Kidney stones are solid formations that form in the kidneys from substances dissolved in urine. Small stones often cause no symptoms and pass out with urine unnoticed, while large ones cause severe pain and require urgent assessment by a doctor. Below — definition, mechanism, stone types, colic symptoms, risk factors, diagnosis.
1. Definition: urolithiasis and nephrolithiasis
Urolithiasis is a disease that arises from the formation of stones, or calculi, in the organs of the urinary system. The most common form is nephrolithiasis (kidney stone disease): calculi are deposited in the kidneys, from where they pass into the ureters and become lodged there or move on to the bladder and urethra.
Urinary stones are aggregates of various salts, in particular uric acid and oxalic acid salts; their size ranges from "sand" to large formations, and stones may be multiple and bilateral. Metabolic disorders — urinary diatheses: uric acid, urate, purine, oxalic acid, and calcium phosphate — play a special role in their occurrence. The disease occurs more often in men than in women.
2. Mechanism of stone formation
Stones arise from the accumulation of chemical substances in urine: the concentration rises to a level at which salts precipitate and form solid conglomerates. Primary stones are caused by a metabolic disorder, while secondary stones result from the deposition of salts around fragments of mucus, pus or blood clots in another disease.
Underlying this are changes in colloidal balance in the tissues and renal parenchyma. A separate mechanism is hypocitraturia, that is, a low level of citrate in urine: citrate forms soluble complexes with calcium and inhibits the crystallization of its salts. Changes in the urinary tract, their infection, dyskinesias and urinary stasis also contribute.
3. Renal colic: symptoms
The movement of a stone from the kidney to the urethra can cause renal colic. The pain has characteristic features:
- begins in the side of the abdomen or in the lower back;
- spreads to the upper thigh area, into the groin, scrotum or around the vaginal opening;
- has a wave-like course: periods of sharp intensity alternate with periods of reduced pain;
- is accompanied by nausea, vomiting, frequent urges to urinate, cloudy urine;
- is combined with elevated temperature, a feeling of heat, cold or shivering.
Other clinical signs of nephrolithiasis are hematuria, pyuria and spontaneous passage of stones with urine. Colic is often accompanied by fever and leukocytosis, not always caused by a purulent infection.
4. Risk factors
The likelihood of stones increases with insufficient water intake, with conditions that raise the concentration of certain substances, in particular metabolic syndrome, and with the use of certain medications, in particular aspirin, antacids, diuretics, antibiotics. Dietary factors — excess salt, a high-protein diet low in fiber, a large amount of mineralized water; general factors — physical inactivity or bed rest, frequent kidney and urinary tract infections, diseases of the gastrointestinal tract and liver, hyperparathyroidism, hypervitaminosis D, hypovitaminosis A.
Separately — heredity and previous episodes: stones recur more often in those who have already had them and in those whose close relatives have been affected.
5. Diagnosis
The doctor usually makes the diagnosis based on the clinical picture, taking into account concomitant diseases, medications taken, dietary patterns and cases of stones in the patient and family. If needed, urine and blood tests are ordered.
For severe pain, the patient is referred to a hospital for imaging studies: computed tomography — for adults, ultrasound — for pregnant women and children under 16 years of age. After spontaneous passage of a calculus, it is collected for examination.
6. When to see a doctor immediately
Prolonged lower back pain that cannot be relieved, together with fever and leukocytosis, may indicate apostematous nephritis — an indication for hospitalization.
Call 103 or 112 if severe pain is combined with high temperature, heat, cold or shivering.
This material is for reference purposes and does not replace consultation with a doctor.
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This content is for reference and does not replace a doctor's consultation. Medical disclaimer