Enterobius vermicularis as a cause of acute appendicitis: a case report

Enterobius vermicularis, commonly known as the pinworm, is a prevalent intestinal nematode, particularly affecting children worldwide. Although infection is often asymptomatic, it may occasionally lead to complications, including appendiceal involvement. The role of E. vermicularis in the pathogenesis of acute appendicitis remains controversial and is frequently overlooked. We report a case of a 10-year-old child who presented with intermittent right lower quadrant abdominal pain without fever or systemic symptoms. Initial ultrasound revealed small mesenteric lymph nodes, with no clear evidence of appendiceal pathology. Empirical treatment with antibiotics and anti-inflammatory agents failed to relieve the symptoms. A follow-up ultrasound demonstrated a thickened retrocecal appendix with hypoechoic intraluminal content. Due to persistent pain, a laparoscopic appendectomy was performed, revealing a white, non-segmented roundworm within the appendiceal lumen. Histopathological examination and direct microscopic analysis confirmed follicular appendicitis with intraluminal nematodes morphologically consistent with E. vermicularis. Postoperative parasitological examination further supported the diagnosis, with detection of characteristic eggs using the Scotch tape test, while stool examinations remained negative. These findings suggested E. vermicularis as the most likely etiological agent and supported its pathogenic role in the patient's clinical presentation. The patient was treated with albendazole, followed by a second dose 2 weeks later. Simultaneous treatment was administered to household contacts, and strict hygiene measures were recommended to prevent reinfection. Clinical recovery was complete, with no postoperative complications. This case highlights the importance of considering parasitic infections in the differential diagnosis of acute abdominal pain, even in the absence of systemic inflammatory markers, particularly in endemic or underrecognized settings. Early recognition and targeted therapy are essential to prevent recurrence and intra-familial transmission.