Abdominal pain after a motor vehicle accident

A 22-year-old man was brought to the ED complaining of abdominal pain after a rollover motor vehicle accident. He was the front seat passenger and was wearing a seat belt. Although he was trapped in the vehicle and it caught on fire, he did not suffer any cutaneous burns.

History The patient's past medical history was significant for attention-deficit hyperactivity disorder. He admitted to using tobacco and alcohol socially, but denied illicit drug use. He denied any medication use or drug allergies. A review of systems was positive for complaints of abdominal pain and anxiety.

Physical examination The patient's vital signs were: BP, 112/51 mm Hg; heart rate, 110 beats/minute; respirations, 23; SpO₂, 95% on room air; and temperature, 37.4° C (99.3° F). On ED arrival, he was awake, alert, and oriented but appeared anxious and agitated. His pupils were equal, round, and reactive to light. His head was normocephalic with a 2-cm laceration on the left ear. The patient's neck was without cervical spine tenderness. On lungs auscultation, he had equal bilateral breath sounds. His heart rate and rhythm were normal and all pulses were palpable equally. His abdomen was soft and diffusely tender to palpation, with an ecchymotic area consistent with the car's restraining device (seat belt sign). A Focused Abdominal Sonography for Trauma (FAST) examination was negative. The musculoskeletal examination revealed full range of motion throughout without obvious swelling or deformity.

Diagnostic tests A complete blood cell count was abnormal with leukocytosis with a white blood cell count of 18,400/mcL. His coagulation factors were within normal limits. An arterial blood gas analysis showed elevated PaO₂ of 122 mm Hg (normal range, 35 to 45 mm Hg) and low PaCO₂ of 29 mm Hg (normal range, 80 to 100 mm Hg) with a normal base deficit. A metabolic panel revealed various mild electrolyte abnormalities, elevated glucose of 145 mg/dL, and elevated ALT and AST at 41 and 52, respectively.

A chest CT showed opacities in the anterior right upper and middle lobes concerning for pulmonary contusion or aspiration. The patient also had a small right pneumothorax as well as a right scapular fracture and a right fifth rib fracture. CT of the abdomen revealed an acute, traumatic, right-sided lumbar hernia with colon and fat herniation. Perihepatic and perisplenic fluid were seen without any evidence of hepatic or splenic laceration (Figure 1). CT of the pelvis showed irregularity of the bladder associated with low-density fluid surrounding the bladder dome, concerning for bladder rupture. A cystogram confirmed intraperitoneal bladder rupture along the right posterior wall of the bladder. A right ankle radiograph revealed a comminuted fracture of the distal fibular diaphysis and a fracture through the posterior malleolus with slight comminution of the posterior tibial plafond articular margin. This was further evaluated with right lower extremity CT.

The seat belt sign is a clue that the patient has suffered a traumatic lumbar hernia.1 Lipomas usually present as nonpainful, round, mobile masses, with a characteristic soft, doughy feel. The overlying skin appears normal.

Most blunt abdominal injuries are a result of motor vehicle crashes. Abrupt shearing forces in the crash can result in tears of solid organs or vessels resulting in hemorrhage.2 Although CT of the abdomen showed perihepatic and perisplenic fluid, no radiologic evidence of laceration to either organ was found. CT was also negative for any evidence of extravasation to suggest vascular injury.

Acute lumbar hernias are rare in blunt abdominal trauma, and are most commonly caused by sudden blunt force trauma to the abdomen during a crash, usually as a result of compression and shear forces associated with a seat belt that is positioned over the abdomen rather than the bony pelvis. During a crash, the blunt force from the malpositioned belt can increase intra-abdominal pressure sufficient to cause disruption of the abdominal wall musculature.

A lumbar hernia usually involves protrusion of extraperitoneal fat or bowel through an area of weakness in the posterolateral abdominal wall bounded superiorly by the 12th rib, inferiorly by the iliac crest, posteriorly by the erector spinae muscle, and anteriorly by the posterior border of the external oblique muscle (Figure 2).3 The hernia can contain fat, omentum, stomach, cecum, small bowel, kidney, or sigmoid colon. Delayed diagnoses of an acute lumbar hernia are therefore common because hernias are easily overlooked while other traumatic injuries are being addressed.

Physical examination can reveal hematoma, flank ecchymosis, and reducible mass with pain just superior to the iliac crest. Auscultation over the area may reveal bowel sounds. However, initial physical examination findings may be normal, and diagnosis may not be made without an abdominal CT scan or intraoperatively during exploratory laparotomy. Abdominal CT scan is the diagnostic study of choice for suspected lumbar hernia in patients whose condition is stable.4 Abdominal CT is the most valuable imaging test because it can reveal the muscular and fascial layers, show the presence of defects, and reveal the contents of the hernia before repair. If acute lumbar hernias are missed they can increase in size, resulting in long-term morbidity ranging from chronic lower back pain to bowel incarceration in 25% and strangulation in 10% of patients.3,5 Esposito and Fedorak reported that the presence of an acute traumatic lumbar hernia alone is an indication for laparotomy because of the high incidence of associated hollow viscus and mesenteric injuries.5

Early surgical intervention has been shown to reduce postoperative pain, minimize morbidity, and provide a more rapid return to normal activities. The surgical approach to acute lumbar hernia includes primary repair by layered reapproximation, use of synthetic absorbable or nonabsorbable mesh, and myocutaneous flap closure.

The case patient was taken to the OR for an exploratory laparotomy because of the findings of definitive bladder rupture on cystogram as well as abdominal CT finding of traumatic lumbar hernia. Intraoperatively, he was found to have multiple serosal tears of the sigmoid colon, so sigmoid colectomy with primary anastomosis was performed. His bladder injury was repaired. Although the peritoneum was intact, a clear herniation was palpable, and when the peritoneum was incised an 8-cm tear in the abdominal musculature was easily identified along the superior aspect of the iliac spine. Fat herniation through this deformity was reduced and the torn muscle was reapproximated with a nonabsorbable suture. The peritoneum was then closed over the repair.

Hospital course On hospital day 1, after undergoing exploratory laparotomy, the patient was evaluated by the orthopedic service in regard to the right scapular fracture as well as the right trimalleolar fracture. The decision was made to treat the scapular fracture nonoperatively; however, the right ankle was splinted and definitive operative fixation was planned for when the patient became more medically stable. On postoperative day 1, the patient was started on low-molecular-weight heparin for deep venous thrombosis prophylaxis. He remained hemodynamically stable and had no clinical deterioration related to the pulmonary contusions, as he was being maintained on 2 L of supplemental oxygen via nasal cannula. The small pneumothorax seen on the previous day's CT was not visible on plain radiograph.

His early hospital course was notable for an ileus that required decompression via nasogastric (NG) tube. By hospital day 8, he was tolerating a regular diet. He then underwent open reduction and internal fixation of right posterior and lateral malleolus fracture. He was made non-weight-bearing to the extremity. Perioperatively, the acute interventional perioperative pain service placed a right sciatic nerve block for pain control. The block was removed on hospital day 13.

The patient's abdominal staples and ear sutures were removed on hospital day 14 without complication. That same day, he underwent a cystogram for postoperative evaluation of the bladder repair. (The indwelling urinary catheter had been maintained for bladder decompression.) The cystogram revealed satisfactory filling of the bladder without extravasation, so the urinary catheter was discontinued on hospital day 15. The rest of his hospital stay was unremarkable, and he was discharged home on hospital day 17.

Post hospital care The patient followed up with the trauma service as an outpatient for about 3 months. At that time, he denied issues with pain, shortness of breath, nausea, or vomiting. He was experiencing regular bowel movements and reported normal appetite. His abdominal incision and right ankle operative site were well healed without signs of infection. He also reported that he had been cleared for full weight-bearing from an orthopedic standpoint, so he was released to return to work without restriction by trauma services. He was advised to follow up on an as-needed basis.

Acute lumbar hernia, although rare, is commonly seen in deceleration accidents and is a serious condition that remains a challenge in acute blunt abdominal trauma. The initial diagnosis is by physical examination, and should be suspected in a patient who has a seat belt sign, flank fullness or bruising, and localized or referred pain. CT imaging is extremely useful for examining trauma patients, allowing earlier detection and excellent identification of the contents of a hernia, associated injuries, and disrupted muscle layers. Early exploratory laporotomy is recommended to identify hollow and solid viscus injuries and reduce and repair the hernia.

1. Guly HR, Stewart IP. Traumatic hernia. J Trauma. 1983;23(3):250–252. Ovid Full Text Bibliographic Links [Context Link]

2. Peitzman AB, Schwab CW, Yealy DM, Rhodes M. The Trauma Manual: Trauma and Acute Care Surgery. 3rd ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2008:243. [Context Link]

3. Swartz WT. Lumbar hernia. In: Nyhus LM, Condon RE, eds. Hernia. 2nd ed. Philadelphia: Lippincott; 1978:409–426. [Context Link]

4. Killeen KL, Girard S, DeMeo JH, et al. Using CT to diagnose traumatic lumbar hernia. AJR Am J Roentgenol. 2000;174(5):1413–1415. Bibliographic Links [Context Link]

5. Esposito TJ, Fedorak I. Traumatic lumbar hernia: case report and literature review. J Trauma. 1994;37(1):123–126. Ovid Full Text Bibliographic Links [Context Link]

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