Strongyloidiasis

Thanks to the Human Dx Project for providing us with this fascinating case of a middle aged woman with history of asthma who presented with acute onset of fever and epigastric abdominal pain as well as a chronic progressive cough, found to be febrile, tachycardic, and ill appearing, with E coli bacteremia of unknown source.  Further history taking revealed a similar hospitalization several months prior with idiopathic E coli bacteremia.  Strongyloides titers were sent and markedly elevated.  She was treated with ceftriaxone and ivermectin and made a full recovery.


Clinical Pearls: 

  • Absence of eosinophilia does not rule out strongyloides.  Keep in mind that those presenting with severe illness and hemodynamic instability are commonly in a high cortisol state which can lead to eosinophil apoptosis.  Also, in those with history of steroid use (even for short periods of time), eosinophil count can be negative.
  • Think of strongy in anyone with the right travel history, older age, malnutrition, HIV, or steroid use.
  • Signs and symptoms can be quite non-specific so a high index of suspicion is required to make the diagnosis.
  • Think of strongyloides in a patient with history of recurrent GNR bacteremia of unknown etiology!

Strongyloidiasis 

Epidemiology

  • Higher incidence noted going from yellow to orange to red on the map above
  • Epidemiology
    • Typically in travelers to endemic areas, immigrants from endemic regions, or anyone with barefoot contact with infested soil.
    • Risk factors include older age, malnutrition, HIV, and steroid use
  • Signs and symptoms
    • Infected people can be asymptomatic or minimally symptomatic for years:
      • Could also have mild waxing and waning GI, skin, or pulmonary symptoms for years
      • Eosinophilia without symptoms
    • Skin: urticarial, larvae currens (see picture below), angioedema, erythrodermalarvae currens
    • Pulmonary: chronic cough, hemoptysis, recurrent pneumonia, astham that gets worse with steroids
    • GI: upper abdominal pain, duodenitis, diarrhea, anorexia, recurrent enteric GNR bacteremia
    • Disseminated disease/hyperinfection syndrome:
      • Increased parasite burden due to autoinfection (see picture below)
      • Massive dissemination of larvae to lungs, liver, heart, CNS, and endocrine glands
      • Can present with septic shock or multiorgan failure

        Strongy life cycle
        Greaves, D. BMJ 2013; 347:f4610
  • Diagnosis:
    • Stool O&P: <50% sensitive and requires multiple samples due to intermittent shedding
    • Serologies: 89% sensitive
  • Treatment:
    • Ivermectin or albendazole
    • Hyperinfection/disseminated disease: above PLUS broad-spectrum antibiotics

Quick review of endemic dimorphic fungi:

  • Southwest US ⇒ Cocci
  • Ohio & Mississippi River Valley ⇒ Histo
  • Southeast/South-central US ⇒ Blasto
  • Southeast Asia ⇒ Penicillium
  • South America ⇒ Paracocci, histo, blasto, cocci

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