Trauma in children

In brief summary, children have increased suceptibility to injury from trauma when compared to adults. In many ways they are disadvantaged; for instance small bodies experience force transfer more evenly and injuries multiply as the result. Their small heads with tight brains are more prone to raised ICP, they have more pulmonary contusions as their elastic ribs transfer impact forces to the lungs and solid organs. Their spines can flex deceptively, injuring the spinal cord while leaving no radiological evidence. In spite of this, children tend to do better than adults in terms of their recovery and complication rate when it comes to trauma. They are extubated faster and their mortality is lower.

Question 17 from the second paper of 2005 asked the candidates to "Outline  the  differences  in  management of  multi-trauma  occurring in  a  6-year-old child, compared with management of multi-trauma occurring in an adult." This can be answered reasonably well after reviewing the most recent paediatric ATLS manual, or even the trauma chapter of the most recent version of an Advanced Paediatric Life Support course handbook. In the absence of either of these resources, one must resort to some sort published literature. Of these, the 1998 article by Reichmann offers insight into the difference of trauma patterns between children and adults. The college were not looking for anything like that. Judging by the college answer to Question 17, they wanted a generic approach to paediatric trauma, and how that differs to the adult trauma approach. The best article to answer such a question would probably be a critical overview by Wetzel and Burns (2002). If these links break or the articles are somehow wiped from human history, Oh's Manual has an entire chapter dedicated to the issue of paediatric trauma (Ch 110, "Paediatric Trauma" by Kevin McCaffery.) The greatest detail about specific organ injuries can be found in the article by Avarello and Cantor (2007): These resources have been remixed and recombined into the summary which follows.

In brief summary:

Airway:  More difficult anatomy; cricothyroidotomy is challenging Breathing: Tension pneumothorax is harder to identify.  Ribs rarely fracture (cartilaginous): force is transmitted to the lungs, causing more pulmonary contusions. Hypoxia is of more rapid onset. Circulation: Increased reserve of compensation: more blood may be lost before manifestations of shock are seen. Disability: Modified GCS must be used. Greater risk of raised ICP because of anatomical differences (bigger brain, smaller skull). C-spine injury is usually much higher (C1-C3) and is possible without radiological evidence (SCIWORA). Exposure: Hypothermia is more likely (mass:BSA ratio)

Injury patterns as compared with adults: - more multiple injuries - improved survival from trauma - shorter ICU stay, fewer complications - need to consider non-accidental causes Burns are of a different pattern :more head/face from falling pots, more hands from grabbing hot objects Abdominal issues: - Organs are unprotected by rib cage - Spleen and liver are often lacerated - Shallow pelvis fails to protect the bladder - Kidneys are more mobile and less defended - Laparotomy is rarely indicated Metabolic problems: Hyperglycaemia and glycogen reserve depletion is more rapid; hypercatabolism develops early Family and social issues: - counselling of carer - Guilt, blame, etc

Unique issues in paediatric patterns of injury: 

Difference in trauma patterns among children and adults

From Reichmann et al, as well as Avarello and Cantor (2007):

• Children were mainly hurt as pedestrians, whereas adults had an accident more often as car passengers. 
• Children have better survival then adults 
• Children suffer fewer in-hospital complications
• Duration of ventilation is shorter
• Smaller body: force is more widely distributed, making multiple injuries more likely.

Paediatric airway in trauma

Airway injuries are less common in children, because:

• The neck is shorter
• The larynx is more anterior and therefore more protected
• Tracheobronchial tree  is more elastic and less prone to traumatic disruption

Airway management may be more complex:

• The airway may be rendered more difficult by need for C-spine stabilisation
• Cricothyroid membrane may be diffciult to locate

Paediatric chest injury

The pattern of paediatric chest injuries is similar to the adult pattern epidemiologically. However, in children there are fewer rib fractures.

• Immature ribcage is largely cartilaginous; more of the impact is transmitted to the viscera (the ribs would normally absorb a lot of the force by breaking). Contusions of the thoracic organs are therefore more severe.
• Hypoxia is of faster onset: children have a higher basal metabolic rate and therefore will run out of oxygen faster than adults when the respiration is compromised.
• Short neck makes distended neck veins and tracheal deviation difficult to assess

Paediatric circulatory collapse due to haemorrhage

Haemorrhagic shock is a late feature:

• Compensation will occur up until nearly 50% of the blood volume is lost
• Blood dose is 10ml/kg per bolus
• Decent crystalloid resuscitation volume is 50ml/kg (Wetzel et al, 2002)

Lowest acceptable systolic blood pressures per age group are as follows:

• 60 mm Hg in term neonates (0 to 28 days)
• 70 mm Hg in infants (1 month to 12 months)
• 70 mm Hg + (2 age in years) in children 1 to 10 years of age
• 90 mm Hg in children over 10 years of age

Paediatric traumatic brain injury:

It is the major cause of death in the paediatric trauma population. And head injury is the most common injury in paediatric trauma (87% - Schalamon et al, 2003). Long-term outcome from paediatric trauma is mainly determined by the severity of their brain injury.  There are several key differences between children and adults which make traumatic barin injury more deadly in this population: 

• Less room for brain swelling. Adult brain volume is reached well before the skull stops growing (6 years vs. 16 years) - i.e. for a period of ten years an abnormally large brain sits snugly inside an unsuitably small skull.
• Less myelination (thus, greater propensity towards oedema)
• Less CSF volume relative to brain volume
• Less intracranial blood volume relative to brain volume
• More intracellular sodium in the neurons and glial cells
• Impaired ability to excrete sodium from the neurons

Management of traumatic brain injury in the paediatric setting is complicated by several factors:

• A modified GCS is required
• There is no agreed-upon ICP threshold in children (most would use 20 mmHg)
• The CPP threshold is also debated (most people would use 40-50 mmHg)
• Evidence for the utility of decompressive craniectomy is even weaker than in adults
• For use of therapeutic hypothermia in children with raised ICP, the evidence is as conflicted as among adults- i.e. it is unclear whether it is dangerous or merely pointless. 

Paediatric spinal injury

Paediatric spinal (particularly C-spine) injury patterns differ from adult patterns because:

• The head is relatively bigger
• The infantile vertebral column can lengthen significantly without rupture
• The interspinous ligaments are more elastic
• The vertebra are immature and ossify slowly and progressively over the course of childhood

Specific anatomic differences of the paediatric C-spine (almost verbatum from Avarello et al, 2007):

• Increased flexibility of
• Flatter facet joints with a more horizontal orientation
• Basilar odontoid synchondrosis fuse at 3 to 7 years of age
• Apical odontoid epiphysis fuse at 5 to 7 years of age
• Posterior arch of C1 fuses at 4 years of age
• Anterior arch fuses at 7 to 10 years of age
• Increased preodontoid space up to 4 to 5 mm (3 mm in an adult)
• Pseudosubluxation of C2 on C3 seen in 40% of children
• Prevertebral space size may change because of variations with respiration 

The result of these differences:

• High lesions are more common (C1-C3)
• There may be nothing to see radiologically (SCIWORA, spinal cord injury without radiological abnormality) - MRI and CT may yield no useful information and look normal even when there are obvious  neurological signs.
• Radiologic interpretation is a problem due to progressive and incomplete ossification of the bony elements. For exmaple, epiphyses of spinous process tips may mimic fractures.

Paediatric abdominal injury

The abdomen of a poorly cooperative child is difficult to examine and the idnex of suspicion needs to be higher for blunt abdominal trauma.

• Abdominal visceral injury is more likely: abdominal viscera are proportionally larger, and less protected by the more transverse ribs (i.e. more of the liver and spleen stick out into the abdomen).
• Of the abdominal viscera which are affected, the most frequently injured organ is the spleen.
• There are more bladder rupture injuries and the pelvis is shallow and more of the full bladder extends into the abdominal cavity
• Aerophagia due to crying is a major problem, as it leads to gastric distension and aspiration, as well as ventilation failure due to diaphragmatic splinting.
• Kidneys are lss protected by fat and muscle, and more mobile: thus, more susceptible to deceleration injury (Avarello et al, 2007)

Characteristic childhood abdominal injury patterns exist, which are somewhat different from their counterpart injuries among adults doing childish things:

• Handlebars of the bicycle are likely to cause duodenal and pancreatic injuries
• Lap belt injuries in motor vehicle accidents lead to small bowel rupture
• Chance fractures of the L-spine (due to hyperflexion) need to be suspected if there is a history of hyperflexion injury.

A CT of the abdomen is the gold standard. Oh's Manual quotes the 2000 study by Coley et al which concluded that "FAST has insufficient sensitivity and negative predictive value to be used as a screening imaging test in hemodynamically stable children with blunt abdominal trauma."

Unlike adults who barely need to fart wrong to score a trauma laparotomy, the management of paediatric abdominal trauma is surprisingly conservative even for severe solid organ injuries. Specific indications for an urgent laparotomy are listed in Oh's Manual:

• Penetrating injury
• Perforated hollow viscus
• Haemodynamic instability after good fluid resuscitation
• Peritonism
• Diaphragmatic rupture

Paediatric burns

The pattern of injury is typically different to adults:

• Facial and head burns are more common: the children who pull the handle of a pot-full of hot liquid onto themselves off a high overhead bench are usually the recipients of these.
• Severe hand injuries from grabbing hot objects are more common
• Burns of the "seat", genitals and perineum are more common among infants and young toddlers because of being lowered into an inappropriately hot bath

Non-accidental injury

Oh's Manual gives several characteristic features of non-accidental injury which are reproduced below:

• Delayed presentation
• Injuries inconsistent with history provided
• Injuries inconsistent with developmental stage
• Suspicious pattern of injury:
  • Bruises in the shape of belt buckles, hand prints
  • Multiple bruises of different ages
  • Multiple fractures of different ages
  • Multiple burns of different ages
  • Retinal haemorrhages
  • Bite marks
  • Bleeding or trauma to the anus or genitals
  • Specific fracture patterns, eg. spiral humeral fractures
• Risk factors:
  • Congential abnormalities
  • Physical or intellectual disability
  • Adoption
  • Young or single parents
  • Substance abuse
  • Parents who were themselves abused
  • Environmental stress, eg. relationship breakdown or divorse.

ICU-specific issues to consider

• Vasopressin response to injury is finite. A relative vasopressin deficiency may develop in the course of the post-trauma SIRS.
• Stress response triggers dramatic hyperglycaemia, followed by rapid glucose exhaustion. Children recovering from mutli-trauma will rapidly burn through their glycogen stores and then develop an acute "nutritional catastrophe", which is unresponsive to nutritional intervention and which is characterised by catabolism and structural protein loss
• Hyperglycaemia offers abundant substrate to the synthesis of excess lactate, and lactic acidosis will develop.
• Hypothermia is more likely in children due to their high surface area–to–body mass ratio. It is a negative prognostic indicator: at temperatures below 32°C, mortality approaches 100%. 

Social factors

Remember the family:

• Counseling will be required.
• Guilt, fear, blame, accusations, etc- even when the injury is accidental.
• Family breakdown is a common consequence of the death of a child.