Emphysematous urinary tract infections (UTIs) are infections of the lower or upper urinary tract associated with gas formation. They may manifest as cystitis, pyelitis, or pyelonephritis.
Issues related to emphysematous UTIs will be reviewed here. Diabetes mellitus is a major risk factor for these infections and is also associated with an increased risk of asymptomatic bacteriuria and certain symptomatic UTIs such as cystitis, renal and perinephric abscess, and Candida infections [1-3]. (See "Asymptomatic bacteriuria in patients with diabetes mellitus" and "Acute uncomplicated cystitis and pyelonephritis in women" and "Renal and perinephric abscess" and "Candida infections of the bladder and kidneys" and "Susceptibility to infections in persons with diabetes mellitus" and "Acute complicated cystitis and pyelonephritis".)
The pathogenesis of emphysematous UTIs is poorly understood. Elevated tissue glucose levels in diabetic patients may provide a more favorable microenvironment for gas-forming microbes. However, bacterial gas production does not fully explain the pathologic and clinical manifestations of emphysematous UTIs [4,5].
Diabetes mellitus and urinary tract obstruction are the major risk factors for emphysematous urinary tract infections (UTIs). In different series, diabetes was present in more than 80 percent of patients with emphysematous pyelonephritis [4,6-9], at least 50 percent of patients with emphysematous pyelitis, and 60 to 70 percent of patients with emphysematous cystitis [5,10]. In addition, most patients were women, similar to the predominance of women in acute uncomplicated cystitis and pyelonephritis [4,5,10], and most patients were over age 60 [4,5,10].
One of the largest published experiences comes from a retrospective study of 48 patients in Taiwan who were diagnosed with either emphysematous pyelonephritis or emphysematous pyelitis . Diabetes was present in 96 percent and urinary tract obstruction in 22 percent. The mean patient age was 60 years (range 37 to 83 years) and women outnumbered men 6:1. Similar findings were noted in a literature review of 135 patients with emphysematous cystitis: diabetes was present in 67 percent, the mean age was 66 years, and women accounted for 64 percent of cases .