Sand in the kidneys
Sand in the kidneys is the formation and accumulation in the cups and renal pelvis of a protein—crystalline suspension containing micro-fragments with a diameter of up to 1 mm. In the absence of other urological pathology, it is asymptomatic. Some patients have dysuria, increased urge to urinate, pain in the lumbar region, subfebrility. It is diagnosed with the help of general and biochemical analysis of urine, ultrasound of the kidneys. The therapeutic program includes the correction of lifestyle, diet, drinking regime, treatment of urological, endocrine and other underlying pathology, the appointment of renal phytopreparations, antispasmodics, NSAIDs, diuretics.
In the latest edition of ICD-10, the sand detected in the kidneys is not considered as a separate nosological unit. In fact, microlithiasis is a premorbid condition or the initial reversible stage of kidney stone disease. According to the results of observations, with a thorough study, micro-increments in the kidneys and urine are determined in 70% of the subjects, which is associated with increasing inactivity of the population, irrational nutrition, insufficient water intake. Sand formation is more often observed in men aged 20-55 years. Due to the small particle size, the detection of renal microlithiasis using traditional screening diagnostic methods presents certain difficulties.
Reasons
Since the appearance of microliths is usually one of the initial signs of kidney stones, their formation is caused by the same exogenous and endogenous etiological factors as larger concretions. In most cases, microlithiasis becomes a consequence of metabolic disorders, while diseases of the kidneys and other organs of the urinary system create prerequisites for stone formation. Specialists in the field of urology and nephrology identify the following reasons for the formation of sand:
Unfavorable heredity. The risk of renal microlithiasis increases in patients who have been diagnosed with urolithiasis or metabolic disorders predisposing to it. Genetic prerequisites for the formation of sand exist in patients suffering from idiopathic familial hyperuricemia, urinary diathesis, oxalosis, hereditary cystinuria, etc.
Alimentary factors. Urate kidney sand is more often detected with an unbalanced diet with an excess of animal proteins. When eating large amounts of beans, beets, sorrel, spinach, deciduous vegetables, the risk of precipitation of oxalates increases. Microliths are formed faster with an imbalance of vitamins D, A, C, drinking hard water with calcium, magnesium, phosphorus ions.
Hyperfunction of the parathyroid glands. The reason for the formation of microcalcinate sand is the high concentration of parathyroid hormone, which enhances the tubular reabsorption of calcium ions in the kidneys. An increase in the level of parathyroid hormone is noted in hyperplasia, tumors of the parathyroid glands, hereditary osteodystrophy, Zollinger-Ellison, Albright syndromes.
Urological diseases. The provoking factors of microlith formation in diseases of the urinary organs are stagnation, which contributes to an increase in urine concentration, and a change in its pH. The risk of concretion formation increases with chronic pyelonephritis, glomerulonephritis, medicinal nephropathies, shrunken kidney, genitourinary fistulas, anomalies of the kidney structure.
The probability of sand detection during kidney screening is increased in residents of countries with humid and hot climates, bedridden patients, people leading a sedentary lifestyle, suffering from genital infections, diseases of the gastrointestinal tract, liver, biliary tract, caries, chronic tonsillitis, sarcoidosis, leukemia, Crohn’s disease. The risk group also includes patients who use sulfonamides, diuretics, corticosteroids for a long time.
Pathogenesis
The basis for the formation of sand in the kidneys is the acceleration of precipitation of the lithic components of urine (calcium, magnesium, oxalates, urates, phosphates, amino acids, etc.) in conditions of increasing their concentration and pH instability. Protein molecules, erythrocytes, leukocytes, microorganisms, and renal epithelium can participate in the formation of an organic matrix on which salt crystals are deposited.
When an imbalance occurs between the quantitative and qualitative ratio of salts and protective colloids that hold the mineral components of urine in a dissolved state, compounds with an increased concentration crystallize on the organic matrix. As a result, a protein-salt suspension is formed in the kidneys, containing microliths up to 0.8-0.9 mm in diameter and not formed into larger concretions. Like stones with kidney stones, sand in composition can be carbonate, urate, oxalate, phosphate, cystine, protein, mixed.
Symptoms of sand in the kidneys
Most patients have no symptoms. A clinical debut is possible when the mucous membrane is injured due to the movement of sand through the urinary tract. In such cases, there is dysuria, frequent urge to urinate, a feeling of incomplete emptying of the bladder, cutting pains in the lumbar region with irradiation to the groin or upper abdomen (sometimes the pain syndrome resembles renal colic). With severe damage to the epithelium of the kidneys and ureters, blood appears in the urine. In extremely rare cases, the general condition of the patient is disturbed: there is a rise in body temperature to subfebrile figures, chills, excessive sweating, pallor of the skin and mucous membranes, nausea and vomiting.
Complications
Prolonged course of microlithiasis increases urinary stagnation, which is the main predisposing factor for the reproduction of pathogenic microorganisms. Infections of the kidneys and urinary tract develop – pyelonephritis, ureteritis, cystitis. In the absence of treatment of bacterial processes, pionephrosis may occur.
The main danger of sand present in the kidneys is the progression of nephrolithiasis with the formation of large concretions, obstruction of the urinary tract, impaired renal function up to chronic renal failure, which occurs several years after the onset of the disease and is characterized by a progressive decrease in the filtration capacity of nephrons. In some patients, the situation is aggravated by persistent arterial hypertension against the background of a violation of renin-angiotensin-aldosterone regulation.
Diagnostics
Diagnosis is often difficult because clinical symptoms are absent or are non-specific, characteristic of other renal pathology. It is possible to confirm the presence of sand in the kidneys only after a comprehensive laboratory and instrumental examination. The diagnostic plan for a patient with suspected microlithiasis includes the following methods:
Kidney sonography. Most often, the patient learns about the possible presence of microcrements in the urinary tract during a planned ultrasound of the kidneys for another disease. Since the size of sand particles does not allow them to be reliably visualized, microlithiasis is usually described as an increase in echogenicity and can be overdiagnosed.
General urinalysis. Sand in the form of salt crystals is determined in the urine sediment. An important sign is a change in the pH of the medium to the acidic or alkaline side, depending on the type of stone formation. The study is supplemented with a biochemical analysis of urine, which allows to detect an increase in the concentrations of calcium, oxalates, uric acid, magnesium, and inorganic phosphorus.
Large microliths can be detected during excretory urography, radioisotope nephroscintigraphy, however, these methods are more informative in the following stages of kidney stone disease. For a comprehensive assessment of the state of the urinary system, an overview urography, CT, MRI of the kidneys, ureters, bladder, urethra are prescribed. If there are indications, the blood is examined to detect elevated levels of uric acid, calcium, magnesium, and parathyroid hormone.
Differential diagnosis of renal microlithiasis is performed with chronic interstitial nephritis, malignant neoplasms, tuberculous kidney damage, acute and chronic pyelonephritis, nephropathy with lead poisoning. In addition to visiting a nephrologist and urologist, patients are recommended to consult an oncologist, a phthisiologist, an infectious disease specialist, a therapist, an endocrinologist.
Treatment of sand in the kidneys
Therapeutic tasks in the presence of renal microlithiasis are the removal of protein-crystalline formations from the urinary organs, relief of pathological symptoms (if any), prevention of repeated lithification. Non-drug methods are considered to be leading, which, if necessary, are supplemented with drugs to improve urodynamics, dissolve microliths, and increase the stability of urine. If there is sand in the kidneys , it is shown:
Correction of lifestyle and habits. The patient is recommended to increase physical activity: swimming, yoga, physical therapy, long walks, refusal to use the elevator. Microlith formation slows down when quitting smoking and alcohol abuse.
High-liquid drinking regime. The volume of liquid consumed should be 1.7-3.0 liters of pure still water per day. This allows you to increase diuresis and reduce the concentration of urine, which accelerates the removal of existing sand and prevents the formation of new microliths.
Control of bladder emptying. With regular urine discharge, its stagnation decreases, excessive reabsorption decreases, filtration improves. Timely emptying of the bladder is especially important in patients with other diagnosed uropathology.
Changing the power supply. It is recommended to exclude coffee, strong tea, caffeine-containing drinks from the diet, limit the use of spices, smoked meats, marinades, salt, fatty dishes. In the presence of micronutrients, the restriction of meat and fish products is effective, with oxalate microlithiasis — sorrel, rhubarb, leafy vegetables, with phosphate — a dairy diet.
Drug therapy is aimed at the etiopathogenetic treatment of diseases complicated by nephrolithiasis. To dissolve sand, normalize the pH level, and prevent further stone formation, herbal preparations and phytopreparations with a litholytic, anti-inflammatory, uroseptic, diuretic, antispasmodic effect are used.
The selection of a specific drug is carried out taking into account the composition of the sand detected in the kidneys. In the presence of pronounced clinical symptoms, antispasmodics, nonsteroidal anti-inflammatory drugs, thiazide diuretics are prescribed. Surgical treatment is not carried out, because the size of the micro-increments allows them to stand out independently without the risk of obstruction of the urinary tract.
Prognosis and prevention
With timely diagnosis and proper medical tactics, it is usually possible to achieve stable remission. The prognosis is favorable. Prevention methods include therapy of pathological conditions that can be complicated by the formation of sand, sufficient motor activity, a balanced diet with a sufficient amount of vitamins, trace elements, phytonutrients.
A special role in the prevention of renal microlithiasis in predisposed patients is played by compliance with a high-liquid drinking regime, correction of the diet in the presence of hereditary burden with restriction of the use of certain foods in accordance with data on metabolic disorders and the composition of stones in sick relatives, regular urine screening.
