A Common Diagnosis Delayed by Three "Wrong Footing" Anchoring Errors - it is Difficult to Remember What You Have Forgotten.

Unlabelled: Very often in clinical practice, an inflamed pelvic appendix shows left lower quadrant abdominal pain as the primary painful area. The clinicians are anchored to the most prominent symptom, thereby taking an unnecessary detour in reaching an accurate diagnosis. A 40-year-old man presented to our emergency department with persistent lower left abdominal pain with a fever of 38 oC from a day earlier. He had a good appetite and repeatedly complained of severe constipation at the time of his visit. Physical examination revealed tenderness in the lower left abdomen without a peritoneal sign. Abdominal ultrasound and non-contrast-enhanced computed tomography revealed a left hydroureter. The next day, a radiologist pointed out the possibility of appendicitis. An urgent laparoscopic appendectomy was performed. The intriguing point of this case is the diagnostic delay because of three anchoring biases. First, the typical right lower abdominal pain of appendicitis was shielded by the intense left lower abdominal pain. Moreover, the presence of a left hydroureter distracted the physicians from the actual location of the pain. Furthermore, the presence of constipation anchored the physicians to constipation as the cause of abdominal pain. In overcoming these biases, specific diagnostic strategies to avoid biases should be implemented.

Learning Points: If a patient has unexplained lower left abdominal pain, it is advisable to deploy a "searchlight" strategy.When a hydroureter was found to have no apparent source obstruction, a vertical tracing strategy should have been undertaken to detect its root cause.To avoid the wrong diagnosis through anchoring bias, pivot and cluster strategy - deploying differential diagnosis specific to the initial diagnosis (constipation in this case) - should be adopted at the start, considering the important differential diagnosis and thus preventing a missed diagnosis.