Sections View Full Chapter Figures Tables Videos Annotate Full Chapter Figures Tables Videos Supplementary Content + Download Section PDF Listen ++ For further information, see CMDT Part 35-23: Strongyloidiasis + Key Features Download Section PDF Listen +++ +++ Essentials of Diagnosis ++ Transient pruritic skin rash and lung symptoms Anorexia, diarrhea, abdominal discomfort Hyperinfection in immunocompromised persons; larvae detected in sputum or other fluids Larvae detected in stool Eosinophilia +++ General Considerations ++ Infection is caused by Strongyloides stercoralis The primary host is humans The parasite's life cycle Maintains its life cycle both within humans and in soil Infection occurs when filariform larvae in soil penetrate the skin, enter the bloodstream, and are carried to the lungs and ascend the bronchial tree to the glottis The larvae are then swallowed and carried to the duodenum and upper jejunum, where they mature to the adult stage Autoinfection can occur in humans, when some rhabditiform larvae develop into filariform larvae that penetrate the intestinal mucosa or perianal skin, and enter the circulation Parasite can cause severe infections in immunocompromised persons due to its ability to replicate in humans +++ Demographics ++ Infects tens of millions of persons in tropical and subtropical regions Endemic in some temperate regions of North America, Europe, Japan, and Australia A related parasite, Strongyloides fuelleborni, infects humans in parts of Africa and New Guinea + Clinical Findings Download Section PDF Listen +++ +++ Symptoms and Signs ++ Most infected persons are asymptomatic +++ Acute syndrome ++ Pruritic, erythematous, maculopapular rash, usually of the feet Pulmonary symptoms (including dry cough, dyspnea, and wheezing) Eosinophilia Gastrointestinal symptoms +++ Chronic infection ++ Epigastric pain, nausea, diarrhea, and anemia Maculopapular or urticarial rashes of the buttocks, perineum, and thighs due to migrating larvae Large worm burdens can lead to malabsorption or intestinal obstruction Eosinophilia is common but may fluctuate +++ Hyperinfection syndrome ++ Dissemination of large numbers of filariform larvae to lungs, CNS, kidneys, and liver in immunocompromised persons Persons at risk include Those receiving corticosteroids and other immunosuppressive medications Those with hematologic malignancies, malnutrition, or alcoholism Those infected with AIDS Pulmonary findings Pneumonitis Cough Hemoptysis Respiratory failure Sputum may contain adult worms, larvae, and eggs CNS disease Meningitis Brain abscesses Cerebrospinal fluid may contain larvae Gastrointestinal symptoms Abdominal pain Nausea, vomiting Diarrhea More severe findings related to intestinal obstruction, perforation, or hemorrhage Bacterial sepsis, probably secondary to intestinal ulcerations Various presentations can progress to shock and death +++ Differential Diagnosis ++ Hookworm disease Ascariasis Giardiasis Amebiasis Acute eosinophilic pneumonia Tropical pulmonary eosinophilia Peptic ulcer disease Cutaneous larva migrans + Diagnosis Download Section PDF Listen +++ +++ Laboratory Tests +++ Detection of eggs and larva ++ Eggs are seldom found in feces Diagnosis usually based on identification of rhabditiform larvae in stool or duodenal contents Larvae must be distinguished from hookworm larvae, which may hatch after stool collection Repeated examinations of stool or examination of duodenal fluid may be required because the sensitivity of individual tests is only about 30% +++ Serologic and hematologic findings ++ Eosinophilia and mild anemia are common Enzyme-linked immunosorbent assay (ELISA) Sensitivity and specificity ~90% Cross-reactions with other helminths can occur +++ Hyperinfection ++ Diagnosed by identification of large numbers of larvae in stool, sputum, or other body fluids There may be hypoproteinemia, malabsorption, abnormal liver function, and pulmonary infiltrates Eosinophilia may be absent + Treatment Download Section PDF Listen +++ +++ Medications ++ Continue treatment until parasite has been fully eradicated Ivermectin Treatment of choice 200 mcg/kg orally daily for 1–2 days For hyperinfection, administer daily until clinical syndrome has resolved and larvae have not been identified for at least 2 weeks Thiabendazole 25 mg/kg orally twice daily for 3 days Relatively poorly tolerated Albendazole 400 mg orally twice daily for 3 days Less effective than ivermectin + Outcome Download Section PDF Listen +++ +++ Follow-Up ++ Follow-up examinations for larvae in stool or sputum are necessary, with repeat dosing if the infection persists With continued immunosuppression, eradication may be difficult Regular repeated doses of ivermectin may be required +++ Prognosis ++ Mortality rate of hyperinfection syndrome Approaches 100% without treatment About 25% with treatment +++ When to Refer ++ Immunocompromised patients Disseminated disease +++ When to Admit ++ Patients with the hyperinfection syndrome Severe pulmonary symptoms