In my last post, I noted that nonoperative management is the norm for dealing with high grade renal injuries. One of the possible options, angioembolization, was relatively infrequently used at only 6% of the time.
For management of other organs like the spleen, there are several angioembolization options. Depending on the type and severity of injury, selective (partial) or nonselective (main splenic artery) embolization can be carried out. For the liver, only selective embolization can be used. But what about the kidney?
Are there consequences of nonselective renal embolization? Or should we always strive for selective control? The urology group of the University of Tennessee – Knoxville published a series of papers on their experience using embolization in patients with the most severe injuries (Grade 5). They retrospectively examined just over 3 years of admissions with this injury. Numbers were very small (6 men, 3 women).
But they also published a second paper, extending the review dates to capture one more male patient. And they followed this group for 1.5 to 5 years (mean 2.5 years) to determine if any delayed complications surfaced.
Here are the factoids:
- Seven patients underwent full, nonselective embolization, and the other three had “super selective” embolization
- All patients had control of bleeding without surgical intervention
- Followup CT imaging showed no persistent extravasation or expanding hematoma
- No patient developed complications, such as a retroperitoneal abscess, prolonged fever, or hypertension while in the hospital or during short-term followup
- Most patients showed a very small increase in serum creatinine (mean 0.04), but one patient increased from 1.1 to 1.7
- On longer term followup, one patient, age 51, developed hypertension 10 months after his injury. It is not possible to determine whether he was one of the 20% of older adults who develop hypertension, or whether it was due to the procedure. it was well-controlled with a single antihypertensive med.
- None developed altered renal function, stones, chronic pain, fistula, or pseudoaneurysm
Bottom line: Obviously, the data is very limited with only 10 patients. However, it is very interesting to note that the majority of these patients underwent nonselective embolization of the renal artery without any adverse event. The one case of hypertension occurred with nonselective embolization, although I have seen several case reports where this occurs with selective embolization as well.
It is now well-accepted that high-grade renal injury can and should be managed nonoperatively if the patient’s hemodynamic status is reasonable. I recommend a trip to interventional radiology if the patient has active extravasation or a high-grade (Grade 4 or 5) injury, as these patients are at risk for loss of the entire kidney otherwise. Selective embolization can be attempted first, but don’t be shy to take out the entire organ if need be.
- Percutaneous embolization for the management of Grade 5 renal trauma in hemodynamically unstable patients: initial experience. J Urology 181:1737-1741, 2008.
- Intermediate-term follow-up of patients treated with percutaneous embolization for Grade 5 blunt renal trauma. J Trauma 69(2):468-470, 2010.
A synopsis of contemporary management of renal injury was presented at the annual meeting of the American Association for the Surgery of Trauma last year. The Genito-Urinary Trauma Study Group (GUTS [groan!]) prospectively collected data on high-grade (grades 3-5) renal injuries from 14 Level I trauma centers over a 14 year period.
Here are some factoids from the article:
- Expectant management (nonoperative or minimally invasive angio/stenting/drainage) was the norm, with 80% of these high-grade injuries dealt with in this manner
- Only 6% of patients undergoing minimally invasive treatment underwent angioembolization
- As expected, the higher the grade, the more likely the kidney would be removed (Grade 4 = 15%, Grade 5 = 62%)
- Once operative management was performed, the nephrectomy rate escalated to 67%
- Nephrectomy was more common in patients with penetrating trauma (60%)
Bottom line: Nonoperative management of renal injuries has long been the norm. This more recent review confirms it. Once the abdomen is opened, the chance of losing the entire kidney skyrockets. Expectant management (repeat exam and labs) is very common, and very successful.
Angiography is an important adjunct, but was not used very commonly in this study. Perhaps the surgeons were concerned about complications from embolizing part or all of the kidney? I’ll discuss the consequences of this in my next post.
Reference: Contemporary management of high-grade renal trauma: Results from the American Association for the Surgery of Trauma Genitourinary Trauma study. J Trauma 84(3):418-425, 2018.
Hematuria ranges from microscopic to gross. Microscopic means blood that can only be seen with a microscope, and gross means visible to the naked eye. In trauma, we only care about gross hematuria, which ranges from the faintest of pink to the deepest red.
In trauma, gross hematuria is a result of an injury to kidney, ureter or bladder. Blunt injury to the ureter is so rare it’s reportable, so you can pretty much forget that one unless the mechanism is extreme. So you really just need to focus on kidney and bladder.
Any victim of blunt trauma that presents with visible hematuria needs to be evaluated by CT of the abdomen and pelvis with an added CT cystogram. Standard CT technique is done without a urinary catheter, or with the catheter clamped. Only 50% of bladder injuries show up with this technique.
CT cystogram is an add-on to the standard CT, and consists of the administration of contrast into the bladder which is then kept under pressure while the scan is done. Delayed slices through the pelvis after the bladder is depressurized and emptied is routine. Nearly 100% of bladder injuries are detected using this technique.
If the CT shows a renal laceration or hematoma, the patient should be admitted and managed according to your solid organ injury protocol. Kidney injuries fare better that livers and spleens, and only rarely require surgery. If no kidney or bladder injury is seen, the default diagnosis of a renal contusion is the culprit. No treatment is needed, and the patient can be discharged if no other injuries are present. The blood will clear over a few days, but may disappear and reappear a few times in the process. The patient can followup with their primary care physician in a week or two.
Yesterday, I wrote about using acute kidney injury (AKI) as a predictor for multiple organ failure. But what about kidney failure that we may inadvertently create through the use of IV contrast during CT scan evaluation? Contrast is generally safe for use in the general trauma population, but is known to cause renal problems in high risk groups like the elderly and critically ill.
Investigators at UCSD retrospectively reviewed ICU patients who had no history of pre-existing renal disease. A total of 570 eligible patients were identified, and 170 (30%) developed AKI. Being old (age>=75) or severely injured (ISS>=25) was a predictor of AKI, but IV contrast was not. Even during subgroup analysis, the addition of contrast to the elderly or severely injured patient population did not predict AKI.
Bottom line: This limited study shows that IV contrast exposure may be considered safe, even in the elderly and severely injured. However, I still recommend that all risks and benefits be thoroughly weighed in every patient, and that scans that have little diagnostic and therapeutic benefit be avoided.
Reference: Is contrast exposure safe among the highest risk trauma patients? AAST 2011 Annual Meeting, Paper 69.
Organ failure after major trauma is relatively common. Acute renal failure can occur for a variety of reasons, and tends to occur early. This abstract from Denver Health looked at acute kidney injury as a predictor for the development of multiple organ failure.
The authors retrospectively reviewed 12 years of their registry data for patients at high risk for developing organ failure. They found that multiple organ failure (MOF) developed in 21% and that 8% died. They also noted that if acute kidney injury (AKI, serum creatinine > 1.8mg/dL) occurred by day 2, it predicted the failure of additional organs. Specifically, 80% of these patients developed MOF, with a 34% mortality. Renal failure was a better predictor of multiple organ failure than heart, liver or pulmonary failure seen on day 2.
Bottom line: Early kidney failure, as shown by creatinine elevation, is a reliable predictor of multiple organ failure in severely injured patients. Prevention of acute kidney injury makes sense and may help, but further investigation is needed to demonstrate the mechanism.
Reference: Acute kidney injury and post-trauma multiple organ failure: the canary in the coal mine. AAST 2011 Annual Meeting, Paper 20.