Diaphragmatic rupture often results from blunt abdominal trauma, which is usually associated with motor-vehicle accidents and hence a predominance of young males.
Estimated incidence is ~4.5% (range 0.8-8%) of patients who sustain blunt abdominal or lower thoracic trauma 1-2; the most common herniated viscera are the stomach and colon. The most common cause is motor vehicle collisions and the most common group of patients is unsuprisingly young men.
The left-hemidiaphragm is involved 3 times more frequently than the right, possibly because the liver has a buffering effect. Most ruptures are longer than 10 cm and occur at the posterolateral aspect of the hemidiaphragm between the lumbar and intercostal attachments, spreading radially.
It is rare to see rupture of the diaphragm without evidence of abdominal trauma, and usually there is visceral injury above and below the diaphragm.
It is frequently not recognized at the time of trauma and the interval between injury and the onset of symptoms. However, if the diagnosis is not made in the first 4 hours, it may be undiagnosed for months or years.
Specific diagnostic findings of diaphragmatic rupture on chest radiographs may not be seen in up to 50% of cases 1. However, the following signs are helpful in making the diagnosis:
- inability to trace the normal hemidiaphragm contour
- intrathoracic herniation of a hollow viscus (stomach, colon, small bowel) with or without focal constriction of the viscus at the site of the tear (collar sign)
- if large, positive mass effect may cause contralateral mediastinal shift
- visualisation of a nasogastric tube above the hemidiaphragm on the left side
Direct discontinuity of the hemidiaphragm may be seen with or without intrathoracic herniation of abdominal contents. The stomach and colon are the most common viscera to herniate on the left side and the liver is the most common viscus to herniate on the right side.
Other signs of diaphagmatic rupture includes:
- the collar sign (or hour glass sign) 3: a waist-like constriction of the herniating hollow viscus at the site of the diaphragmatic tear and is classical of diaphragmatic rupture
- the dependent viscera sign: when a patient with a ruptured diaphragm lies supine at CT examination, the herniated viscera (bowel or solid organs) are no longer supported posteriorly by the injured diaphragm and fall to a dependent position against the posterior ribs
- segmental non recognition of diaphragm
- focal diaphragmatic thickening
- thoracic fluid abutting the abdominal viscera
Indirect features include:
- 1. Killeen KL, Mirvis SE, Shanmuganathan K. Helical CT of diaphragmatic rupture caused by blunt trauma. AJR Am J Roentgenol. 1999;173 (6): 1611-6. AJR Am J Roentgenol (abstract) - Pubmed citation
- 2. Nchimi A, Szapiro D, Ghaye B et-al. Helical CT of blunt diaphragmatic rupture. AJR Am J Roentgenol. 2005;184 (1): 24-30. AJR Am J Roentgenol (full text) - Pubmed citation
- 3. Oikonomou A, Prassopoulos P. CT imaging of blunt chest trauma. Insights Imaging. 2011;2 (3): 281-295. doi:10.1007/s13244-011-0072-9 - Free text at pubmed - Pubmed citation