Severe Ascariasis in a 1-Year-Old

The Pathogen

Why "Severe" in a 1-Year-Old Is a Medical Emergency

1. Pulmonary Phase (Loeffler Syndrome)

• Larvae traversing alveoli cause eosinophilic pneumonitis (Loeffler syndrome): wheezing, dyspnea, paroxysmal nonproductive cough, high fever, urticaria, angioedema
• Peripheral eosinophilia and transient infiltrates on CXR
• Larvae (not eggs) may be found in sputum/gastric aspirates at this stage
• Self-limited (2-3 weeks), but distressing and potentially severe in infants

2. Intestinal Phase - Complications (especially severe at age 1)

Diagnosis

Fertilized, unembryonated egg of A. lumbricoides on microscopy

Treatment

⚠️ Age-Specific Drug Dosing (Critical for a 1-Year-Old)

• The FDA notes safety is "uncertain" in children under 6 years, but studies using albendazole in children as young as 1 year suggest it is safe
• WHO guidelines for mass drug administration include children aged 12-23 months at a half-dose (200 mg)
• Ascariasis should always be treated even if asymptomatic - to prevent serious complications - Harrison's, 22e, p. 1859

Pulmonary Ascariasis (Severe Loeffler Syndrome)

• No anthelmintic is needed in the pulmonary phase alone (self-limited)
• If severe pneumonitis: corticosteroids to reduce inflammation
• In cases with ongoing pulmonary + intestinal involvement: 2 doses of albendazole (200 mg in this age group) one month apart - the first kills mature intestinal worms, the second kills those that were still migrating during the first dose
• Sleisenger & Fordtran's GI Disease, p. 2267

Intestinal Obstruction (Management Algorithm)

Partial obstruction          →    Conservative management:
                                  • IV fluid resuscitation
                                  • Nasogastric (NG) decompression
                                  • IV antibiotics
                                  • Piperazine instilled via NG tube
                                    (75 mg/kg/24h × 2 days; max 3.5 g)
                                    [paralyzes worms, allows passage]
                                  • Albendazole 200 mg once AFTER
                                    obstruction resolves

Complete obstruction         →    Surgical emergency:
(or volvulus, intussusception,    • Enterotomy with manual worm removal
perforation, peritonitis)         • Albendazole post-op to kill remaining worms

• Harrison's 22e, p. 1859; Sleisenger & Fordtran's, p. 2267

Note on piperazine: It paralyzes worms (flaccid paralysis via GABA agonism) and is historically preferred for obstruction because paralyzed worms pass naturally without dying in situ. It is not widely available in many countries.

Biliary/Pancreatic Ascariasis

• Conservative first: IV fluids, bowel rest, antibiotics
• Albendazole is NOT effective for worms already inside the bile duct (poorly concentrated in bile; paralyzed worms in the duct cannot exit and may become trapped)
• Give albendazole only after worms have migrated back out of the duct
• Emergent ERCP with balloon/basket/forceps extraction for: acute cholangitis, obstructive jaundice, acute pancreatitis
• Avoid sphincterotomy - it facilitates future worm entry into the ducts
• Sleisenger & Fordtran's GI Disease, p. 2268

Key Points for Infants Specifically

1. Intestinal obstruction is the most feared complication - the immature, narrow lumen of a 1-year-old makes this especially likely with heavy worm burdens
2. Albendazole 200 mg single dose (not 400 mg) is the WHO-recommended dose for children under 24 months
3. Malnutrition risk is amplified - monitor weight, albumin, vitamins A and C; supplement as needed
4. Never withhold treatment - even asymptomatic ascariasis should be treated in a 1-year-old given the risk of complications
5. Fever or other anthelmintic drugs (including antipyretics) can stimulate worm migration to ectopic sites - monitor closely during treatment
6. Infection control: treat the household, improve sanitation; reinfection is the rule in endemic settings without environmental interventions

Summary Table