Diaphragmatic Trauma

Basics

Description

  • Penetrating injury:
    • Accounts for 67% of diaphragmatic traumas
    • Violation of the diaphragm by penetrating object (most commonly stab and gunshot wounds)
    • May involve any portion of diaphragm
    • Smaller defect compared with blunt injuries (more likely to be missed)
  • Blunt injury:
    • Accounts for 33% of diaphragmatic traumas
    • Increased intra-abdominal or intrathoracic pressure is transmitted to diaphragm, causing rupture (most common mechanism is MVA)
    • Injuries are more commonly left-sided:
      • Left hemidiaphragm has posterolateral embryologic point of weakness
      • Right hemidiaphragm is protected by liver
      • Injuries are larger than with penetrating injury (frequently between 5–15 cm in length)
  • Diaphragmatic defects do not heal spontaneously because of pleuroperitoneal pressure gradient:
    • May exceed 100 cm H2O during maximal respiratory effort
    • Promotes herniation of abdominal contents through tear in diaphragm

Epidemiology

Incidence

Uncommon; <1% of all traumatic injuries

Mortality; 25% for all patients with diaphragmatic trauma

Etiology

  • Lateral torso impact is 3 times more likely to result in ipsilateral diaphragmatic rupture than frontal impact
  • Strangulated abdominal organs may perforate and spill abdominal contents into chest
  • Suspect diaphragmatic injury:
    • Penetrating trauma to thoracoabdominal area
    • Injuries that cross plane of the diaphragm, which can extend up to the 4th rib

Diagnosis

ALERT

In the acute phase, there may be no abdominal visceral herniation, and in 10–50% of patients, diagnosis may be delayed for days to weeks.

  • This injury may even be missed on initial CT scan, laparotomy, or laparoscopy
  • Delayed presentations may present with strangulation, incarceration, or cardiac tamponade

Signs And Symptoms

  • Vary depending on whether phase is acute, latent, or obstructive:
    • Acute (at time of injury):
      • Chest pain
      • Shoulder or epigastric pain with respiratory distress
      • Abdominal pain
      • Abdominal distention
    • Latent (days to years):
      • Abdominal discomfort from intermittent herniation of abdominal contents into thorax
      • Abdominal pain that is worse postprandially
      • Exacerbated by lying supine
      • Pain radiating to left shoulder
      • Nausea, vomiting
    • Obstructive (visceral obstruction or ischemia):
      • Severe abdominal pain
      • Obstipation
      • Nausea, vomiting
  • Respiratory compromise, sepsis, and death

Physical Exam

Physical exam should focus on airway, breathing, circulation, and focused examination of the neck and chest

  • Vitals: Tachypnea, hypotension
  • Assess for mediastinal shift, tracheal deviation, asymmetrical chest expansion
  • Listen for bowel sounds on pulmonary exam, may have decreased or absent breath sounds
  • Abdominal tenderness, progressing to peritonitis

Essential Workup

Findings are related to abdominal contents herniating into thorax:

  • All patients need initial CXR
  • CT is preferred modality for stable patients
  • Diagnosis may be difficult in latent phase because of intermittent nature of herniation
  • Contrast studies of GI tract may be helpful

Diagnostic Tests And Interpretation

Lab

  • No lab studies confirm or rule out presence of diaphragmatic injury
  • Assessing pleural fluid for amylase can suggest diaphragmatic tear

Imaging

  • CXR:
    • Normal or nonspecific 20–50% of the time
    • Nonspecific findings include:
      • Elevated hemidiaphragm
      • Irregular diaphragm contour
      • Mediastinal shift away from affected side
      • Unilateral pleural thickening or pleural effusion
      • Areas of atelectasis or consolidation at bases
      • Small hemothorax or pneumothorax
      • Presence of abdominal viscera above hemidiaphragm is pathognomonic of diaphragmatic rupture and herniation
  • CT:
    • Findings include discontinuity of diaphragmatic crura, intrathoracic herniation of abdominal content, dependent viscera sign
    • Sensitivity 33–83% and specificity 76–100% for diagnosing diaphragmatic injury
  • US:
    • May be used, particularly on right side with accompanying hepatic herniation
  • MRI:
    • Is useful in its ability to visualize the diaphragm as a discrete structure, but is not practical in acute settings or in concern for acute obstruction

Diagnostic Procedures/Surgery

  • Thoracoscopic and laparoscopic exploration may be indicated:
    • Especially when suspicion is high despite negative imaging results
    • Facilitates minimally invasive repair
  • Video-assisted thoracic surgery (VATS) may be performed for both diagnosis and treatment in suspected cases of penetrating thoracoabdominal diaphragmatic injuries
  • CT pleurogram:
    • Contrast is injected through a chest tube
    • CT showing contrast extravasation into the abdomen is consistent with a diaphragmatic tear
    • Requires chest tube placement

Differential Diagnosis

  • Atelectasis
  • Hemothorax
  • Pneumothorax
  • Pneumoperitoneum
  • Pulmonary contusion
  • Gastric dilation, intra-abdominal fluid
  • Traumatic pneumatocele
  • Subdiaphragmatic abscess
  • Intrathoracic cyst
  • Empyema
  • Congenital eventration of the diaphragm

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