Paediatric urolithiasis is rare (14.5 per 100,000) and usually presented with vague symptoms like abdominal pain which are easily attributed to other more common conditions. Correct diagnosis is often delayed and complicated with end stage renal failure.
An 8-year-old girl presented with dysuria and lower abdominal pain for 10 months. She has been treated for recurrent urinary tract infection in polyclinic. Subsequently she got more lethargic, paler and puffier. Further history noted patient was passing stones in urine intermittently for 4 months with largest stone was 1cm in size. She came from consanguineous parents and two out of five of her siblings passed away at young age due to renal disorder. Full blood count shows microcytic hypochromic anaemia (haemoglobin 5.3g/dL), renal profile shows urea 42.6mmol/L, potassium 5.6mmol/L, creatinine 1,510μmol/L. Electrolytes showed hypocalcemia 1.14mmol/L and hyperphophataemia 2.6mmol/L. Serum uric acid 523μmol/L. ALP 336U/L. Blood gases shows severe metabolic acidosis with bicarbonate 9.7mmol/L. Random urine calcium/creatinine ratio is 0.13 (normal <0.09 in 7-8 year-old girl). Abdominal X-ray and ultrasound show right staghorn calculi with left renal calculi. Patient was referred to Sarawak General Hospital for haemodialysis, extracorporeal shock wave lithotripsy and further workup for inherited disorders.
DISCUSSION & CONCLUSION
Hypocalcemia with hypercalciuria is suggestive of familial idiopathic hypercalciuria (4 per hundred) and hypoparathyroidism (7.2 per million). Extensive familial studies are needed. Patient with multiple visits with similar presentation warrants further investigations. High index of suspicion of inherited disease is required. An early onset of disease, positive family history and consanguineous parents are the red flags for prompt investigation. “Horses” are more common, but we should not forget the “zebras”.