CHAPTER
I 17 I
The child with abdominal injury
Blunt trauma causes the majority of abdominal injuries in children. Most occur because of accidents on the roads, although a significant number happen during recreational activities. A high index of suspicion is necessary if some injuries are not to be missed.
The abdominal contents are very susceptible to injury in children for a number of reasons.The abdominal wall is thin and offers relatively little protection.The diaphragm is more horizontal than in adults, causing the liver and spleen to lie lower and more anteriorly.
Furthermore the ribs, being very elastic, offer less protection to these organs. Finally, the bladder is intra-abdominal, rather than pelvic, and is therefore more exposed when full.
Respiratory compromise can complicate abdominal injury because diaphragmatic irritation or splinting may occur – reducing the use of the diaphragm during breathing.
may be the cause of blood loss. The abdomen should be assessed urgently to establish whether early operative intervention is necessary. In other circumstances, the abdominal examination is carried out during the secondary survey.
The abdomen should be inspected for bruising, lacerations, and penetrating wounds.
Major intra-abdominal injury can occur without obvious external signs, and visible bruising is therefore highly significant. Children with visible abdominal bruising, especially if associated with a lumbar spine fracture, have a high incidence of bowel perforation. A high index of suspicion and frequent repeated clinical assessment is appropriate in such cases. The external urethral meatus should be examined for blood.
Gentle palpation should be carried out. This will reveal areas of tenderness and rigidity. Care should be taken not to hurt the child because his or her continued cooperation is important during the repeated examinations that form an important part of management.
Rectal and vaginal examinations are mandatory in an adult with multiple injuries. In children every effort should be made to limit rectal examination to that performed by the surgeon who is going to operate on that child. Even then it should only be done if the result of the examination will alter the management.Vaginal examination should not be performed on children.
Aids to assessment
Both gastric and urinary bladder drainage may help the assessment by decompressing the abdomen.
Gastric drainage
Air swallowing during crying with consequent acute gastric dilatation is common in children. Early passage of a gastric tube of an appropriate size is essential. The tube should be aspirated regularly and left on free drainage at other times. A massively distended stomach can mimic intra-abdominal pathology needing laparotomy, and cause serious diaphragm splintage with consequent respiratory compromise.
Urinary catheterisation
Catheterisation of a child should only be performed if the child cannot pass urine spontaneously, or if continuous accurate output measurement is required. The route (urethral or suprapubic) will depend on factors related to signs of urethral, bladder, or intra-abdominal or pelvic injury (such as blood at the external meatus, or bruising in the scrotum or perineum). If a boy requires urethral catheterisation, urethral damage must be excluded first. The catheter should be silastic and as small as possible in order to reduce the risk of subsequent urethral stricture formation.
Investigations Blood tests
Intravenous access will have already been secured during the primary survey and resuscitation, and at that time blood will have been drawn for baseline blood counts, urea and electrolytes, and cross-matching. An amylase estimation should be requested and can usually be performed on the sample sent for urea and electrolytes. Arterial blood gases should be sent if indicated. Repeated monitoring of blood parameters may be appropriate in some patients.
Radiographs Views of the lateral cervical spine, chest, and pelvis will have been obtained during the course of the primary survey. Neither a normal chest radiograph
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nor a normal pelvic radiograph excludes abdominal injury. A plain abdominal radiograph may be helpful to look for the position of the gastric tube, distribution of abdominal gas, presence of free gas, and soft tissue swellings including a full bladder.
Renal injury may need investigation by intravenous urography. Blood at the external urethral meatus will require investigation using retrograde urethrography.
Computed tomography A double contrast CT scan of the abdomen (with intravenous and intragastric contrast) is the radiological investigation of choice in children. CT will alert the surgeon to solid organ rupture, free intraperitoneal contrast from a perforated viscus, the presence or absence of two functioning kidneys, and free intraperitoneal contrast from a ruptured bladder.
Ultrasound This may be readily available and give early information on free fluid and lacerations in the liver, spleen, or kidneys. A normal ultrasound early on does not exclude injury.
Diagnostic peritoneal lavage This should rarely be used in children, as the presence of intraperitoneal blood per se is not necessarily an indication for laparotomy. Once lavage fluid has been introduced, the peritoneum shows signs of irritation for up to 48 hours, and hence reduces the possibility of accurate repeated assessment. Peritoneal lavage should therefore only be carried out by the surgeon managing the case and will be needed only where facilities for imaging (CT and ultrasound) and for regular clinical reassessment are absent.
A lavage should be considered positive if the red cell count is over 100 000/mm3, the white cell count over 500/mm3, or if enteric contents or bacteria are seen. Laboratory analysis gives the best sensitivity and specificity for this test. Bedside estimation is dangerously unreliable. This technique is described in Chapter 24.
DEFINITIVE CARE
Non-operative management
Until the early 1980s, both adult and paediatric patients with haemoperitoneum would undergo laparotomy. Damage to the spleen or liver would result in splenectomy or partial hepatectomy respectively. It has since been shown that the haemorrhage is often self-limiting, and many of these operations can therefore be avoided. As well as avoiding the morbidity associated with laparotomy, this approach also reduces the number of children at risk of overwhelming, potentially fatal sepsis following splenectomy.
For non-operative management to be undertaken the following are essential:
• Adequate observation and frequent monitoring.
• Precise fluid management.
• The immediate availability of a surgeon trained to operate on the paediatric abdomen (should this become necessary).
The need for clotting factors such as platelets, fresh frozen plasma, or cryoprecipitate must be monitored. Vigorous and early management of coagulopathy is indicated in order to improve clotting and hence achieve haemostasis.
Indications for operative intervention
Children whose circulation is not stable after replacement of 40 ml/kg of fluid are probably bleeding into the thoracic or abdominal cavities. In the absence of clear
THE CHILD WITH ABDOMINAL INJURY
thoracic bleeding, urgent laparotomy may be necessary. All children with penetrating abdominal injuries and those with definite signs of bowel perforation will require urgent laparotomy.
A non-functioning kidney, as demonstrated on contrast studies, may have suffered renal pedicle injury. These require immediate exploration to ascertain whether the kidney can be saved. The warm ischaemia time for a kidney is only 45–60 minutes.
It is essential that the surgeon performing these procedures is competent to deal with paediatric trauma and can perform any reconstructive surgery that may be required.
SUMMARY
THE CHILD WITH ABDOMINAL INJURY
Indications for operative intervention following abdominal injury Laparotomy
Refractory shock Penetrating injuries Signs of bowel perforation Renal exploration
Non-functioning kidney
• The assessment and management of airway, breathing, and circulation must be carried out first. Abdominal assessment is only carried out at this stage if shock is refractory
• Abdominal assessment consists of careful observation and gentle, repeated palpation.
Gastric and urinary drainage aid this assessment
• Abdominal CT scan is the investigation of choice. Diagnostic peritoneal lavage is rarely used in children
• Some children with visceral injury may be managed non-operatively if essential requirements are met. Others will need urgent operative intervention
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