A review of the clinical course of 65 children who had renal trauma has been carried out. The largest percentage of such injuries occurred in the age group 10-14 and were seen after falls or automobile accidents. Of the injuries, 74% were classified as contusions and needed only conservative management. Fifteen patients were found to have preexisting renal disease. Hydronephrotic kidneys constituted the largest share of these. Two patients had ruptured teratoma of the renal cortex (Wilms' tumor). The high incidence of such renal abnormalities clearly indicates the need for complete urological investigation, no matter how trivial the injury appears, or how slight the attendant hematuria or discomfort.
Lester Persky, William E. Forsythe. Renal Trauma in Childhood. JAMA. 1962;182(7):709–712. doi:10.1001/jama.1962.03050460001001