Teaching Case

Post traumatic microscopic hematuria in a 7 year old boy. Pre pelvic artery traumatic dissection or thrombosis shown by enhanced CT

A 7 year old boy fell down from a 150 cm height. He was referred to our institution for diffuse abdominal pain. Vital parameters were normal. Temperature was 38°c. Dipstick examination of urine showed microscopic hematuria (3+). On day 1, Ultrasound was performed and showed free fluid in the Douglas cul-de-sac. No renal or bladder abnormality was noticed. On day 3, enhanced CT was performed.

Renal parenchymal injuries occur in 1.2 to 15% of all cases of pediatric trauma and predominate on the left side. Anatomical factors can explain the higher frequency of renal lesion in children as compared with adults (proportionally larger, more lobulated, more mobility, less fat, thinness of peritoneal covering). This case report confirms that minimal injury can lead to severe renal lesion in children. Otherwise, contrary to adults, the degree of hematuria cannot predict the severity of renal lesions. Children with pedicular lesion sometimes present with absent or microscopic hematuria. Renal trauma often associates with extra urinary lesions (liver, spleen, pancreas). In children with microscopic hematuria, normal B-mode ultrasound cannot eliminate pedicular lesion. Color/power doppler could have shown decreased vasculature, but it was not performed on day 1 in this child. Enhanced CT is the reference method in such clinical situation. CT can show renal and extra renal lesions. In case of renal injury, it can orient treatment toward surgery or conservative management. In this case, CT was inadequately delayed, so that no vascular surgery could be performed. However, it is well known that even with prompt vascular repair, there is usually loss of function. Anatomically, involvement of the pre-pelvic renal artery was likely. The terminal type of renal vasculature can explain the anterior location of ischemia. Medullary enhancement was caused by collateral peripheral vessels. Surgery was not performed so the precise type of vascular lesion remained unknown. Thrombosis and/or dissection are two possible causes.