Urinary calculous disease in south-eastern Nigeria.

Prospective observations are reported on 96 South Eastern Nigerians with urinary calculi, during a five year period. An overall hospital incidence of 19.1 per 100,000, and male: female ratio of 2.7:1, were obtained. There were 79% upper-urinary tract stones and 21% lower-tract stones. Thirty-two per cent of the patients were idiopathic stone formers. Other associated aetiologic factors include obstructive uropathy (29%), UTI (30%) prolonged catheterisation (9%), hyperuricaemia (6%), foreign body in the bladder (3.8%) and hyperparathyroidism (2.5%). The lower socio-economic group accounted for 55% of the patients. Fifty three (55%) stones were removed surgically whilst 38% (45%) were passed spontaneously. Mean size of the latter was 6.3 mm +/- 1.6 mm, and of the former 17.7 mm +/- 9.5 mm. Five patients did not know when they passed the stones. Clinical features were similar to other reported series but six females had pyonephrosis, one with nephrocutaneous fistula. One urethral stone was recovered from a periurethral abscess. Infection and dietary intake appear to be important aetiologic agents. Ninety-eight per cent of stones contained calcium. Other components were similar to other reported series, but it was not possible to detect any case of cystinuria. The relatively high incidence in contrast to most other Nigerian centres may be due to high consumption of calcium/magnesium-rich sea foods and vegetables, as well as the soft water of the South-East. Endemic bladder stones were absent in the series. The close similarity with caucasian stone patterns is a curiosity and of particular interest, deserving further elucidation.