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Mechanism of injury
Regions of the abdomen
History
Examination
Investigations
Specific injuries
Pelvic injury
Retroperitoneal haemorrhage
NB If rapid surgical haemostasis is provided in penetrating trauma, delaying
or limiting fluid resuscitation before surgery may improve outcome
Mechanism of injury
- blunt injuries most common cause. GI injury associated with use of seat
belts. Abdominal and pelvic injuries more likely with side-on collisions whether
occupants are on impact or non-impact side. Liver, spleen and kidneys organs
most likely to be damaged in blunt trauma
- stab and laceration wounds. Entry sites do not accurately predict nature of
deeper injury. Thoracic injury should be suspected with upper abdominal wounds
and vice versa. Note that the diaphragm extends as high as T4 in expiration
Intra-abdominal injury occurs in 44% of anterior abdominal wounds, 29% of flank
wounds and 15% of back wounds. Organs most likely to be affected are liver,
small bowel, colon and stomach
- gunshot wounds depend on missile calibre, velocity and trajectory. Laparotomy
should be performed in all cases when peritoneal violation cannot be excluded as
89% of such patients have intra-abdominal injury. Note that gunshot wounds may
have a circuitous trajectory and thus may injure multiple non-contiguous wounds
Regions of the abdomen
3 distinct anatomical compartments: peritoneum, retroperitoneum and pelvis
- peritoneal cavity subdivided into:
- intrathoracic segment
- covered by bony thorax and includes diaphragm, liver,
spleen, stomach and transverse colon
- abdominal segment
- retroperitoneum
- aorta, vena cava, pancreas, kidneys, ureters and
portions of duodenum and colon
- injuries to this region notoriously difficult to
diagnose because the area is remote from physical examination and is not sampled
by peritoneal lavage
- pelvic organs
- rectum, bladder, iliac vessels, internal genitalia
of women
- injury also difficult to diagnose early because of anatomical location
History
Mechanism of injury
- Blunt injury. Important questions:
- time of injury
- mechanism
- estimated speed of impact
- damage to involved vehicles
- use
and type of restraining device
- condition of injured persons
- Penetrating
injury:
- time of injury
- type of weapon (eg knife length, handgun calibre)
- distance from assailant (particularly for shotgun wounds)
- number of stab
attempts or shots
- amount of blood at scene
Examination
- clinical examination should include thoracic cage, back and pelvis
including perineal and rectal examination for anal tone, prostatic position,
blood or other evidence of injury
- gastric aspirate and urine should be
inspected for blood
- listening for bowel sounds is not useful
- serious
intra-abdominal pathology cannot be excluded in presence of impaired
consciousness, intellectual disability or other injury. Even in alert patients
abdominal tenderness is absent in 25-30% of with intra-abdominal injury. As many as 20% of patients with acute haemoperitoneum will have
benign abdominal examination when first seen in A&E
- laparotomy is indicated without further investigation for:
- shocked patients
with signs of intra-abdominal haemorrhage (eg peritonism or increasing
distension)
- patients with penetrating trauma and evisceration or
peritonism
Investigations
CXR
- (preferably erect) essential.
- ? free intraperitoneal gas, herniation of abdominal contents through ruptured
diaphragm or other abnormalities
AXR
Of no benefit
Diagnostic peritoneal lavage
- rarely indicated if FAST and CT are available
CT (contrast enhanced)
- indications:
- to assess retroperitoneum
- indeterminate diagnostic peritoneal lavage
- DPL contraindicated
- persistent abdominal pain despite a negative DPL
- penetrating flank trauma
- mild abdominal tenderness in alert patients
- contraindications: haemodynamically unstable patients
- can detect very small quantities of blood in abdominal cavity
- sensitive method of detecting injury to solid organs (eg up to 98%
sensitive for splenic injuries when IV contrast given)
- detection of bowel
and pancreatic lesions is less sensitive, although helical abdominal CT has higher
sensitivity for detecting blunt bowel injury
- has advantage of delineating
nature of intra-abdominal injury
- in absence of splenic or liver injuries the presence of free fluid in the
abdominal cavity on CT suggests an injury to GI tract and/or its mesentery, and
mandates further surgical evaluation
Ultrasound
Can be performed in resuscitation room without compromising resuscitation.
91-100% sensitive and >98% specific in detecting haemoperitoneum. Less
sensitive in detecting nature of injury, particularly in liver, pancreas and
bowel.
FAST
- focused abdominal sonography for trauma
- aim of assessment is to detect haemoperitoneum
- sensitivity is poor in some series although specificity is high. As a
result patients with a normal FAST require further evaluation
- ~30% of patients with intra-abdominal injury do not have haemoperitoneum
(majority do not require intervention).
Diagnostic laparoscopy
- may be useful in haemodynamically stable patient
- good for looking at diaphragm and identifying need for laparotomy but may miss
specific organ injuries, particularly of bowel
- best suited for evaluation of equivocal penetrating wounds
Angiography
Almost no role in diagnosis of abdominal trauma however transcatheter
embolisation has a role in management of persistent hepatic bleeding (not
stopped by surgery) and in patients with bleeding from a traumatized lumbar or
intercostal artery
Laparotomy
Specific injuries
Splenic injury
- when associated chest or neurological injuries are severe minor splenic
injury may not initially be detected unless further investigation is undertaken.
Left rib fractures associated with a 4 times increased odds of splenic
injury but if this is the only risk factor the incidence of splenic injury
is low.
- minor trauma may cause injury to enlarged spleen (eg from malaria, lymphoma,
haemolytic anaemia
- immediate splenectomy indicated in patients with severe multiple injuries,
splenic avulsion, fragmentation or rupture, extensive hilar injuries, failure of
haemostasis, peritoneal contamination from GI injury or rupture of diseased
spleen
- conservative non-operative approach:
- stable patients <55 yrs in whom
associated abdominal injuries have been excluded
- observe in hospital for 10-14 days, bed rest for 1 week
- no strenous activity for 6-8 weeks
- no contact sports for 6 months
- NB delayed rupture and haemorrhage may occur. Usually in first 48 h
- nonoperative management of children with splenic or hepatic injury
- if patient is haemodynamically stable
- requires replacement of
<1/2 of estimated blood volume (ie requires <40 ml/kg)
- free of
concomitant intra-abdominal injury requiring exploration
- splenectomy avoided in >90% of children (only 13-50% of adults).
- polyvalent pneumococcal vaccine should be given after splenectomy
Hepatic injury
- second most commonly injured after blunt abdominal trauma
- most frequently missed injury in trauma deaths
- diagnosis made at laparotomy in unstable patients and by CT in stable
patients. Latter enables conservative treatment in selected patients,
particularly children. Patients should be stable, have no associated abdominal
injuries, and be assessed repeatedly, including follow up CT
- dilutional coagulopathy and thrombocytopaenia are common following hepatic
repair
- complications of liver injury:
- early: relate to hypoperfusion or massive blood transfusion
- late: sepsis
Management
- Non-operative management. Criteria:
- haemodynamically stable
- absence of peritoneal signs
- other intra-abdominal injury can be excluded with reasonable certainty
- limited on-going transfusion requirements
- Operative management
- Packing and limited surgery may be best initial procedure particularly
when coagulopathy or hypothermia develops
GI tract injury
- more common following penetrating trauma
- <5% of patients following
blunt trauma. More common following direct blow to epigastrium
- both DPL and CT may fail to diagnose duodenal perforation or haematoma. A high
index of suspicion should be maintained in patients with persistent abdominal
pain and tenderness
- duodenal rupture
- classically encountered in the intoxicated unrestrained
driver involved in a frontal impact RTA. 40% have associated injury
- bloody NG aspirate should raise
suspicion of injury
- contrast CT are indicated in high-risk patient following completion of secondary
survey. (Alternative: duodenal "C-loop" gastrograffin studies
- appearance of transverse linear ecchymosis on abdominal wall (seat belt sign)
or presence of anterior lumbar compression fracture should raise suspicion of
intestinal injury
- colon injury
- rare following blunt trauma
Pancreatic injury
- often associated with duodenal, hepatic and splenic trauma
- clue to diagnosis is in history. Most often due
to direct epigastric blow compressing pancreas against vertebral column
- also
occurs in association with lower thoracic or upper lumbar vertebral #s
- contrast CT most useful investigation but may not identify significant
pancreatic trauma in the immediate post-injury period. Helical abdominal CT
identifies approximately 2/3.
- initial raised plasma amylase does not predict pancreatic or hollow viscus injury.
Subsequent rise in amylase over next 24 h more useful
Treatment
- severe injuries to the body of the pancreas are best managed by distal
pancreatectomy
- the majority of penetrating injuries can be managed with stump drainage alone.
- pancreaticoduodenectomy indicated in fewer than 5% of cases.
Complications
Common
- fistulae
- abscess
- pseudocyst are common
Urinary tract and renal injury
- more common after blunt than penetrating injury
- identification and treatment of other major injuries takes precedence
- gross haematuria requires investigation (CT is examination of choice if
haemodynamically stable), while microscopic haematuria does not unless there is
unexplained shock. Degree of macroscopic haematuria not related to severity of
injury
- majority of renal injuries can be treated conservatively
- bladder rupture commonly associated with pelvic fractures
- >95% have
macroscopic haematuria
- Retrograde cystography is investigation of choice
- Intraperitoneal rupture requires operative repair while extraperitoneal rupture
can be treated conservatively
- urethral trauma should be suspected if there is blood at meatus, perineal
injury or abnormal position of prostate. Treatment is suprapubic drainage and
delayed definitive repair
Diaphragmatic injury
- <5% of cases of blunt trauma
- left sided in 80%
- suspect with penetrating injury below 5th rib
- diagnosis may be difficult, especially in presence of IPPV, and may only
become evident when ventilatory support withdrawn
- ultrasound may be better than CT because of its variable angle of view.
Laparoscopy provides good views of diaphragm
- spontaneous healing does not occur
Penetrating injury
- prophylactic antibiotics for 24h are satisfactory for penetrating injuries
Pelvic injury
Associated with a mortality of 13-23% and significant morbidity. In majority
of patients massive retroperitoneal haemorrhage is direct cause or a major
contributing factor to mortality
Mechanism of injury
Significant pelvic fractures are due to high energy blunt trauma. Usually a
RTA, fall or crush injury.
Clinical features
- suggested by pain on movement, structural instability, gross haematuria,
peripelvic ecchymoses
- rectal examination mandatory to identify rectal injury and prostatic position
- if patient has a stable pelvic fracture hypotension is probably due to
haemoperitoneum
Management
- bleeding is usually bony or venous in origin
- if patient is still haemodynamically unstable perform early open DPL. If
grossly positive laparotomy should precede external fixation or angiography. If
positive by cell count only risk of major intra-abdominal haemorrhage is low and
control of pelvic bleeding becomes main priority
- early stabilization with external fixators helps to minimize bleeding from
veins and small arterioles near # sites. Also reduces volume of an open pelvis
and thus improves tamponade
- pelvic angiography with embolization often successful in controlling arterial
haemorrhage but logistically difficult
- large vessel bleeding requires surgical control
- early operative stabilization of complex pelvic fractures preferred in ICU:
facilitates respiratory care, pain control and early mobilization
- compound fractures involving perineum, rectum or vagina require aggressive
surgery to avoid high mortality
Complications of comminuted fracture of the pelvis
Acute:
- major haemorrhage (leading cause of death); shock, elevated intra-abdominal
pressure
- visceral and soft tissue injury: fractures may be compound into the
perineum or vagina, or be associated with lacerations into the rectum or bladder
(esp. with lateral compression and vertically unstable injuries).
- urethral injuries common in males. Iinsertion of a urethral urinary
catheter contraindicated
- sacral plexus injury
- ileus
- pain
- fat embolization
- acute respiratory distress syndrome: in about 15%. This is possibly related
to the frequent occurrence of associated thoracic injuries, multiple blood
transfusions, shock, and fat embolization.
- DVT because of stasis resulting from prolonged bed rest, and prophylaxis is
often contraindicated
Late:
- infection-second most common cause of death
- disability/immobility/instability
- incontinence
- pain
Retroperitoneal haemorrhage
- frequent following blunt trauma
- commonly caused by injury to:
- lumbar spine
- pelvis
- bladder
- kidney
- less commonly pancreas, duodenum, major vessels: cause central rather than
lateral or pelvic haematomas
- CT with enteral contrast most useful investigation in stable patient
- central haematoma should be explored with proximal vascular control
- lateral or pelvic haematomas should not be explored unless there is evidence
of major arterial injury, intraperitoneal bladder rupture or colonic injury
© Charles Gomersall and Ross Calcroft September 1999 |
