Actinomycosis as a rare cause of acute appendicitis: Case report and comprehensive literature review

Introduction and importance: Actinomycosis is a rare, chronic bacterial infection caused by Actinomyces species. While it commonly affects the cervicofacial region, thorax, and abdomen, appendicular involvement is extremely uncommon. This case report details the presentation, diagnosis, and management of a 45-year-old female patient with acute appendicitis secondary to actinomycosis. Case presentation: A 45-year-old woman, with an 8-year intrauterine device history, presented with three-day right iliac fossa pain, vomiting, and stable vital signs. Laboratory tests revealed an inflammatory syndrome. Suspecting acute appendicitis, a CT scan confirmed a swollen 10 mm appendix. Laparoscopic surgery revealed a phlegmonous appendix, leading to an uncomplicated appendectomy. Pathological examination confirmed actinomycotic granules, supporting the diagnosis of actinomycosis appendicitis. The patient received 18 million units of intravenous penicillin G daily for 6 weeks followed by a 6-month course of oral amoxicillin (1 g three times daily) thereafter, showing favorable progression with no symptoms. Normal clinical and ultrasound followups were observed at one year. Clinical discussion: Appendiceal actinomycosis is a rare condition. Women, especially those with intrauterine contraceptives, experience an increase in cases due to chronic inflammation. Typically underdiagnosed, actinomycosis mimics other conditions, presenting with nonspecific symptoms. Laboratory results offer limited assistance, and histological confirmation is crucial. Histopathological examination is mandatory for diagnosis confirmation. Management involves surgical resection and prolonged penicillin-based antibiotics, providing a favorable prognosis with low mortality. Conclusion: This case underscores the importance of considering rare etiologies, such as actinomycosis, in the differential diagnosis of appendicitis. Timely recognition and management are crucial for optimal patient outcomes.