Brief Answer: There are different causes of gas in the bladder. You should undergo further laboratory exams and a CT scan to detect the cause in your case. Detailed Answer: Hello, Thank you for using HCM. There are different causes of gas in the bladder. The most common are the recent placement of an indwelling urinary catheter, or the performance of cistoscopy. These are both excluded in your case. Another possible cause can be emphysematous cystitis, which is most frequently in patients with diabetes mellitus presented with dysuria (difficulty during urination), fever and hematuria (blood in urine) . It is a rare entity, caused by gas fermenting bacterial and fungal pathogens, which requires early, aggressive treatment with parenteral antibiotics (such as Piperacillin-tazobactam, or Gentamycine + Piperacillin-tazobactam), and bladder drainage by catheterization. The gold standart to diagnose the emphysematous cystitis, is the CT scan. Beside history, physical examination and CT scan, a full blood count and a urine sample exam would be helpful too. Another probable cause of gas in bladder can be the colovesical fistula (abnormal communication between colon and bladder) which may be developed due to diverticulitis, as in your case. It is presented with dysuria , fever and smelly, turbid urine due to the presence of feces in it. CT scan is again the gold standard to diagnose it , or either rectovesical fistula or colorectal carcinoma which may cause gas in bladder too. If, any of the above mentioned cause, is detected by CT scan , than the adequate solution would be surgery. So, what to do ? - Full blood count - Urine sample exam - CT scan - After receiving the results of the above mentioned exams, you should see a urologist (in case of cystitis), or a surgeon (in case of fistula). Hope this is helpful. Let me know if you need more clarifications. Otherwise please close and rate the answer. Kind Regards, Dr. Juarda