19 - Pinworms Flashcards
T or F: Humans are the only host
true
Describe the pathophysiology (lifecycle) of pinworms
- Human ingests eggs
- Once egg reaches stomach, the outer covering is dissolved in stomach acid and larvae are released
- Larvae hatch in duodenum and mature for 1-2 months
- Live and mate in large intestine
- At night, pregnant females exit anus to lay eggs
- After laying eggs, female pinworms usually die (but may reenter the individual)
- Average lifespan is 4-6 weeks (Total lifespan is 3 months including maturation)
- Within 6 hours of being deposited, the ova become inefective
- Have a thick wall that allow them to remain infective for up to 14-20 days
- Have a sticky layer so they can stick to surfaces (pajamas, furniture, bedding)
List & Describe the 3 methods of pinworm transmission
- Finger to mouth: scratch butt and put finger in mouth
- Inhalation: inhale eggs while fluffing bedding for example
- Retroinfection: when the female worm goes back up the anus instead of dying
What are risk factors for pinworms?
Overcrowded living conditions
Children:
- common in 5-10 yr olds
- uncommon in <2 (because they wear diapers)
Temperate and cold climates
What kills pinworm eggs?
sunlight - recommend patient to keep blinds open
Signs & Sx
- Can be asymptomatic
- Perianal or perineal itching
- WORSE AT NIGHT
- Insomnia, irritability, and restlessness
- Major infestations may have abdominal pain, anorexia, diarrhea
Less common:
- vaginitis
- pelvic inflammatory disease
- urethritis
- dysuria
- UTI
- hives
Red flags/referrals
-Suspected pinworm infestation (need Dr. diagnosis) esp if pregnant, less than 12 yrs old, renal or hepatic dysfunction
-Abdominal pain
-Bloody bowel movements or painful urination
-Fever
Poor appetite
-Suspect sexual abuse
-Vague symptoms and negative visual inspection
Describe the 3 methods of diagnosis pinworms
1) Inspection of perianal area:
* one hour after child falls asleep without wearing underpants, visually examine anus with a flashlight
2) Scotch-tape test:
* first thing in the morning, press a piece of tape on perianal skin, then stick to a glass slide to be examined under a microscope
3) Microscopic evaluation of sublingual (under the nail) sample:
* ova likely found under fingernails in infested person
Goals of treatment
- Eradication of pinworms from patient and household
- Eliminate symptoms (ex. itching)
- Promote good hygiene
- Prevent recurrence and spread
What are some prevention measures that you can recommend to your patient?
Handwashing:
- After using toilet
- After scratching perianal area
- Before and after eating/preparing food
Keeping nails short and discouraging nail biting
List 4 non-pharms for pinworms
- Shower every morning
- Wash pyjamas, towels and underwear in hot water daily for 2 weeks
- Wash hands and fingernails frequently
- Open blinds to kill eggs
Who should be treated for pinworms?
Infested individuals and all household members/close contacts (unless a CI to the medication)
What is the OTC treatment for pinworms?
Pyrantel Pamoate (Combantrin)
Pyrantel Pamoate:
MOA
causes depolarization in the neuromusculature of the pinworms, which leads to paralysis, and therefore pinworms lose their hold on the intestinal wall and are then carried out of the patient through peristalsis in the stool
Pyrantel Pamoate:
Dose?
11 mg/kg
Max single dose = 1 gram
Pyrantel Pamoate:
Is it a single dose treatment?
Yes - for initially asymptomatic patients
No - for initially symptomatic patients we repeat treatment in 2 weeks
