Dr Caleb Lin Emergency Registrar
Peer review: Dr David McCreary
It’s a typical Saturday evening ticked over midnight to Sunday morning. A young intoxicated man stumbles into triage complaining of severe abdominal pain. He tells you he has had “Quite a few” (read as “a lot”) of drinks tonight and shares that a few hours ago, while playfighting with his mate (as one does following “quite a few”), his mate had fallen onto his abdomen.
His initial observations are unremarkable but his abdomen is distended with signs of diffuse peritonism on examination. There are no other focal external signs of injury.
Unfortunately, the CT scanner is currently being held for a stroke and a couple of other trauma calls, so you turn to your trusty ultrasound. This is a peritonitic trauma patient, after all.
WHAT DO YOU SEE ON THE ULTRASOUND?
There is free fluid in the RUQ, LUQ and Pelvis.
Well, now the patient most definitely needs a CT, and probably warrants a bump up the queue.
Take a look at the slices below...
WHAT DO THESE STILL AXIAL CT SLICES SHOW?
The CT confirms your free-fluid US findings. The radiologist helpfully measures the Hounsfield units of the free fluid and determines the fluid to be “ascites quality fluid”. There is no clear cause for ascites (yes, he’s intoxicated but he denies it being a daily habit). The intraperitoneal and retroperitoneal organs are unremarkable.
🤓 EDITOR'S SEGUE: TELL ME MORE ABOUT HOUNSFIELD UNITS:
This is basically a measure of ‘on a scale of black (-1000) to white (+1000), how grey is this?’. Apparently, there are slightly more than 50 shades of grey in radiology.
Air = very black = -1000
Pure water = a bit grey = 0
Soft tissue = a bit more grey = 30-45
Acute blood = getting a little white = 60-90
Cortical Bone = very white = +1000
Case courtesy of Dr Francis Fortin, Radiopaedia.org. From the case rID: 77397
In the meantime, the patient is still in a lot of pain and goes into urinary retention. You insert an In-dwelling catheter to relieve his retention given the size of his bladder on ultrasound. There is immediate resolution of his pain, but you note macroscopic rose haematuria fills the bag.
While you are busy questioning your catheterisation skills, the patient’s bloodwork returns:
This is probably a good point to stop, recap and think where we should go next with this patient. So, what do we know?
Abdominal trauma
Urinary retention
Peritoneal ‘ascites-like’ free fluid
Mild hyponatraemia and creatinine bump on biochemistry
WHAT FURTHER INVESTIGATIONS WOULD BE IMPORTANT NOW TO NARROW DOWN YOUR DIAGNOSIS?
A CT-Cystogram was performed to check bladder integrity:
The CT Cystogram reveals a subtle intramural defect with no contrast extravasation consistent with a contained intraperitoneal bladder rupture. Let’s learn a bit more about that then, shall we?
TRAUMATIC BLADDER RUPTURE
Traumatic Bladder Rupture is found in 1.6% of blunt trauma.
The majority (60%) are extraperitoneal and associated with pelvic and urethral injuries and the rest are intraperitoneal – associated with pregnancy, alcohol binge drinking and abdominal surgery.
A QUICK REMINDER OF OUR ANATOMY
The bladder is predominantly a pelvic organ with the neck fixed to the pelvis by fascia and ligaments. The dome is the most vulnerable area, particularly when the bladder is full. A rupture of the dome near the peritoneal reflection (superiorly) results in an intraperitoneal rupture of the bladder causing intraabdominal peritonism and urinary ascites. A rupture of the dome below the peritoneal reflection (anteriorly or posteriorly) results in an extraperitoneal rupture of the bladder.
The classically described mechanism for intraperitoneal bladder rupture is a compressive force applied to the lower abdomen in a patient with a full bladder – sound familiar?
In the above case, what had likely transpired was an overfilled bladder in context of alcohol intoxication and alcohol-related diuresis. This expanded the bladder into the abdomen and made it prone to rupture from minor blunt trauma, such as the weight of the patient’s equally intoxicated buddy landing on it. This has actually been described in several case reports(1,2)
Source: The Slow Mo Guys - YouTube
Intraperitoneal bladder rupture would result in spillage of bladder contents (i.e. urine) into the abdominal cavity, causing the findings of free fluid on a FAST scan and ascites on CT. The injury to the bladder will cause some haematuria. Finally, the urinary ascites in the peritoneal cavity causes a sodium shift from plasma to ascites and a urea, creatinine, and potassium shift into the plasma, in what is basically reverse peritoneal dialysis(3).
A representation of the electrolyte disturbance in patients with urinary ascites(3)
MANAGEMENT OF BLADDER RUPTURE
This depends on whether the injury is intra- or extra-peritoneal
Intraperitoneal – typically large and do not heal spontaneously
May be conservatively managed with an IDC if small and no peritonism
Extraperitoneal – Split into complex and simple
Complex (usually requires repair) – bladder neck, pelvic, rectal/vaginal injury, urethral injury
Simple – Managed with IDC, majority heal spontaneously
In the case of intraperitoneal rupture above, given the CT cystogram did not demonstrate contrast extravasation, it was elected that the IDC would help with bladder decompression and healing of the bladder dome and peritoneum conservatively. Majority of these patients in other settings may have required open surgery for bladder repair and closure of peritoneum.
PATIENT OUTCOME:
The patient is discharged later that day with catheter education with a plan for a trial of void in 2 weeks at Urology outpatients.
WHAT CAN YOU DO IN THE ED?
Consider the diagnosis of bladder injury in blunt trauma onto a distended bladder. A ten-year review of trauma cases found that less than two-thirds of trauma patients with bladder injuries received timely bladder imaging on initial presentation. This was related to longer catheterization and delay to definitive management.
Consider early IDC insertion in the absence of suspected urethral injury (check out our post on retrograde urethrogram for more on assessing for urethral injury). This will allow you to decompress the bladder which may be definitive care for the injury and aid you in performing a CT Cystogram.
TAKE HOME MESSAGES:
Have a high level of suspicion of bladder injury in context of blunt trauma to the abdomen in a patient with a distended bladder (e.g. an intoxicated patient)
A creatinine rise in a young person with ascites might be a clue – think reverse peritoneal dialysis.
Early, appropriate imaging leads to timely quality care and better patient outcomes.
REFERENCES
Daignault MC, Saul T, Lewiss RE. Bedside ultrasound diagnosis of atraumatic bladder rupture in an alcohol-intoxicated patient: a case report. Critical Ultrasound J. 2012;4(1):9.
Parker H, Hoonpongsimanont W, Vaca F, Lotfipour S. Spontaneous Bladder Rupture in Association with Alcoholic Binge: A Case Report and Review of the Literature. J Emerg Medicine. 2009;37(4):386–9.
Tran HA, Petrovsky N. A swollen abdomen Part 1. Pathology. 2004;36(2):193–5.
DR CALEB LIN
Emergency Registrar, Alfred Health
Dr Caleb Lin is an emergency registrar from Singapore working at the Alfred Hospital in metropolitan Melbourne. He is passionate about medical education, point of care ultrasound and clinical informatics. In his spare time, he enjoys ballroom dancing and guitaring.
