Typical signs of acute appendicitis in ultrasonography mimicked by other diseases?

The diagnosis of acute appendicitis in pediatric patients is difficult. There are patients with positive ultrasonography without clinical or histological confirmation of acute appendicitis. It is essential to recognise these patients to avoid unnecessary surgery.

During 1 year, we compared the patients with 'false-positive' ultrasonography with those with 'true-positive' and those with 'true-negative' ultrasonography.

Eighty-two patients were admitted to our inpatient ward for suspected appendicitis. Ultrasonography was performed on 68 patients. In sixteen cases, the ultrasonography showed typical signs of acute appendicitis though the patients turned out to be negative for acute appendicitis either by an observation period (n = 13) or by negative histology (n = 3). We could not find any significant differences between the groups in terms of age, gender or laboratory inflammation markers, though the latter tended to be elevated in patients with confirmed appendicitis.

There are patients with clearly visible typical signs of acute appendicitis that do not need surgery and cannot be distinguished from others by age, gender or laboratory values. In conclusion, the clinical presentation still is the determining indicator for need of surgery. The underlying cause of the visible changes of the appendiceal area remains unclear, but there are several presumptions.