Ascariasis

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

Complications

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

Treatment

• Oral Albendazole is the drug of choice
• Vitamin supplementation

Prognosis

• 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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