Pinworms Flashcards
what is enterobiasis
- intestinal infection caused by nematode Enterobius vermicularis (aka pinworm, seatworm, roundworm or threadworm
- humans are only natural host, cats and dogs can hold eggs on thier fur but no evidence that they can act as carriers of infection
how is Enterobiasis transmitted
- human-to-human via fecal oral route
- nature eggs are transferred from anus to mouth and ingested
- larvae hatch in small intestine and adults establish in colon
- cycle ~ 1 month and life span of adults is ~2 months
- mature females migrate to anus at night and lay eggs on perianal or perineal skin, eggs become infective in 4-6 hours
- eggs remain infective ~20 days
Pinworm infection is most common in what population
5-14 y/o
- uncommon in children < 2
- estimated that 1/3 children globaly wil be infested durign childhood
*most common intestinal parasite in primary care regardless of socioeconomic circumstances
where is enterobiasis most prevalent
- in temerate and cold climates bc of less frequent bathing and infrequent changing of underlcothing
- overcrowing in shcools and family gatheirngs and inadequate personal and community hygiene are also factors
-
what are the usual consequences of infection
loss of sleep, discomfort due to anal itching and embarrassment do to social connotations of having “worms.”
*often entire family is infected
- secondary bacterial infections can occur as complication of excessive scratching
- rarely associated with signifacnt patholgoy like vulvovaginitis, dysuria, enuresis, urinary tract infection, appendicitis, chronic salpingitis, and ulcerative lesions of the small and large intestine.
goals of therapy for pinworm treatment
Eliminate the infection
Relieve symptoms such as itchiness
Promote good hygiene
Prevent transmission, reinfection and complications
how to assess for pinworms
- most infetions are asymptomatic
- often associated with perianal or perineal itching, esp if high worm burden
- itching is worse at night when females aly eggs that are attached to perianal area by sticky substnace causing pruitus
- itching can cause insomnia and reslessness
*rule out diaper dermatitis, constipation, psoriasis of the anogenital region, and perianal eczema before recommending pinworm treatment
- scratching can cause skin irritation -> if severe skin can break down and allow for secondary bacterial infection, eczematous dermatitis or bleeding
what can extnesive pinwro infection cause
abdominal pain, nausea and vomiting -> not typical of uncomplicated infection
* If abdominal pain, severe diarrhea, bloody bowel movements, dysuria, fever, extreme poor appetite, neurotic excoriation (self-inflicted lesions produced by repetitive scratching) or anogenital symptoms associated with sexual abuse
REFER
how is pinworm diagnosis confirmed
- visual identification of ova or worm itself
- eggs are only seen on occasion in stool, so stool sample is not a reliable diagnosis
most common diagnostic methods are
- Flashlight test
- can directly observe worms during ovipositon
- put child to bed w/o underpants and use flashlight to examine anus after child sleeping for 2-3 horus
- Scotch tape test
- performed at gome in morning before defication or washing
- piece of transpaent adhesive tape pressed on perianal skin, then stuck to slide and examined under microscope
- microscopic analysis of subungual samples
- ova ma be found under fingernails of infected patients, since anla itching is common
prevention of pinworms
difficult.
proper hygiene is helpful and includes careful handwashing after going to the toilet, after scratching the perianal area, and before and after eating or preparing food
is pinworm self limiting
- if ingestion of eggs and subsequent reinfection can be avoided, the infection can be self limited and eradicate in 4-8 weeks
- difficult to achieve and reinfection and ongoing infestion is common
non pharm measures for pinworm
- shower each morning
- avoid co-bathing, reusing or sharing washlcoths during treatment time and 2 weeks after treatment
- handwashing and fingernail cleaning, esp prior to meals or after suing bathroom
- keep fingernails short/clean, avoid nail bting
- discourage children from thumb sucking, pacing hands in mouth of sucking on toys
- encourage all family members to wear cotton underpants washed in hot soappy water, change twice daily
- wash nightclothes, udnerwaer and ahnd towels daily F2W
- change sheets frequently at start of each treatment
- avoid shaking linens or lcothes priot to washing
- wash toilet seat frequently
when is pharmacologic therapy used
- confirmed daignosis by health care provider is recommended before pharmacologic treatment is intiiated to minimize unnecessary exposure to potential adverse effects of the anthelmintics
non prescription treatment for pinworms
pyrantel pemoate
- dosage
- adults & children >1y: 11mg/kg (base)
- single dose PO; repease in 2 weeks
- Maximum base dose = 1g
- adverse effects
- anorexia
- N/V/D
- abdominal cramps,
- HA, dizziness
- drowsiness
- Drug Interactions
- N/A
- Comments
- dosage often expressed as 1 tab (125mg base)/ 11kg (25 lbs)
- avodi in pregnancy in favour of alternative therapies due to insufficient avidence
- caution hepatic impairment
prescription treatment for pinworms
mebendazole
- Dosage
- adults and children >2, 100 mg single dose, repeat after 2 and 4 weeks
- adverse effects
- abdominal pain, diarrhea, vomiting in patietns w/ hgih parasite buden
- less common: dizziness, drowsiness, flatulence, HA, itchiness
- rare: anemia, agrenulocytosis, glomerulonephritis
- Drug interactions
- may raise risk of Stevens Johnson syndrome or toxic epidermal necrolysis when coadministered w/ metronidazole
- Comments
- can chew or crush tabs and mix w/ food
- avoid in first trimester of pregnancy due to limited data
