What is the initial management of a suspected helminth infection in the emergency department?

Initial Management of Suspected Helminth Infection in the Emergency Department

The initial management of a suspected helminth infection in the emergency department should include targeted diagnostic testing based on travel history, focused physical examination for specific manifestations, and empirical treatment with albendazole 400 mg plus ivermectin 200 μg/kg for patients with eosinophilia. 1

Patient Assessment

Travel and Exposure History

• Obtain detailed travel history including:
  • Specific countries/regions visited (particularly tropical and subtropical areas)
  • Duration of stay and timing of return
  • Activities with exposure risk:
    • Walking barefoot on soil/sand
    • Swimming in freshwater lakes/rivers
    • Consumption of raw/undercooked foods
    • Living conditions and sanitation access

Physical Examination

• Focus on:
  • Vital signs (assess for shock or systemic inflammatory response)
  • Skin examination for:
    • Larva currens (serpiginous, rapidly moving rash)
    • Cutaneous manifestations of specific helminths
  • Abdominal examination for:
    • Hepatosplenomegaly
    • Tenderness suggesting obstruction or inflammation
  • Respiratory assessment for Loeffler's syndrome
  • Neurological examination if CNS involvement suspected

Laboratory Investigations

First-line Testing

• Complete blood count with differential (focus on eosinophil count)
• Define eosinophilia as peripheral blood eosinophil count >0.5 × 10⁹/L 1
• Concentrated stool microscopy for ova, cysts, and parasites (3 samples)
• Serological testing based on travel history:
  • Strongyloides serology for all patients
  • Schistosoma serology if freshwater exposure in endemic areas
  • Filarial serology only for those with history of West Africa travel/residence 1

Additional Testing Based on Presentation

• For respiratory symptoms:
  • Chest X-ray
  • Sputum examination for larvae
• For gastrointestinal symptoms:
  • Abdominal imaging if obstruction suspected
• For CNS symptoms:
  • Brain/spine imaging
  • Lumbar puncture if meningitis suspected

Management Algorithm

For Asymptomatic Patients with Eosinophilia

1. Obtain travel history and exposure risk
2. Order first-line testing
3. Consider empirical treatment with albendazole 400 mg single dose plus ivermectin 200 μg/kg single dose for patients >24 months of age 1
4. Arrange follow-up to confirm resolution of eosinophilia

For Symptomatic Patients

1. Isolate patient in emergency department isolation room if highly pathogenic infection suspected 1
2. Determine severity:
   • If evidence of end-organ damage or eosinophil count ≥1.5 × 10⁹/L, consider urgent specialist consultation 1
   • For shock or severe manifestations (e.g., hyperinfection syndrome), admit to high-level isolation unit 1
3. Initiate specific treatment based on suspected helminth:
   • Strongyloidiasis: Ivermectin 200 μg/kg daily for 1-2 days
   • Ascariasis/hookworm: Albendazole 400 mg single dose
   • Tapeworm: Praziquantel 10 mg/kg single dose
   • Schistosomiasis: Praziquantel 40 mg/kg in 2 divided doses

Special Considerations

High-Risk Presentations

• Strongyloides hyperinfection in immunocompromised patients (high mortality)
• Neurocysticercosis with neurological symptoms
• Schistosomiasis with Katayama syndrome (acute febrile illness)
• Toxocariasis with cardiac involvement (rare but potentially fatal) 2

Infection Control

• For suspected highly pathogenic infections:
  • Place patient in emergency department isolation room 1
  • Consider negative pressure room for respiratory symptoms
  • Use appropriate personal protective equipment
  • Minimize contact with other patients

Follow-up Planning

• Arrange follow-up testing to confirm parasite clearance
• Monitor eosinophil count for normalization
• Consider referral to infectious disease/tropical medicine specialist for:
  • Persistent eosinophilia despite treatment
  • Complex or multiple helminth infections
  • Immunocompromised patients

Pitfalls to Avoid

• Failing to consider helminth infections in returning travelers with eosinophilia
• Relying solely on stool microscopy (may be negative during tissue migration phase)
• Overlooking Strongyloides in immunocompromised patients (can cause fatal hyperinfection)
• Treating filarial infections with diethylcarbamazine without ruling out onchocerciasis or Loa loa (can cause severe reactions) 1
• Delaying treatment in patients with evidence of end-organ damage