Renal Trauma
Definition• Trauma is defined as a physical injury or a wound to living tissue caused by an extrinsic agent.
Classification
• According to mechanism
penetrating when an object pierces the skin
blunt
• Blunt renal injury
Mechanism motor vehicle collision, falls , sports and assault
Sudden deceleration or a crash injury may result in contusion and laceration of the parenchyma.
• Penetrating renal injuries
Gunshot and stab wounds
American Association for the Surgery of Trauma (AAST)
> It is based on abdominal CT or direct renal exploration.
> It correlates well with preservation or removal of the injured kidney as well as post-injury mortality and morbidity.
Epidemiology
incidence of urological tract injury following abdominal trauma is approximately 10%Renal trauma 1-5% of all trauma cases
male-to-female ratio 3:1
Both kidneys are at equal disposition for injury
blunt trauma 65-70%
penetrating injuries comprise 40%
Pathology
Lacerations from blunt trauma usually occur in the transverse plane of the kidney.The mechanism of injury is thought to be force transmitted from the center of the impact to the renal parenchyma.
In injuries from rapid deceleration
– the kidney moves upward or downward, causing sudden stretch on the renal pedicle and sometimes complete or partial avulsion
Acute thrombosis of the renal artery may be caused by an intimal tear from rapid deceleration injuries owing to the sudden stretch.
Presentation and Diagnosis
History – mode /mechanism,The diagnosis of renal injury begins with a high index of clinical awareness
Pain may be localized to one flank area or over the abdomen
Retroperitoneal bleeding may cause abdominal distention, ileus, and nausea and vomiting.
Examination
GC- feature of shock heavy retroperitonealbleeding
Ecchymosis in the flank or upper quadrants of the abdomen
Lower rib fractures are frequently found
Pelvic compression tender
Diffuse abdominal tenderness may be found on palpation; an “acute abdomen” usually indicates free blood in the peritoneal cavity.
A palpable mass may represent a large retroperitoneal hematoma or perhaps urinary extravasation.
The abdomen may be distended and bowel sounds absent.
visible evidence of abdominal trauma
Catheterization usually reveals hematuria
Investigations
Laboratory
Hematology- Hb, PCV
Biochemistry- RFT
Urine analysis- microscopic hematuria
Imaging
Radiographic evaluation is also recommended for all patients with a history of rapid deceleration injury and/or significant associated injuries
Xray
Intravenous urography
determine the presence of two functioning renal units
the presence and extent of any urinary extravasation, in penetrating injuries
The technique consists of a bolus intravenous injection of 2mL/kg of radiographic contrast followed by a single plain film taken after 10 minutes.
USG
• First imaging modalities
Advantages are as follows:
Noninvasive
May be performed in real time in concert with resuscitation
May help define the anatomy of the injury
CT
Gold standard for evaluation of stable patients with renal trauma.
CT imaging is both sensitive and specific
for demonstrating parenchymal lacerations and urinary extravasations
delineating segmental parenchymal infarcts
determining the size and location of the surrounding retroperitoneal hematoma and/or associated intra-abdominal injury (spleen, liver, pancreas, and bowel)
Non-operative management
• grade 1-4 blunt renal trauma, stable patients should be managed conservatively with
bed rest
prophylactic antibiotics, and
continuous monitoring of vital signs until hematuria resolves
All grade 1-3 blunt and penetrating injuries in stable patients can be managed conservatively with bed rest, hydration and antibiotics
Persistent bleeding represents the main indication for renal exploration and reconstruction.
Indications for exploration
hemodynamic instability due to renal hemorrhage is an absolute indication for renal exploration
Grade 5 renal injury in a stable patient
expanding or pulsatile peri-renal hematoma seen at laparotomy for associated injuries are other indications for renal exploration.
goal of renal exploration following renal trauma is control of hemorrhage and renal salvage.
Complications
Early complications occur within the first month after injury and can be
Bleeding
infection
peri-nephric abscess
sepsis
urinary fistula
hypertension
urinary extravasation, and
urinoma
Delayed complications include
calculus formation
chronic pyelonephritis
hypertension
arteriovenous fistula
hydronephrosis, and
pseudoaneurysms
Special cases
Pediatric renal trauma:
Children are more prone to renal trauma as the kidneys are lower in the abdomen.
less well-protected by the lower ribs and muscles of the flank and abdomen.
Kidney is more mobile, have less protective peri-renal fat and are proportionately larger in the abdomen than in adults.
Hypotension is a less reliable sign and significant injury can be present despite stable blood pressure.
Pediatric renal trauma
Indications for radiographic evaluation of children suspected of renal trauma include
blunt and penetrating trauma patients with any level of hematuria
patients with associated abdominal injury regardless of the findings of urinalysis
patients with normal urinalysis who sustained a rapid deceleration event, direct flank trauma or a fall from a height.
Urinary Bladder Trauma
blunt
penetrating
iatrogenic trauma
Extraperitoneal bladder perforation accounts for 50%-
71% of bladder rupture,
while 25%-43% are intraperitoneal, and
7%-14% are combined
incidence of intraperitoneal bladder rupture is significantly higher in children because of the predominantly intraabdominal location of the bladder before puberty.
Bladder Injury
The preferred evaluation is by retrograde computed tomography (CT) cystogram to classify the injury as intra or extraperitoneal.
Intraperitoneal injuries will always require open repair
while extraperitoneal injuries can be managed with catheter drainage alone in a majority of cases, with some notable absolute exceptions