I. What is a urinary stone
Certain substances in the human body cannot continue to be broken down and absorbed by the body, resulting in the precipitation of crystalline particles from body fluids, which we call stones. When a stone occurs in the kidney, we call it a kidney stone; when it occurs in the bladder, it is called a bladder stone; primary stones in the ureter are rare and are mostly caused by kidney stones draining downward.
The human urinary system is composed of kidneys, ureters, bladder and urethra. The kidneys and ureters are symmetrically configured according to the body’s central axis. Urine is produced from the kidneys and excreted through the ureter, bladder, and urethra. The stones present in this organ we call urinary stones, also known as urolithiasis. When stones are produced in the human body, some patients suffer from unbearable pain, which causes a lot of inconvenience in life and work. Some patients are oblivious to the fact that even patients without obvious symptoms, when diagnosed with urinary stones, should be treated promptly to avoid delays and damage to parenchymal organs.
Second, the danger of urinary stones
The growth of urinary stones is a long process. Once stones are formed, secondary damage to the kidney will occur, mainly in the form of urinary tract obstruction, secondary infection and epithelial lesions. Stones are unnoticeable when they are very small and have been expelled during normal exercise. However, most patients have symptoms such as dull pain in the kidney area and hematuria as the size of the stone increases; some stones enter the ureter and cause hydronephrosis or renal colic, resulting in unbearable pain.
In clinical cases, patients with hydronephrosis mainly suffer from ureteral obstruction caused by stones lodged in the ureter. When hydronephrosis is mild, the urinary function of the kidney is still good; in moderate hydronephrosis, the urinary function of the kidney is severely impaired; in severe hydronephrosis, which is not relieved in time, the renal parenchyma is highly atrophied and there is no obvious boundary between the cortex and the medulla, the urinary function of the kidney is basically lost.
Urinary tract obstruction can also cause inflammatory reactions caused by non-bacterial infections. Epithelial lesions are mainly the result of epithelial tissue irritation by pelvic and calyx stones in the presence of infection, which can induce carcinogenesis in severe cases. In conclusion, urinary stones are very harmful to human body and should be actively prevented.
Composition of common urinary stones
Clinical observation shows that calcium-containing stones are the most common type of urinary stones. They account for about 70%-80% of all urinary stones. At present, only a few cases of calcium-containing stones have a clear pathogenesis, while the etiology of most calcium-containing stones is not well understood.
The chemical composition of stones can be divided into four categories: calcium-containing stones, infected stones, uric acid stones, and cystine stones. Calcium-containing stones can be divided into: simple calcium oxalate, calcium oxalate and calcium phosphate, and a small amount of uric acid in addition to calcium oxalate; infected stones are mainly composed of ammonium magnesium phosphate and hydroxyapatite; uric acid stones can be divided into: uric acid, uric acid amine or a small amount of calcium oxalate in addition to the above components; cystine stones can be divided into: pure cystine or a small amount of calcium oxalate.
Fourth, what is meant by positive stones, negative stones, “stone street”
Positive or negative urinary stones refer to whether dense shadow can be shown under X-ray. Since most stones contain calcium salts, a positive stone can be seen as a darker image under X-ray fluoroscopy. Since abdominal plain films are negative, a positive stone will appear as a white shadow on an x-ray abdominal plain film. In layman’s terms, a stone with a visible “shadow” on X-ray is called a positive stone.
In contrast to a positive stone, a stone that does not show a dense image on X-ray is called a negative stone. A white image is also not visible on an x-ray abdominal plain. Some stones do not contain calcium or contain very little calcium, such as uric acid stones and cystine stones, which do not show a white image on X-ray abdominal radiographs.
In the human ureter, there are many small stones distributed continuously like a queue, doctors used to call this form of stones “stone street”, some people call it “stone string”, “stone road” and so on. The formation of “stone street” may be due to the formation of several small stones in the kidney entering the ureter one after another, but it is mainly due to the large number of stone particles that enter the ureter after extracorporeal shock wave lithotripsy treatment and cannot be discharged quickly enough to form a “stone street”. Sometimes the “stone street” can cause high fever, severe fluid retention or secondary infection in patients. Therefore, when performing extracorporeal shock wave lithotripsy for larger stones, special attention should be paid to avoid the formation of “stone streets”.
V. What diseases are known to cause urolithiasis
The main causes of urolithiasis are disorders of calcium and phosphorus metabolism and other factors. Patients are more concerned about metabolic disorders. Although there is no final conclusion on the relationship between urinary stone formation and metabolic disorders, but after years of research by medical researchers, calcium and phosphorus metabolic disorders can lead to: hypercalciuria, hyperoxaluria, hyperuricuria, cystinuria, xanthinuria, hypocitraturia, etc. Specific etiologies can be divided into.
1, hypercalciuria: hypercalcemia, hyperparathyroidism, primary distal tubular acidosis, medullary spongy kidney, sarcoidosis, vitamin D toxicity, lacto-alkaline syndrome, prolonged bed rest, Cushing’s syndrome, hyperthyroidism, idiopathic hypercalciuria (absorptive hypercalciuria).
2, hyperoxaluria: primary hyperoxaluria, vitamin B6 deficiency, etc.
3, hyperuricuria: gout, hyperuricemia, hyperuricuria, leukemia, true erythrocytosis, congenital enzyme defects (such as glycogen storage disease), choreoathetosis, etc.
4.Cystinuria: It is a genetic defect.
5.Xanthinuria: an autosomal recessive inherited disorder of purine metabolism.
6, hypocitraturia: alkalosis, hyperparathyroidism, vitamin D toxicity, acidosis, hypokalemia, urinary tract infection.
In addition, patients taking a lot of vitamin D, vitamin C, corticosteroids, aminoglutethimide, tetracycline, aspirin, etc. due to a certain disease can trigger kidney stones. Patients with ulcers taking magnesium silicate can form silicate stones. Patients with glaucoma taking acetazolamide can form calcium phosphate supersaturation and cause stones. Taking sulfonamides leads to stone formation in some patients because the acetyl derivatives are excreted by the kidneys and have low solubility in acidic urine.