Kidney stones and dietary guidelines

Renal Stones - Kidney Stones

Renal stones are a common and serious condition. They often cause pain and inflammation in the urinary tract, and can also lead to eventual kidney failure. Renal stones can form anywhere in the urinary tract. Depending on the site of formation, we distinguish between kidney stones and bladder stones.

Why do stones form?

The process of stone formation begins with the crystallization of substances in supersaturated urine and disrupted urine composition. Several factors influence stone formation: metabolic disorders, age, gender (they occur more frequently in men aged 20 to 50), urinary drainage disorders in benign prostatic hyperplasia. Stones are more common in the summer months and warmer climates due to dehydration. Diet rich in proteins and poor in fibers also contributes to stone formation.

Types of stones

Calcium oxalate stones (60%) and calcium phosphate stones (20%)
The cause can be elevated calcium concentration in the urine due to infections, osteoporosis, vitamin D hypervitaminosis, bone tumors, hyperparathyroidism, and Addison's disease.
Uric acid stones (10%)
They consist of uric acid and are associated with metabolic disorders in gout (gouty arthritis) and insufficient diuresis.
Struvite stones (7%)
By composition, they are primarily magnesium-ammonium-phosphate stones and are associated with bacterial urinary tract infections.
Cystine stones (3%)
They are associated with congenital disorders in cystine absorption.

Symptoms

Characteristic symptoms include sudden onset pain radiating to the genitals, nausea, vomiting, bloated abdomen, chills with elevated body temperature, frequent urination, bloody urine, and urinary tract infection. The diagnosis of urinary stones is based on clinical examination, blood and urine tests, and additional ultrasound and X-ray examinations of the urinary tract.

Treatment of kidney stones

Stones smaller than 3 mm often pass spontaneously, and intervention is usually not required.
Stones larger than 5 mm often do not pass spontaneously, and additional intervention is necessary. This is especially true for stones around 10 mm or larger.

If the stones do not pass spontaneously, various procedures or interventions can be used for removal. The assessment of the need for removal of urinary stones and the selection of the removal method take into account various factors and are in the hands of appropriate specialists.

Possible interventions for the removal of urinary stones include extracorporeal shock wave lithotripsy (ESWL), transurethral nephrolithotripsy, and surgical procedures.

General recommendations for urinary stone occurrence

It is recommended to drink large amounts of fluid (3 liters per day) and to exercise.
Small stones with a diameter of up to 4 mm often pass spontaneously with these measures.
The present pain is usually of a spasmodic nature. It can be alleviated with antispasmodics (Buscopan, Spasmex) and analgesics.

Special dietary recommendations for kidney stones

For calcium oxalate stones, it is necessary to avoid foods high in oxalates (chocolate, celery, grapes, beans, strawberries, spinach, asparagus, beets, black tea, walnuts, hazelnuts).
For uric acid stones, foods that increase the concentration of uric acid in the blood and urine should be limited (fish, offal, brewer's yeast, meat, poultry).
It is advisable to drink Donat-Mg mineral water, especially for heart patients.
Changing the acidity of urine can affect the occurrence of certain types of stones.
Calcium intake from milk does not affect the occurrence of kidney stones, so restricting milk intake is not necessary.
Beverages such as coffee, real tea, cola, lead to dehydration and thereby increase the likelihood of stone formation and are therefore undesirable.
It is advised to reduce salt intake to less than 3 g per day.
Antacids (medications for neutralizing stomach acid) are undesirable or should be used only in case of urgent need.

Recurrence of urinary stones

Urinary stones often recur. The likelihood of recurrence increases over the years:
after 2-3 years, a stone recurs in 40% of patients,
after 7-10 years, a stone recurs in 75%, and
after 15-20 years, in 100% of patients.

Due to the recurrence of urinary stones, it is necessary to undergo urinary tract ultrasound at least once a year.