiology

Malignant arterial hypertension, as a form of arterial hypertension, is not often observed (up to 1% of patients). Primary malignant hypertension is currently extremely rare (0.15-0.20% of all individuals with hypertension). Mostly males under 40 years of age are affected, after 60 years the incidence rate drops sharply, and by 70 years the disease is extremely rare.

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Causes malignant arterial hypertension

Arterial hypertension of any nature (hypertension or symptomatic hypertension) can acquire malignant features during the development process. The most common causes of malignant arterial hypertension are:

• parenchymal kidney diseases (rapidly progressive glomerulonephritis);
• terminal renal failure;
• renal artery stenosis;
• arterial hypertension in smokers.

In some cases, malignant arterial hypertension may develop in endocrine pathology (pheochromocytoma, Conn's syndrome, renin-secreting tumors), in women in late pregnancy and/or in the early postpartum period. Such evolution is mainly observed in untreated or inadequately treated patients.

In contrast to other forms of arterial hypertension, in which gradual elastofibroplastic restructuring of arterioles occurs, the cause of malignant arterial hypertension is acute changes in renal arterioles with the development of fibrinoid necrosis. In malignant arterial hypertension, renal arterioles are often completely obliterated as a result of intimal proliferation, smooth muscle hyperplasia, and fibrin deposition in the necrotic vascular wall. These changes lead to disruption of local autoregulation of blood flow and the development of total ischemia. In turn, renal ischemia leads to the development of renal failure.

Hormonal stress is considered to be a factor responsible for acute vascular changes in malignant arterial hypertension, leading to uncontrolled synthesis of vasoconstrictor hormones and manifested by:

• a sharp increase in vasoconstrictor hormones in the blood (hormones of the renin-angiotensin-aldosterone system, endothelial pressor hormones, vasopressin, catecholamines, pressor fractions of prostaglandins, and so on);
• water-electrolyte disturbances with the development of hyponatremia, hypovolemia and often hypokalemia;
• development of microangiopathies.

Often malignant arterial hypertension is accompanied by damage to erythrocytes by fibrin threads with the development of microangiopathic hemolytic anemia. At the same time, morphological changes in vessels in malignant arterial hypertension are potentially reversible with adequate and constant antihypertensive treatment.

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Symptoms malignant arterial hypertension

Malignant arterial hypertension is characterized by a sudden onset and rapid progression of all symptoms of the disease. The appearance of patients is characteristic: pale skin with an earthy tint. Symptoms of malignant arterial hypertension such as dyspeptic complaints, rapid weight loss up to cachexia often occur. Blood pressure is persistently maintained at a very high level (200-300/120-140 mm Hg). A tendency towards an increase in pulse pressure is revealed; the circadian rhythm of blood pressure changes (periods of nighttime decrease in blood pressure disappear). Hypertensive encephalopathy, transient cerebrovascular accidents with corresponding clinical symptoms often develop.

Heart failure usually occurs as left ventricular failure, with frequent development of pulmonary edema. Echocardiographic examination reveals signs of left ventricular hypertrophy and dilation.

An important clinical and diagnostic criterion for malignant arterial hypertension is changes in the fundus of the eye, manifested by hemorrhages, exudates, and edema of the optic nerve. Characteristic is sudden loss of vision in one or both eyes, developing as a result of hemorrhages or other changes in the retina.

Forms

At the present stage, malignant arterial hypertension is considered as a form of hypertension or symptomatic arterial hypertension, an independent nosological form of the disease, first described by Volhard and Far in 1914 and studied in detail by E.M. Tareev in the middle of the 20th century.

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Diagnostics malignant arterial hypertension

Laboratory diagnostics of malignant arterial hypertension

Kidney damage is characterized by the development of proteinuria (nephrotic syndrome occurs rarely), a decrease in the relative density of urine, and changes in urinary sediment (often erythrocyturia). With a decrease in arterial pressure, the severity of the urinary syndrome decreases. Oliguria, increasing azotemia, and anemia reflect the early and rapid development of terminal renal failure, although renal shrinkage is detected only in some patients. Acute renal failure often develops with malignant arterial hypertension.

Diagnosis of malignant arterial hypertension involves detection of anemia, often with elements of hemolysis, fragmentation of erythrocytes and reticulocytosis; coagulopathy of the disseminated vascular coagulation type with development of thrombocytopenia, appearance of fibrin degradation products in blood and urine; ESR is often increased. Most patients have high plasma renin activity and increased aldosterone levels.

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Treatment malignant arterial hypertension

Malignant hypertension is considered an emergency condition. Initial treatment of malignant hypertension is to reduce blood pressure by 1/3 of the initial level within 2 days, with systolic blood pressure not being reduced below 170 mm Hg and diastolic blood pressure not being reduced below 95-110 mm Hg. For this purpose, intravenous fast-acting antihypertensive agents are used for several days. Further reduction of blood pressure should be done slowly (over the next few weeks) and carefully to avoid organ hypoperfusion and further deterioration of their functions.

Treatment of malignant arterial hypertension: drugs for intravenous administration

Several drugs can be used for intravenous administration.

Sodium nitroprusside is administered for a long time (3-6 days) by drip at a rate of 0.2-8 mcg/kg per minute with titration of the dose every 5 minutes. Constant and careful monitoring of blood pressure and the rate of administration of the drug is necessary.

Nitroglycerin (administered at a rate of 5-200 mcg/min) is the drug of choice for the treatment of arterial hypertension in the context of myocardial infarction, unstable angina, and severe coronary and left ventricular failure.

Diazoxide is administered intravenously at 50-150 mg by jet stream, the total dose should not exceed 600 mg/day. The effect of the drug lasts for 4-12 hours. The drug should not be used if malignant arterial hypertension is complicated by myocardial infarction or dissecting aortic aneurysm.

The ACE inhibitor enalapril may be used intravenously at a dose of 0.625-1.25 mg every 6 hours. The dose is halved when the drug is combined with a diuretic or in severe renal failure. The drug is indicated for severe heart failure; it cannot be used in patients with bilateral renal artery stenosis.

Labetolol, which has both alpha- and beta-adrenergic blocking activity, is administered as a bolus of 20-40 mg every 20-30 minutes for 2-6 hours. The total dose of the drug should be 200-300 mg/day. Bronchospasm or orthostatic hypotension may develop during administration.

Sometimes verapamil is effective when administered intravenously by jet stream at a dose of 5-10 mg. Furosemide is used orally or intravenously as a natriuretic. Additionally, plasmapheresis and ultrafiltration can be used.

Treatment of malignant arterial hypertension: drugs for oral administration

If the above intensive treatment of malignant arterial hypertension, carried out for 3-4 days, achieves the desired result, an attempt can be made to switch to treatment with oral drugs, usually using at least three antihypertensive drugs from different groups, adjusting the doses with the aim of further slowly lowering blood pressure.

When prescribing antihypertensive drugs, it is necessary to clearly establish the cause of the development of malignant arterial hypertension (renoparenchymal, renovascular, malignant arterial hypertension caused by endocrine pathology, ischemic kidney disease, etc.), the state of renal function, concomitant diseases, in order to take into account the advantages and disadvantages of each group of antihypertensive drugs and determine the possibility of their combined use.

Forecast

It is necessary to take into account that effective antihypertensive treatment of malignant arterial hypertension determines the prognosis of patients with malignant arterial hypertension. The survival rate of untreated patients within 1 year is only 20%, while with adequate treatment, the 5-year survival rate exceeds 90%.

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