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Nicole Griglione, MD; Jahnavi Naik, MD; Surprising fi nding on Jennifer Christie, MD Department of Medicine, Division of Digestive Diseases, While looking for the cause of our patient’s intermittent Emory University School rectal bleeding, we discovered something else entirely. of Medicine, Atlanta [email protected]

DEPARTMENT EDITOR Richard P. Usatine, MD A -year-old man went to his primary care Hemoccult negative. Labs were remarkable for University of Texas Health physician for his annual physical. He told his eosinophilia ranging from 10% to 24% over the Center at San Antonio physician that for the past few years, he had past several years (the white blood cell count The authors reported no intermittent, painless rectal bleeding consist- ranged from 5200 to 5900/mcL). potential confl ict of interest ing of small amounts of blood on the toilet pa- A subsequent colonoscopy revealed relevant to this article. per after . He also mentioned that many white, thin, motile organisms dispersed he often spontaneously awoke, very early in throughout the colon (FIGURE 1). Th e organisms the morning. His past medical history was un- were most densely populated in the . Of remarkable. note, the patient also had nonbleeding internal Th e patient was born in Cuba but had hemorrhoids. An aspiration of the organisms lived in the United States for more than was obtained and sent to the microbiology lab 30 years. He was divorced, lived alone, and had for further evaluation. Wet preparation micros- no children. He had traveled to Latin Ameri- copy is shown below (FIGURE 2). ca—including Mexico, Brazil, and Cuba—off and on over the past 10 years. His last trip was approximately 2 years ago. ● WHAT IS YOUR DIAGNOSIS? His physical exam was unremarkable. Rectal examination revealed no masses or ● HOW WOULD YOU MANAGE external hemorrhoids; stool was brown and THIS CONDITION?

FIGURE 1 FIGURE 2 Motile Ova IMAGES COURTESY OF: JENNIFER CHRISTIE, MD

Multiple motile worms were found on colonoscopy, Aspiration on colonoscopy revealed football-shaped dispersed throughout the colon. The worms were eggs that were fl at on one side. concentrated in the right colon.

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115_JFP0210 115 1/20/10 10:20:47 AM Diagnosis: sitic helminth, but tend to be fl at in appear- Enterobiasis ance, unlike the worms in this case. Th e colonoscopy and aspiration results re- ❚ Roundworms are the largest of the par- vealed Enterobius vermicularis, or asitic helminthes listed here, and are common . E vermicularis is the most com- in the southeastern states’ rural population. mon intestinal parasite seen by primary care Larvae penetrate the intestine, enter the lym- physicians in North America and has a wide phatics, and travel to the lungs. Here they may geographic distribution.1 In the United States, cause Loffl er’s pneumonia, which is usually more than 40 million people are estimated self-limited (lasting 1-2 weeks) and often goes to be infected with pinworm, and up to 30% undiagnosed. Juvenile worms are coughed up are children.2 Adult worms are not commonly and swallowed, returning to the small intes- found on colonoscopy, in part because endos- tine, where they mature and survive for 12 to copists are not anticipating them.3 18 months.1 Upon further questioning after the colo- ❚ The whipworm is found in the southeast- noscopy, our patient reported having “worms” ern states, but is more common in immigrants as a child and being treated for them. He de- and migrant workers. A portion of the helminth nied recent symptoms of perianal itching. He burrows into the intestinal wall and may cause also denied a recent history of contact with mild anemia, , symptoms of infl amma- children. tory bowel disease, or rectal prolapse.1 The gravid ❚ Threadworms are prevalent through- female worms out the tropical eastern hemisphere and are migrate from Infection is via the fecal-oral route most commonly found in immigrants. Larvae the cecum to the Th e life cycle of E vermicularis consists of egg, penetrate the skin, migrate through the blood- perianal region larvae, and adult stages. Infection oc- stream to the lungs, and are coughed up and at night curs by the fecal-oral route, with hosts includ- swallowed. Th e fi lariform stage penetrates the to deposit ing humans and cockroaches.4 anal skin or intestinal mucosa, perpetuating their eggs. Th e adult pinworm is very small (females infection, which may persist for 40 years— average 10 mm in length; males are 4 mm in long after the patient has immigrated. Clinical length) with a lifespan of 1 to 2 months. Infec- presentation includes , pneumo- tion begins with of ova, which hatch nia, abdominal cramping, and colitis.1 in the . Th e larvae mature into ❚ have a similar geographic adult worms as they migrate through the small distribution to the threadworm. Necator ameri- intestine. Th e adult worms then reside in the canus is the most prevalent in the cecum, and occasionally the . United States, found in the southeast. Like the Th e gravid female worms migrate to the threadworm, larvae penetrate the skin, usu- perianal region at night to deposit their eggs, ally the feet, causing a rash. Th ey migrate to the laying about 15,000 eggs at once. Th is leads to lungs, where they are coughed up and swal- perianal itching. Reinfection occurs by hand- lowed. In the intestines, they consume blood and to-mouth of the eggs from peri- cause iron defi ciency anemia. Other symptoms anal scratching.1-3 include fatigue, failure to thrive, and depression. Th ese worms may persist for 15 years.1

Differential Dx: Roundworms, Some patients have itching, whipworms, and threadworms others are asymptomatic Other common parasitic helminthes in the Th e classic presentation of United States include includes perianal itching that is worse at night (roundworm) and (whip- and is associated with sleep disturbances, which worm). Strongyloides stercoralis (threadworm) our patient experienced. However, the vast ma- and and Ancylostoma du- jority of patients are asymptomatic, leading to odenale (hookworms) are less common here underdiagnosis of the infection.2 Th is patient’s but should be considered in immigrants, such only complaint was intermittent rectal bleed- as our patient. Tapeworms are another para- ing, which was likely due to his hemorrhoids.

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More common presentations include ab- treated with 1 dose of oral dominal , anorexia, , and diar- (100 mg), (400 mg), or rhea. However, case reports have described a pamoate (11 mg/kg, maximum dose 1 g) variety of presentations, some with signifi cant (strength of recommendation [SOR] B).8-10 morbidity and mortality, often related to migra- Some sources suggest pregnant patients be tion of the worms into the genitourinary tract treated with pyrantel pamoate (a Category C and pelvic cavity.3 Th ese include vulvovaginitis, drug in pregnancy), whereas others recom- pelvic infl ammatory disease, pelvic abscesses mend deferring treatment until after delivery, and granulomas, urinary tract , pros- as harm to the fetus by pinworm infection has tatitis, epididymitis, , enterocolitis, not been reported in the literature (SOR C).1,3,11 and bowel obstruction.3,5-7 Physical exam fi nd- Regardless of which antiparasitic is used, ings may include perianal excoriation, with or treatment should be repeated after 10 to 14 days, without bacterial superinfection. given the high relapse rate. Repeat treatment is especially important with mebendazole, which is active only against worms—not eggs. The Scotch tape test Household members should also be clinches the diagnosis treated, as the infection is readily transmitted Th e “Scotch tape test” is the most commonly and others may have asymptomatic infection used diagnostic test for pinworm infection. A (SOR B).1,3,12 In order to prevent reinocula- clinician applies a piece of clear cellulose ace- tion or spread of the infection, patients should Treatment tate tape to the unwashed perianal skin in the practice good hand , including trim- should be morning on 3 separate occasions. He or she ming their fi ngernails. Th e patient and family repeated after then applies the tape to glass slides and sends members should wash all sheets, clothes, and 10 to 14 days, them to the lab.1 towels. Pets need not be treated, as they can- given the high Th e characteristic fi ndings are long, oval, not serve as reservoirs.1,3 relapse rate. colorless eggs, 50 to 60 micrometers in length, ❚ A good outcome. We treated the patient which are fl at on one side FIGURE( 2). with mebendazole 100 mg once and repeated Th e patient’s perianal area may also be treatment 10 days later. We taught the patient examined with a fl ashlight late at night or how to prevent reinfection, and we asked him early in the morning; occasionally glistening to follow-up at the clinic, as needed. adult worms are found. Stool samples are of- ten negative for worms and eggs; thus, stool examination is rarely helpful. Strength of recommendation (SOR)

A Good-quality patient-oriented evidence B Inconsistent or limited-quality Tx: Antiparasitics for patients patient-oriented evidence

and others in household C Consensus, usual practice, opinion, Patients with pinworm infection are initially disease-oriented evidence, case series

References 1. Juckett G. Common intestinal helminths. Am Fam Physician. 7. Zahariou A, Karamouti M, Papaioannou P. Enterobius vermic- 1995;52:2039-2041. ularis in the male urinary tract: a case report. J Med Case Re- 2. Weller PF, Nutman TB. Intestinal . In: Kasper Dl, ports. 2007;1:137. Available at: www.jmedicalcasereports.com/ Braunwald E, Fauci AS, Hauser SL, Longo DL, Jameson JL, eds. content/1/1/137. Accessed July 9, 2008. Harrison’s Principles of Internal Medicine. 16th ed. New York, 8. Horton J. Albendazole: a review of antihelmintic effi cacy and NY: McGraw-Hill; 2005:1259. safety in humans. Parasitology. 2000;121(suppl):S113-S132. 3. Petro M, Iavu K, Minocha A. Unusual endoscopic and micro- 9. St Georgiev V. Chemotherapy of enterobiasis (oxyuriasis). scopic view of Enterobius vermicularis: a case report with a re- Expert Opin Pharmacother. 2001;2:267-275. view of the literature. South Med J. 2005;98:927-929. 4. Chan OT, Lee EK, Hardman JM, et al. Th e cockroach as a host for 10. Jagota SC. Albendazole, a broad-spectrum anthelmintic, in the Trichinella and Enterobius vermicularis: implications for public treatment of intestinal and cestode infection: a mul- health. Hawaii Med J. 2004;63:74-77. ticenter study in 480 patients. Clin Th er. 1986;8:226-231. 5. Jardine M, Kokai GK, Dalzell AM. Enterobius vermicularis and 11. Hamblin J, Connor PD. Pinworms in pregnancy. J Am Board colitis in children. J Pediatr Gastroenterol Nutr. 2006;43:610-612. Fam Pract. 1995;8;321-324. 6. da Silva DF, da Silva RJ, da Silva MG, et al. Parasitic infection 12. Yang YS, Kim SW, Jung SH, et al. Chemotherapeutic trial to of the appendix as a cause of acute appendicitis. Parasitol Res. control enterobiasis in schoolchildren. Korean J Parasitol. 2007;102:99-102. 1997;35:265-269.

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