Spontaneously resolving acute appendicitis: clinical and sonographic documentation

To document findings in a subgroup of patients with acute appendicitis that spontaneously resolved.

From February 1989 through December 1995, nine patients were seen with a diagnosis of acute appendicitis that did not necessitate immediate surgery. Clinical, ultrasound (US), and pathologic findings were retrospectively reviewed.

Four of the nine patients underwent elective appendectomy 15-84 days (mean, 52 days) after initial presentation, and five did not undergo surgery. Seven patients experienced spontaneous pain relief before admission to the hospital, and two improved within a few hours of being admitted. No patient had an indication of peritoneal irritation at physical examination. Four patients had a normal white blood cell count, and five had leukocytosis. Maximum appendiceal diameter was 9-12 mm. Five patients had inflamed periappendiceal fat. No patient had abscess or appendicolithiasis shown at US. A normal appendix was identified at follow-up (mean, 40 months; range, 1-60 months) in four of five patients who did not undergo elective appendectomy. Two patients experienced recurrent bouts of pain, and one of these patients underwent appendectomy before the planned elective procedure.

On the basis of clinical, US, and pathologic findings, mild acute appendicitis spontaneously resolved in a subgroup of patients.