Traumatic Diaphragmatic Rupture

Traumatic diaphragmatic rupture is a tear of the diaphragm from blunt or penetrating trauma, which allows abdominal viscera to herniate into the chest. It is found in 0.8 to 5% of blunt trauma patients with major injury, and in 10 to 15% of penetrating injuries to the lower chest.

Blunt injury (road traffic collision with lateral impact, falls) produces a large radial tear of the posterolateral left hemidiaphragm (in 70 to 90%), since the liver protects the right side. Penetrating injury produces small defects that enlarge over months. Diagnosis is delayed or missed in up to a third, and presents years later with herniation or strangulation.

Pathophysiology. A sudden rise in intra-abdominal pressure (up to 100 cmH2O) against a fixed diaphragm tears its weak tendinous part. The pressure gradient between the abdomen (positive) and the chest (negative during inspiration) then pulls viscera (stomach, colon, omentum, small bowel, spleen) through the defect, with progressive enlargement. Herniated bowel can obstruct, strangulate and perforate.

Acute: chest and abdominal pain, shoulder tip pain, dyspnoea, tachypnoea, tachycardia and hypotension from associated injuries (liver and spleen injury, haemothorax, pelvic fracture). Reduced breath sounds, bowel sounds in the chest and a scaphoid abdomen may be found. Delayed: postprandial pain, vomiting, dyspnoea, constipation, obstruction or strangulation.

Haemodynamic instability, respiratory failure or suspected strangulation needs urgent surgery.

• High clinical suspicion in any major thoracoabdominal trauma, since early signs are often absent.
• Chest radiograph: elevated or indistinct hemidiaphragm (the commonest sign), abnormal gas shadow or bowel in the chest, mediastinal shift, and a nasogastric tube coiled in the chest. A normal film is found in up to 50% of cases.
• CT chest and abdomen with contrast (multiplanar): discontinuity of the diaphragm, herniation of viscera, "collar" sign (waist like constriction at the defect), "dependent viscera" sign (the organs lying against the posterior ribs), and sensitivity of about 80 to 90%.
• MRI for stable patients when CT is unclear, and thoracoscopy or laparoscopy for diagnosis in penetrating injuries (up to 100% sensitivity).
• Ultrasound for the diaphragm movement and haemothorax. Contrast study if hollow viscus herniation is suspected.
• Look for associated injuries: aortic, hepatic, splenic, pelvic and spinal injuries.

Differential diagnosis.

• Diaphragmatic eventration or paralysis
• Haemothorax or pneumothorax
• Subpulmonic effusion
• Congenital diaphragmatic hernia or hiatus hernia
• Gastric dilatation

• Resuscitation with the trauma team, using oxygen, intravenous access and early blood products if bleeding. Avoid placing a chest drain blindly in a suspected hernia, and use finger thoracostomy to prevent injury to herniated bowel.
• Gastric decompression with a nasogastric tube if bowel is in the chest.
• Acute repair: urgent laparotomy (preferred in the acute setting to assess abdominal injuries), or thoracoscopy or laparoscopy in stable patients, with reduction of viscera, inspection for ischaemia and resection if needed, and repair of the diaphragm with interrupted or continuous non-absorbable sutures (0 or 2-0 polypropylene or braided) in one or two layers. Large defects need mesh (polytetrafluoroethylene or biologic) or tissue transfer.
• Chronic or delayed repair: thoracotomy or thoracoscopy to divide adhesions between viscera and lung, usually with a transthoracic approach.
• Antibiotic prophylaxis: cefazolin 2 g intravenously at induction, with additional cover for bowel injury (metronidazole 500 mg). Tetanus prophylaxis in penetrating injury.
• Postoperative: nasogastric decompression, chest drain, analgesia with epidural or block, and early physiotherapy.
• Treat respiratory failure from pulmonary hypoplasia or contusion with lung protective ventilation.

Complications and prognosis. Strangulation, bowel perforation, empyema, respiratory failure, recurrence (about 5%) and chronic pain. Mortality is 15 to 30% in blunt trauma, mainly from associated injuries, and rises with delay.

Monitoring. Daily chest radiograph in the early period, review of bowel function, and follow up imaging (CT) at 3 to 6 months.

Referral and escalation. Refer immediately to the trauma and thoracic or general surgical teams, with intensive care for respiratory failure.