Ascaris Lumbricoides
Ascaris Lumbricoides: Excerpt from The 5-Minute Pediatric Consult
Suzanne Dawid, MD, PhD
Ascaris Lumbricoides - BASICS
Ascaris Lumbricoides - description
Ascaris lumbricoides is a large roundworm, 15–40 cm in length, which infects humans via eggs found in soil. Animals are not affected.
Ascaris Lumbricoides - general prevention
Infection control:
- Appropriate disposal of human excrement and hand washing could eliminate this infection.
- In communities with high Ascaris carriage, biannual administration of pyrantel pamoate or mebendazole is effective.
Ascaris Lumbricoides - epidemiology
Ascaris Lumbricoides - incidence
- All ages may be affected; however, children are more frequent hosts owing to oral behavior and tend to have a higher worm burden.
- Ascariasis is more common where sanitation is poor and population dense.
- Eggs are viable for up to 6 years in temperate climates.
Ascaris Lumbricoides - prevalence
~1/4 of the world’s population is infested with this worm.
Ascaris Lumbricoides - pathophysiology
- Eggs are ingested from soil contaminated with human feces.
- Larvae are liberated in the small intestine.
- Larvae invade the venous system and travel to the portal circulation, inferior vena cava, and finally, pulmonary capillaries.
- During migration through the pulmonary vessels, an eosinophilic response is evoked.
- Larvae penetrate the alveoli, are expelled by coughing, and swallowed.
- Larvae become adult worms in the small intestine.
- Mechanical obstruction from the mass of worms in the gut may be observed in children.
Ascaris Lumbricoides - etiology
Children commonly get this infection from playing in dirt contaminated with Ascaris eggs.
Ascaris Lumbricoides - DIAGNOSIS
Ascaris Lumbricoides - signs & symptoms
Ascaris Lumbricoides - history
- Most patients with moderate infections are asymptomatic.
- History or passage of large worms in the stool or vomitus is suggestive.
- Symptoms during the pulmonary stage include cough, dyspnea, fever, and pulmonary infiltrates in the presence of eosinophilia.
- Cough, dyspnea, and fever if pulmonary involvement
- Rarely, the infection presents as intestinal obstruction, with an incidence of ~2 children per 1,000 infected.
Ascaris Lumbricoides - physical exam
- Chest: May have rales or wheezing if Ascaris is in the lungs
- Abdomen: Auscultate and palpate for signs of obstruction.
Ascaris Lumbricoides - tests
Ascaris Lumbricoides - lab
Microscopic examination of stool specimens:
- Will demonstrate the characteristic eggs
- During the pulmonary phase, eosinophils and larvae may be seen; however, stool may be negative.
- Serologic tests are unnecessary and are poorly specific to the diagnosis.
Ascaris Lumbricoides - imaging
- Chest radiograph, if cough is present
- Abdominal plain film if abdominal signs or symptoms
Ascaris Lumbricoides - differencial diagnosis
- Ascariasis should be considered in the differential diagnosis when a patient presents with pneumonia and peripheral eosinophilia.
- The diagnosis of Ascaris infection should be considered whenever intestinal obstruction is seen in an endemic area.
- This infection may be associated with other parasites acquired from contaminated soil.
Ascaris Lumbricoides - TREATMENT
Ascaris Lumbricoides - medication
- Either albendazole 400 mg as a single dose or mebendazole 100 mg b.i.d. daily for 3 days is currently considered to be first-line therapy. A single dose of Ivermectin at 150–200 mcg/kg is also effective.
- Neither regimen is approved for children <2 years old; limited studies suggest that the medications are safe.
- Piperazine citrate (75 mg/kg/d for 2 days; maximum, 3.5 g) has been historically used for cases of intestinal obstruction but it is no longer available in the US.
Ascaris Lumbricoides - surgery
Surgery may be required for severe intestinal or biliary tract obstruction.
Ascaris Lumbricoides - FOLLOW UP
- Treatment as specified above is highly effective.
- Re-examination of stool specimens 3 weeks after therapy to determine that the eggs are eliminated can be considered, but is not essential.
- Reinfection is problematic in endemic areas.
Ascaris Lumbricoides - prognosis
- Once intestinal infection is detected and treated, the prognosis is excellent.
- If obstructive or respiratory complications have occurred, the prognosis is less favorable.
- The case fatality rate in the US is 3%.
Ascaris Lumbricoides - complications
- Bronchopneumonia may be seen during the migrational stage, producing fever, cough, dyspnea, wheeze, eosinophilia, and pulmonary infiltrates.
- Heavy infestations may cause abdominal pain, malabsorption, and growth failure.
- Children may experience obstruction (ileocecal), malabsorption, or intussusception.
- Perforation of a viscus or migration into the appendix, biliary, or pancreatic ducts may rarely occur.
Ascaris Lumbricoides - bibliography
American Academy of Pediatrics. Ascaris lumbricoides infections. In: Pickering LK, ed. 2003 Red Book: Report of the Committee on Infectious Diseases. 27th ed. Elk Grove Village, Ill: American Academy of Pediatrics; 2006:218–219.- O’Lorcain P, Holland CV. The public health importance of Ascaris lumbricoides. Parasitology. 2000;121(suppl):S51–S71.
Ascaris Lumbricoides - CODES
Ascaris Lumbricoides - icd9
127.0 Ascariasis
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Book Source Details
- Book Title: The 5-Minute Pediatric Consult
- Author(s): M. William Schwartz MD; et al.
- Year of Publication: 2008
- Copyright Details: The 5-Minute Pediatric Consult, Copyright © 2008 Lippincott Williams & Wilkins.
More About Ascariasis
More Medical Textbooks Online about Ascariasis
Review other book chapters online related to Ascariasis:
Medical Books Excerpts
- Ascariasis
- "Professional Guide to Diseases (Eighth Edition)" (2005)
- [ read ]
Copyright notice for book excerpts: Copyright © 2008 Lippincott Williams & Wilkins. All rights reserved.
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More About This Book:
Title: The 5-Minute Pediatric Consult
Authors: M. William Schwartz MD; et al.
Publisher: Lippincott Williams & Wilkins
Copyright: 2008
ISBN: 0-7817-7577-9
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