3. EPIDEMIOLOGY CLASSIFICATION & GENERAL MANAGEMENT PRINCIPALS
3.1. Definition and Epidemiology
Trauma is defined as a physical injury or a wound to living tissue caused by an extrinsic agent. Worldwide, there are over four million injury-related deaths ever year which constitute nearly 8% of all deaths [10]. About 25% of them are violence related. For young people (5 - 29 years old), three of the top five causes of death are injury-related (road traffic injuries, homicide, and suicide). Tens of millions more people suffer non-fatal injuries each year which lead to acute care visits, hospitalizations, and often result in temporary or permanent disability and the need for long-term physical and mental health care and rehabilitation. Twice as many males than females are killed each year because of injuries and violence [10].
Trauma is therefore a serious public health problem with significant social and economic costs. Considerable variation exists in the causes and the effects of traumatic injuries between geographical areas, as well as between low, middle, and high-income countries with about 90% of injury-related deaths occur in low- and middle-income countries [10].
3.2. Classification of trauma
Traumatic injuries are classified by the World Health Organization (WHO) into intentional (either interpersonal violence related, war-related or self-inflicted injuries), and unintentional injuries (mainly road traffic accidents/injury, falls, and other domestic accidents). Intentional trauma accounts for approximately half of the trauma-related deaths worldwide [11]. A specific type of unintentional injury is iatrogenic injury which occurs during therapeutic or diagnostic procedures by healthcare personnel. Traumatic insults are classified according to the basic mechanism of the injury into penetrating, when an object pierces the skin, and blunt injuries. Penetrating trauma is further classified according to the velocity of the projectile into:
1. high-velocity projectiles (e.g. rifle bullets - 800-1,000 m/sec);
2. medium-velocity projectiles (e.g. handgun bullets - 200-300 m/sec);
3. low-velocity items (e.g. knife stab).
High-velocity weapons inflict greater damage due to a temporary expansive cavitation that causes destruction in a much larger area than the projectile tract itself. In lower velocity injuries, the damage is usually confined to the projectile tract. Blast injury is a complex cause of trauma which includes blunt and penetrating trauma and burns.
The most commonly used classification grading system is the AAST (American Association for the Surgery of Trauma) injury scoring scale [12]. It is useful for managing renal trauma, but for the other urological organs, the injuries are commonly described by their anatomical site and severity (partial/complete).
3.3. General management principals
3.3.1. The Initial evaluation
The initial emergency assessment of a trauma patient is beyond the focus of these guidelines. It is usually carried out by emergency medicine and trauma specialised personnel following advanced trauma life support (ATLS) principles. Detailed further assessment involves cross-sectional imaging, laboratory analysis and specialist surgical input. The management of individual organ injury will follow in the sections below. Tetanus vaccine status should be assessed for all penetrating injuries.
3.3.2. Polytrauma managed in major trauma centres leads to improved survival
Urological trauma is often associated with significant injuries in the polytraumatised patient [13]. Lessons from civilian trauma networks, military conflict, and mass casualty events have led to many advances in trauma care [14-16]. These include the widespread acceptance of damage control principles and trauma centralisation to major trauma centres staffed by dedicated trauma teams. The re-organisation of care to these centres has been shown to reduce mortality by 25% and length of stay by four days [14]. Urologists increasingly understand their role in the context of polytrauma with the ultimate aims of improving survivability and decreasing morbidity in these patients.
3.3.3. Damage control
Damage control is a life-saving strategy for severely injured patients that recognises the consequences of the lethal triad of trauma - hypothermia, coagulopathy, and acidosis [17-19]. The first of a three phased approach consists of rapid control of haemorrhage and wound contamination. The second phase involves resuscitation in the intensive care unit (ICU), with the goal of restoring normal temperature, coagulation, and tissue oxygenation. The final stage involves definitive surgery when more time-consuming reconstructive procedures are performed in the stabilised patient [20]. Urological intervention needs to be mindful of the phase of management. Temporary abbreviated measures followed by later definitive surgery are required. Complex reconstructive procedures, including organ preservation, are not undertaken. The decision to enter damage control mode is taken by the lead trauma clinician following team discussion.
Urological examples include haemodynamically unstable patients due to suspected renal haemorrhage or pelvic fracture with associated urethral or bladder injury. The options of abdominal packing and temporary urinary drainage by ureteric, bladder or urethral catheterisation are valuable adjuncts to care.
3.3.4. Mass casualty events and Triage
A mass casualty event is one in which the number of injured people and the severity of their injuries exceed the capacity of the facility and staff [21]. Triage, communication, and preparedness are important components for a successful response.
Triage after mass casualty events involves difficult moral and ethical considerations. Disaster triage requires differentiation of the few critically injured individuals who can be saved by immediate intervention from the many others with non-life-threatening injuries for whom treatment can be delayed and from those whose injuries are so severe that survival is unlikely in the circumstances [22,23].
3.3.5. The role of thromboprophylaxis and bed rest
Trauma patients are at high risk of deep venous thrombosis (DVT). Concerns about secondary haemorrhage result in prolonged post-injury bed rest DVT which effectively compounds this risk. Established prophylaxis measures reduce thrombosis and are recommended following systemic review [24]. However, the strength of evidence is not high and as yet there is no evidence to suggest that mortality or pulmonary embolism risk is reduced [25]. Compression stockings and low molecular weight heparins are favoured. The risk of secondary haemorrhage in isolated renal trauma is low and the practice of strict bed rest has waned in patients who are able to mobilise [26].
3.3.6. Antibiotic stewardship
Single shot antibiotic doses are common in major trauma. The indication for continuing antibiotics is governed by injury grade, associated injuries and the need for intervention. Patients with urinary extravasation tend to be kept on antibiotics but there is no evidence base for this. Antibiotics should be avoided in lesser trauma e.g. Grade 1-3 renal trauma, and regular review should be undertaken for those continued on antibiotics.
3.3.7. Urinary catheterisation
Prolonged catheterisation is required in all forms of bladder and urethral injury. Catheterisation is not necessary in stable patients with low-grade renal injury. Patients with heavy haematuria, who require monitoring or ureteric stenting, benefit from catheterisation. This can be removed once haematuria lightens and there is an improvement in the clinical situation. The shortest possible period of catheterisation is advised.