Emphysematous cystitis (EC) refers to gas forming infection of the bladder wall.
The condition is rare and usually confined to certain patient subgroups.
Risk factors include:
- diabetes mellitus
- considered the commonest predisposing factor 6
- may be present in ~50% of cases 2
- female sex: reported M:F ratio 1:2
- immunocompromised state
- neurogenic bladder
- transplant recipients
Symptoms and signs can be non-specific as they can be with non-emphysematous cystitis. A history of pneumaturia may be present. Most often the diagnosis is made incidentally during imaging examination.
Emphysematous cystitis may be caused by bacterial or fungal infection. The most common causative organism is E. coli, with other organisms including Enterobacter aerogenes, Klebsiella pneumonia, Proteus mirabilis, Staphylococcus aureus, streptococci, Clostridium perfringens and Candida albicans.
Conventional radiography characteristically shows curvilinear or mottled areas of increased radiolucency in the region of the urinary bladder, separate from more posterior rectal gas. Intraluminal gas will be seen as an air-fluid level that changes with patient position, and, when adjacent to the nondependent mucosal surface, may have a cobblestone or “beaded necklace” appearance. This is thought to reflect the irregular thickening produced by submucosal blebs as seen at direct cystoscopy.
CT is a highly sensitive examination that allows early detection of intraluminal or intramural gas. CT is also useful in evaluating other causes of intraluminal gas such as enteric fistula formation from adjacent bowel carcinoma or inflammatory disease.
Can demonstrate echogenic air within the bladder wall with dirty shadowing artefact. Ultrasound will also commonly demonstrate diffuse bladder wall thickening and increased echogenicity.
Potential complications include:
- bladder rupture with septicemia and peritonitis
Gas within the bladder wall is virtually always due to emphysematous cystitis. Intraluminal gas within the bladder has a more broad differential. See article: gas in the urinary bladder.
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