Blunt renal trauma in childhood. Features indicating severe injury. The clinical presentation of children with blunt renal trauma may differ from that of adults. The clinical features at presentation of 50 consecutive children (20 severe injuries, no pedicle injuries) admitted over a period of almost 8 years were reviewed to determine if there were clinical clues to major renal trauma in childhood. Gross haematuria and low haematocrit were the most helpful factors at the time of presentation and correlated well with severe renal injury. Hypotension was seen in 4 patients and only 1 had severe renal trauma. Suspicion of a major renal injury should be high when there is gross haematuria or a low haematocrit. In this study only 1 of 20 patients with major renal injury demonstrated clinical signs of shock. Unlike adults, hypotension does not appear to be a reliable indicator of the severity of renal injury in children and diagnostic evaluation should not be reserved only for those in shock. 