ABSTRACT
Urolithiasis in childhood differs considerably from that in adults. It is much rarer (with a prevalence of between 0.1 and 0.9 cases per 1000 hospital admissions) in developed countries than in less developed countries. In children, the presentation is often less specific, the aetiology different and the management more complicated compared with that in adults. Interestingly, children presenting with renal stones tend to have a lower than average weight and height, suggesting either that they occur in chronically sick children or that they lead to poor growth, perhaps associated with chronic infection, vomiting or pain (Coward et al. 2003). Some children, especially those who are born prematurely and/or have profound immobility, are at higher risk of stones. The aetiology of paediatric urolithiasis is changing (Figure 56.1). Whereas the frequency of a metabolic abnormality was only 16 per cent in a series of 120 paediatric cases reported from the UK in 1977, current data from the same institution suggest a frequency of 44 per cent (Coward et al. 2003). Furthermore, urolithiasis is becoming more common in all age groups, and the age of first stone
formation is falling, especially in women (Robertson et al. 1999). Twenty per cent of people who develop a renal stone do so before the age of 20 years. In adults, stones now occur almost as commonly in women as in men. However, in children, boys are still affected twice as frequently as girls, and at a younger age (Coward et al. 2003). Urea-splitting organisms, typically Proteus mirabilis (colonizing the foreskin) but also commonly Escherichia coli and other Gram-negative organisms, convert urea to ammonium, increasing urinary pH and favouring supersaturation of triple phosphate. Most infective stones occur in children with otherwise normal urological tracts, but there is an increased incidence in children with augmented bladders or obstructive lesions and in the presence of foreign bodies.
