Double trouble and the pitfalls of confirmation bias- A case report of acute appendicitis, arising in a duplex appendix

Abstract

With an incidence of 0.004% [1], the likelihood of discovering a duplex appendix is very rare. Here, we present a case of a 43 year old man, whom underwent a laparoscopic appendicectomy and washout for what appeared to be a simple case of appendicitis, as confirmed by CT scanning. Despite an uncomplicated operation, the patient continued to spike high grade fevers with persisting abdominal pain. A repeat laparoscopic exploration was conducted, revealing a 2nd gangrenous appendix. Upon removal of the 2nd appendix, the subsequent histopathology report established that both appendix samples had a base and a tip, confirming that two distinct appendices had indeed been removed. This case highlights the pitfalls and confirmation bias: Namely, a tendency to preferentially look for information that confirms a pre-conceived diagnosis, simultaneously dismissing information which may point to an alternative diagnosis. In doing so, we prematurely stop searching for alternative or additional explanations for the patient’s presentation - which in this case resulted in a missed 2nd appendix.