Gas in the bladder wall on canine abdominal radiographs
10-year-old crossbreed bitch with pollakiuria, stranguria and haematuria for 2 weeks, not improving on empirical antibiotics. She has not been catheterised or had a cystocentesis recently. Ventrodorsal and lateral abdominal radiographs:
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What does the highlighted finding indicate and what should you do next?
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A. Pneumoperitoneum from bladder rupture; urgent laparotomy
Free peritoneal gas collects under the diaphragm and outlines the serosa of several organs, and bladder rupture usually causes effusion with loss of serosal detail. Here the gas is confined to the outline of the bladder.
B. Iatrogenic gas in the bladder lumen; of no significance
Air introduced by catheterisation forms bubbles in the non-dependent part of the lumen, not a rim outlining the whole wall. Moreover, this bitch has not been catheterised or punctured.
C. Emphysematous cystitis; look for diabetes and culture urine
Correct. A radiolucent line outlining the bladder wall on both views indicates intramural gas produced by glucose-fermenting bacteria, mainly E. coli. Look for diabetes mellitus (glucosuria) and hyperadrenocorticism, although it also occurs in dogs without these diseases, and culture the urine with susceptibility testing.
D. Superimposed colonic gas; repeat with abdominal compression
Superimposed bowel can mislead on a single view, but here the gas consistently follows the bladder outline on both orthogonal views, which rules out chance summation.
lightbulb Key takeaway
A rim or bubbles of gas outlining the bladder wall on two views are typical of emphysematous cystitis. On ultrasound the wall is hyperechoic with reverberation and 'dirty' shadowing, and CT shows whether gas extends to the kidneys or retroperitoneum. Treat according to the urine culture, for several weeks, and address the cause (diabetes, Cushing's).
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Updated: November 1, 2026 · Educational content for veterinary professionals. It does not replace current clinical guidelines or the judgement of the attending veterinarian.