Is "pain before vomiting" useful?: Diagnostic performance of the classic patient history item in acute appendicitis.

Background: In most surgical textbooks, it has been stated that pain almost always precedes vomiting in patients with appendicitis. However, the usefulness of this classic history item, "pain before vomiting", has been investigated in only one study nearly 50 years ago, in which the cause of abdominal pain could not be identified in more than 40% of patients. Accordingly, our objective was to evaluate the performance of pain before vomiting for the diagnosis of acute appendicitis in patients who presented with both acute abdominal pain and vomiting.

Methods: A retrospective chart review of adult outpatients with abdominal pain and vomiting at three acute care hospitals was performed. The reference standard for appendicitis was a CT scan evaluated by two radiologists. Diagnostic performance of pain before vomiting and the value it added to the Alvarado score were evaluated.

Results: Among 310 patients, 24 patients were diagnosed with appendicitis. Diagnostic performance of pain before vomiting was a sensitivity of 95.8% (95% confidence interval [CI] 79.8-99.3) and a specificity of 16.6% (95% CI 12.6-21.4). When combined with the Alvarado score, it ruled out appendicitis in an additional 12% (increased from 32% to 44%) of patients without any false negatives.

Conclusions: "Pain before vomiting" is useful for ruling out appendicitis in patients with abdominal pain and vomiting.