No abstract

The daily intake of 103 recurrent idiopathic calcium stone formers and 146 controls was assessed by means of a computer-assisted 24-h dietary record. Timed 24-h urine samples were collected over the same period to assess the relationship between dietary intake of nutrients and urinary risk factors for calcium stones. After standardisation for sex, age and social status a total of 128 subjects underwent final statistical analysis; 64 renal stone formers and 64 controls. Significant increases in the consumption of animal and vegetable protein and purine were identified as the nutritional factors that distinguished renal stone formers from controls. As expected, the daily urinary excretion of calcium and oxalate was higher and the daily urinary excretion of citrate was lower in stone formers than in controls. No difference with respect to daily urinary uric acid excretion was recorded. Daily urinary excretion of calcium was correlated to dietary protein intake while daily urinary oxalate was correlated to dietary vitamin C intake. It was concluded that renal stone formers could be predisposed to stones because of their dietary patterns. A link between the protein content of the diet and urinary calcium was confirmed, but dietary animal protein had a minimal effect on oxalate excretion.

No abstract

The question of a familial predisposition towards stone formation in primary nephrolithiasis has not been explored completely. In a sample of 214 calcium stone patients, and 428 age and sex-matched controls we observed a higher frequency of stones among the first degree relatives of stone patients compared to the relatives of controls. A family history of renal stones was more common among the female (45 per cent) than among the male patients (31 per cent). There was no relationship between family history of renal stones, and abnormal calcium and oxalate excretion rates. A significant association between a family history and a higher urinary pH was observed among the female calcium stone patients. A genetic defect in urinary acidification with variable expressivity might be associated with a high frequency of stone formation. Moreover, uric acid excretion was higher in male stone patients with a family history of stones. Finally, the parents and siblings of the renal stone patients were affected more by calculi than were the corresponding relatives of their spouses.

Extracorporeal shock wave lithotripsy (SWL) treatment for renal stones has been proved safe and effective in the last 10 years. However, we needed to observe the patients for a longer period than a 3-month control to settle the fate of residual fragments. Two hundred fifty-four patients treated with SWL for different types of stones in solitary kidneys have been examined between 24 and 56 months (mean 42 months) after the treatment. When discharged, 31.5% (80) of the patients were stone free, whereas '65.3% (166) had stone dust or passable fragments. After 3 months, 162 (64.8%) of 250 were stone free, and 84 (33.6%) had dust or passable fragments. Twenty-nine (74.4%) of the infected patients had residual fragments, which regrew after discharge in 19 patients (65%). There were 136 stone-free patients (55%) after a followup longer than 24 months (mean 42 months). Recurrence of stones was observed in 34 patients (13.8%), and regrowth of fragments was observed in 55 patients (22.3%). Of 85 évaluable patients with dust and fragments at 3-month followup, 55 (64.7%) had fragment regrowth, 22 (25.8%) were unchanged, and 8 patients (9.4%) were stone free at long-term followup. The fragments still present after 3 months are unlikely to be cleared in a longer followup. The observed incidence of new-onset hypertension in this series was 6.1% (15 patients). In conclusion, SWL should be considered the safe first-choice treatment for all renal stones, in some cases together with auxilliary tools such percutaneous methods.

Our schedules for the suspension or substitution of antithrombotic therapy, although tested in a small number of patients, allowed us to perform SWL without hemorrhagic or thromboembolic complications.

A primary abnormality of bone metabolism could be a reasonable explanation of reduced bone density observed in renal stone formers on a low calcium diet since serum parathyroid hormone levels are in the normal range. From a therapeutic point of view these data confirm that restriction of dairy products in renal stone formers should be avoided.

Extracorporeal shockwave lithotripsy without ECG triggering has been found to be fast and efficient and not correlated with the occurrence of dysrhythmic episodes of any particular clinical significance. No significant correlation was found between the occurrence of dysrhythmia, the side treated, the number and strength of the shockwaves, or the administration of analgesics. It was found, however, that dysrhythmia occurred almost exclusively in treatments involving the kidneys. The ECG-triggering option was indispensable in some patients in order to complete the lithotripsy without complications.