Discussion
Bicycle injuries constitute to be a common cause of childhood trauma presenting to the emergency department. Among them, handlebar injuries are an uncommon variety, found to be 1.15 per 100,000 cases.7 It results when the body of the child strikes the handlebar of the cycle as the child falls off. During this, force transmitted through the handlebar may cause significant injuries even with low speed.2 Common abdominal injuries due to it includes injuries to the pancreas, small bowel, mesentery, liver, and spleen.8
Retroperitoneal bleeding secondary to handlebar injury, however, is less common with one reported case of retroperitoneal hematoma, where conservative management was opted. Retroperitoneal hematoma encountered in trauma are mostly caused by blunt injuries. Majority of them are due to renal injuries and other causes such as vascular injuries, pelvic injuries and rarely blunt trauma to retroperitoneal structures as duodenum and pancreas.6
In a study by Clarnette et al, 32 children with blunt abdominal trauma due to handlebar injuries were identified and among them nine had splenic trauma and rest involved liver, pancreas, kidney, urethral and bowel injuries. However, none of them were reported to have retroperitoneal hematoma or mesenteric injuries.9
CT scan is an important modality in case of abdominal trauma for further assessment and appropriate management. Though in cases of hemodynamically unstable patients following blunt abdominal trauma with eFAST scan positive, immediate exploratory laparotomy should be done. However, in our case, CT scan was done later once hemodynamically stability of the patient was achieved. As CT scan showed mesenteric injury with retroperitoneal hematoma, it assisted surgeons for prior discussion of the operative approach in this case. This case not only highlights the importance of CT scan but also the fact that in cases where CT scan is not feasible, retroperitoneal hematoma though uncommon in bicycle handlebar injury should be suspected. In absence of CT scan, high suspicion is to be accounted when the intraoperative finding is not proportionate to the clinical picture of the patient. In such cases, retroperitoneal approach may be needed. As the mortality rate ranges from 18-60 % with traumatic retroperitoneal hematoma, this emphasizes its importance of early recognition and management.5
Furthermore, the clear history of handlebar injury in our patient helped us to suspect major abdominal injury in this case. Hence, a detailed history to recognize the mechanism of injury, whether it involves handlebar-related injuries or not might aid the practitioner in early diagnosis of serious abdominal injuries in child bicyclists.
This case particularly highlights upon the unusual instance where retroperitoneal hematoma due to mesenteric vascular injury occurred in the absence of any solid or hollow viscus injury. The crucial role of imaging studies in such cases need to be over-emphasized. Prompt decision making for initial resuscitation and eventual surgical management is key, owing to this infrequent nature of blunt abdominal trauma.