Diagnosis of urolithiasis
Last reviewed: 23.04.2024
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Laboratory diagnosis of urolithiasis
Examine the urine sediment, paying special attention to salt crystals. Crystals of oval calcium oxalate monohydrate are similar to erythrocytes. The crystals of calcium oxalate dihydrate are pyramidal in shape and resemble an envelope. Calcium phosphate crystals are too small to be detected in a conventional light microscope and are similar to amorphous fragments. Crystals of uric acid also usually resemble amorphous fragments, but they are characterized by a yellow-brown color. Somewhat less often, uric acid dihydrates can be rhomboid or resemble hexahedral rhombuses on a deck of cards. In normal urine, you can detect any of these crystals, their presence is not considered a diagnostic sign of the disease. However, cystine crysalls always mean cystinuria. Cystine crystals are flat hexagonal plates, similar to benzene rings, but unlike them, the rings of cystine crystals can have equal or unequal facets. Crystals of ammonium phosphate with magnesium resemble rectangular prisms similar to "coffin lids" in shape.
In the presence of stones (spontaneously released or obtained as a result of surgical intervention) determine their chemical composition. The composition of the stones - a mixture of minerals with organic substances, most often they identify oxalates, phosphates, urates, carbonates. Less common are cystine, xanthine, protein, cholesterol stones. Stones, as a rule, are layered, the number of stone-forming minerals is not more than 3, other minerals are found in the form of impurities.
Oxalatite stones
These stones are formed by calcium salts of oxalic acid, dense, black-gray, with a spiky surface. They easily injure the mucous membrane, as a result of which the blood pigment stains them in a dark brown or black color.
Phosphate stones
Contain calcium salts of phosphoric acid. Their surface is smooth or slightly rough, the form is diverse, the consistency is soft. They are white or light gray, are formed in alkaline urine, grow rapidly, easily break up.
Uranium stones
They consist of uric acid or its salts. The stones are yellow-brick, of solid consistency, with a smooth surface.
Carbonate stones
Formed by calcium salts of carbonic acid. They are white, with a smooth surface, soft, of various shapes.
Cystine stones
They consist of a sulfur compound of the amino acid cystine. They are yellowish-white, round in shape, soft in consistency, with a smooth surface.
Protein stones
They are formed mainly from fibrin with an admixture of salts and bacteria. Small size, flat, soft, white.
Cholesterol stones
They consist of cholesterol, they are very rare in the kidneys. They are black, soft, easily crumbled.
Instrumental methods of diagnosis of urolithiasis
For the diagnosis of urolithiasis, x-ray methods of research are widely used. On the roentgenograms of the kidneys, ureters and bladder, calcium stones are revealed, but without differentiation of their types. On the radiographs of the kidneys, ureters and bladder in combination with tomograms or the use of digital methods of imaging kidneys, ureters and the bladder, it is easier to locate kidney stones and identify them. Oxalatite stones are usually small, dense, with clear boundaries. Cystine stones are poorly visible, soft and waxy. Struvite stones (from magnesium phosphate and ammonium) are irregular in shape, dense. Urine stones are transparent in X-rays and are not visible on the radiographs of the kidneys, ureters and bladder.
Intravenous pyelography
Helps to clarify the localization of stones in the urinary tract, the degree of obstruction and kidney function. X-ray obstruction, detected on the pyelogram, suggests the presence of a uric acid stone. However, a non-contrast CT scan can be required to exclude a malignant tumor of the urinary tract epithelium. In the study of kidney stones, the diagnostic value of ultrasound echography is less.
Ultrasound examination of the organs of the urinary system
It allows you to determine the obstruction, as well as the size and location of larger stones.
Cystoscopy
It is shown for the detection and extraction of stones from the bladder, as well as the removal of stones from the ureter located near the ureter-bladder anastomosis.
Differential diagnosis of urolithiasis
In the presence of signs of renal colic, it is necessary to exclude diseases that occur with pain syndrome [cholelithiasis, acute appendicitis, myocardial infarction, duodenal ulcer and stomach ulcer, pancreatitis, psaas abscess, acute or exacerbation of chronic pyelonephritis, urotububerculosis, papillary necrosis, kidney tumors, infarction of the kidney, thrombosis of the renal and hepatic veins, and in females (especially in adolescence) - gynecological diseases: acute adnexitis, ectopic pregnancy, ovarian cysts , Endometriosis and others.].
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