Strongyloidiasis


Epidemiology

Geography

  • Endemic in Subtropical/Tropical Regions: prevalence may be >25%
    • Highest Rates Occur in Military Personnel/Travelers Returning from Endemic Areas and Immigrants/Refugees from Endemic Areas
  • Sporadic in Southeastern US, Appalachia, and Southern Europe
  • Cases May Also Occur Due to Transmission in Long-Term Care Settings

Microbiology


Diagnosis

Stool Ova and Parasite Exam (see Stool Ova and Parasite Exam)

  • Larvae are First Detected in the Stool Approximately 3-4 wks After Initial Dermal Penetration

Clinical Manifestations

Typical Strongyloidiasis

General Comments

  • Most Patients with Strongyloidiasis Do Not Experience Significant Symptoms

Allergic/Immunologic Manifestations

Dermatologic Manifestations

  • General Comments
    • Symptoms May Wax and Wane Over Years
  • “Ground Itch”
    • Physiology: due to larvae penetrating the skin
    • Clinical (Acute Infection): most commonly on the feet
    • Clinical (Chronic Infection)
      • Angioedema (see Angioedema)
      • Eruption on Buttocks
      • Erythroderma (see Erythroderma) (J Am Acad Dermatol, 2003) [MEDLINE]
      • Larva Currens (“Running Larva”): pathognomonic of Strongyloidiasis
      • Non-Palpable Purpura (see Purpura)
      • Periumbilical Purpura (see Purpura): occurs in disseminated infection
      • Pruritus (see Pruritus)
      • Urticaria (see Urticaria)

Gastrointestinal Manifestations

Hematologic Manifestations

  • Peripheral Eosinophilia (see Peripheral Eosinophilia)
    • Clinical: peripheral eosinophilia may be absent in cases with concomitant pyogenic infection or corticosteroid administration

Pulmonary Manifestations

  • General Comments
    • Symptoms May Wax and Wane Over Years
  • Asthma-Like Illness (Br Med J, 1973) MEDLINE and [MEDLINE]
    • Epidemiology
      • May Occur with Chronic Strongyloidiasis
    • Clinical
      • Asthma Paradoxically Worsens with Corticosteroid Administration
  • Restrictive Lung Disease
    • Epidemiology
      • Occurs with Chronic Strongyloidiasis
    • Epidemiology
      • Case Reports (Am J Respir Crit Care Med, 1995) [MEDLINE]
  • Simple Pulmonary Eosinophilia (Loffler Syndrome) (see Simple Pulmonary Eosinophilia)

Strongyloides Hyperinfection Syndrome

General Comments

  • Repeated Autoinfection within the Gastrointestinal Tract Increases the Parasite Burden, Resulting in the Hyperinfection Syndrome
    • Rhabditiform Larvae Transform into Filariform Larvae, Which Then Penetrate the Intestinal Wall to Enter the Bloodstream
    • Massive Dissemination of Filariform Larvae Occurs to the Lungs, Liver, Heart, Central Nervous System, and Endocrine Glands
  • Risk Factors
    • General Comments
      • Retrospective Case Review of Strongyloides Hyperinfection Syndrome Cases (Infection, 2015) [MEDLINE]
        • Immunosuppression was Present in Most Cases of Hyperinfection Syndrome (with Chronic Long-Term Corticosteroids Being the Most Common Immunosuppressive)
    • Anti-Tumor Necrosis Factor-α Therapy (see Anti-Tumor Necrosis Factor-α Therapy, [[Anti-Tumor Necrosis Factor-α Therapy]])
      • Case Report in Filipino RA Patient Treated with Anti-TNFα Therapy in Addition to Prednisone and Methotrexate (J Clin Rheumatol, 2007) [MEDLINE]
    • Hypogammaglobulinemia (see Hypogammaglobulinemia)
    • Impaired Cell-Mediated Immunity (with TH-2 Helper Cell Dysfunction)
      • Alcoholism (see Ethanol)
      • Congenital Immunodeficiency
      • Corticosteroids (see Corticosteroids)
        • Even Short Corticosteroid Courses Can Lead to Severe (and Potentially Fatal) Hyperinfection Syndrome (Trans R Soc Trop Med Hyg, 2007) [MEDLINE]
      • Cytotoxic Agents
        • However, in Contrast to Other Immunosuppressives, Cyclosporine A Has Activity Against Strongyloides (see Cyclosporine A, [[Cyclosporine A]]): it is unclear if this activity is sufficient to inhibit the development of the hyperinfection syndrome
      • Hematopoietic Stem Cell Transplantation (HSCT) (see Hematopoietic Stem Cell Transplantation, [[Hematopoietic Stem Cell Transplantation]])
      • Human Immunodeficiency Virus (HIV) (see Human Immunodeficiency Virus)
        • Risk of Hyperinfection Syndrome is Less with HIV than with HTLV-1
        • However, Immune Reconstitution Syndrome (IRIS) May Be a Risk Factor for Disseminated Strongyloidiasis
      • Human T-Lymphotropic Virus Type I (HTLV-I) Infection (see Human T-Lymphotropic Virus-1)
        • HTLV-1 Decreases the Production of IL-4, IL-5, IL-13, and IgE: these are all required for host defense against Strongyloides
      • Malignancy
      • Malnutrition (see Malnutrition)
    • Organ Transplant (Donor-Derived Strongyloidiasis)

Gastrointestinal Manifestations

  • General Comments
    • Retrospective Case Review of Strongyloides Hyperinfection Syndrome Cases (Infection, 2015) [MEDLINE]
      • Gastrointestinal Symptoms were Present in 71.2% of Cases
  • Abdominal Pain (see Abdominal Pain)
  • Anorexia (see Anorexia)
  • Diarrhea (see Diarrhea)
  • Nausea/Vomiting (see Nausea and Vomiting)

Hematologic Manifestations

  • Peripheral Eosinophilia (see Peripheral Eosinophilia)
    • Epidemiology
      • Retrospective Case Review of Strongyloides Hyperinfection Syndrome Cases (Infection, 2015) [MEDLINE]
        • Peripheral Eosinophilia Occurred in Only 34.3% of Cases

Neurologic Manifestations

  • Meningitis
    • Microbiology
      • Gastrointestinal Flora: Klebsiella, etc
      • Streptococcus Gallolyticus (Formerly Streptococcus Bovis) (Clin Microbiol Infect, 2015)[MEDLINE]

Pulmonary Manifestations

  • General Comments
    • Retrospective Case Review of Strongyloides Hyperinfection Syndrome Cases (Infection, 2015) [MEDLINE]
      • Respiratory Symptoms were Present in 88.6% of Cases
  • Cough (see Cough)
  • Dyspnea (see Dyspnea)
  • Hemoptysis (see Hemoptysis)
  • Pulmonary Infiltrates/Pneumonia
  • Respiratory Failure (see Respiratory Failure)
    • Epidemiology
      • May Occur (Chest, 2005) [MEDLINE]
      • Retrospective Case Review of Strongyloides Hyperinfection Syndrome Cases (Infection, 2015) [MEDLINE]
        • Respiratory Failure Requiring Mechanical Ventilation Occurred in 67.9% of Cases
  • Wheezing/Bronchospasm (see Wheezing)
    • Physiology
      • Adult Parasites Localize within the Bronchial Tree and Lay Eggs Which Develop into Larvae in the Airway

Other Manifestations

  • Bacteremia (see Bacteremia)
    • Epidemiology
      • Retrospective Case Review of Strongyloides Hyperinfection Syndrome Cases (Infection, 2015) [MEDLINE]
        • Concomitant Bacterial Infection Occurred in 38.4% of Cases
    • Physiology: bacteria originate from either the lung or gastrointestinal tract (J Gastroenterol Hepatol, 2002) [MEDLINE]
    • Microbiology
      • Gastrointestinal Flora: Klebsiella, etc
      • Streptococcus Gallolyticus (Formerly Streptococcus Bovis) (Clin Microbiol Infect, 2015)[MEDLINE]
    • Clinical
  • Fever (see Fever)
  • Sepsis (see Sepsis)
    • Epidemiology
      • Retrospective Case Review of Strongyloides Hyperinfection Syndrome Cases (Infection, 2015) [MEDLINE]
        • Shock Occurred in 57.3% of Cases
        • Predictors of Shock
        • Concomitant Bacterial Infection
        • Peripheral Eosinophilia (see Peripheral Eosinophilia)

Treatment

Ivermectin (see Ivermectin)


Prognosis


References