Careful patient selection is key to optimizing treatment for adults with uncomplicated acute appendicitis, a secondary analysis of the APPAC II randomized trial showed.

“When evaluating patients with uncomplicated acute appendicitis for non-operative management, the emphasis…should be on ruling out patients that already have or who are at risk of developing complicated acute appendicitis,” Dr. Paulina Salminen of the University of Turku told Reuters Health by email. “The importance of this pre-interventional selection is highlighted especially now, as recent evidence shows that even oral antibiotic monotherapy is a feasible treatment alternative for uncomplicated acute appendicitis, possibly enabling future outpatient management.”

“We would suggest to consider including the findings of this study in the evaluation by referring patients with appendiceal diameter 15 mm or more, or body temperature over 38 degrees, to initial appendectomy,” she said.

As reported in JAMA Surgery, for the prespecified secondary analysis of the Finnish trial, Dr. Salminen and colleagues analyzed data from 583 patients (mean age, 35; 43 percent women) with uncomplicated acute appendicitis randomized to receive oral antibiotics or intravenous and oral antibiotics in the APPAC II trial.

Twenty-nine patients (5 percent) were primary nonresponders to antibiotics who underwent a surgical procedure and subsequently were found to have complicated acute appendicitis.

As Dr. Salminen noted, appendiceal diameter greater than or equal to 15 mm on CT (adjusted risk ratio, 5.5) and a body temperature of more than 38 °C on admission (aRR, 4.1) were associated with primary nonresponsiveness to antibiotic therapy. The authors note, “Optimal treatment outcomes for these patients might be achieved with initial appendectomy instead of nonoperative treatment, similar to patients presenting with an appendicolith, which has been reported to be associated with a more complicated course of appendicitis.”

Three U.S. surgeons commented on the findings in emails to Reuters Health.

Dr. David Renton, a surgeon at The Ohio State University Wexner Medical Center in Columbus, said, “These findings seem feasible and mirror what we see clinically. The only concern is that, if you respond to antibiotic therapy, you still have your appendix. This study looks only at one-year follow up. Any time during the rest of your life, you can get another bout of appendicitis. If you have an operation and have your appendix removed, this chance drops to near zero.”

“Conservative management of acute uncomplicated appendicitis is possible, but very careful patient selection must be undertaken to ensure complications don’t arise,” he said. “We forget these days, but appendicitis used to be a fatal problem. If the patient does not seem to be responding to just antibiotic therapy, prompt surgical consultation should be undertaken to see if the patient needs their appendix removed.”