Clinical evaluation of children under 2 years old with urinary system stone disease

Urinary system stone disease is a health problem with increasing incidence in children. Urinary system stone disease in the first 2 years of life differs from other age groups in terms of both etiology and prognosis, and there is also the opinion that it is a separate clinical entity by some authors. In this study, demographic and clinical data of patients aged 0-2 years who were diagnosed with urinary system stone disease between January 2015 and December 2021 were retrospectively analyzed. The study included 202 patients, 117 (57.9%) of whom were male, with a mean age of 8.1±5.6 months. The mean follow-up period was 24.5±18.3 months. Forty-two (20.8%) of the patients were premature. 47 (23.3%) had a history of neonatal intensive care. 115 (56.9%) had a family history of urinary tract stone disease. The most common presenting symptom was restlessness in 76 (37.6%) patients, 30 (14.9%) had dark urine, and 66 (32.7%) were asymptomatic. 134 (66.3%) were on formula. 117 (57.9%) patients used bone broth with marrow in their soups and meals after the transition to supplementary food. In the results of urinary stone metabolic tests of the patients at admission were normal in 93 (46%) patients. 59 (29.2%) patients had hypocitraturia, 46 (22.7%) had hypercalciuria, 8 (3.9%) had hypomagnesuria, 5 (2.4%) had hyperoxaluria and 1 (0.5%) had cystinuria. Stone analysis was performed in 9 patients (4.5%): calcium oxalate stones were found in 4 of them. When we analyzed the factors involved in the etiology of stones, we found metabolic disorder in 112 (55.4%) patients, urinary system anomaly in 9 (4.5%) patients, history of recurrent UTI in 33 (16.3%) patients, and drug use in 42 (20%) patients. In the remaining 45 patients, no cause could be identified; 30 (50%) of these patients consumed formula and 30 (50%) consumed bone broth. The number of patients defined as 'microlithiasis' with a stone size less than 3 mm on the first USG was 53 (26.2%). The stone localizations at presentation were as follows: 109 (54%) patients had stones in the lower pole, 67 (33.2%) had stones in the middle pole, 15 (7.4%) had stones in the upper pole and 11 (5.4%) had stones in the pelvic-oral junction. There were no patients with stones in the ureter and bladder. On initial USG, stones were bilateral in 81 patients (40.1%) and unilateral in 121 patients (59.9%). The most preferred medical treatment option was potassium citrate given to 135 patients. 18 patients required surgical treatment. The preferred method was ESWL in 14 patients, PCNL in 6, and open surgical treatment was required in 3. During follow-up, stones disappeared in 160 (79.2%) patients, and the size/number of stones decreased in 28 (13.9%) patients. 6 (3%) patients continued to have stones. In 8 patients (4%), stone size/number increased. History of urinary tract infection (45% vs 28%) and family history of stone disease (61% vs 43%) were higher in the group with ≥3 mm stone size compared to the group with microlithiasis. Patients with ≥3 mm stones had a higher rate of spontaneous stone passing compared to patients with microlithiasis (13% vs 2%). Patients with ≥5 mm stones had a higher rate of NICU history (35% and 20%) and urinary tract infection history (74% and 32%) than patients with <5 mm stones. The mean age at the time of diagnosis was higher in the group requiring surgical treatment than in the group not requiring surgical treatment (10 months and 6 months). History of urinary tract infection (78% and 38%) and history of spontaneous stone passing (56% and 6%) were higher in patients who needed surgical treatment compared to patients who did not need surgical treatment. We found that the most common etiologic factors in children younger than 2 years with urinary tract stone disease were metabolic disorders, mainly hypocitraturia and hypercalciuria. In almost ¼ of the cases, no etiologic cause could be identified; in these cases, we think that nutritional factors such as formula and bone broth use may be related with stone formation. The stones disappeared in most of the cases during follow-up. Key Words: Urinary System Stone Disease in Children, Pediatric, Infant, Urolithiasis