Pain as the only consistent sign of acute appendicitis: lack of inflammatory signs does not exclude the diagnosis.

Background: The clinical diagnosis of acute appendicitis in adults remains tricky, but radiological examinations are very helpful to determine the diagnosis even when the adult patient presents atypically. This study was designed to quantify the proportion of patients with a preoperative diagnosis of acute appendicitis that had isolated right lower quadrant pain without biological inflammatory signs and then to determine which imaging examination led to the determination of the diagnosis.

Methods: In this monocentric study based on retrospectively collected data, we analyzed a series of 326 patients with a preoperative diagnosis of acute appendicitis and isolated those who were afebrile and had isolated right lower quadrant pain and normal white blood cell counts and C-reactive protein levels. We determined whether the systematic ultrasonography examination was informative enough or a complementary intravenous contrast media computed tomography scan was necessary to determine the diagnosis, and whether the final pathological diagnosis fit the preoperative one.

Results: A total of 15.6% of the patients with a preoperative diagnosis of acute appendicitis had isolated rebound tenderness in the right lower quadrant, i.e., they were afebrile and their white blood cell counts and C-reactive protein levels were normal. In 96.1% of the cases, the ultrasonography examination, sometimes complemented by an intravenous contrasted computed tomography scan if the ultrasonography result was equivocal, fit the histopathological diagnosis of acute appendicitis.

Conclusions: The diagnosis of acute appendicitis cannot be excluded when an adult patient presents with isolated rebound tenderness in the right lower quadrant even without fever and biological inflammatory signs. In our study, ultrasonography and computed tomography were very helpful when making the final diagnosis.