From the Guidelines
Gas in the urinary bladder with a negative urinalysis should be further investigated with cystoscopy to rule out clinical mimics of interstitial cystitis/bladder pain syndrome (IC/BPS) such as bladder cancer, bladder stones, and intravesical foreign bodies, as recommended by the AUA guideline 1. When evaluating a patient with gas in the urinary bladder and a negative urinalysis, it is essential to consider various potential causes, including emphysematous cystitis, recent instrumentation, fistula formation with the bowel, or trauma.
- The patient's symptoms, such as the number of voids per day, sensation of constant urge to void, and the location, character, and severity of pain, pressure, or discomfort, should be thoroughly documented 1.
- A brief neurological exam to rule out an occult neurologic problem and an evaluation for incomplete bladder emptying to rule out occult retention should be performed on all patients 1.
- Urine culture may be indicated even in patients with a negative urinalysis to detect lower levels of bacteria that are clinically significant but not readily identifiable with a dipstick or on microscopic exam 1.
- Given the potential for severe complications, such as emphysematous pyelonephritis or urosepsis, prompt treatment with broad-spectrum antibiotics, such as fluoroquinolones or trimethoprim-sulfamethoxazole, should be considered, especially in diabetic and immunocompromised patients 1.
- Hospitalization may be necessary for severe cases requiring IV antibiotics, and patients should increase fluid intake, control blood glucose if diabetic, and seek prompt follow-up imaging to confirm resolution.
From the Research
Gas in Urinary Bladder with Negative Urinalysis
- The presence of gas in the urinary bladder can be an indication of an underlying condition such as a colovesical fistula (CVF) 2.
- A CVF is an abnormal connection between the colon and the bladder, which can be caused by diverticular disease, colon cancer, or bladder cancer 2.
- Symptoms of CVF include pneumaturia (passing gas in the urine), urinary tract infections, dysuria, frequency, fecaluria, and hematuria 2.
- Diagnostic investigations for CVF include computed tomography (CT) scans, barium enemas, and cystography, with CT scans being the most effective in identifying the fistula 2.
- In cases where a CVF is suspected, a CT scan followed by a colonoscopy is recommended as the first-line investigation to rule out malignancy as a cause of CVF 2.
- Other conditions such as inflammation, malignancy, surgical manipulations, and radiation therapy can also lead to the development of urinary bladder fistulae, which can be confirmed and managed with the help of imaging techniques such as CT cystography 3.
- The use of antibiotics prior to outpatient cystoscopy is not necessary in patients with no clinical signs or symptoms of acute urinary tract infection, including asymptomatic bacteriuria, as the risk of developing a urinary tract infection after cystoscopy is low 4, 5.
- However, oral prophylactic antibiotics such as ciprofloxacin or trimethoprim can reduce the risk of bacteriuria after flexible cystoscopy 6, 5.