Renal hypertensia are a consequence of damage of a renal artery or its branches (renovascular hypertensia) or develop as a result of defeat of a parenchyma of kidneys at nefropatiya of various nature (renal and parenchymatous hypertensia).
At renal hypertensia disturbance of a water salt metabolism with increase in volume of the circulating plasma, and also increase in secretion by a kidney of vasoactive substances is the cornerstone of increase of arterial pressure.
Renovascular hypertensia quite often proceed zlokachestvenno and badly corrections give in. On the other hand, renal and parenchymatous hypertensia not always are distinguished in time, especially, if in a clinical picture of a nephropathy the prevailing symptom is increase of arterial pressure. In particular it concerns to patients with a hypertensive form of chronic nephrite who it is sometimes long are observed and treated with the diagnosis an idiopathic hypertensia. It is essential that treatment of the patient with renal hypertensia is not limited to use of anti-hypertensive drugs, but consists also in complex therapy of a nephropathy, and at renovascular hypertensia — and in use of endovascular and surgical methods of treatment.
The following pathology of vessels is the cornerstone of renovascular hypertensia:
Atherosclerosis. The atherosclerosis of a renal artery leading to a vessel stenosis is the most frequent reason of renovascular hypertensia. Atherosclerotic plaques at the same time are located in the mouth of a renal artery and not always extend to its main trunk. Quite often, however, the renal artery is surprised atherosclerosis not separately, and against crushing atherosclerotic damage of an aorta and its branches. Also atherosclerotic aneurisms of a ventral aorta with narrowing of the renal arteries departing from it can be observed. Usually heavy occlusion is observed on the one hand, there are bilateral hemodynamically significant stenoses of renal arteries less often.
Atherosclerotic forms renovascular to hypertensia are more inherent to people of advanced and senile age, usually with symptoms and other localizations of atherosclerosis — coronary, cerebral arteries, vessels of the lower extremities. However atherosclerosis of renal arteries with the phenomena of renovascular hypertensia can occur also at persons of young, mature or middle age.
Fibromuscular dysplasia of renal arteries. It is characterized by a fibrous or fibromuscular thickening of an internal and average cover of a vessel. This disease is observed mainly at women, in 1/4 cases has bilateral character and is registered usually at young or mature age.
Nonspecific aorto-arteritis (Takayasu's illness). Assume that autoimmune process is the cornerstone of it. The disease arises at young women more often and is characterized by the fever, arthralgias increased by SOE, signs of damage of an aorta and its main branches. When involving renal arteries renovascular hypertensia in most cases develops.
Embolisms and fibrinferments of renal arteries. A source such embolisms are, as a rule, endocardiac blood clots at rheumatic heart diseases or a cardiosclerosis with a ciliary arrhythmia.
Most often atherosclerosis is the reason of thrombosis of renal arteries, is more rare — arteritis of renal arteries.
Acute thromboembolic occlusion of a renal artery has a bright clinical picture, being shown by an attack of the sharpest pains in lumbar area and in a stomach, is frequent with an anury, sharp increase of arterial pressure and the subsequent uric syndrome in the form of a hamaturia — as a result of the developing kidney heart attack. However thromboembolisms of branchings of renal arteries and heart attacks of kidneys caused by them can proceed and asymptomatically. If at such patients chronic hypertensia develops, then it can have the mixed character, i.e. is caused both by narrowing of a vessel, and defeat of a parenchyma as a result of forming of the centers of a nephrosclerosis on site of heart attacks of kidneys.
Other reasons. As the rare reasons of renovascular hypertensia aneurisms of renal arteries, their inborn stenoses, a hypoplasia of vessels of kidneys, excesses as a result of a nephroptosis, etc. are described.
Parenchymatous renal hypertensia
The following diseases can be the cause of parenchymatous renal hypertensia: • acute and chronic glomerulonephritis; • pyelonephritis; • diabetic glomerulosclerosis; • diffusion diseases of connecting fabric with vasculites and defeat of a parenchyma of kidneys: nodular periarteritis, system lupus erythematosus, scleroderma; • amyloidosis of kidneys, polycystosis, tuberculosis, hydronephrosis, tumors of kidneys, nephropathy of pregnant women; • a nephrosclerosis as an outcome of many of the listed diseases.
Pathogeny of renal hypertensia
At renovascular hypertensia the stenosis of the main trunk of a renal artery leads to lowering of perfusion of renal fabric that activates a renin-angiotenzinovuyu system. The excess amount of angiotensin II which possesses powerful pressor action is formed, stimulates secretion of Aldosteronum with the subsequent delay of sodium, strengthens adrenergic nervous influences. Assume that this mechanism can take place and at parenchymatous hypertensia — as a result of defeat of a set of average and small arteries, however the delay of ions of sodium in an organism with the subsequent delay of liquid is prevailing in genesis of hypertensia at patients with defeat of a parenchyma of kidneys.
The signs allowing to reveal renovascular or parenchymatous hypertensia
Renovaskulnrny hypertensia. Young or, on the contrary, advanced age of the patient: existence of the arterial hypertension which is badly giving in to medicamentous therapy; identification of systolic noise in a mesogaster on the right or to the left of a navel.
At intravenous urography reduction of the sizes of a kidney on the party of the struck vessel, a delay of emergence of radiopaque substance in a kidney of the reduced size is found. At an isotope renografiya the delay of hit of isotope in the affected kidney and reduction in the rate of allocation from it is observed. The ultrasonography allowing to find asymmetry in sizes of kidneys and the doppler sonography giving information on decrease in a blood-groove on one of renal arteries is used.
In the presence of the listed signs arteriography as only this research allows to reveal a renal artery stenosis finally is carried out.
Diagnosis of parenchymatous hypertensia is based on the fullest inspection of the patient directed to recognition of defeat of renal fabric and to establishment of the nature of a disease.
Treatment of patients with renal hypertensia
Renovascular hypertensia. At atherosclerosis of renal arteries balloon angioplasty with stenting of a vessel (in case of limited defeat on a short site) or surgical correction is applied — when defeat extends from a ventral aorta to the mouth of a renal artery.
At a fibromuscular dysplasia good results are yielded by balloon angioplasty and other endovascular methods of treatment.
At contraindication to the listed interventions or at their inefficiency for the purpose of correction of arterial hypertension carry out medicamentous therapy by means of antagonists of calcium, α-adrenoblockers, diuretics.
At a unilateral renal artery stenosis with success also angiotensin-converting enzyme inhibitors can be applied, however they are contraindicated to patients with a bilateral stenosis or with a stenosis of an artery of the only kidney as in these cases they can cause an acute renal failure.
At parenchymatous diseases of kidneys as anti-hypertensive all drugs of the main groups can be used (antagonists of calcium, angiotensin-converting enzyme inhibitors, α-and β-adrenoblockers, loopback diuretics). In an end-stage of a renal failure for lowering of arterial pressure the hemodialysis and/or transplantation of a kidney can be required.