1. Prevention of calcium-containing urinary tract stones
(1) Increase fluid intake: The recommended daily fluid intake is 2.5 to 3.0L or more, so that the daily urine volume is maintained at 2.0 to 2.5L or more. Patients with urolithiasis are advised to measure the specific gravity of urine at home by themselves so that the specific gravity of urine is below 1.010 is appropriate to achieve and maintain a reliable dilution of urine. Excessive consumption of caffeine, black tea, grape juice, apple juice and Coca Cola should be avoided. Drinking more orange juice, sour fruit vine juice and lemonade is recommended.
(2) Dietary regulation: Maintain a comprehensive balance of dietary nutrients, with emphasis on avoiding excessive intake of one of these nutrients.
1) Dietary calcium content.
It is recommended to consume more dairy products (milk, cheese, yogurt, etc.), tofu and small fish. The daily intake of calcium for adults should be 800 to 1000mg (20 to 25mmol). A low-calcium diet is recommended for patients with absorptive hypercalciuria and a calcium-restricted diet is not recommended for other patients.
2) Limit dietary oxalic acid intake in patients with calcium oxalate stones, especially in patients with hyperoxaluria, should avoid foods rich in oxalic acid such as kale, almonds, peanuts, beets, parsley, spinach, rhubarb, black tea and cocoa powder. Among them, spinach has the highest content of oxalic acid, and patients with calcium oxalate stones should pay more attention to avoid eating spinach.
3) Limit the intake of sodium: high sodium diet will increase urinary calcium excretion, the daily sodium intake should be less than 2g.
4) Limit excessive intake of protein.
It is recommended to consume a nutritionally balanced diet and it is important to maintain a balanced nutrition of 3 meals in the morning, midday and evening. Avoid excessive intake of animal protein, which should be limited to 150g per day. Among them, the daily protein intake of patients with recurrent stones should not exceed 80g.
5) Reduce body weight: maintain a body mass index (BMI) between 11 and 18 for patients with urinary stones.
6)Increase the intake of fruits and vegetables: increasing the intake of fruits and vegetables can prevent the recurrence of stones in patients with hypocitraturia.
7)Increase coarse grains and fiber diet: rice bran can reduce urinary calcium excretion and decrease the recurrence of urinary stones.
8) Reduce the intake of vitamin C. Patients with recurrent calcium oxalate stones are advised to avoid high doses of vitamin C. It is recommended that their daily intake of vitamin C should not exceed 1.0 g.
9) Restrict the intake of purines to less than 500 mg per day, including purine-rich foods such as animal offal (liver and kidney), poultry skin, herring with skin, sardines, anchovies, etc.
(3) Prophylactic treatment: Although there are many types of drugs used for the prophylactic treatment of calcium-containing stones, the only ones that have been shown to be effective are alkaline citrate, thiazide diuretics and allopurinol.
1) Thiazide diuretics: Thiazide diuretics (such as benfotiamine, trichlorothiazole, hydrochlorothiazide and indapamide) can reduce urinary calcium levels in patients with normal urinary calcium of 25 mg of dihydrochlorothiazole twice daily or 4 mg/d of trichlorothiazole.
Although alkaline citrate is most indicated for patients with stones with hypocitraturia, it is now believed that the indication may be extended to patients with all types of calcium-containing stones. The usual dose is 1-2 g of sodium potassium hydrogen citrate (Yolite) 3 times/d, 1-2 g of potassium citrate or 3 g of sodium potassium citrate 2 to 3 times/d.
5) Allopurinol: Allopurinol can reduce the production of urate, lower the concentration of serum urate and reduce the excretion of urate in the urine. In addition, allopurinol can also reduce urinary oxalate excretion. Recommended allopurinol for the prevention of uric acid stones and calcium oxalate stones with hyperuricuria patients, the usage is 100mg, 3 times a day, or 300mg, once a day.
6) magnesium agent: magnesium by combining with oxalate and reduce the supersaturation of calcium oxalate, thus inhibiting the formation of calcium-containing urinary tract stones. Supplementary magnesium in the promotion of urinary magnesium increase at the same time, can increase the content of urinary citrate, and improve the pH of urine. Thus, magnesium is effective in reducing the recurrence of calcium oxalate stones. It is indicated for patients with calcium oxalate stones with or without hypomagnesuria.
Because calcium-containing stone patients with hypomagnesuria are not many (<4%), therefore, in addition to citrate, it is not recommended that other magnesium salts alone for the prevention of recurrence of calcium-containing urinary tract stones.
7)Glucosamine: Glucosamine can inhibit the growth of calcium oxalate stones and is suitable for the treatment of recurrent calcium oxalate stones, but there is a lack of basis for the application of synthetic or semi-synthetic glucosamine for the prevention of recurrence of calcium-containing urinary tract stones.
8) Vitamin B6: Vitamin B6 is one of the coenzymes in the metabolism of oxalic acid in the body, and deficiency of the vitamin in the body can cause an increased excretion of oxalic acid. Large doses of vitamin B6 (300-5.0mg/d) have a therapeutic effect on patients with primary hyperoxaluria. Vitamin B6 is mainly used in patients with mild hyperoxaluria and primary hyperoxaluria.
9) Chinese herbs: Chinese herbs that are considered to have some preventive effect on calcium-containing stones include zedoary, fatty sea, money grass, corn husk and plantain core. However, there is a lack of reports on clinical efficacy.
2, prevention of uric acid stones The key to prevent uric acid stones lies in three aspects: increasing urine volume, improving the pH of urine and reducing the formation and excretion of uric acid.
(1) Drink a lot of water: keep the daily urine volume above 2000ml.
(2) Alkalinize urine: to maintain the pH of urine between 6.5 and 6.8, you can give sodium potassium hydrogen citrate (Youlet) 1 to 2g, 3 times/d, potassium citrate 2 to 3g or sodium potassium citrate 3 to 6g, 2 to 3 times/d, or sodium bicarbonate 1.0, 3 times/d.
(3) Reduce the formation of uric acid: for those with increased blood uric acid or uric acid, take 300mg/d of allopurinol orally. folic acid can inhibit xanthine oxidase activity more effectively than allopurinol. 5mg/d of folic acid orally is recommended.
3. Prevention of infected stones Low calcium and low phosphorus diet is recommended. Aluminum hydroxide or aluminum carbonate gel can combine with phosphorus ions in the small intestine to form insoluble aluminum phosphate, thus reducing the absorption of phosphorus in the intestine and the excretion of urinary phosphorus.
For amyl phosphate and carbonate apatite stones caused by bacterial infection with urease, the stones should be removed surgically if possible.
The use of antibiotics based on drug sensitivity testing is recommended for the treatment of infections. It is emphasized that anti-infective therapy requires an adequate course of medication. In the initial phase of antibiotic therapy, the dose of antibiotics is relatively high (therapeutic dose), and the urine is made sterile by 1 to 2 weeks of treatment, after which the drug dose can be halved (maintenance dose) and maintained for 3 months. Attention should be paid to monthly bacterial cultures, and if bacteria are found again or if the patient has symptoms of urinary tract infection, the drug should be restored to the therapeutic dose to better control the infection.
Acidified urine can improve the solubility of phosphate and can be treated with amyl chloride 1g, 2-3 times/d or methionine 500rng, 2-3 times/d.
Urease inhibitors should be used in patients with severe infections. Acetohydroxamic acid and hydroxyurea are recommended. The first dose of acetohydroxamic acid is recommended to be 250mg twice a day for 3 to 4 weeks, and if the patient can tolerate it, the dose can be increased by 250mg three times a day.
4. Prevention of cystine stones Pay attention to drink a lot of water to increase the solubility of cystine and ensure that the daily urine volume is above 3000ml, i.e. drink at least 150ml/h.
Alkalinize the urine so that the pH of the urine reaches 7.5 or more. You can take sodium potassium hydrogen citrate (Youlait) 1~2g, 3 times/d.
It is advisable to consume a low-protein diet based on vegetables and cereals, and avoid excessive consumption of methionine-rich foods (soy, wheat, fish, meat, beans and mushrooms, etc.), as a low-protein diet can reduce the excretion of cystine.
Limit sodium intake to less than 2g/d as recommended.
When urinary cystine excretion is higher than 3mmol/24h, apply thioprostenol (α-mercaptopropionylglycine) 250-2000mg/d or captopril 75-150mg/d.
5. Prevention of other rare stones (1) Prevention of drug stones 1) Prevention of calcium-containing drug stones: stones caused by calcium supplementation and VitD supplementation are associated with increased excretion of urinary calcium, and supplementation with high doses of Vit C may promote excretion of urinary oxalic acid. Therefore, the prevention of stones from calcium-containing drugs focuses on reducing urinary calcium and urinary oxalate excretion and decreasing urinary calcium salt and oxalate saturation.
2) Prevention of non-calcium-containing drug stones: The best way to prevent indinavir stones is to drink enough water, with a daily intake of 3000 ml or more, to prevent the precipitation of drug crystals. Acidification of the urine so that the urine pH is below 5.5 may facilitate the dissolution of drug crystals.
The prevention of aminopterin, acetazolamide and sulfonamide stones is to drink plenty of water to dilute the urine and to apply alkaline drugs appropriately to raise the pH of the urine, thus increasing the dissolution of drug crystals.
(2) Prevention of purine stones: Purine stones (mainly including 2,8-dihydroxyadenine stones and xanthine stones) should be prevented by adopting a low purine diet; allopurinol can inhibit xanthine oxidase, which can reduce the excretion of 2,8-dihydroxyadenine and thus play a role in preventing the occurrence of stones. Theoretically, alkalinization of urine can promote the dissolution of 2,8-dihydroxyadenine stones. However, it is extremely difficult to raise the urine pH above 9.0 clinically through drugs. Therefore, the practical application of alkalinized urine is not of great value.