Blunt injuries occur either as a result of a direct blow to the kidney or a rapid acceleration or rapid deceleration (or a combination of two or all three). The commonest cause of renal injuries in urban societies is motor vehicle accidents, either where a pedestrian has been hit by a car (direct injury combined with rapid acceleration and then deceleration) or where, for example, the occupants of a car have come to a sudden halt (rapid deceleration). Seemingly trivial injuries such as a fall from a ladder while gardening, direct falls onto the flank, or sporting injuries can lead to significant renal injuries (Fig. 5.1).
5. TRAUMATIC UROLOGICAL EMERGENCIES 55
TABLE 5.1. Summary of mechanisms, causes, staging, and treatment of renal injuries
Mechanisms and cause Blunt or penetrating
Blunt—direct blow or acceleration/ deceleration (road traffic accidents, falls from a height, fall onto flank) Penetrating—knives, gunshots, iatrogenic, e.g., percutaneous nephrolithotomy (PCNL)
Imaging and staging Computed tomography—accurate, rapid,
images other intra-abdominal structures Staging—American Association for the Surgery of Trauma Organ Injury Severity Scale: I, contusion; II, <1 cm laceration; III, >1 cm laceration; IV, laceration into collecting system; V, shattered kidney
Treatment Conservative—95% of blunt injuries, 50%
of stab injuries, 25% of gunshot wounds can be managed nonoperatively (cross-match, bed rest, observation) Exploration if
Persistent bleeding (persistent
tachycardia and/or hypotension not responding to appropriate fluid and blood replacement) Expanding perirenal haematoma Pulsatile perirenal haematoma
A penetrating injury such as a stab wound to the flank can be associated with an underlying renal injury, but remember also that lower chest and anterior abdominal stab wounds may inflict renal damage. In the case of gunshot wounds to the abdomen or chest, it is not always obvious that the kidneys might have been injured. The very fact that a patient has sustained a lower chest or abdominal gunshot wound is an indication for renal imaging, in the form of a computed tomography (CT) scan, since the bullet may pass through the kidney as it 'tumbles' around the abdomen. The bottom line is, be suspicious that the kidney has been injured until proven otherwise.