Abdominal trauma - Clinical Tree

Essentials

1
One in 10 deaths from trauma is due to abdominal injuries.
2
Abdominal injuries may be occult—overshadowed by more apparent external and orthopaedic injuries—and may be missed initially.
3
Detection of intra-abdominal injuries requires a high index of suspicion to avoid preventable morbidity and mortality.
4
Computed tomography scanning provides organ-specific diagnosis but requires sufficient stability for transfer from the resuscitation area.
5
Bedside investigations, such as focused assessment sonography in trauma (FAST), assist in the evaluation of suspected intra-abdominal trauma, but they have limitations.
6
Intra-abdominal trauma frequently coexists with other systemic trauma. Evaluation and disposition are greatly enhanced by early involvement of senior trauma surgeons.

Introduction

One in 10 deaths from trauma is due to abdominal injuries. These may be difficult to detect initially, as the abdominal cavity cannot be viewed with the naked eye; plain radiography is insensitive to intra-abdominal bleeding and solid organ injury. Moreover, signs and symptoms of blood loss may be attributed to more obvious injuries. It is therefore not surprising that missed abdominal injuries are a major cause of preventable death in trauma patients. A high index of suspicion should be maintained for this important cause of morbidity and mortality.

A stepwise approach to the management of the multiply injured patient will address the possibility of significant intra-abdominal injury. The principles of initial management are to identify the presence or otherwise of such injury, the need for surgery and the most appropriate timing of interventions. This process requires the presence of an experienced clinician at the earliest possible stage to direct and co-ordinate the trauma team. Ideally, the trauma surgeon should be present at the initial resuscitation.

The initial resuscitation, history, examination and specific investigations are reviewed in turn in the following text.

Primary and secondary surveys

Assessment of circulation during the primary survey may include evaluation for possible intra-abdominal haemorrhage, particularly in the unstable patient requiring continued fluid resuscitation without other identified sources of haemorrhage. When the abdomen is being examined, expose the patient fully, including an examination of the back as well as the rectum and vagina.

History

The history and knowledge of the mechanism of injury will provide vital clues to the likelihood of significant intra-abdominal trauma ( Box 3.5.1 ). Ambulance personnel will be able to provide valuable details of the incident. It is important to remember that trauma does not skip body regions and that significant intra-abdominal injuries frequently occur in the absence of external signs of abdominal trauma. Other important aspects of focused history are summarized by the acronym AMPLE: Allergies, Medications, Past medical history, Last ate and drank, Events associated with the trauma incident.

Box 3.5.1

Risk factors for intra-abdominal injury in trauma patients

High-speed vehicular collisions
Pedestrian struck by vehicle
Fall from greater than standing height
Hypotension or history of hypotension (systolic blood pressure <100 mmHg) at any time
Presence of significant chest or pelvic injuries
Significant injuries on physically opposing sides of the abdomen

Abdominal examination

Penetrating injuries are overt and dramatic. Blunt trauma is more common and more difficult to assess on clinical grounds. Bruising and abrasions are associated with intra-abdominal pathology. The spleen and liver are the most commonly injured organs, with different patterns of injury seen in blunt and penetrating injuries ( Table 3.5.1 ). Marks from lap-type seatbelts carry a high association with Chance fractures ( most common in T12, L1, and L2), small bowel injury and pancreatic injury. Palpation of the abdomen may reveal local/generalized tenderness and evidence of peritonism, but it is less reliable in detecting retroperitoneal injury and in the presence of an altered sensorium. Auscultation is rarely useful; however, the absence of bowel sounds should increase the suspicion of intra-abdominal injury.

Table 3.5.1

Organ injuries associated with blunt and penetrating trauma

Reproduced with permission from American College of Surgeons Committee on Trauma. Advanced Trauma Life Support Student Course Manual . 10th ed. Chicago: ACS; 2018.

	Blunt trauma (%)	Stabbing (%)	Gunshot (%)
Spleen	40–55	–	–
Liver	35–45	40	30
Retroperitoneal haematoma	15	–	–
Small bowel	5–10	30	50
Diaphragm	–	20	–
Colon	–	15	40
Abdominal vascular structures	–	–	25

Examination of the abdomen is not complete until the back, buttocks and perineum have been fully exposed. In obese patients, skin folds may obscure penetrating injuries. Rectal examination may demonstrate frank blood from injured bowel and may allow direct palpation of fractures or breaches of bowel wall integrity. Vaginal examination is similarly important and, in the unresponsive patient, may detect a tampon (essential to remove) or gravid uterus.

Although unexplained hypotension suggests intra-abdominal haemorrhage, not all patients with significant blood loss will display the typical pattern of hypotension and tachycardia, especially young patients and those on heart rate–limiting medications. More important are trends over time in pulse, blood pressure and capillary refill time and in response to fluid resuscitation. Continuing falls in blood pressure and rises in pulse rate indicate ongoing haemorrhage, which, if no other source is identified, must be assumed to be intra-abdominal. Abdominal distension does not occur until several litres of blood have been sequestered and can initially be confused with obesity.

Once the patient has been examined, unless there is suspicion of a urethral injury, a urinary catheter should be inserted, Blood at the urethral meatus or a scrotal haematoma is suggestive of urethral injury, and a urological opinion should be sought before attempting to insert a catheter. In these circumstances, a suprapubic catheter may be preferable. Patients with a suspicion of abdominal injury also require a gastric catheter. Nasogastric catheterization is more comfortable for the patient than the oral route but is contraindicated by evidence of basilar skull fracture. Gastric decompression may be both diagnostic and therapeutic. Penetration of the stomach or proximal small bowel will produce a bloodied aspiration. Aspiration of air will relieve gastric tamponade, which is occasionally an unrecognized cause of hypotension from impaired venous return.

A penetrating object, such as a knife protruding from the abdomen, should be left in situ unless it is an immediate threat to life. It may be tempting to remove such an object from a stable patient, but this can lead to disastrous consequences if the object is adjacent to or penetrating vascular structures. The sudden release of a tamponade may be rapidly fatal. The only place to remove a penetrating object is in an operating theatre, with staff on hand capable of dealing with all possible complications.

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