What is the scientific name for pinworms?
- enterobiasis vermicularis
What are the normal hosts of pinworms?
- only humans!
- they do not live in the soil or the water and are not transmitted through animal feces
Explain the pathophysiology of a pinworm infection?
- human ingests the mature pinworm eggs. Ince the ova reaches the stomach, the outer coating is dissolved and the larvae are released
- larvae hatch in the duodenum
- maturing takes 1-2 months
- live and mate throughout the length of the large intestine attached to the mucosa
- at night, pregnant females exit the anus to lay eggs, leaving as many as 10,000 to 15,000 ova on the perianal skin
- after laying eggs, the female pinworms typically die (but may reenter the individual)
- average lifespan is 4-6 weeks
- within 6 hours of deposited, the ova become infective
- have a thick wall that allow them to remain infective for 14 to 20 days
- have a sticky outer later that allow ova to stick well to various surfaces. May be transferred to night clothes, bedding, dust, etc
- touching the perianal skin (by scratching) can loosen the eggs, thereby releasing them into he environment
- most commonly eggs are found on hands and under fingernails leading to transmission
What causes the itch from the eggs around the anus?
- the sticky outer coating causes the itch
Can the pinworm eggs be spread to fomites?
YES
What are the three methods of transmission of pinworms?
- finger to mouth
- inhalation
- retroinfection (if the eggs are not washed off and allowed to hatch, they will hatch and the worms can travel back up into the large intestine)
What are the risk factors associated with a pinworm infection?
- overcrowded living conditions
- children (common to 5-10 y/o, uncommon in under 2 y/o)
- temperature and cold climates
Why are these infections more likely in cold climates?
- these eggs are denatured by sunlight
Pinworm infections are very uncommon in children under the age of ____. Why?
2
- babies have diapers- they do not have the chance to scratch and aurtoinnoculate themselves
What are the signs and symptoms of pinworm infection?
- can be asymptomatic
- perianal or perineal itching that becomes worse at night
(scratching can lead to a skin breakdown) - insomnia, irritability and restlessness
- major infestations may have symptoms of abdominal pain, anorexia and diarrhea
- less common presentation: vaginitis, pelvic inflammatory disease, urethritis, dysuria, UTIs
What are the red flags associated with a pinworm infection?
- suspected pinworm infestation (especially if pregnant, < 12 y/o, renal or hepatic dysfunction
- should see the physician asap if there is: abdominal pain, bloody BMs or painful urination, fever, poor appetite, suspected sexual abuse
- vague symptoms and negative visual inspection
What are the three ways that a differential diagnosis can be done of a pinworm infection?
- visual inspection of the perianal area
- scotch-tape test
- microscopic evaluation of subungual sample (ova likely found under the fingernails or an infected individual)
What are the things to recommend for prevention of infection?
- handwashing (after using the toilet, after scratching the perianal area, before and after eating/preparing food)
- keeping nails short and discouraging nail biting
What are the non-pharm treatment options for pinworms?
- shower every morning
- wash bedclothes, towels and underwear in hot water daily for 2 weeks
- wash bed linens every 3 to 7 days for 3 weeks
- change night clothes and sheets are the start of treatment
- wash hands and clean fingernails frequently
- clean floors or bedrooms, ensure blinds and curtains are open as eggs are destroyed by the sunlight (want to recommend vacuuming to decrease the chance of the eggs going airborne)
- clean toilet seats daily
- discourage thumb sucking
Who should be treated in a pinworm infection?
- infested individuals and ALL household members/ close contacts need to be treated unless there is a contraindication to the medication
What is the mechanism of action of pyrantel pamoate?
- causes depolarization in the neuromusculature of the pinworms, which leads to paralysis, and therefore the pinworms lose their hold on the intestinal wall and are then carried out of the patient through in the stool
- highly efficacious (approx. 90% cure rate)
What is the dose for pyrantel pamoate?
Over 1 y/o: 11 mg/kg as a base and then repeat in 2 weeks for those that are experiencing symptoms (max dose: 1 gram)
Dose pyrantel pamoate treat eggs?
- no, it does not treat eggs
- it is important that the person do non-pharms to go along with this-this is the only thing that will cause the eggs to die
What is the age limit for use of pyrantel pamoate?
2 y/o
What are the side effects generally associated with pyrantel pamoate?
- nausea, vomiting, tenesmus, anorexia, diarrhea and abdominal cramps, dizziness and drowsiness
What are the contraindications associated with using pyrantel pamoate?
- liver disease
- pregnancy, breastfeeding
- children under 2
What is the timeframe that the patient should expect relief from perianal itching?
- 7-14 days, if not we need to recommend that they repeat treatment
- if not resolved in 7 days of the second tx, then refer to the physician
If adverse effects last longer than _____ days, then need to refer to the physician?
- 3 days
What side effects should be patient be warned of and not drive or operate heavy machinery until the effect of these symptoms are determined?
- dizziness or drowsiness
if these sx last longer than 24 hours, need to refer to a physician
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