| History | Number | Percentage (%) |
| Urinary tract infection | 10 | 33.3 |
| Bilharzia | 7 | 23.3 |
| Congenital malformation | 4 | 13.3 |
| Trauma | 2 | 6.7 |
| Bladder lithiasis | 2 | 6.7 |
| None | 5 | 16.7 |
| Total | 30 | 100 |