Oxalate in urine
Last reviewed: 23.04.2024
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Oxalates in urine are oxalate calcium or ammonium, that is, salts of organic oxalic acid belonging to the class of dicarboxylic acids.
These salts are present among more than one and a half hundred chemical substances that make up the composition of urine.
In nephrological practice, clear symptoms of the patient having too much oxalate in the urine are pollakiuria (frequent urination), polyuria (increased urine volume), fatigue, abdominal pain and kidney colic.
But in many cases, such clinical manifestations are not observed, and the metabolic disorder in the meantime is progressing ... Its almost inevitable result is the formation in the kidney or bladder of stones (stones). 76% of these stones are insoluble in biological fluids inorganic compound calcium oxalate in urine.
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Oxalates in the urine during pregnancy
The content of salts, including calcium oxalate in urine, as a rule, decreases during childbearing.
And if oxalates in the urine during pregnancy exceed the norm, the reasons can be in the same problems with the kidneys, as well as arising or worsened inflammatory diseases of the urinary tract. Symptoms of oxaluria are the same: pollakiuria and polyuria, increased fatigue and painful sensations in the lower abdominal cavity.
In addition, oxalates in the urine during pregnancy can appear due to a desire to "saturate" the body with vitamins (for the benefit of the unborn child) and excessive consumption of vegetables and fruits rich in oxalic acid. Another reason is that pregnant women often reduce their fluid intake - to fight swelling. This reduces the formation of urine, but helps to increase its concentration. What to do with oxalate in the urine of pregnant women? Find a reasonable compromise in the issue of "drinking or not drinking" and be sure to establish proper nutrition with oxalate in the urine (which will be discussed below).
Oxalates in the urine of a child
In small amounts, oxalates in the urine of a child (as in adults) may be present. But kidney metabolism disorders in children, unfortunately, are diagnosed more often.
Let's start with a fairly rare but very severe case of a high content of oxalate in the urine of a newborn - a congenital anomaly of oxalate salt exchange, that is, a genetically caused violation of biochemical transformation in the body of glycine and glyoxylic acid. This is the so-called oxalose or primary hyperoxaluria. This disease progresses and leads to the formation of oxalate stones in the bladder, as well as to the diffuse deposition of calcium salts in kidney tissue, severe chronic renal failure, vascular insufficiency (expansion of the subcutaneous capillaries and stagnation of blood in them), pathological brittle bones, etc.
Oxalates in the urine of an infant may be associated with pathologies such as malabsorption in the small intestine, impaired absorption of bile acids from the digestive tract, congenital small intestine or partial atresia.
Oxalates in the urine of a child after six years, as well as in adolescence - oxaluria - are a consequence of the presence in the diet of a large number of foods with a significant content of oxalic acid. Or for the same reasons as in adults (see - Causes of the appearance of oxalates in urine).
What does oxalate in urine mean?
The permissible daily norm of oxalates in urine in adults (that is, the volume of their excretion from the body) is up to 40 mg, in children of the first year of life it is 1-1.3 mg. To reveal oxalates in 24-hour urine (isolated within 24 hours), laboratory studies of its physico-chemical and biochemical composition for determining the density and level of acidity (pH), the presence of protein, particles of epithelium, erythrocytes and leukocytes, of any microorganisms and, finally, crystals of salts - oxalates, urates, phosphates and salts of hippuric acid.
Urologists note that with normal acidity of urine (pH> 5 and <7, an average of about 6) salts in urine oxalate are not formed, but in acidic or alkaline urine, as well as with a sharp change in acidity level, the crystals of oxalic acid salts precipitate . And if the crystals of oxalate in the urine are contained in quantities significantly exceeding the physiological norms accepted in medicine, then it is about oxaluria.
By the way, the level of acidity of urine and in healthy people can change for a short time - from pH 4.5 to pH 8. This is an indicator that the kidneys are coping well with excretion of acid metabolic products from the body and thus contribute to maintaining the optimal level of acidity of blood - pH 7 , 35-7.4.
Decoding of oxalates in the analysis of urine
Let's see what can show the decoding of oxalates in the analysis of urine and what makes it possible for urologists and nephrologists to draw conclusions about certain metabolic disturbances and the presence or absence of pathologies of the kidneys and the urinary system.
So, in the norm of urine should be transparent, and when processing it on a centrifuge, a sediment is obtained, which is studied under a microscope.
Urate and oxalate in urine
In addition to oxalates, urate may contain urate, the sodium salt of uric acid. Most often this occurs against the background of increased acidity of urine with increased consumption of protein foods and foods containing a large number of purines (young meat, liver and other offals, brewer's yeast, ceps, cocoa and chocolate). Urates and oxalates in urine can appear with dehydration (after severe vomiting or diarrhea), as well as in a number of diseases, including chronic kidney failure, pyelonephritis, urolithiasis, gout, tumors, leukemia.
Protein and oxalate in urine
If protein and oxalate in the urine are found in the analysis, then proteinuria (protein in the urine) may be due to excessive physical exertion or significant hypothermia that preceded the delivery of the analysis, as well as fever or the patient having scarlet fever, infectious hepatitis, osteomyelitis. Protein and oxalate in the urine of pregnant women are possible with nephropathy.
Oxalates and phosphates in the urine
Phosphoric acid lime, calcium phosphate or magnesium, that is, phosphates, appear in the urine with a reduced level of acidity, which is facilitated by a diet rich in phosphorus: sea fish and seafood, milk and sour milk products, buckwheat and oatmeal. In addition, such a result of analysis is possible with hyperparathyroidism, diabetes, with certain mental illnesses, as well as with leukemia. And in children under 5 years of age, oxalates and phosphates in the urine speak not only of problems with excretion of oxalic acid salts, but also about vitamin D deficiency (rickets).
Oxalates and white blood cells in the urine
If, during examination in a microscope, from one to five white blood cells are in the field of vision, this is considered to be a perfectly normal indicator. But if oxalates and white blood cells in the urine are increased, then this indicates either chronic pyelonephritis (inflammation of the kidneys) or inflammatory diseases of the urinary tract, such as cystitis or urethritis. By the way, with the same diseases, as well as inflammatory processes in the urethra or vagina, oxalates and mucus secreted by their mucous membranes can be found in the urine.
The causes of the appearance of oxalate in the urine
And now we will take a closer look at the causes of the appearance of oxalates in the urine.
In most cases, the increase in oxalates in the urine is attributed to excessive consumption of products containing oxalic acid and its compounds (sorrel, spinach, tomatoes, beets, asparagus, citrus fruits, etc.). Or, bind oxalates in urine to an adult with pyelonephritis, diabetes, Crohn's disease, or ethylene glycol poisoning.
That is, in the latter case, a person should drink car antifreeze or brake fluid, of which the component is ethylene glycol. Indeed, when ingested, it decomposes with the release of oxalic acid, hence the oxalate in the urine of an adult. Now it becomes clear that oxalate stones in male kidneys are detected by doctors twice as often as in women's ...
But to explain the reason for the appearance of oxalates in the urine and such a serious pathology as the violation of oxalate metabolism, one can not do without physiology and biochemistry. So, there is a connection between the increased content of calcium oxalate in the urine and diseases of the small intestine. With a number of pathologies, the process of absorption of calcium oxalate in the small intestine (in the ileum) is disrupted, and then the urinary system has to work with increased stress, that is, there is an increase in oxalate in the urine.
This occurs with changes in the obligate intraluminal microflora of the small intestine - a lack of anaerobic bacteria that irreversibly cleaves oxalic acid in the intestine - Oxalobacter formigenes. When her presence is normal, the oxalates practically do not reach the kidneys and bladder. But why in the body the population of this symbiotic bacterium decreases - one can only guess.
As for the abuse of products with a high content of oxalic acid, there can be no objection. However, it should not be forgotten that oxalic acid is formed in the human body itself - in the small intestine: during the oxidation of glyoxylic acid, during the decomposition of oxaluric acid (monouret of oxalic acid), and also as a result of the oxidation of vitamin C (which is the aggregate of the derivatives of L -gulonic acid).
You are wondering why oxalic acid is needed for our body? And produced by the body, and more than 5% of the exogenous oxalic acid (that is, entering the body with food) circulate in the blood and enter into biochemical reactions and various metabolic processes, providing assimilation of calcium, stability of biological membranes, contractile function of muscle tissues, etc.
Other reasons for the appearance of oxalates in urine are:
- in excess of production of bile acids or impaired absorption of their salts in the digestive tract;
- in decreasing the activity of some enzymes;
- in renal tubular acidosis;
- in violation of calcium metabolism and idiopathic hypercalciuria;
- in the deficiency of magnesium or vitamin B6 in the body;
- in excess of consumption of vitamin C (more than 5 mg per day).
Treatment of oxalate in urine
How to remove oxalate from urine? To date, the most effective treatment of oxalates in urine is vitamin B6, magnesium, the correct drinking regime and, most importantly, proper nutrition.
Urologists recommend drinking at least two or two and a half liters of water during the day, as well as reducing the intake of table salt (which detains fluid in the body).
In addition, finding oxalates in the urine of an adult or oxalate in the urine of a child, doctors prescribe the intake of vitamin B6 (pyridoxine hydrochloride) and magnesium preparations that help normalize the excretion of oxalic acid salts from the body. For example, the drug Magne-B6 contains both vitamin B6 and magnesium. Adults should take 2 tablets three times a day (while eating, drinking a glass of water); children after 6 years - on a tablet three times a day. Magne-B6 with caution prescribed with a deficiency of calcium in the body, diabetes and peptic ulcer of the stomach and duodenum. In addition, it should be borne in mind that magnesium reduces the absorption of iron, so you need to monitor the level of hemoglobin in the blood.
To prevent the crystallization of calcium oxalate in the urine, potassium citrate (potassium citrate) is prescribed - 10-20 mEq of potassium 3 times a day (during meals), the maximum daily dose is 100 mEq of potassium. Also, Asparkam (potassium and magnesium) may be recommended in tablets of 0.35 g - twice a day (after meals).
How to remove oxalate from urine by increasing diuresis? Traditionally used diuretic herbs with oxalate in the urine - corn stigmas, field horsetail, mountain bird (sporich), peppermint, strawberry and cowberry leaf, field fieldie, black elderberry - are used as water infusions. Recall that 200 ml of boiling water you need to take a tablespoon of herbs and insist in a closed container for 20 minutes. This amount is calculated for one day and is drunk in two or three doses.
Nutrition with oxalate in urine
Proper nutrition with oxalate in the urine is to exclude or maximize the reduction in the diet products with a high content of oxalic acid and its salts.
Such products include: potatoes, tomatoes and eggplant; beans and soybeans; beets, chard and celery; green peppers and chili peppers; parsley and leek; spinach and sorrel, as well as, asparagus, rhubarb, parsnip.
Salts of oxalic acid are also rich in oranges, apples, plums, grapes, gooseberries, raspberries, blackberries, red currants, cranberries, kiwi, persimmons, figs and dates. Among other products of this category, nutritionists celebrate tea, coffee, cocoa, chocolate, walnuts and cedar nuts, cashews, peanuts, almonds, sesame seeds and sunflower seeds, which everyone loves. Do not use unripe fruits, because they contain glyoxylic acid.
Diet with oxalate in the urine provides a full-fledged intake of calories and involves the use of a sufficient number of proteins, fats and carbohydrates. So you can eat almost anything, except those products that have just been listed.
What to do with oxalate in urine? Be sure to see a nephrologist! Elevated oxalates in the urine present a real threat to the development of oxalate-calcium crystalluria, and after it - the formation of stones in the kidney or bladder.