Metabolic evaluation kidney ureteral stones
If you have a high risk of forming more stones (See Causes of Kidney and Ureteral Stones), your doctor will do a metabolic evaluation. This is a series of blood and urine tests to determine which additional treatment you may need.
Depending on the test results, you may get medication. Generally, the medication will cause little or no side effects. In addition, it may be helpful to consider lifestyle changes (See Prevention of Stone Recurrence). Your doctor will discuss your individual situation and treatment options with you.
As part of the metabolic evaluation your doctor will ask you to collect your urine in 2 separate periods of 24 hours. This is done some 3 weeks after your stone has passed or has been removed. The amount of urine is measured and so are the levels of different substances in the urine.
Urine substances include calcium, magnesium, oxalate, and uric acid.
Two to three months after you start medication, the doctor will take another urine sample to check if the dosage should be adjusted. For a large part, treatment depends on the kind of stone you had.
If you had a calcium-oxalate stone you may have a high risk of forming more stones but this is not always the case. After you have had a calcium-oxalate stone you should:
- Eat fewer oxalate-rich foods (for instance rhubarb, beet, okra, spinach, Swiss chard, sweet potatoes, tea, chocolate, and soy products)
- Reduce consumption of purine rich foods
- Don’t take more than the daily recommended amount of vitamin C
- In all cases, check with your doctor for personal advice
If the metabolic evaluation shows that you have a high risk of forming more stones you will get medication to reduce the risk of recurrence.
If you had a calcium-phosphate stone you may have a high risk of forming more stones but this is not always the case. The type of treatment you get depends on the cause of the stone.
Uric acid stones
If you had a uric acid stone you have a high risk of forming more stones. Eating less purine rich foods can lower the chance of you forming another stone. High levels of purine are found in certain types of fish (like herring, mussels, smelt, sardines, anchovies), red meat and organs (heart, liver, kidney).
You will get medication to keep the pH-value of your urine between 6.2 and 6.8. You can check the pH-value of the urine easily at home with dipstick tests.
Ammonium urate stones
If you had an ammonium urate stone you have a high risk of recurrence and you may also have a urinary tract infection. You will get antibiotics to treat the infection and you will need to take medication to keep your pH-levels between 5.8 and 6.2.
Struvite and infection stones
If you had a struvite or an infection stone, you have a high risk of forming more stones. You may need to take antibiotics to make sure the infection does not come back.
If you had a cystine stone you have a high risk of forming more stones. You need to drink enough fluids to produce at least 3 litres of urine every day. Eating less salt will lower the level of cystine in your urine. You will get medication to increase the pH-value of your urine to 7.5 or higher. On top of that you may get medication to reduce the level of cystine.
There are other types of stones that are very uncommon. Your doctor will discuss your individual situation and treatment options with you.