Therapeutic target
To avoid stone recurrence (recurrence of urinary stones).
Therapy recommendations
Note: Calcium phosphate stones can exist in two forms: carbonate apatite (pH > 6.8) and carbonate apatite (pH range of 6.5-6.8).
Reduction of risk factors
- Behavioral risk factors
- Dehydration (dehydration of the body due to fluid loss or lack of fluid intake).
- High protein (protein-rich) diet
- Disease-related risk factors
- Hyperparathyroidism (HPT).
- Renal tubular acidosis (RTA; complete or incomplete RTA type I or combined RTA type I and II; see under laboratory diagnostics) → carbonate apatite
- Urinary tract infection → carbonate apatite precipitates at high urine pH > 6.8
Nutritional therapy
- Fluid intake 2.5-3 l / day
- Limit protein intake (intake: 0.8-1.0 g/kg bw/day).
- Limit table salt intake (circa 3 g table salt per day, equivalent to 1.2 g sodium)
- Alkaline-rich, alkalizing diet with potatoes, vegetables, salads, legumes and fruit; dietary supplements with alkalizing (basic) mineral compounds potassium citrate, magnesium citrate and calcium citrate, as well as vitamin D and zinc (zinc contributes to the normal acid-base balance).
Active substances of metaphylaxis
- Acidification with L-methionine (dose 200-500 mg 3 times a day, target urine pH: 5.8-6.2 ; this improves the solubility of calcium phosphate in urine when stone formation occurs at urine pH values constant > 6.2.
- Administration of thiazides (lower renal calcium excretion highly efficiently).
- Restoration of acid-base balance, i.e., alkalinization (primary goal in renal tubular acidosis; therapy monitoring by blood gas analysis, ABG).
Operative therapy
- Parathyroidectomy (removal of parathyroid glands) – in the presence of primary hyperparathyroidism/parathyroid hyperfunction (elevated serum calcium; laboratory diagnosis: determination of intact parathyroid hormone).
