Pneumaturia refers to the passage of gas while voiding urine. If it is passed at the end of urination it is called terminal pneumaturia, which occurs since free gas tends to accumulate in the dome of the urinary bladder.


Possible causes of pneumaturia include:

(1) fistula between the gastrointestinal tract and the urinary excretion system

(2) urinary tract infection with a gas-forming bacteria (which could occur secondary to #1)

(3) recent air insufflation of the urinary bladder during cystoscopy or catheterization


Clinical features of gastrointestinal tract fistula:

(1) The fistula may arise anywhere in the GI tract but usually involves the terminal ileum or colon.

(2) The fistula usually extends into the urinary bladder but also may involve the renal pelvis or ureters.

(3) Common preceding conditions include:

(2a) Crohn's disease

(2b) cancer, especially of the colon

(2c) diverticulitis

(2d) iatrogenic

(4) If the colon is involved, then fecal material with food debris may be seen in the urine sediment.


Urinary tract infection due to a gas-forming bacteria:

(1) Risk factors include diabetes mellitus and immunosuppression.

(2) There are signs and symptoms of a urinary tract infection with pyuria.

(3) Intramural gas seen on imaging studies.


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