Helminth

Strongyloides

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Strongyloides, Strongyloides stercoralis, Strongyloidiasis

  • Classification
  1. Nematode: Roundworm
  • Epidemiology
  1. Responsible for most U.S. cases fatal Helminth disease
  2. Endemic areas
    1. Tropical Asia
    2. Sub-Saharan Africa
    3. Latin America
    4. Pockets in Rural southeastern United States
    5. Pockets in Eastern Europe
  • Pathophysiology
  1. Adult roundworms live in the Small Intestine
  2. Larvae infect perianal skin
  • Risk Factors
  • Hyperinfection (Immunocompromised)
  • Differential Diagnosis
  • Symptoms
  1. Often asymptomatic in immunocompetent patients
  2. Larva currens
    1. Recurrent serpiginous Urticaria
    2. Onset in perianal area
    3. Migratory rash to buttocks, groin, trunk
  3. Gastrointestinal side effects
    1. Abdominal Pain or Abdominal Bloating
    2. Diarrhea
  4. Pulmonary involvement
    1. Cough
    2. Shortness of Breath
    3. Dyspnea
    4. Hemoptysis
  • Labs
  1. Eosinophilia (blood or stool)
    1. May be only finding in immunocompetent patients
  2. Guaiac-positive stools
  3. Rhabditiform larvae present in sample
    1. Stool sample or duodenal aspiration
    2. False Negative test: 70% of cases
  • Management
  1. Ivermectin (now preferred agent)
    1. Dose: 200 mcg/kg orally daily for 2 days
    2. Repeat every 15 days for disseminated infection until stool testing negative (and then one more treatment)
    3. Continuous dosing daily for hyperinfection (e.g. Sepsis, Meningitis) continued until stool and Sputum negative for 2 weeks
  2. Other agents
    1. Albendazole 400 mg orally twice daily for 7 days (for asymptomatic of intestinal infection)
    2. Thiabendazole (not available, poorly tolerated, less effective)
  • Complications
  • Hyperinfection
  • Prognosis
  1. Hyperinfection mortality rate in immunosuppressed: 87%
  • References
  1. Gilbert (2016) Sanford Guide, IOS version, accessed 9/12/2016
  2. Siddiqui (2001) Clin Infect Dis 33:1040-7 [PubMed]