Paediatric Abdominopelvic Trauma

Introduction

• 90% due to blunt trauma
• Overall mortality <5%
• 30% have injury to one or body regions (RCH)
• Differences from adults
  • Rib cage does not extend as far down
  • Ribs are more compliant
  • Abdominal wall and musculature thinner and less protective
  • Less soft tissue between organs to absorb kinetic energy
  • Bladder not protected by bony pelvis
  • Gaseous distension of stomach can occur early and impair ventilation/impair examination
  • Compliant body may show no signs of serious injury despite massive force
  • Tachycardia may be only sign
  • Hypotension is a late, pre-terminal sign
  • Adult protective systems are often ill-fitting and may predispose to injury
  • Small size means single impact can affect multiple body sites
  • Liver and spleen take up more room in abdominal cavity

Mechanisms

• Falls are most common
• MVA
• Run over in driveway
• NAI

Examination

• Primary survey
• Secondary survey
  • Abdominal examination should be performed repeatedly and preferably by the same clinician
  • Early use of opiate analgesia improves examination reliability
  • Any external signs warrant at least prolonged observation, even in absence of other positive findings
  • If minor injuries only, mobility of the patient can be a useful screening tool
• Q3-5min obs in critically unwell child
• Must observe vital signs, esp. looking for tachycardia closely
• Seatbelt sign
  • 15% of children with this have intra-abdominal injuries and 50% of these require an intervention

Investigations

• Bloods
  • FBC, Chem20, Lipase, Group and save
  • Some studies have shown raised transaminases with normal examination is associated with non-specific intra-abdominal injuries
  • Normal lipase does not rule out pancreatic injury
• Obtain urine
• FAST
  • Stable and free fluid identified – CT
  • Deteriorating and free fluid identified – Operative intervention
  • Sensitivity probably around 90-100% to rule out free intra-peritoneal fluid
  • RCH states not routinely performed as evaluation of fluid volume can be difficult and ultimately the presence of blood does not indicate surgery
• CT scan with contrast
  • Investigation of choice for stable abdominal trauma in consultation with paediatric surgeons
  • Additional oral contrast may aid in diagnosis of duodenal or pancreatic injuries, but controversial
  • Should be reserved for those in whom a high index of suspicion exists for intra-abdominal injury
• Formal USS
  • Takes longer than CT
  • Tenderness, ileus, luminal distension all make examination difficult
  • Really only warranted if CT unavailable

General management

• Up to 2x 20mL/kg boluses of crystalloid
• If fluid therapy still required, blood 10mL/kg boluses indicated
  • 8mL/kg raises Hb by 10g/L
• Early gastric decompression
• IDC if urine output needs monitoring
  • CI if blood at meatus or bruising of perineum – need retrograde urethrogram and surgical opinion
• All patients undergoing CT should have NG/OG prior
  • Reduces risk of vomiting in CT
  • Allows for oral contrast to be given
  • Protects against risks of acute gastric dilatation

Penetrating injury

• Almost always mandates exploration by laparoscopy/otomy
• Thinner abdominal wall means peritoneal cavity penetration is more likely
• Gunshot wounds all need exploration in theatre
• Erect CXR or lateral decubitus film can identify free air

Pelvic fractures

• Severe forces required
• Greater elasticity at pubic symphysis, SI joints and plasticity of bone means fracture requires higher forces
• Avulsion fractures can occur
• Single fractures occur more commonly due to laxity of joints
• 19% will have co-existing visceral injuries
• Mortality rate <6% in studies
• Vascular injury and exsanguination are rare events in pelvic trauma

Disposition

• All children with significant injury require admission
• All patients with free intra-peritoneal air require laparotomy
• Surgical colleagues should have involvement in this decision
• Younger children with significant mechanisms should all be observed for at least 12-24 hours
• In older children, repeated normal examination may allow discharge and close follow-up with LMO within 24 hours
• Children with ongoing abdominal pain, despite normal imaging, should not be discharged from ED

Spleen (RCH)

• Isolated injuries can be managed conservatively in almost all cases
• Typically slow initial bleeding (like all solid organs) but risk of late sudden exsanguination
• Children more stable than adults with similar injuries
• Bed rest until pain settles
• F/U USS at 3 months but not essential if clinically well
• Indications for laparotomy
  • Haemodynamic instability despite resuscitation
  • Transfusion of >40mL/kg during resuscitation
• Late rupture
  • 6% of adult patients. Rare in children.
  • Unclear if related to early mobilisation/activity
  • Strict bed-rest until abdominal pain subsides, restricted activity for 3 months then full return to activity (some reports suggest 6 weeks is enough)
  • Most important part is educating parents of signs of late rupture
  • Can still be treated conservatively
• Loss of splenic function
  • Need 1/3 of spleen (in adults) for immunological fx
  • If suspicious, immunise and start Pen V
  • Look for Howell-Jolly bodies on blood film (suggesting function alasplenia)

Liver (RCH)

• 80% can be treated conservatively
• Surgical intervention warranted if >40mL/kg resuscitation over 2 hours with ongoing instability
• Surgery is complex and carries a high morbidity/mortality risk
• Should transfer all to tertiary centre
  • If too unstable, urgent packing of liver prior to t/f may allow for this
• CT scan with contrast is ideal if surgeon is to have any chance of identifying injury on laparotomy
• Same disposition as splenic injuries with bed rest until pain settles, then 3 months of reduced activity
• Late problems
  • Continued bile leak
    • Slowly increasing abdominal distension
    • Rising bilirubin
    • USS evidence of increasing ascites
• Carries greater risk of fatal haemorrhage than splenic injury

Pancreas (RCH)

• Routine oral intake witheld until lipase normalised and resolution of symptoms
• No indication for urgent laparotomy in isolated pancreatic injuries
• Duct integrity is key and may require later ERCP
• Late problems
  • Pseudocyst formation
    • Worsening abdo pain, nausea or vomiting
    • Lipase + USS can confirm
    • Drainage if continues to enlarge

Intestinal injuries (RCH)

• Uncommon
• Usually rapid deceleration causing shear injury at DJ flexure, terminal ileum, caecum or sigmoid colon, abdominal crush injuries or penetrating injury
• Diagnosis often delayed
• Repeated examination, bowel sound assessment, repeat X-rays for free air may be required
• If devascularised tissue, may present with associated perforation days later
• Any free intra-peritoneal air demands urgent laparotomy

Duodenum (RCH)

• Suspect if bruising to epigastrium, severe epigastric tenderness or bilious vomiting
• Often associated pancreatic injuries
• Bicycle handlebars and seat belt injuries are common causes
• May be intramural haematoma or perforation/rupture
• Haematoma
  • Seen on CT but upper GI contrast study will confirm
  • Can treat with NG drainage but obstruction may take 3 weeks to resolve
• Perforation
  • Free air may be retroperitoneal (ground glass retroperitoneum)

Kidney (RCH)

• Suspect on history, wounds, bruising in flank or frank/microscopic haematuria
• If microscopic haematuria evident, further Ix is warranted
• If well, USS is simplest way to identify kidney injury, however, contrast CT is Ix of choice and gives evidence of renal function
• Antibiotics indicated for all renal trauma patients and continued at prophylactic dose until injuries have healed
• Indications for laparotomy
  • Ongoing blood loss despite resuscitation
  • Majority of explorations will lead to nephrectomy
• Late problems
  • Continued haematuria due to AV fistula
  • Loss of function: Significant injury requires repeat USS and DMSA scan at 3 months
  • F/u blood pressure for one year

Microscopic haematuria

• In asymptomatic, adult patients no imaging is required. Just need follow-up 
• In paediatrics, some experts advocate imaging in patients with microscopic haematuria due to increased risk of significant renal injury
  • Cut-offs from 5-50 RBC/HPF have been advocated
  • Very little evidence for these cut-offs (Morey et al)
  • <50RBC/HPF has low likelihood of associated renal injury
• DFTB
  • Trend of microscopic haematuria is more useful (DFTB)
  • If down-trending, less likely to be significant injury
  • No role for dipstick testing
  • Repeat examination, FBC and urine MCS at 4 hours – If stable and no further haematuria, safe for discharge
• Macroscopic haematuria always warrants imaging

Bladder (RCH)

• Look for evidence of urine extravastation (oedema of scrotum, lower abdomen, upper thighs), bruising in suprapubic region, blood at external urethra, failure to pass any urine
• Rx
  • Urinalysis
  • Monitoring of urine output
  • CT scan with contrast
• Laparotomy reserved for intraperitoneal rupture. If any evidence of injury to bladder neck, insertion of SPC under USS guidance with referral to paediatric urologist is safest course

Urethra (RCH)

• Straddle injury, pelvic fracture, blood at meatus, high-riding prostate in older boys
• Serious further injury can be caused by IDC attempts
• Rx
  • CT with contrast and ascending contrast urethrogram
  • Refer
  • SPC under USS guidance if bladder drainage required prior to t/f

Last Updated on October 27, 2021 by Andrew Crofton