Toddlers & kidney stones

In the past few years, a dramatic increase in paediatric urolithiasis has been observed. This observation has been seen in adolescents without any known metabolic disturbances, but it could be due to their sodium and carbohydrate-filled diet.

The stone diseases can also be caused because of genetic, metabolic, and dietary reasons. There are several reasons that contribute to paediatric stone disease, and the medical treatment is done under the endourologic management. Proper diet and medication can completely treat the paediatric stone patient.

There are a lot of paediatric patients that have metabolic abnormalities as well. In the initial phases of the paediatric stone disease, it is very common to see 24-hour urine values for creatinine, sodium, calcium, oxalate, uric acid, and even citrate. The accuracy of the 24-hour urine collection method is rather limited.

Because of the random urine spot sampling, ratios are used, i.e urine calcium to urine creatinine ratios(Uca : Ucr). They are used with sensitivities and specificities up to 90% and 84% respectively. They also evaluate hypercalciuria, which is a known risk factor for urolithiasis.

Size matters

It is usually advised to measure the intake of urinary supersaturation products, i.e., calcium oxalate, urate, as it helps in identifying the chances of stone formation risks in children. The initial treatment includes conservative management of paediatric nephrolithiasis, provided there is no infection, fever, nausea, anorexia etc. If any such symptoms are seen in the child, then, immediate endourologic intervention is needed. When the stone diseases are being managed in the paediatric population, one should keep in mind that stones that are less than 3mm in dimension are more likely to spontaneously pass.

However, stones measuring more than 4mm in the distal ureter require endourologic treatment. In order to facilitate distal stone passage, with the help of  medical expulsive therapy, use of antagonists, calcium channel blockers and steroids has proven to be effective. When it comes to assessment of  urolithiasis, ultrasonography is limited when compared with CT, but it has this distinct advantage of no associated ionising radiation, which gives it an upper hand.

Therefore, ultrasonography should be considered as a screening tool in case of workup for non-emergent abdominal or flank pain. Since children are always at a risk of recurrence of urolithiasis, the radiation exposure should also be limited, particularly the gonadal exposure.

The evolution of new techniques and miniaturisation of instruments have completely changed the management of paediatric stone disease. Despite the encouraging results, the concern still remains regarding the safety of endourologic treatment in kids, and how it might affect the growth of the kidney.

Although shock wave lithotripsy is still considered first-line therapy for upper tract calculi measuring less than 1.5 cm, evidence is  accumulating that eteroscopy with laser lithotripsy and stone basketing may be more effective in treating upper tract stone disease in children. Although percutaneous nephrolithotomy remains the most effective technique for large upper tract stone burdens, there are now reports of laparoscopic and robotic-assisted laparoscopic pyelolithotomy in major pediatric academic centres with extensive laparoscopic and robotic experience.

(The author is consultant urologist, Park Hospital)