UROLITHIASIS: OVERVIEW

Abstract

A 16-year-old boy died at E Amrah, Egypt, perhaps because he had a bladder stone, containing calcium phosphate and uric acid; what is remarkable is that this happened nearly 7000 years ago. Indeed, since trephining and circumcision had ritual a connotation, ‘cutting for the stone’ is probably the oldest purely surgical procedure. Even then, there was no lack of concepts concerning a etiology including overfeding, familial predisposition, and the composition of the blood. By 1663 Rofink had classified uroliths according to their size, shape, surface and colour and by the 18th century they were recognized to contain uric acid, oxalic acid, cystine and organic material. By the 19th century, phosphate stones were regarded as an affliction of poverty, urate stones as one of affluence. Even today 70% of humans with urolithiasis are obese, 90% of those with uric acid stones. Perhaps the strangest aspect of the history of urolithiasis is a relatively recent change in its epidemiology. Bladder stones were much more common than kidney stones until about 100 years ago, and especially common in children. This increase has been blamed on affluence and increased dietary protein but this seems hard to believe when poverty with high intake of vegetable protein was blamed for bladder stones and when an eightfold increase in calcium oxalate stones occurred between 1964 and 1971; during this period protein intake rose by less than 5%. Other factors such as low fibre and excess of refined carbohydrate associated with 'affluent' diets may predispose to urolithiasis. In particular, there may be peaks of increased urinary calcium following ingestion of sugary food or drinks.