Trauma to the Urinary Tract and Other Urological Emergencies
Initial resuscitation of the traumatized patient
The resuscitation of the traumatized patient is usually initiated in the field by the paramedic team and is continued systematically once the patient reaches the emergency department by a rapid multidisciplinary prioritybased approach.
Goals of resuscitation:
Restoration of cardiac, pulmonary, and neurological function.
Diagnosis of immediate life-threatening conditions.
Prevention of complications from multisystem injuries.
The initial resuscitation process can be divided into three phases—the primary survey, the secondary survey, the definitive survey.
Primary survey
ABC: assess the patient’s Airway, Breathing, and Circulation.
Airway and Breathing
Establish a secure airway.
Ventilate by oxygen mask or endotracheal intubation and mechanical ventilation.
Immobilize the cervical spine.
Circulation
Assess circulatory function by pulse rate and BP.
The commonest cause of hypotension in the polytraumatized patient is hypovolaemia secondary to haemorrhage. With hypovolaemic shock, an immediate bolus of intravenous isotonic crystalloid solution should be given and the patient’s response (pulse rate, BP) is assessed.
Radiological imaging
Determined by local facilities. Increasingly, in the severely traumatized patient, CT of chest, abdomen, and pelvis is used to identify significant chest, abdominal, and pelvic injuries. If not available, arrange supine chest, abdomen, and pelvic X-rays to identify the presence of rib and pelvic fractures and to identify the presence of significant quantities of blood in the chest, abdomen, and pelvis and in patients with persistent hypotension from presumed bleeding, search for occult haemorrhage using a diagnostic peritoneal lavage or focused abdominal USS.
Hypovolaemic shock is not always associated with hypotension. In young patients, compensatory mechanisms, e.g. rapid vasoconstriction can compensate for as much as a 35% volume loss without significant decreases in BP.
Remember non-hypovolaemic causes of hypotension:
Tension pneumothorax.
Cardiac tamponade.
Myocardial infarction. Neurogenic (SCI).
Urinalysis
Routinely performed in every trauma patient because it provides valuable information regarding the likelihood of injuries to the upper and lower urinary tract. The absence of haematuria, however, does not exclude a urinary tract injury (e.g. haematuria may be absent in acceleration/deceleration renal injuries (see 
p. 508)).
p. 508)).As life-threatening injuries are found during the primary survey, resuscitation efforts are initiated concurrently (e.g. chest drain for pneumothorax). The decision to transfer a patient from the emergency room to either the operating room or angiography suite is made during the primary survey.
Secondary survey
Performed after completion of the primary survey. Take a completehistory and perform a physical examination from head to toe. Arrange selective skeletal X-rays according to physical findings.
Definitive survey
During this phase, focus attention on identifying specific organ injuries using clinical and radiographic means. Genitourinary injuries are usually recognized during the definitive survey.
During all phases of the initial resuscitation, assess vital signs (BP, respiratory rate, blood gases, urinary output, and body temperature) continually. Vascular pressure monitoring, using central venous and pulmonary arterial catheters, can be performed selectively. Frequent re-evaluation should be performed to detect changes in the patient’s condition and the appropriate actions taken.
Renal trauma: classification, mechanism, grading
Classification
Two categories—blunt and penetrating. See Table 11.1. Proportion of all renal injuries that are blunt—Europe 97%, United States 90%, South Africa 25-85%. Proportion depends on whether urban or non-urban community.
This classification is useful because it predicts the likely need for surgical exploration to control bleeding. Experience from large series shows that 95% of blunt injuries can be managed conservatively whereas 50% of stab injuries and 75% of gunshot wounds require exploration.
Blunt injures
Direct blow to the kidney.
Rapid acceleration or rapid deceleration.
A combination of the above.
Rapid deceleration frequently causes renal pedicle injuries (renal artery and vein tears or thrombosis, PUJ disruption) because the renal pedicle is the site of attachment of the kidney to other fixed retroperitoneal structures.
Penetrating injuries
Stab or gunshot injuries to the flank, lower chest, and anterior abdominal area may inflict renal damage. Fifty percent of patients with penetrating trauma and haematuria have grade III, IV, or V renal injuries. Penetrating injuries anterior to the anterior axillary line are more likely to injure the renal vessels and renal pelvis, compared with injuries posterior to this line where less serious parenchymal injuries are more likely. Thus, renal injuries from stab wounds to the flank (i.e. posterior to the anterior axillary line) can often be managed non-operatively.
Wound profile of a low-velocity gunshot wound is similar to that of a stab wound. High-velocity gunshot wounds (>350m/s) cause greater tissue damage due to stretching of surrounding tissues (‘temporary cavity’).
Mechanism
The kidneys are retroperitoneal structures surrounded by perirenal fat, the vertebral column and spinal muscles, the lower ribs, and abdominal contents. They are, therefore, relatively protected from injury and a considerable degree of force is usually required to injure them (only 1.5-3% of trauma patients have renal injuries). Associated injuries are, therefore, common (e.g. spleen, liver, mesentery of bowel). Renal injuries may not initially be obvious, hidden as they are by other structures. To confirm or exclude a renal injury, imaging studies are required. In children, there is proportionately less perirenal fat to cushion the kidneys against injury and thus, renal injuries occur with lesser degrees of trauma.
Staging of the renal injury
Using CT, renal injuries can be staged according to the AmericanAssociation for the Surgery of Trauma (AAST) Organ Injury Severity Scale. Higher injury severity scales are associated with poorer outcomes.
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Paediatric renal injuries
The kidneys are said to be more prone to injury in children because of the relatively greater size of the kidneys in children, the smaller protective muscle mass and cushion of perirenal fat, and the more pliable rib cage.
Table 11.1 Summary of mechanisms, causes, grading, and treatment of renal disease | ||||||||||||||||||||||||||||||
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Renal trauma: clinical and radiological assessment
The haemodynamically stable patient
History: nature of trauma (blunt, penetrating)
Examination: pulse rate, systolic BP, respiratory rate, location of entry and exit wounds, flank bruising, rib fractures. The lowest recorded systolic BP is used to determine need for renal imaging.
Urinalysis: crucial for determining likelihood of renal injury and, therefore, of the need for radiological tests.
Haematuria (defined as >5 erythrocytes per high powered field or dipstick-positive) suggests the possibility of a renal injury; however, the amount of haematuria does not correlate consistently with the degree of renal injury.
Do FBC and serum chemistry profile.
Indications for renal imaging
Macroscopic haematuria.
Penetrating chest and abdominal wounds (knives, bullets).
Microscopic (>5 RBCs per high powered field) or dipstick haematuria in a hypotensive patient (systolic BP <90mmHg recorded at anytime since the injury).1
A history of a rapid acceleration or deceleration (e.g. fall from a height, high speed motor vehicle accident). Falls from even a low height can cause serious renal injury in the absence of shock (systolic BP <90mmHg) and of haematuria (PUJ disruption prevents blood reaching the bladder).
Any child with microscopic or dipstick haematuria who has sustained trauma.
Adult patients with a history of blunt trauma and microscopic or dipstick haematuria need not have their kidneys imaged as long as there is no history of acceleration/deceleration and no shock since the chances of a significant injury being found are <0.2%.
Degree of haematuria vs severity of injury
While significant renal injury is more likely with macroscopic haematuria, in some cases of severe renal injury, haematuria may be absent. Thus, the relationship between the presence, absence and degree of haematuria and the severity of trauma is not absolute. Broadly speaking, in blunt trauma, macroscopic haematuria predicts the likelihood of significant renal injury (Table 11.2). Conversely, in penetrating trauma, haematuria may be absent in severe renal injury (renal vascular injury, PUJ, or ureter avulsion).
The haemodynamically unstable patient
Haemodynamic instability may preclude standard imaging such as CT, the patient having to be taken to the operating theatre immediately to control the bleeding. In this situation, an on-table IVU (Box 11.1) is indicated if:
A retroperitoneal haematoma is found and/or
A renal injury is found which is likely to require nephrectomy.
Box 11.1 What imaging study?
The IVU has been replaced by contrast-enhanced CT scan as the imaging study of choice in patients with suspected renal trauma. Compared with IVU, it provides clearer definition of the injury, allowing injuries to the parenchyma and collecting system to be more accurately graded and, therefore, determines subsequent management. An arterial-venous phase scan is done within minutes of contrast injection, followed by a repeat scan 10-20min after contrast administration to allow time for contrast to reach collecting system.
While ultrasound can establish the presence of two kidneys and identify blood flow in the renal vessels (power Doppler), it cannot accurately identify parenchymal tears, collecting system injuries, or extravasation of urine until a later stage when a urine collection has had time to accumulate.
Imaging is designed to:
Grade injury.
Document presence and function of contralateral kidney.
Detect associated injuries.
Detect pre-existing renal pathology in affected kidney.
On contrast enhanced CT look for:
Depth of parenchymal laceration.
Parenchymal enhancement (absence of enhancement suggests renal artery injury).
Presence of urine extravasation (medial extravasation of contrast suggests disruption of PUJ or renal pelvis).
Presence, size, and position of retroperitoneal haematoma (haematoma medial to the kidney suggests a vascular injury).
Presence of injuries to adjacent organs (bowel, spleen, liver, pancreas, etc).
Presence of a normal contralateral kidney.
On-table IVU
When, because of shock and need for immediate laparotomy, a patient is transferred immediately to the operating theatre without having hada CT scan and a retroperitoneal haematoma is found, a single shot abdominal X-ray, taken 10min after contrast administration (2mL/kg of contrast), can establish the presence/absence of a renal injury and the presence of a normally functioning contralateral kidney where the ipsilateral kidney injury is likely to necessitate a nephrectomy.
* Remember, in young adults and children, hypotension is a late manifestation of hypovolaemia: blood pressure is maintained until there has been substantial blood loss.
Renal trauma: treatment
Conservative (non-operative) management
Most blunt (95%) and many penetrating renal injuries (50% of stab injuries and 25% of gunshot wounds) can be managed non-operatively.
Dipstick or microscopic haematuria: if systolic BP since injury has always been >90mmHg and no history of acceleration or deceleration, imaging and admission is not required.
Macroscopic haematuria: in a cardiovascularly stable patient, having staged the injury with CT, admit for bed rest (no hard and fast rules as to duration) and observation until the macroscopic haematuria, if present, resolves (cross-match in case BP drops); give antibiotics if urinary extravasation.
Surgical exploration
Is indicated (whether blunt or penetrating injury) if:
The patient develops shock which does not respond to resuscitation with fluids and/or blood transfusion.
The haemoglobin decreases (there are no strict definitions of what represents a ‘significant’ fall in haemoglobin).
There is urinary extravasation and associated bowel or pancreatic injury.
Expanding perirenal haematoma (again the patient will show signs of continued bleeding).
Pulsatile perirenal haematoma.
An expanding and/or pulsatile perirenal haematoma suggests a renal pedicle avulsion. Haematuria is absent in 20%.
Technique of renal exploration
Midline incision allows:
Exposure of renal pedicle, so allowing early control of the renal artery and vein.
Inspection for injury to other organs.
Lift the small bowel upwards to allow access to the retroperitoneum. Incise the peritoneum over the aorta, above the inferior mesenteric artery. A large peri-renal haematoma may obscure the correct site for this incision. If this is the case, look for the inferior mesenteric vein and make your incision medial to this. Once on the aorta, the inferior vena cava may be exposed, then the renal veins and the renal arteries. Pass slings around all of these vessels. Expose the kidney by lifting the colon offof the retroperitoneum. Bleeding may be reduced by applying pressure to the vessels via the slings. Control bleeding vessels within the kidney with 4/0 vicryl or monocryl sutures. Close any defects in the collecting system with 4/0 vicryl. If your sutures cut out, place a strip of Surgicel over the site of bleeding, place your sutures through the capsule on either side
of this, and tie them over the Surgicel. This will stop them from cutting through the friable renal parenchyma.
of this, and tie them over the Surgicel. This will stop them from cutting through the friable renal parenchyma.
Finding a non-expanding, non-pulsatile retroperitoneal haematoma at laparotomy
The finding of an expanding and/or pulsatile retroperitoneal haematoma at laparotomy will often indicate a renal pedicle injury (avulsion or laceration), and nephrectomy may be required to stop further haemorrhage.
Controversy surrounds the correct management of the finding at laparotomy of a non-expanding, non-pulsatile retroperitoneal haematoma. Most can be left alone. Remember, exploration increases the chances of loss of the kidney (because of bleeding which can becontrolled only by nephrectomy). The decision to explore is based on whether pre-operative or on-table imaging has been done and is normal or abnormal:
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Urinary extravasation
Not in itself necessarily an indication for exploration. Almost 80-90% of these injuries will heal spontaneously. The threshold for operative repair is lower with associated bowel or pancreatic injury—bowel contents mixing with urine is a recipe for overwhelming sepsis. In these situations, the renal repair should be well drained and omentum interposed between the kidney and bowel or pancreas.
If there is substantial contrast extravasation, consider placing a JJ stent. Repeat renal imaging if the patient develops a prolonged ileus or a fever since these signs may indicate the development of a urinoma which can be drained percutaneously. Renal exploration is required for a persistent leak.
Devitalized segments
Exploration is usually not required for patients with devitalized segments of kidney and with urinary extravasation.1
Early
Delayed bleeding: 1.5% of surgically treated patients, 4% of surgically treated penetrating injuries, 1-6% of paediatric blunt injuries managed non-operatively, 20% of conservatively managed stab injuries. 75%require surgery and of these, 60% require nephrectomy.
Urinary extravasation and urinoma formation: blunt injury 2-20%; penetrating injury 10-25%. If low volume and non-infected, often heal spontaneously; large volume—consider a trial of JJ stenting with renal repair if extravasation persists.
Abscess formation: flank pain, fever, ileus. CT or USS is diagnostic. Treat by percutaneous drainage.
Renal arteriovenous fistulas: commonest cause is percutaneous renal biopsy, i.e. iatrogenic. Often small and heal spontaneously, but may manifest with retroperitoneal bleeding; collecting system bleeding (heavy haematuria); microscopic haematuria; abdominal bruit; hypertension; tachycardia; high output heart failure. Diagnosis is confirmed by selective renal arteriography. Treat by arterial embolization (treatment of choice); partial nephrectomy; complete nephrectomy.Related posts:
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