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General Considerations

  • Ascaris lumbricoides (roundworm)
  • Most common helminthic infestation in the world
  • Usually asymptomatic and most common in children ages 1 to 10 years
  • Most often found in distal small bowel
  • Life cycle
    • Infection is through contaminated soil
    • Involves GI tract of host twice
    • First time as egg
    • Migrates through lungs
    • Adult travels up trachea
    • Returns to GI tract for maturation (2 months)

Clinical Findings

  • Colicky pain
  • Hematemesis
  • Eosinophilia
  • Cough and dyspnea 

Imaging Findings

  • Chest may show fleeting, patchy areas of airspace disease
  • Long, tubular filling defects, especially in distal small bowel
  • The worm ingests barium and the barium may be seen as a thin line of contrast in the center of the worm, especially after the remainder of the barium exits the small bowel. 
  • Ball of worms
  • Filling defects in the biliary system

Differential Diagnosis

  • Biliary colic
  • Intestinal obstruction
  • Community-acquired pneumonia


  • Appendicitis
  • Jaundice (if bile ducts are involved)
  • Pneumonia
  • Bowel perforation
  • Mechanical obstruction


  • Oral Albendazole is the drug of choice
  • Vitamin supplementation


  • 95% cure rate after single-dose drug administration with high re-infection if patient remains in endemic area


Ascariasis. There are serpiginous filling defects in the distal small bowel (red arrows)representing adult roundworms.
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Ascariasis. DR Haburchak. eMedicine