A”pin”dicitis: A Case of Adult Appendicitis in the Setting of Enterobius vermicularis. LT Isaac Ilaoa DO (Associate) LCDR Catherine Berjohn MD, MPH (Associate) LCDR Nehkonti Adams MD (Associate) CAPT Mary Bavaro MD (Fellow) Department of Internal Medicine and Infectious Diseases Naval Medical Center, San Diego, CA

Case 24 year old female presented with 36 hours of abdominal pain. Described pain as: – Sharp/stabbing – Initially mid abdomen, but migrated to right lower quadrant – Unrelieved by Ibuprofen – Exacerbated by movement Associated symptoms: – Nausea, with non-bloody emesis – Non-bloody diarrhea – Fever to F Review of systems: otherwise negative

PMH Past medical history surgical history – Depression – Generalized Anxiety Past surgical history – Dilation and Curettage – Laparoscopy for left ovarian cyst (age 13) Social history – Married, with 3 children – Denied Tobacco, Alcohol, or Illicit drug use

Physical Exam Vital signs: – Temperature: 97.5 degrees Fahrenheit – Blood pressure: 99/52 mmHg (consistent with baseline) – Heart Rate: 89 beats per minute – Respiratory rate: 18 respirations per minute – Oxygen saturation: 98% on room air Physical: – Abdomen: Soft, with bowel sounds present Localized tenderness to right lower quadrant Positive rebound tenderness Positive guarding

Labs/Rads Complete blood cell count – Absolute Eosinophil count of 770 per microliter (normal less than 500) – White blood cells: 9,400 per microliter Normal metabolic panel Urinalysis: within normal limits Computerized Tomography of the abdomen and pelvis: – “borderline dilated appendix with surrounding inflammatory changes. An acute appendix is not excluded”.

Enterobius vermicularis: “The Pinworm” Epidemiology: – Humans only known host – Predominance in… Children (ages 5-9 years) Closed-crowded living spaces – One of the most common human parasites Prevalence estimated to be approximately 40 million in the United States

Enterobius vermicularis

Clinical Manifestations Most common symptom is perianal itching – Aka pruritus ani Up to 1/3 can be asymptomatic Other reported associations – Appendicitis – Mesenteric Abscess – Enterocolitis – Vulvovaginitis – Salpingitis, oophoritis

Diagnosis

Discussion The role of E. vermicularis in appendicitis? – E. vermicularis detected in 0.6 – 13 % of resected appendices. - Appendicitis versus “Appendiceal Colic”

E. vermicularis AbsentTotalPresent Inflammation 231,0851,108 No Inflammation Adapted from: Table 1. Histological features of appendices

E. vermicularis AbsentTotalPresent Inflammation 763,3093,385 No Inflammation 681,5951,663 Adapted from: Table 2. Pathology distribution of E. vermicularis

Conclusion Despite the high prevalence of E. vermicularis this case highlights an interesting and uncommon presentation of this infection. Although there is a known relationship between pinworm infections and appendicitis, appendiceal colic was the most likely etiology in this case.

References Akbulut S, et al; Unusual histopathological findings in appendectomy specimens: A retrospective analysis and literature review. World J Gastroenterol 2011 Apr21;17(15): Arca MJ, et al; Clinical manifestations of appendiceal pinworms in children: an institutional experience and a review of the literature. Pediatr Surg Int 2004 May; 20(5):372-5 Centers for Disease Control and Prevention. Enterobiasis (Enteroblus vermicularis) (Accessed on Sep 25, 2014). no abstract available Dahlstrom J.E., et al; Enterobius vermicularis: A possible cause of symptoms resembling appendicitis. Aust. N.Z. J. Surg. (1994) 64, , 1994 May 24 Invisible Tape. Officeworks [ dispensers/invisible-tape]

Isik B, et al; Appendiceal Enterobius vermicularis infestation in adults. Int Surg 2007 Jul-Aug; 92(4):221-5 Lamps LW. Infectious causes of Appendicitis. Infect Dis Clin N Am 24 (2010) doi: /j.idc Life cycle of Enterobius vermicularis. Centers for Disease Control and Prevention Jan 10. [ Ramezan M, et al; Relationship between Enterobius vermicularis and the incidence of acute appendicitis. Dept of Community and Preventive Medicine, ISMSU Isfahan, Iran. Vol 38 No.1 January 2007

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