Enterobius vermicularis (pinworm)
Jump to navigation
Jump to search
Epidemiology
- most common helminth infection among children in USA
- primarily parasite among young children, but rapid maturation of egg allows transmission from child to child & child to adult within family & institutional setting
- infection from ingestion of eggs on contaminated hands, food or water[5]
Pathology
- male & female worms reside primarily in the cecum & adjacent areas
- females grow to up to 13 mm in length & have a pointed posterior end, hence the common name pinworm
- both sexes have prominent lateral alae (seen in cross-section) & a prominent esophageal bulb
- gravid females migrate to the anus & deposit eggs in perianal folds[5]
- females may be found on surface of stool specimen or on the perianal skin where the eggs are deposited, especially at night
- hatched larvae migrate back into the anus & colon resulting in re-infection[5]
- males are rarely seen
- adult worms may migrate to ususual sites such as vagina, fallopian tubes & peritoneum
- death of adult worms in ectopic sites may provoke an inflammatory granulomatous reaction
- eggs are infective within 1 hour of deposition
- complete development to gravid adult takes 1 month
Clinical manifestations
- infection may be asymptomatic
- pruritus ani, irritability & loss of sleep may occur
- enuresis may be presenting symptom
Laboratory
- scotch tape test: Enterobius vermicularis on perianal skin
- diagnosis is made by recovery of eggs & less commonly adult female worms from the perianal skin using the scotch tape test after the child has gone to bed or 1st thing in the morning
- eggs are colorless, ovoid with 1 side flattened
- eggs measure 50-60 by 20-40 um
- only 5-10% of cases identified during routine stool examination
- diagnosis may take several samples taken on different days
Complications
Management
- mebendazole discontinued, use albendazole[3]
- pyrantel pamoate (Pin-X) is OTC
- piperazine citrate
- treat entire household[5]
- clean all bedding & clothing[5]
More general terms
Additional terms
- mebendazole (Vermox, Emverm)
- piperazine
- pyrantel (Antiminth)
- scotch tape test; pinworm prep; Enterobius vermicularis in tissue
References
- ↑ Clinical Diagnosis & Management by Laboratory Methods, 19th edition, J.B. Henry (ed), W.B. Saunders Co., Philadelphia, PA. 1996, pg 1283
- ↑ Harrison's Principles of Internal Medicine, 13th ed. Isselbacher et al (eds), McGraw-Hill Inc. NY, 1994, pg 917
- ↑ 3.0 3.1 Prescriber's Letter 19(3): 2012 Alternatives to Vermox for Treatment of Intestinal Worms Detail-Document#: http://prescribersletter.com/(5bhgn1a4ni4cyp2tvybwfh55)/pl/ArticleDD.aspx?li=1&st=1&cs=&s=PRL&pt=3&fpt=25&dd=280308&pb=PRL (subscription needed) http://www.prescribersletter.com
- ↑ 4.0 4.1 4.2 Kang WH, Jee SC Enterobius vermicularis (Pinworm) Infection. N Engl J Med 2019; 381:e1. July 4, 2019 PMID: https://www.ncbi.nlm.nih.gov/pubmed/31269369 https://www.nejm.org/doi/full/10.1056/NEJMicm1811156
- ↑ 5.0 5.1 5.2 5.3 5.4 5.5 5.6 5.7 5.8 Grimm L What's Eating You: 12 Common Intestinal Parasites. Medscape. November 25, 2019 https://reference.medscape.com/slideshow/intestinal-parasites-6010996
- ↑ 6.0 6.1 Grim L You've Got Worms! Common Intestinal Parasites Medscape. Jan 23, 2023 https://reference.medscape.com/slideshow/intestinal-parasites-6014593