title: Acute acalculous cholecystitis: challenging the myths.
abstract: BACKGROUND
  Acute acalculous cholecystitis (AAC) is traditionally known to occur in critically ill patients, following cardiac surgery, abdominal vascular surgery, severe trauma, burns, prolonged fasting, total parenteral nutrition, or sepsis, and is believed to have a worse prognosis as compared with acute cholecystitis associated with stones. Our observation of de novo presentation of AAC in several outpatients in the absence of critical illness or predisposing factors prompted us to undertake this study. The aims of the present study were to examine the prevalence of AAC patients in the outpatient setting in our hospital, to identify associated risk factors and to assess the clinical course and outcome of these patients.
  
  
  METHODS
  All patients who had a cholecystectomy (laparoscopic or open surgery) for acute cholecystitis at National University Hospital from January 2001 to May 2005 were reviewed from a prospectively maintained database. The demographic characteristics, clinicopathologic features, operative parameters, postoperative course, and histopathology of the patients were reviewed.
  
  
  RESULTS
  Eleven of 133 patients with acute cholecystitis fulfilled the criteria for the diagnosis of AAC. Patients' ages ranged from 30 to 69 years (mean 52.39 years). All these patients presented as outpatients. None of the patients had any critical illness predisposing to AAC. The mean age was slightly less in the AAC group as compared with the remaining patients with acute cholecystitis (52.39 years vs 55.22 years, p=0.54). There was male predominance in the AAC group (male:female = 9:2). The time from admission to surgery, operative procedure, operative time, and postoperative stay were not statistically different from the remaining patients with acute cholecystitis.
  
  
  CONCLUSIONS
  AAC can occur in young and middle-aged healthy individuals, the presentation is no different from acute calculous cholecystitis, the prognosis is good if diagnosed and treated early.
authors.affiliation: Department of Surgery, National University Hospital, Yong Loo Lin School of Medicine, Singapore.
authors.forename: Iyer Shridhar
authors.initials: IS
authors.lastname: Ganpathi
authors.forename: Ravishankar K
authors.initials: RK
authors.lastname: Diddapur
authors.forename: Huang
authors.initials: H
authors.lastname: Eugene
authors.forename: Masud
authors.initials: M
authors.lastname: Karim