A retroperitoneal abscess due to
H. parainfluenza is very rare. There have been only a few reported cases of these abscesses, mainly involving the psoas muscle [
2,
3]. One case reports a retroperitoneal abscess caused by
H. parainfluenza after ERCP [
1]. According to Riahi
et al., possible explanations for the abscess include infection secondary to retroperitoneal perforation occurring during sphincterotomy or introduction of the bacterium from the upper airway during the ERCP and subsequently to the retroperitoneal space via a perforation in the performance of the sphincterotomy [
1]. Our case also involved ERCP with papillotomy, a possible port of entry for the bacterium. The common duct stone was too large (3 to 4 cm) to remove via ERCP; therefore an open cholecystectomy and CBD exploration was performed. If
H. parainfluenza was introduced during the ERCP, there was no evidence of perforation or abscess and the CBD was intact at operation. It is well understood that
H. parainfluenza is a common inhabitant of the mucosal surfaces of the human upper respiratory tract [
4]. There is a possibility that the patient may have subsequently coughed up and swallowed the
H. parainfluenza, moving it into the gastrointestinal tract and allowing it to track back along the T-tube. Another possibility may be that
H. parainfluenza, is a rarely identified bacterium found in the intestinal tract of healthy patients, and seldom causes problems until surgical manipulation allows it to manifest as an abscess. Our patient had no other source of infection (upper respiratory, pneumonia, otitis, etc), nor did the abscess grow any other organism other than
H. parainfluenza.