Metabolic and Clinical Characteristics of Children with Urolithiasis from Southern India.

OBJECTIVE: To study the etiological profile and patterns of clinical presentations of urolithiasis (UL) in children. METHODS: This observational study included patients <18 y with UL, who were referred to the pediatric nephrology clinic. Clinical features, family history, consanguinity and estimated glomerular filtration rate (eGFR) at presentation and follow-up were recorded. The children were evaluated using relevant blood and urine investigations. RESULTS: A total of 72 children with UL were evaluated for the study. The etiology of UL (n = 72) included hyperoxaluria (n = 25; 34.7%), idiopathic hypercalciuria (n = 21; 29.2%), idiopathic hyperuricosuria (n = 3; 4.2%), cystinuria (n = 3; 4.2%), urate transporter defect (n = 2; 2.8%) and mixed stones (predominant component calcium oxalate) (n = 9; 12.5%). No etiology was detected in 4 cases (5.5%). Common presenting complaints included flank pain (n = 41; 56.7%), hematuria (n = 29; 40.3%), urinary tract infection (UTI) (n = 29; 40.3%) and vomiting (n = 11; 15.3%). The median age of presentation was 60 (36, 96) mo. Family history and consanguinity were present in 30 cases (41.7%) and 28 cases (38.9%) respectively. Stone analysis was done in 20 cases, of which 9 cases were mixed stones (predominant calcium oxalate) and 6 were calcium oxalate stones. CONCLUSIONS: Among children with urolithiasis, hyperoxaluria, idiopathic hypercalciuria, idiopathic hyperuricosuria, and cystinuria were the predominant identifiable entities, together accounting for 72% of cases; and renal colic, hematuria and UTI were the commonest clinical complaints.

Etiological Profile of Nephrocalcinosis in Children from Southern India.

OBJECTIVE: To study the etiological profile and patterns of clinical presentation of nephrocalcinosis. METHODS: In this observational study, patients 18 years or younger, referred to the pediatric nephrology clinic with nephrocalcinosis were evaluated for etiology. Symptoms/signs at presentation, estimated glomerular filtration rate (eGFR) at presentation and follow-up, and growth parameters were recorded. RESULTS: The etiology of nephrocalcinosis (n=54) included distal renal tubular acidosis (n=18; 33.3%), primary hyperoxaluria (n=9; 16.7%), Bartter syndrome (n=7; 13%), Dent disease (n=4; 7.4%), cystinosis, familial hypomagnesemia with hypercalciuria and idiopathic hypercalcemia of infancy (2 each). Idiopathic nephrocalcinosis was seen in 5 (9.3%) children. Clinical features included failure to thrive (53.7%), polyuria (44.4%), bony deformities (31.5%) and hypokalemic paralysis (11.1%). At a median (IQR) follow-up of 24 (8, 56) months, the mean (SD) eGFR had improved from 59 (25.5) to 77 (31.48) mL/min/1.73m2 (P<0.01). Consanguinity was present in 50% (27/54). Genetic analysis in 5 primary hyperoxaluria cases confirmed AGXT mutations in 4; and GRHPR mutation in 1 child. CONCLUSIONS: Distal RTA, primary hyperoxaluria and Bartter syndrome were the common etiologies of nephrocalcinosis in our patient population.

Systemic lupus erythematosus complicated by a Gitelman-like syndrome in an 8-year-old girl.

An 8-year-old girl with recently diagnosed Systemic Lupus Erythematosus (SLE) (class 4 lupus nephritis with autoimmune hemolytic anemia) presented to the pediatric nephrology clinic with polyuria, tiredness and cramps; laboratory investigations revealed refractory hypokalemia, hypomagnesemia, metabolic alkalosis, hypocalciuria and hyperchloriuria. There was no history of diuretic administration. These features were consistent with the Gitelman syndrome. She required large doses of potassium and magnesium supplementation along with spironolactone, for normalization of the serum potassium and magnesium levels. Immunosuppressive therapy was continued with cyclophosphamide pulses administered on a monthly basis. The doses of potassium and magnesium supplements were tapered off over the next 6 months. The clinical exome sequencing was negative for any mutations in the SLC12A3 gene. An 'acquired' form of Gitelman syndrome has been reported earlier in association with Sjogren syndrome and systemic sclerosis. Though tubular disorders such as renal tubular acidosis have been reported in association with SLE, a Gitelman-like syndrome has not been reported earlier. This case adds Gitelman-like tubulopathy to the clinical spectrum of tubular disorders complicating SLE.