We would like to respond to Dr Ylitalo's letter about the case report¹ that we wrote in the February issue of JAOA—The Journal of the American Osteopathic Association. Dr Ylitalo raised two issues—one regarding whether pneumaturia is pathognomonic for emphysematous cystitis, and the other regarding the mortality rate associated with the disease. 

Pathognomonic is defined by the Bantam Medical Dictionary as, “describing a symptom or sign that is characteristic of or unique to a particular disease.”² We concede that pneumaturia is also frequently encountered in cases of colovesical fistula caused by Crohn's disease or diverticular disease.³ Because of the limited amount of available information on emphysematous cystitis alone, it is difficult to calculate the true frequency of pneumaturia in this condition. Nevertheless, emphysematous cystitis is, by definition, a gasforming infection—albeit sometimes only a small volume of gas is formed. Thus, it could be theorized that the frequency of pneumaturia approaches 100% in emphysematous cystitis, making pneumaturia truly pathognomonic for emphysematous cystitis. Pneumaturia in the suspected presence of a urinary tract infection should lead physicians to strongly consider emphysematous cystitis. 

Little information was available in the literature regarding the mortality rate of emphysematous cystitis. Among the literature that we reviewed, most of the published sources combined mortality data for emphysematous cystitis, emphysematous pyelitis, and emphysematous pyelonephritis—if the sources listed mortality data at all. 

In a review of 135 cases, Thomas et al⁴ suggested that emphysematous cystitis alone had a mortality rate of 7%, and the mortality rate for all emphysematous diseases approached 14%. Mokabberi et al⁵ and Grupper et al⁶ reported that the mortality rate of emphysematous cystitis alone is about 20%, as we mentioned in our case report.¹ However, as a result of the rarity of this condition, we acknowledge that 20% mortality is only an estimate. As pointed out by Dr Ylitalo, Schaeffer and Schaeffer⁷ reported that emphysematous pyelonephritis is the more severe form of emphysematous, with a reported mortality rate of 19% to 43%, and that emphysematous pyelonephritis calls for surgical debridement more frequently then does emphysematous cystitis. 

As to the manner of intervention, Thomas et al⁴ suggested that in 90% of the reviewed emphysematous cystitis cases, patients were treated with medicines, and in the remaining 10% of cases, patients received a combination of medicinal and surgical treatment. Although surgery is rarely required for patients with emphysematous cystitis, it is one treatment option after medicinal treatment has failed, as indicated by our case report.¹ We would respectfully disagree with Dr Ylitalo's assertion that disease mortality is related to the need for surgical intervention. 

Our case report¹ focused on the opportunity to make a diagnosis with a complete and detailed medical history and physical examination—while understanding that immunocompromised patients are at higher risk for emphysematous infections. The ability to obtain crucial diagnostic information from a patient's medical history may be limited by the patient's degree of comfort in providing potentially vital information. Nevertheless, obtaining such information begins with physicians understanding the need to ask.