The increase in the excretion of soluble substances in urine, calcification, and urinary tract obstruction creates conditions for the formation of urinary stones.
This article is professionally advised by Dr. Tra Anh Duy, Men’s Health Center.
Urinary stones are formed due to the natural crystallization of inorganic crystals in urine. Stones primarily appear in the kidneys and may then move down to the ureters or bladder, causing obstruction or being expelled through the urethra; hence they are also referred to as kidney stones.
Classification
- Based on chemical composition, urinary stones include calcium stones, magnesium ammonium phosphate stones, cystine stones, and urate stones.
- Urinary stones can also be classified based on clinical examination, with doctors prescribing appropriate methods according to the location of the stones, including stones in the kidneys, ureters, bladder, and urethra.
Causes
Stones primarily appear in the kidneys and may then move down to the ureters or bladder.
The process of stone formation is quite complex, and there is currently no clear unified theory regarding the underlying causes. Common causes include:
Increased excretion of soluble substances in urine
Increased calcium excretion
- When the calcium level in urine exceeds 100-175 mg/day, the risk of urinary stones increases.
- Excessive intake of calcium-rich foods such as milk, butter, and cheese.
- High vitamin D intake enhances intestinal calcium absorption.
- Prolonged immobility can lead to calcium deposits.
- Conditions affecting calcium metabolism such as hyperparathyroidism, metastatic bone cancer, and bone marrow cancer.
Increased oxalate excretion
- May be due to excessive consumption of oxalate-containing foods such as spinach, okra, beets, kale, celery, and soy milk.
- However, the primary cause is still a genetic defect in the process of glyoxylic acid metabolism.
Increased cystine excretion
- Typically rare and due to genetic disorders.
Increased uric acid excretion
- Caused by excessive protein intake from foods such as meat, seafood, and poultry.
Changes in the physical properties of urine
- When patients engage in strenuous work, drink little water, or are in hot weather leading to dehydration, urine flow decreases, increasing the concentration of salts and organic substances in urine, thus raising the risk of stone formation.
- Changes in urine pH levels due to food, drink, or medication can make certain inorganic salts difficult to dissolve in alkaline environments, leading to precipitation and stone formation.
Drinking less water or hot weather can lead to dehydration, decreasing urine flow, which increases the concentration of salts and organic substances in urine, raising the risk of stone formation. (Image: Pexels).
Calcification
- Calcifications are commonly found in the renal papillae, and under suitable conditions, they can serve as a nucleus for insoluble substances in urine to adhere to, leading to the formation of kidney stones.
- Moreover, bacterial debris, renal epithelial cell debris, and blood clots can also serve as nuclei for stone formation.
Urinary tract obstruction
- When there is a congenital or acquired obstruction of urine flow, it leads to urinary retention, creating conditions for the deposition of substances that form stones.
- When stones do not move and do not cause blockage, they generally do not lead to symptoms, although patients may experience accompanying urinary infections.
- When stones cause blockage, symptoms may include severe abdominal or flank pain, known as renal colic, hematuria, cloudy or foul-smelling urine, reduced or absent urine output, painful urination, and systemic symptoms such as high fever, chills, and nausea.
Symptoms
- Abdominal distension, tenderness in the flank area where stones are located, positive kidney percussion test, and positive kidney palpation test if there is significant hydronephrosis. In cases of severe kidney infection with pus retention, there may be abdominal wall rigidity.
- In some cases, patients may have a “silent stone” condition. Stones may have formed long ago and caused hydronephrosis without symptoms, leading to a subjective mindset in patients. By the time of detection, severe complications may have caused infections and significant irreversible kidney damage, potentially requiring nephrectomy.
Treatment
Currently, the treatment of urinary stones involves a combination of medical and surgical approaches.
- Medical treatment is applied in cases of small stones (up to 2 mm), combined with smooth muscle relaxants, anti-inflammatory agents, and diuretics to expel stones from the body.
- Surgical treatment includes various methods such as extracorporeal shock wave lithotripsy (ESWL), laser-assisted endoscopic lithotripsy, percutaneous nephrolithotomy (PCNL), and laparoscopic or open surgery depending on the specific location of the stones. Surgeons will base their choice of the least invasive and safest method on clinical results, stone location, and size.
The treatment of urinary stones combines medical and surgical methods.
Prevention
- Prevent and thoroughly treat any urinary tract infections.
- Avoid holding urine while engaging in daily activities.
- Drink enough water daily (>2 liters per day).
- Engage in healthy and moderate physical activities.
- Avoid excessive salt intake and limit animal protein consumption.
- This is a common condition that can recur in patients with a history of stones. Therefore, patients with a history of stones should have regular check-ups and monitoring to detect stones early.
Diagnosing disease through urine
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