Nutritional aspects in primary hypercalciuria

A 48-year-old businessman presented himself at our Stone Centre 6 years ago, subsequent to a recent recurring episode of right kidney colic followed by the expulsion of a calcium oxalate stone with traces of calcium phosphate. The medical history of the patient revealed a pneumonia in his youth, cured without repercussions, a duodenal ulcer treated with ranitidine and antacids, and a history of bilateral kidney stones, with at least 5 episodes in 13 years, one of which was treated with ESWL for left ureteral stone. In that occasion a pyelography was performed and was found to be normal except for hydronephrosis due to the stone which was later broken up. He had not been referred to a specialized Centre for stone disease and the only advice given had been to eliminate milk, yoghurt and cheese from his diet and to drink plenty. The patient had only partially followed these instructions due to problems connected with his intense and stressful lifestyle. On occasions when his arterial blood pressure had been measured it had, he reported, been “a little” high, but no provisions were then taken. He had approached our Centre following the advice of one of our patients whom he knew. The family medical history was negative for kidney stones; the father, who had died as a result of a myocardial heart attack, had hypertension and was diabetic in his later years; the mother was in good health considering her age. The objective examination did not show any pathology except a high arterial blood pressure (170/110 mmHg) and he was slightly overweight (87 kg) with BMI of 26.8. The patient was subjected to our screening protocol for the recurring kidney stones which involved: 1) a 3-day dietary diary together with an investigation into the frequency of consumption of food substances over a period of 6 months; 2) renal echography and pyelography (if not already carried out); 3) a blood sample to study the levels of glucose, urea, creatinine, uric acid, sodium, potassium, chloride, bicarbonate, calcium, phosphorus, parathormone, cholesterol, triglycerides; and 4) a collection of the urine over 24 hours in order to determine the urinary stone risk profile on a free diet and with the advice not to change dietary habits or lifestyle. The investigation of the diet showed a high consumption of meat, dressed-pork products, sugar (in the numerous coffees), a poor intake of fruit and vegetables and a moderate excess of alcohol. The echography was negative and the blood sample showed high level of uric acid (7.7 mg/dl), cholesterol (252 mg/dl) and triglycerides (268 mg/dl). The urinary stone risk profile, which is shown in detail in Table I (left side), highlighted, above all, hypercalciuria (520 mg/day) and a high saturation level for calcium oxalate (15.36) and for calcium phosphate (3.40), together with a modest hypocitraturia (340 mg/day), hyperoxaluria (37 mg/day) and hyperuricosuria (720 mg/day).