title: Clinical Features of Tuberculous Versus Crohn's Anal Fistulas, in Korea.
abstract: OBJECTIVE
  In Western countries, tuberculous anal fistula may not be an issue because tuberculosis [TB] is not common, and this is a very rare form of extrapulmonary manifestation of TB. However in TB-endemic countries, careful diagnostic differentiation is required because the clinical features of TB anal fistula and Crohn's disease [CD] anal fistula are similar, with distinguishing features remaining unclear. We aimed to analyse the clinical features of TB versus CD anal fistulas.
  
  
  METHODS
  Among 13872 patients who underwent anal fistula surgery from 2003 to 2014, 87 patients with TB fistulas and 116 patients with CD fistulas were included. Data on the annual incidence of TB and CD, as well as the clinical, pathological, ultrasonographic, colonoscopic and surgical data were analysed.
  
  
  RESULTS
  Compared with CD, the TB group was older [median: 37 vs 22 years] and underlying chronic illness was more common [20.3% vs 2.6%]. In the TB group, 46 patients [59.7%] showed active or inactive pulmonary TB, and acid-fast bacilli and caseating granuloma were found in 56.3% and 62.1%, respectively. During colonoscopy, mucosal lesions were observed more frequently in CD [96.9% vs 16.9%].
  
  
  CONCLUSIONS
  TB anal fistula is clinically very similar to CD anal fistula. In Korea, the incidence of CD anal fistula has recently increased in prevalence, whereas the prevalence of TB anal fistula is decreasing but is still persistent. We recommend that clinicians should prepare for a possibility of TB as well as CD anal fistula in TB-endemic countries including Korea.
authors.affiliation: Department of Gastroenterology, Daehang Hospital, Seoul, Korea yschoi427@naver.com.
authors.forename: Yong-Sung
authors.initials: YS
authors.lastname: Choi
authors.affiliation: Department of Surgery, Daehang Hospital, Seoul, Korea.
authors.forename: Do-Sun
authors.initials: DS
authors.lastname: Kim
authors.affiliation: Department of Surgery, Daehang Hospital, Seoul, Korea.
authors.forename: Jae-Bum
authors.initials: JB
authors.lastname: Lee
authors.affiliation: Department of Gastroenterology, Daehang Hospital, Seoul, Korea.
authors.forename: Jong-Kyu
authors.initials: JK
authors.lastname: Kim
authors.affiliation: Department of Surgery, Daehang Hospital, Seoul, Korea.
authors.forename: Hyung-Joong
authors.initials: HJ
authors.lastname: Jung
authors.affiliation: Department of Surgery, Daehang Hospital, Seoul, Korea.
authors.forename: Seong-Dae
authors.initials: SD
authors.lastname: Lee
authors.affiliation: Department of Surgery, Daehang Hospital, Seoul, Korea.
authors.forename: Kee-Ho
authors.initials: KH
authors.lastname: Song
authors.affiliation: Department of Surgery, Daehang Hospital, Seoul, Korea.
authors.forename: Doo-Han
authors.initials: DH
authors.lastname: Lee
authors.affiliation: Department of Pathology, Daehang Hospital, Seoul, Korea.
authors.forename: Mi-Jung
authors.initials: MJ
authors.lastname: Kim
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D003424:Crohn Disease / Q000150:complications / Q000175:diagnosis*; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012003:Rectal Fistula / Q000209:etiology* / Q000473:pathology; D056910:Republic of Korea; D012189:Retrospective Studies; D014385:Tuberculosis, Gastrointestinal / Q000150:complications / Q000175:diagnosis*; D055815:Young Adult
keywords: Clinical feature; Crohn's disease; anal fistula; incidence; tuberculosis