Blunt abdominal trauma

Assessment of the abdomen is incorporated in the primary survey if the patient is haemodynamically unstable

Unstable patients with a FAST exam positive for free fluid should proceed directly to theatre for a laparotomy



The majority of significant blunt abdominal trauma is sustained in road traffic crashes (50-75% of cases). Falls, sporting injuries and assaults are other leading causes.

Mechanisms of injury include

  • Direct blows to the abdomen.
    • Injuries to solid organs from direct force
    • Blunt force can press the abdominal contents against the vertebral column
      • Eg: retroperitoneal portion of duodenum vs thoracic vertebrae
  • Injuries from sudden increased intraabdominal pressure (eg: lap belts)
  • Shearing forces to both solid and hollow viscus from rapid deceleration


Blunt abdominal injury algorithm 


blunt flow


Clinical findings


In patients that are haemodynamically stable, abdominal exam is deferred to the secondary survey

  • Look
    • Abdominal contusions, abrasion, haematomas,
      • A “seatbelt sign” (large contusion from the lap portion of the belt) has an association with significant intraabdominal injury.1
    • Abdominal distension
  • Palpate
    • Focal tenderness, rebound tenderness/peritonism
      • Caution in patient with painful distracting injuries
      • Patients with altered level of consciousness or spinal cord injuries should be considered as having clinically “unassessable” abdomens
    • It is recommended that patients with suspected blunt abdominal trauma have serial clinical examination performed
    • PR: May detect blood, high riding prostate, decreased tone, bone fragments from pelvis #. Perform if indicated.
    • PV: if new onset PV bleeding since trauma




Blood tests

  • Blood gas
    • Haemoglobin decrease if bleeding (though there may be a lag in Hb drop in acute bleeding)
    • Initial lactate levels >4 correspond to 20% mortality. In patients with a lactate >4, clearance is associated with survival.2
    • A base deficit of -6 or less is also associated with increased injury severity3
  • FBC
    • Hb as above
    • WCC is often elevated following significant trauma
  • LFTs
    • There is a correlation in raised transaminases and hepatic trauma, more so in the paediatric population.4 Normal LFTs do not rule out a liver injury.
  • Lipase
    • Elevated lipase levels are suggestive of pancreatic injury, but normal levels do not rule this out
  • bHCG
    • should be obtained on all women of childbearing age
  • Coags
    • Standard investigation for patients with significant injuries. Can guide blood product replacement
  • Ethanol
    • Most institutions request this as standard for trauma patients
  • Group and hold/cross match



  • Gross haematuria generally indicates significant injury to the renal tract and should prompt further investigations depending on the likely source eg: CT abdo with arterial and venous phases for kidney trauma, retrograde urethrogram for urethral trauma, CT cystogram for bladder trauma
  • Patients who have microscopic haematuria may have significant intraabdominal injuries – further investigations should be requested if the patient is shocked or if there are clinical concerns for major intraabdominal trauma.5
  • Note that severe injuries (eg: renal avulsion) may have no haematuria – around 5% of renal pedicle injuries, and 20% of renovascular injuries have no haematuria


Diagnostic peritoneal lavage

  • Once a mainstay of trauma investigations to detect free fluid from solid organ or hollow viscus injury, this has now been largely replaced by USS and CT scanning. Very rarely (if ever) utilised.



  • Plain radiology
    • There is no role for a plain abdominal xray in patients with blunt abdominal trauma
    • A CXR may be useful to determine if there are lower rib #s – these have an association with liver and spleen injuries. Occasionally free air might be seen under the diaphragm indicating a perforated viscus.
    • Patients with pelvic trauma can have associated intraabdominal injury.
    • Plain films of the vertebral column may assist in the diagnosis of spinal #s (if a CT of this area is not being performed)
  • Bedside ultrasound (eFAST)
    • In unstable patients, ultrasound (eFAST) can be utilised to determine if there is free intraabdominal fluid
    • Ultrasound has a limited role in stable patients. If free fluid is seen, the patient should progress to CT. A negative FAST scan does not rule out significant solid organ, retroperitoneal or hollow viscus trauma.
  • CT abdomen/pelvis (with contrast)
    • A CT scan with contrast is the most useful diagnostic modality for determining if a patient has intraabdominal injuries after blunt trauma. Oral and rectal contrast is very rarely required and not utilised routinely
    • As always, there is a tension between radiation/contrast exposure and diagnosing significant injuries.
    • A decision to perform a CT scan should be based on
      • Clinical findings (significant abdominal tenderness on exam, large abdominal contusions)
      • Investigation findings (eg: haematuria, abnormal blood results, positive FAST, raised lactate)
      • Mechanism
        • eg: lap belt only worn (high chance of mesenteric injury)
      • Other injuries
        • eg: a flexion distraction vertebral fracture (aka. Chance #) is often associated with intraabdominal injuries
        • lower rib fractures or pelvis fractures
      • The assessability of the patient (level of consciousness, distracting injuries, spinal injuries)


Note that CT might not detect

  • Occult hollow viscus or pancreatic injury. Patients with ongoing significant abdominal pain should be admitted for observation. CT findings that are associated with hollow viscus injury include, mural bowel wall thickening , free fluid without solid organ injury and mesenteric changes.
  • Diaphragm rupture. Direct vision with either VATS or laparoscopy/laparotomy may be required

CT findings

  • Normal CT
    • A normal CT reliably rules out solid organ injury but might not detect some mesenteric, pancreatic or diaphragm injury
      • Patients with concern for these injuries (eg: based on mechanism, investigations, ongoing significant pain) or are unassessable should be admitted for serial abdominal examination
  • Free air or free fluid from suspected hollow viscus injury or other suspicious CT findings
    • Consult general surgical colleagues – likely require operative management
  • Solid organ injury
    • CT provides organ specific injury diagnoses and can grade the severity of the injury
      • AAST (America Association for the Surgery of Trauma) is the most commonly utilised injury score for solid organ injury
      • Extravasation of contrast (a “blush”) can indicate active bleeding that might be amenable to intervention
    • Consult general surgical colleagues
      • Non-operative management is the treatment modality of choice for most haemodynamically stable patients with solid organ injury
    • Patients who develop persistent haemodynamic stability or peritonitis should proceed immediately to the operating room


Specific injuries


Splenic trauma

  • The spleen is the most commonly injured organ in blunt abdominal trauma. Splenic injuries were traditionally treated with splenectomy, but the vast majority (around 85%) are now managed conservatively with either bed rest and observation or selective embolization. 6
    • The aim is to prevent the morbidity associated with surgery and to preserve the spleen’s immune function.
  • Patients that are haemodynamically unstable should proceed to the operating theatre.


spleen grade


Indications for angiography include

  • Evidence of contrast extravasation/blush
  • Splenic vascular injury eg: pseudoaneurysm, AV fistula
  • High grade (AAST III+) lacerations
  • Significant haemoperitoneum
  • Patients at risk of deterioration
    • Hb drop
    • Transient tachycardia or hypotension
    • Blood product requirement
  • At risk from complications of laparotomy eg:
    • TBI
    • Elderly/comorbid
  • Patients that are managed non-operatively, should be observed in an environment that can closely monitor the patient for the develop haemodynamic instability with an operating room immediately available



Liver trauma

  • Non operative management of hepatic injuries is now the standard of care for stable patients without peritonism.7
  • Angiography should be considered in patients with evidence of contrast extravasation or higher grade injuries (III+)
  • Patients with higher grade injuries (III+) that are managed non-operatively are at risk of bile leaks, hemobilia, bile peritonitis, bilious ascites, haemoperitoneum, abdominal compartment syndrome, missed injuries, hepatic necrosis, hepatic abscess, and delayed haemorrhage so should therefore be closely monitored in a suitable environment
Liver grading


Renal trauma

  • Around 10% of patients with blunt abdominal trauma sustain renal injuries.8
  • Most blunt renal injuries are haemodynamically stable and can be managed non-operatively – this includes high grade injuries9,10
  • Patients that are haemodynamically unstable or who have renal pedicle avulsion should have operative management
  • Angiography and selective embolization have a role in patients with higher grade injuries and evidence of active bleeding on CT
  • Complications of renal injuries include: delayed haemorrhage, persistent haematuria, urine extravasation with urinoma formation, infection and hypertension. Patient will need to be observed and closely monitored.


kidney grade


Diaphragm rupture

  • Diaphragm injuries are more common in penetrating trauma but can occur with significant blunt force where there has been a sudden increase in intraabdominal pressure. The left diaphragm is more likely to be injured as the liver provides some protection to the right side.
  • CXR might reveal some non-specific signs (eg: raised or indistinct hemidiaphragm).
  • CT has a sensitivity of around 82-87% for detecting diaphragm injury – a negative CT does not rule out diaphragm injury and if strongly suspected, direct operative visualisation is recommended as a missed diaphragm rupture can lead to significant morbidity from abdominal organ herniation/strangulation and diaphragm paralysis.11
  • Because of the difficulty in diagnosis, diaphragm injuries can present late – even months or years after the initial injury.


Disposition – interhospital transfer guidelines


no surg


blunt dest


complex liver




  1. Wotherspoon S, Chu K, Brown AF. Abdominal injury and the seat‐belt sign. Emergency Medicine Australasia. 2001 Mar 1;13(1):61-5.
  2. Odom SR, Howell MD, Silva GS, Nielsen VM, Gupta A, Shapiro NI, Talmor D. Lactate clearance as a predictor of mortality in trauma patients. Journal of Trauma and Acute Care Surgery. 2013 Apr 1;74(4):999-1004.
  3. Davis JW, Mackersie RC, Holbrook TL, Hoyt DB. Base deficit as an indicator of significant abdominal injury. Annals of emergency medicine. 1991 Aug 1;20(8):842-4.
  4. Karam O, La Scala G, Le Coultre C, Chardot C. Liver function tests in children with blunt abdominal traumas. European journal of pediatric surgery. 2007 Oct;17(05):313-6.
  5. Investigating microscopic haematuria in blunt abdominal trauma
    EMJ Best Bets 2002
  6. Stassen NA, Bhullar I, Cheng JD, Crandall ML, Friese RS, Guillamondegui OD, Jawa RS, Maung AA, Rohs Jr TJ, Sangosanya A, Schuster KM. Selective nonoperative management of blunt splenic injury: an Eastern Association for the Surgery of Trauma practice management guideline. Journal of Trauma and Acute Care Surgery. 2012 Nov 1;73(5):S294-300.
  7. Stassen NA, Bhullar I, Cheng JD, Crandall M, Friese R, Guillamondegui O, Jawa R, Maung A, Rohs Jr TJ, Sangosanya A, Schuster K. Nonoperative management of blunt hepatic injury: an Eastern Association for the Surgery of Trauma practice management guideline. Journal of Trauma and Acute Care Surgery. 2012 Nov 1;73(5):S288-93.
  8. Broghammer JA, Fisher MB, Santucci RA. Conservative management of renal trauma: a review. Urology. 2007 Oct 31;70(4):623-9.
  9. van der Wilden GM, Velmahos GC, D’andrea KJ, Jacobs L, DeBusk MG, Adams CA, Gross R, Burkott B, Agarwal S, Maung AA, Johnson DC. Successful nonoperative management of the most severe blunt renal injuries: a multicenter study of the research consortium of New England Centers for Trauma. JAMA surgery. 2013 Oct 1;148(10):924-31.
  10. Shoobridge JJ, Corcoran NM, Martin KA, Koukounaras J, Royce PL, Bultitude MF. Contemporary management of renal trauma. Reviews in urology. 2011;13(2):65.
  11. Dwivedi S, Banode P, Gharde P, Bhatt M, Johrapurkar SR. Treating traumatic injuries of the diaphragm. Journal of Emergencies, Trauma and Shock. 2010 Apr;3(2):173.

Related Guidelines

About this guideline

First published: February 2018 (Author: Emma Batistich)
Updated April 2021 (Christopher Harmston)
Approved by: Northern Region Trauma Network, ADHB, WDHB, CMDHB, NDHB, NRHL, St John
Review due: 2 years