Management of Worm Infestation

Introduction

Helminthic infestations (worm infestations) are a significant cause of morbidity in children, particularly in developing countries. They contribute to malnutrition, growth retardation, anemia, and cognitive deficits. The most common infestations are caused by Soil-Transmitted Helminths (STH): Ascaris lumbricoides (Roundworm), Trichuris trichiura (Whipworm), and Hookworms (Ancylostoma duodenale and Necator americanus). Other important infections include Enterobius vermicularis (Pinworm), Strongyloides stercoralis, and various tapeworms (Cestodes).

General Management Principles

• Diagnosis: Confirmation is usually via stool microscopy for eggs/ova. Enterobius requires the perianal adhesive tape test (scotch tape test). Strongyloides requires stool examination for larvae.
• Family Treatment: For highly contagious infestations like Enterobius and Hymenolepis nana, treating all family members is crucial to prevent reinfection.
• Hygiene: Interventions must include hand washing, nail trimming, and sanitary disposal of feces.
• Complications: Management extends beyond deworming to treating complications like anemia, intestinal obstruction, or seizures (in neurocysticercosis).

Management of Intestinal Nematodes (Roundworms)

1. Ascariasis (Ascaris lumbricoides)

• Drug of Choice:
  • Albendazole: 400 mg oral single dose (200 mg for children 1–2 years).
  • Mebendazole: 100 mg twice daily for 3 days OR 500 mg single dose.
• Alternatives:
  • Ivermectin: 150–200 µg/kg single dose.
  • Pyrantel Pamoate: 11 mg/kg (max 1 g) single dose.
  • Nitazoxanide: Effective alternative; dose varies by age (100 mg BID for 1-3 yrs; 200 mg BID for 4-11 yrs; 500 mg BID for >12 yrs) for 3 days.
• Management of Complications (Intestinal Obstruction):
  • Conservative: Intravenous fluids, nasogastric suction, electrolyte correction.
  • Piperazine Citrate: 75 mg/kg/day for 2 days (causes flaccid paralysis, aiding expulsion without agitation). Note: Withdrawn in many markets.
  • Surgery: Indicated for complete obstruction, volvulus, or perforation.

2. Hookworm (Ancylostoma duodenale, Necator americanus)

• Drug of Choice:
  • Albendazole: 400 mg single dose. (Highly effective).
• Alternatives:
  • Mebendazole: 100 mg twice daily for 3 days or 500 mg single dose. (Single dose mebendazole has lower cure rates for hookworm compared to albendazole).
  • Pyrantel Pamoate: 11 mg/kg (max 1 g) daily for 3 days.
• Supportive Care:
  • Iron Supplementation: Critical for treating iron deficiency anemia caused by chronic blood loss.
  • Nutritional Support: High-protein diet for hypoproteinemia.

3. Trichuriasis (Trichuris trichiura / Whipworm)

• Drug of Choice:
  • Mebendazole: 100 mg twice daily for 3 days. (Single doses are less effective).
  • Albendazole: 400 mg once daily for 3 days. (Single dose albendazole has low cure rates for Trichuris).
• Alternative:
  • Ivermectin: 200 µg/kg daily for 3 days.
  • Combination Therapy: Albendazole + Ivermectin or Albendazole + Oxantel pamoate shows improved efficacy for heavy infections.

4. Enterobiasis (Enterobius vermicularis / Pinworm)

• Strategy: Treat the entire household simultaneously. A second dose is required to kill worms that hatch from eggs after the initial dose.
• Regimen:
  • Albendazole: 400 mg single dose; repeat in 2 weeks.
  • Mebendazole: 100 mg single dose; repeat in 2 weeks.
  • Pyrantel Pamoate: 11 mg/kg (max 1 g) single dose; repeat in 2 weeks.
• Hygiene Measures: Essential to prevent autoinfection. Daily morning bathing, frequent changing of bed linen/underwear, and keeping fingernails short.

5. Strongyloidiasis (Strongyloides stercoralis)

• Drug of Choice:
  • Ivermectin: 200 µg/kg/day orally for 2 days. (More effective than albendazole).
• Alternative:
  • Albendazole: 400 mg twice daily for 7 days.
• Hyperinfection Syndrome: Occurs in immunocompromised children. Requires prolonged treatment (Ivermectin for 7–14 days or until larvae are cleared from stool/body fluids) and reduction of immunosuppressive therapy.

Management of Cestodes (Tapeworms)

1. Intestinal Tapeworms (Taenia saginata, T. solium, Diphyllobothrium latum)

• Drug of Choice:
  • Praziquantel: 5–10 mg/kg single oral dose.
• Alternative:
  • Niclosamide: 50 mg/kg single dose (chewed thoroughly).
  • Nitazoxanide: Also effective.
• Diphyllobothrium latum: May require Vitamin B12 supplementation due to megaloblastic anemia.

2. Hymenolepiasis (Hymenolepis nana / Dwarf Tapeworm)

• Drug of Choice:
  • Praziquantel: 25 mg/kg single dose. A repeat dose after 10 days may be needed as it is less effective against the cysticercoid stage.
• Alternative:
  • Nitazoxanide: 100–500 mg BID (age-dependent) for 3 days.

3. Neurocysticercosis (Larval T. solium)

• Symptomatic Therapy: Antiepileptics for seizures (primary focus).
• Antiparasitic Therapy: Indicated for viable parenchymal cysts.
  • Albendazole: 15 mg/kg/day (divided into 2 doses, max 800-1200 mg) for 10–14 days. Taken with a fatty meal to increase absorption.
  • Praziquantel: 50 mg/kg/day for 10–14 days.
  • Combination: For >2 cysts, Albendazole + Praziquantel is more effective.
• Corticosteroids: (Prednisolone/Dexamethasone) Must be started before or with antiparasitics to manage the inflammatory response caused by dying cysts.
• Calcified Cysts: Do not require antiparasitic therapy; treat seizures if present.

4. Hydatid Disease (Echinococcus granulosus)

• Surgery: Treatment of choice for large, complicated cysts.
• PAIR: Percutaneous Aspiration, Injection (of protoscolicidal agent), and Re-aspiration.
• Chemotherapy:
  • Albendazole: 15 mg/kg/day (max 800 mg) for 1–6 months. Used as an adjunct to surgery/PAIR (to prevent secondary seeding) or as primary therapy for small/inoperable cysts.

Management of Tissue Nematodes

1. Visceral Larva Migrans (Toxocariasis)

• Mild Disease: Often self-limiting.
• Treatment: Albendazole (400 mg BID for 5 days) or Mebendazole.
• Adjunct: Corticosteroids for severe inflammation (e.g., ocular or CNS involvement).

2. Cutaneous Larva Migrans (Creeping Eruption)

• Drug of Choice: Albendazole (400 mg daily for 3–7 days) OR Ivermectin (200 µg/kg single dose).
• Topical: Thiabendazole applied topically.

Prevention and Control Strategies

• Mass Drug Administration (MDA): WHO and National programs recommend periodic deworming (Albendazole 400 mg) every 6–12 months for preschool and school-age children in endemic areas (prevalence >20%) to reduce worm burden and transmission.
• WASH: Improvement in Water, Sanitation, and Hygiene is the only definitive way to prevent reinfection.
  • Safe disposal of excreta.
  • Hand washing.
  • Washing raw fruits/vegetables.
  • Wearing shoes (to prevent Hookworm/Strongyloides).