Gouty nephropathy - Causes, symptoms and treatment. MF.

Gouty nephropathy is a kidney damage that occurs with gout. Gout is a disease characterized by deposition in various organs and tissues of urate crystals( uric acid salt).Most men suffer from gout, and half of the patients develop gouty nephropathy.

Causes of gouty nephropathy

At the heart of the disease is an increase in the synthesis of uric acid in the body and / or a decrease in the ability to remove it. This causes an increase in the concentration of uric acid and its derivatives in the blood, the accumulation of urate in the kidneys, which leads to urate nephrolithiasis( the formation of stones in the calyx-pelvis kidney system).With the adherence of inflammation, pyelonephritis develops( infectious disease of the renal pelvis and kidney tissue).In addition, urates have a direct toxic effect on the tissue of the kidneys, causing interstitial nephritis. In some cases, acute obstruction of the renal tubules with urate crystals is possible. This complication is called acute urinary acid nephropathy. All these factors directly or indirectly cause damage to kidney tissue with the development of renal failure.

Diagnosis and symptoms of gouty nephropathy

The following clinical forms of gouty nephropathy are distinguished:

• urate nephrolithiasis;
• chronic tubulointerstitial nephritis;
• Acute uric acid nephropathy.

Urinary nephrolithiasis is diagnosed with kidney stones. As a rule, the process is bilateral, characterized by the repeated formation of stones after their removal. Often there are coral stones, completely filling the renal pelvis, which can lead to complications such as bleeding or pyelonephritis.

Uranium stones are X-ray negative, that is, they can not be determined by radiography. Ultrasound is the method of choice for the diagnosis of this disease.

Another dangerous complication of urate nephrolithiasis is renal colic. Renal colic is, as a rule, an acute disturbance of the patency of the urinary tract, accompanied by a delay in urine. This complication is characterized by severe pain syndrome.

During the examination, it is possible to detect blood in the urine as a result of injury to the urinary tract wall by a stone, an increase in the number of leukocytes and the appearance of bacteria in the urine during the formation of secondary pyelonephritis. Without treatment, renal colic can lead to the development of hydronephrosis( enlargement of the renal pelvis due to the impossible retention of urine), severe pyelonephritis, and ultimately damage to the kidney tissue with the formation of terminal renal failure. In the absence of renal colic and inflammatory phenomena in laboratory tests with urate nephrolithiasis, there are no changes.

For chronic tubulointerstitial nephritis is characterized by urinary syndrome in combination with arterial hypertension. Urinary syndrome is diagnosed with the appearance of a small amount of protein( up to 2 g / l) in the urine and microhematuria( the presence of more than 3-4 erythrocytes in the urine without changing the color of urine).In case of exacerbation of chronic diseases, after the infection, a significant increase in the release of protein and the emergence of macrohematuria( visible blood in the urine) is possible.

1,2 - Macrogematuria, 3 - the norm.

Chronic tubulointerstitial nephritis is also characterized by arterial hypertension. Usually, blood pressure is controlled by taking medications. The appearance of malignant( uncontrolled) hypertension indicates a significant damage to the tissue of the kidneys with the replacement of its scar tissue.

Acute uric acid nephropathy develops suddenly. The amount of urine drops drastically. The attack is accompanied by intense pains in the lumbar region, macrogemuria, can be complicated by renal colic and hypertensive crisis. In this case, the excretory function of the kidneys does not suffer. With the passage of time, urine disappears, acute renal failure rapidly develops with a pronounced poisoning of the body with harmful products of vital activity.

The diagnosis of gout is based on the detection of an elevated uric acid level in a blood test. When gout is diagnosed, gouty nephropathy becomes most likely.

Treatment of gouty nephropathy

Acute uric acid nephropathy refers to life-threatening conditions and its treatment is carried out according to the rules for the treatment of acute renal failure.

In the presence of stones that prevent the normal flow of urine, their surgical removal is indicated.

After this, intensive intravenous infusion of large volumes of fluid is prescribed in combination with diuretics. This leads to the excretion of urate and uric acid. Also shown are the applications of alkaline solutions( 4% sodium hydrogencarbonate) to dissolve the urate crystals. If there is no effect of therapy within 60 hours, dialysis is indicated urgently.

In the treatment of chronic forms of gouty nephropathy( urate nephrolithiasis and chronic interstitial nephritis) the following tasks should be solved.

1. Normalization of uric acid level .To do this, a low-purine diet is prescribed in combination with an abundant alkaline drink. Alcohol, meat, products containing yeast, mollusks, mackerel, sardines are excluded from the diet. The drug of choice in this situation is allopurinol. It reduces the formation of uric acid and promotes the dissolution of urate. To enhance the excretion of uric acid, uricosuric drugs, such as sulfinpyrazone, benzobromarone, are used. A combination of these groups of drugs is possible.

2. Anti-hypertensive drugs, such as angiotensin receptor blockers( losartan), or angiotensin-converting enzyme( enalapril) inhibitors are used to treat high-pressure .Many drugs of these groups have nephroprotective( protective) action, which is especially important for the prevention of the development and progression of renal failure.

3. Treatment of chronic pyelonephritis is carried out with the help of antimicrobial agents. Timely treatment of inflammation allows to significantly significantly delay the development of renal failure in time.

The prognosis for acute forms of gouty nephropathy with timely and adequate treatment is favorable. In a chronic process, renal failure is formed approximately 10-15 years after the manifestation of the disease. Each fourth patient with gout ultimately develops the terminal stage of kidney failure.

Doctor therapist, nephrologist Sirotkina EV