Hypertensive nephropathy is a group of pathological conditions united by a combination of persistent increase in blood pressure and damage to the excretory system up to the development of chronic renal failure. Manifestations depend on the form of pathology, usually there are symptoms of hypertension (cardialgia, headache, cardiac arrhythmias) and abnormalities of water-salt metabolism (changes in diuresis, the appearance of edema). Diagnostics – analyzes, pressure monitoring, ECG, ultrasound, ultrasound of the urinary system organs. Treatment is determined by the etiology and degree of damage to the excretory system, includes antihypertensive agents, salt intake restriction, supportive measures.
Meaning
Hypertensive nephropathy is a collective name for renal pathological conditions caused by persistent hypertension of a primary nature. Some authors also include kidney damage caused by a secondary increase in blood pressure in this group. In particular, the so–called “renal vicious circle” fits this criterion – an increase in blood pressure provokes kidney damage, and damage to the juxtaglomerular apparatus further increases blood pressure. This type of nephropathy is the second most common, mainly affects the elderly. Women suffer somewhat more often than men, but in the latter nephropathy is complicated by urodynamic disorders. The prevalence and sexual distribution of the disease correspond to the epidemiology of hypertension.
Causes
The main cause of hypertensive nephropathy is a persistent increase in blood pressure for a long period (months and years). There is primary sclerosis (primary-shrunken kidneys), which lies in the pathogenetic basis of nephrological disorders. However, not all patients with hypertension have such disorders, which indicates the presence of certain concomitant factors that make the renal elements more susceptible to the influence of high blood pressure. Those in modern urology include the following circumstances:
- Old age. People over 40-50 years of age are more likely to develop hypertension, a number of metabolic processes change, the elasticity of the vascular wall decreases, and the regenerative potential decreases. As a result, damage to the nephrons due to high blood pressure is not fully restored, the nephrons are replaced by connective tissue, which leads to nephropathy.
- Bad habits. Smoking, drinking alcoholic beverages, overeating increase the load on many body systems, including the excretory system. In the presence of hypertension, this serves as an additional factor that increases the likelihood of hypertensive nephropathy.
- Genetic predisposition. As with hypertension, kidney damage from high blood pressure in some individuals is easier than in others. In some cases, the family type of inheritance of such features has been proven, which indicates their genetic nature.
- The presence of concomitant pathologies. The presence of diabetes mellitus, diseases of the urinary system, chronic infectious pathologies of other organs facilitates the development of nephropathy from increased blood pressure.
Pathogenesis
The pathogenesis processes in the case of hypertensive nephropathy are complex and diverse, which causes a rich and diverse clinical picture of this condition. According to the most generally accepted opinion, high blood pressure negatively affects the walls of small-caliber renal vessels, first reducing their elasticity, and then leading to hyalinosis and sclerosis. This makes it difficult to nourish the renal tissue, stimulates the formation of connective tissue scar elements in it. In the later stages, the death and sclerosis of nephrons and tubules occurs, the number of functioning units decreases, which clinically leads to the development of CRF, and morphologically – to the picture of a primary shrunken kidney.
Additional and concomitant pathological processes (atherosclerosis of the renal vessels, angiopathy in diabetes, urodynamic disorders, inflammatory changes in pyelonephritis and glomerulonephritis) accelerate and aggravate nephropathy. When elements of the juxtaglomerular apparatus are involved in the process, renin production increases, which increases the level of pressure in the arteries by activating the renin-angiotensin-aldosterone system. This leads to the formation of a “vicious circle” and is also a factor that worsens the condition of patients with this pathology.
Symptoms
The manifestations of pathology are often erased, since nephrogenic symptoms are masked for a long time by complaints caused by hypertension and concomitant diseases. One of the first complaints of patients with this nephropathy is nocturia – an increase in the proportion of nocturnal diuresis. This leads to the fact that the patient may wake up at night (often several times) due to the urge to urinate. The consequence is a decrease in the quality of sleep, lack of sleep and related manifestations – decreased ability to work, headaches, irritability. The severity of nocturia is higher, the more severe the kidney damage.
As hypertensive nephropathy progresses, fluid retention in the body joins the symptoms, which is manifested by facial edema. Initially, they arise in the morning and disappear within a few hours after waking up, gradually become more persistent, persist for a long time. Edema is aggravated by the use of foods that can act as an osmotic factor – salty and spicy dishes, alcoholic beverages. The development of edema reflects violations of water-salt metabolism, which can negatively affect the course of the underlying disease – arterial hypertension. Due to the slowing down of the withdrawal of fluid and electrolytes, the volume of circulating blood increases, which increases the pressure on the vascular walls.
With a prolonged course of pathology, in addition to nocturia and edema, a decrease in the volume of daily diuresis or the amount of urine excreted is recorded. Patients note a decrease in fluid portions with each urination, sometimes false urges are possible. This indicates a significant decrease in the glomerular filtration rate, which indicates a condition bordering on chronic chronic renal failure. When it is attached, in addition to the above edema, headaches, cardialgia, an unpleasant (ammonia) odor from the mouth and from the patient’s body is detected, itching occurs, dryness of the mucous membranes and skin.
Complications
The most common complication (according to some authors – a natural outcome) of hypertensive nephropathy is chronic renal failure (CRF). It occurs due to the death of most of the functional units of the kidney – nephrons and organ ischemia due to vascular disorders, leads to azotemia and a number of metabolic disorders. Acute forms of insufficiency against the background of hypertension alone develop extremely rarely. Complex pathogenetic relationships in this pathology can also stimulate the development of urolithiasis, facilitate infection and inflammation (glomerulonephritis, nephritis), urodynamic disorders.
Diagnostics
The presence of hypertensive nephropathy is determined by a nephrologist or cardiologist, depending on the prevalence of manifestations from one or another system. In any situation, close cooperation between specialists is important to clarify the issues of diagnosis, treatment and prognosis of the disease. In general, the diagnostic process can be divided into two parts – determining the causes of a persistent increase in blood pressure and the presence of associated renal lesions. For this purpose, a number of instrumental and laboratory techniques are used:
Questioning and anamnesis collection. The patient is asked how long he has had signs of hypertension (headaches, palpitations and others), whether there is an established diagnosis of hypertension. The diagnostic criterion for nephropathy due to high blood pressure is its presence for at least 10 years in patients under the age of fifty, and 5 years – in older persons. During the examination, attention is paid to the presence or absence of edema, their severity, the nature of distribution (mainly on the face in the first half of the day).
- Blood biochemistry. At the initial stages of nephropathy, pathological changes of nephrogenic genesis in the blood are not determined. With a strong decrease in glomerular filtration and an increase in signs of CRF, there is a decrease in the level of total protein, hyporegenerative anemia, an increase in the values of nitrogen, urea, creatinine and lipids. There is protein in the urine (up to 1-3 g / l), the severity of proteinuria directly depends on the degree of kidney damage.
- Functional renal tests. The most informative method is a urine sample by urine according to Zimnitsky – with its help, the volume of daily diuresis, the density of the secreted fluid, the ratio of day and night urine volume is estimated. With hypertensive nephropathy, nocturia occurs (an increase in nocturnal diuresis), a decrease in the total daily amount of urine. The Rehberg test allows you to find out the glomerular filtration rate: with nephropathy, its value will be less than 60, the more pronounced the damage to the nephrons, the lower the indicators.
- Instrumental research. Excretory urography confirms a slowdown in the filtration rate – the contrast is excreted by the kidneys much longer than the reference values. On ultrasound of the kidneys, initially no changes may be noted, with a long-term state, the size of the organs decreases, their surface becomes bumpy, the cup-pelvic system is deformed.
Differential diagnosis is performed with other types of inflammatory and non-inflammatory nephropathy. At the stage of the occurrence of CRF, it is extremely difficult to differentiate hypertensive nephropathy itself from other similar conditions, since it is not known for sure what occurred primarily – kidney disease or an increase in blood pressure. To confirm the diagnosis, hormone levels, radioisotope studies, and other types of diagnostic measures may be prescribed.
Treatment
The therapy of this kidney lesion is complex, inextricably linked with the treatment of the main pathology – arterial hypertension. Therefore, many specialists develop therapeutic measures primarily taking into account the elimination of elevated blood pressure, taking into account the fact that there is reduced glomerular filtration in the pharmacokinetics of the drugs used. Thus, the treatment regimen for hypertensive nephropathy is a modified version of antihypertensive therapy and consists of the following non-medicinal and pharmacological components:
- Non-medicinal activities. For patients with arterial hypertension with signs of kidney damage, it is important to observe an optimal water regime, reduce the intake of sodium chloride in the diet (maximum – 2.4 grams per day). At the same time, the complete abolition of table salt can cause hyponatremia, increase blood nitrogen levels, and reduce the intensity of renal blood flow. Therefore, the development of a diet for hypertensive forms of damage to the excretory system should be carried out individually, taking into account the indicators of a particular patient.
- Angiotensin converting enzyme inhibitors. ACE inhibitors are most effective in a number of forms of arterial hypertension, have a nephroprotective effect. Their use not only helps to reduce protein in the urine, but also activates the processes of renal blood flow.
- Angiotensin receptor blockers. They include a group of drugs, the effect of which is largely similar to ACE inhibitors, since the purpose of their effect is to block the same mechanism of increasing blood pressure. In severe forms of nephropathy, the combined use of medications from the two listed groups is possible.
- Calcium antagonists. These drugs contribute to increased blood supply to the kidneys, which reduces the rate of degradation of nephrons, the processes of renal tissue sclerosis. Their use in combination with angiotensin receptor blockers and ACE inhibitors effectively reduces the severity of proteinuria.
- Auxiliary means. The treatment of pathology must necessarily include drugs to combat concomitant disorders. Most often, diuretics are prescribed to normalize the daily volume of urine and reduce edema, statins and antiplatelet agents to improve the rheological properties of blood, hypoglycemic drugs – in the presence of diabetes and reduce glucose tolerance.
Before and during treatment, mandatory monitoring of the excretory function of the kidneys is required by monitoring the biochemical parameters of urine and blood, regular assessment of blood pressure is required. The effectiveness of therapeutic measures is maximal with a steady maintenance of blood pressure levels no more than 130/60 and proteinuria no higher than 0.5 g / l, even short-term periodic violations of the therapy regimen significantly worsen the course of the disease. With the development of signs of CRF, the appointment of hemodialysis and infusion therapy is indicated.
Prognosis and prevention
The prognosis is relatively favorable with compliance with the rules of diet and treatment regimen, regular monitoring of blood pressure, metabolic processes and biochemical indicators of kidney function. Neglecting the prescriptions of a specialist is fraught with an increase in renal lesions to the level of CRF and uremia, complications from the cardiovascular and nervous systems are possible due to hypertensive phenomena (heart attack, stroke). Preventive measures are shown to all persons with a persistent increase in blood pressure. These include the delivery of general and biochemical blood and urine tests at least once every 6 months with their subsequent interpretation by a nephrologist. Such monitoring allows early detection of signs of kidney damage and correction of the main antihypertensive therapy.