Urates in the urine

The constant renewal of nucleic acids and proteins in the body's cells occurs through the metabolism of purine nucleotides and the exchange of nitrogen-containing protein (purine) bases. At the final stage of this biochemical process, 2,6,8-trioxypurine is formed - uric acid, the main part of which is excreted by the kidneys. Uric acid salts - urates - under certain conditions can accumulate in the kidneys and bladder, and then doctors determine urates in the urine - in the form of small particles similar to yellowish grains.

Causes of urates in urine

When they say that the key reasons for the appearance of urates in urine are due to excessive consumption of purines with food (i.e. animal proteins), they are only noting the tip of the metabolism "iceberg". It is known that food purines are only slightly involved in the synthesis of tissue nucleic acids, but, nevertheless, their excess increases the risk of urates.

The lion's share of exogenous purine bases (amino- and oxypurines) are converted into 2,6-dioxypurine (hypoxanthine), then into xanthine and, finally, are oxidized to uric acid. At different stages of its formation, pathogenesis may be associated with insufficient enzyme activity.

Thus, inactivation of allosteric enzymes of purine nucleotide metabolism (FRDP synthase, GGPRT, etc.) leads to an increase in the level of uric acid in the blood plasma (hyperuricemia) and increased excretion of urates in the urine (uraturia).

The final stage of uric acid formation is provided by the enzyme xanthine oxidase, synthesized in the cells of the intestine and liver, the level of which can also cause problems in the form of hereditary xanthinuria.

The causes of the appearance of urates in urine may be due to defects in the genes responsible for the excretion of uric acid by the kidneys - SLC2A9, SLC17A1, SLC22A11, SLC22A12, ABCG2, LRRC16A, etc.

In addition, the factor of functional disorders of the kidneys should be taken into account, because urine, with which metabolites and excess salts are excreted from the body, is formed in them - as a result of glomerular filtration of blood plasma and reabsorption of water and the main volume of substances needed by the body. Disturbances in these biochemical processes can also cause the appearance of uric acid salts in the urine.

High concentrations of poorly soluble uric acid and urates in urine are not a medical indication, but are associated with various diseases and pathologies. Their ICD 10 code is E79.0 - E79.9 (disorders of purine and pyrimidine metabolism).

In one way or another, these disorders include pyelonephritis and renal tuberculosis; renal acidosis in diabetes mellitus and alcoholism; fatty infiltration of the kidneys; prolonged starvation or rapid weight loss; Conn's syndrome (primary hyperaldosteronism); fluid loss with prolonged vomiting and diarrhea; a drop in the level of potassium in the blood; hematological oncopathologies (leukemia, lymphoma ); taking certain medications (for example, ascorbic acid, antibiotics and thiazide diuretics).

The consequences of purine metabolism disorders are manifested by chronic and acute renal failure, and with increased urine acidity (pH less than 5), urates in the urine precipitate in the renal tubules with subsequent crystallization, the formation of urate sand and stones (stones) and the development of urolithiasis - one of the varieties of urolithiasis. Crystals of uric acid salts (most often calcium) can also settle in joint tissues, causing inflammation of the joints and periarticular structures.

Symptoms of urates in urine

Nephrologists emphasize the fact that there are no symptoms of urates in urine, and a person does not feel anything when his urine contains uric acid salts.

The first signs of purine metabolism pathology may appear only after the increase in urine acidity, which contributes to the formation of crystals. And only by urine analysis can a disorder be identified that can lead to serious kidney problems.

Urate in urine during pregnancy, the appearance of which is most often associated with either vomiting and dehydration during early toxicosis, or with increased consumption of protein foods, also does not manifest itself in any way.

In the case of xanthinuria, a fairly rare pathology of uric acid metabolism, xanthine crystals can settle in muscle tissue and cause pain during physical exertion.

Urate in the urine of a child, or rather their high concentration, leaves traces of pink and orange on diapers. But in the case of genetically determined Lesch-Nyhan syndrome (ICD 10 code - E79.1), it does not come down to urates, although the content of uric acid in the blood serum (due to the complete blocking of one of the enzymes of purine metabolism) is simply off the scale. As a result, urate concretions are formed in the urinary tract, and granular accumulations of crystallized uric acid ( tophi ) under the skin. A child with this syndrome from early childhood lags behind in the development of motor skills, psyche and mental abilities; spasticity, involuntary movements and manifestations of aggression (also in relation to oneself: the child bites his fingers, tongue and lips) are noted. If the functional disorder of the kidneys is not treated, then the prognosis is a fatal outcome before the child reaches 10 years of age.

Diagnostics of urates in urine

The most accessible diagnostic test for urates in urine is a laboratory test of urine composition.

Necessary tests: blood - for acidity and uric acid; urine - for pH level and for the content of uric acid (or xanthine) and its salts (Na, Ca, K, Mg). A characteristic sign of the presence of crystallized uric acid in the urine is a yellow sediment; with urates, the urine is cloudy, and the sediment has a more saturated color - up to reddish-brown.

Nephrologists and urologists also perform instrumental diagnostics – ultrasound examination (US) of the kidneys, which can detect urate sand in them.

And differential diagnostics is aimed at accurately determining the composition of salts in the urine, since in addition to urates, it may contain oxalates (calcium oxalate) and phosphates (calcium or magnesium phosphate).

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Treatment of urates in urine

The main method recommended in clinical practice for treating urates in urine is diet therapy.

Diet for urates in urine - No. 6 according to Pevzner, plant-based and dairy, with a strict restriction on the consumption of animal proteins (per day - no more than one gram of boiled meat per kilogram of weight). In addition, red meat and concentrated meat broths are excluded; meat by-products, lard and sausages; fish, eggs, legumes, mushrooms; everything spicy, salty and sour; chocolate, cocoa and coffee. It is very important to reduce the daily amount of salt as much as possible - to 7-8 g.

The diet should include dairy products, vegetables, cereals, fruits and berries (not sour); the daily volume of liquid consumed should be at least 2.5 liters; alkaline mineral table water is useful for lowering the pH of urine.

Medications most commonly used for urate in urine include:

• vitamins A, B6, E
• orotic acid in the form of potassium orotate tablets (increases protein synthesis, increases diuresis); taken orally at 0.25-0.5 g up to three times a day (60 minutes before meals). The dose for children is 10-20 mg per kilogram of body weight.
• Benzobromarone (Normurat, Azabromarone, Hipurik, Urikonorm, etc.) - inhibits the absorption of uric acid in the renal tubules and increases its excretion. Dose - 50-100 mg once a day (during meals).
• K-Na hydrogen citrate (Blemaren, Soluran) - maintains neutral urine pH; dosage is determined individually based on test results.
• Allopurinol (Allohexal, Milurit, Zyloprim) – by blocking the enzyme xanthine oxidase, it reduces the synthesis of uric acid and helps break down urates; it is used for hyperuricemia and Lesch-Nyhan syndrome.

The drug Etamid (Etebenecid) reduces the content of uric acid in the blood, delays its reabsorption in the kidneys and promotes its elimination from the body. Method of administration: orally 0.35 g 3-4 times a day (after meals). It should be taken for 12 days, 5 days break, and then taken for another week.

Among the remedies that homeopathy offers for the treatment of urates in urine, preparations based on the extract of the seeds of the poisonous plant autumn crocus (Colchicum autumnale) are noted.

Traditional treatment of this pathology involves phytotherapy - treatment with herbs, in particular: a diuretic decoction of knotweed (a tablespoon per 250 ml of boiling water, take 1/3 cup three times a day) and an infusion of madder roots (in the same dosage).

The best prevention of the appearance of urates in urine - to prevent complications of protein metabolism disorders and uric acid metabolism - is proper nutrition with a reduction in the proportion of meat products in the diet.