This pop quiz involved a young woman who fell from a jet ski at high speed and was initially okay. Later that day, she developed lower abdominal pain and sought evaluation in your ED. There were a number of thoughtful answers via the comments section and Twitter.
According to the First Law of Trauma, the pain is related to the mishap until proven otherwise. You must approach it like any moderate speed motor vehicle crash. In many ways, this mechanism is similar to a motorcycle or bicycle crash, without the road rash. However, high speed and water can also combine to cause a unique injury, the so called water ski / jet ski douche and enema. This occurs when the rider enters the water with a significant feet first component, causing a jet of water to be forced into the vagina or rectum.
As always though, start with a thorough history and physical exam. In this case, the patient has diffuse lower abdominal tenderness, but no other findings on exam. Because of the possibility of water jet injury, a thorough exam of both vagina and rectum is indicated. This requires a speculum and anoscope. Any anomalies that are noted are an indication to proceed to the OR for a thorough exam under anesthesia.
Blunt abdominal injury is also a concern, so FAST may be performed. However, the abdominal pain is an indication for abdominal/pelvic CT using our blunt trauma imaging protocol. A solid organ injury can be managed in the usual manner. But if any anomalies other than the trace pelvic fluid occasionally seen in young women is present, the patient must go to OR.
If the patient does need an operation, start with vaginal and rectal exams again, under anesthesia. Most vaginal lacerations are small and easily closed. However, there have been reports of extensive laceration with heavy bleeding. Simple rectal tears may be repaired, but more complicated ones may also require fecal diversion. If the injury appears complex, a laparotomy will be necessary, and diversion with a colostomy will usually be required.
Bottom line: This injury is an example of what I call a two-factor mechanism: blunt trauma plus high pressure injection in this case. The trauma professional needs to recognize both and resist the temptation to focus on the more obvious one. Think through the evaluation and management algorithms for each one, combining them where appropriate.