Strongyloides stercoralis hyperinfection - a dreaded but still missed diagnosis

Abstract

Strongyloides stercoralis (S. stercoralis), an intestinal nematode, is endemic in tropical and subtropical regions, being less prevalent in temperate climates. The number of infected persons worldwide ranges between 10 million and 100 million people. In Brazil the reported prevalence is 13%. Chronic infection may be asymptomatic or accompanied by gastrointestinal and respiratory symptoms. Under immunosuppressive conditions, the infection assumes serious proportions frequently accompanied by septic shock, disseminated intravascular coagulopathy and respiratory distress syndrome. The authors report a case of a 50-year-old female patient who was a chronic user of glucocorticoids and had been seeking medical attention for two months because of continuous gastrointestinal symptoms. She was admitted to the emergency room with clinical signs of septic shock and died after four days despite an adequate antibiotic regimen, vasopressor drugs, and ventilatory support. The autopsy revealed the unsuspected finding of S. stercoralis hyperinfection and septicemia.

DisseminatedStrongyloides stercoralisinfection in the setting ofEscherichia colimeningitis and bacteraemia in a patient living with HIV on high-dose corticosteroid therapy

“…His main complaints were headache, high fevers and a possible episode of syncope a few hours prior, which led us to the workup for meningitis. As confirmed in our case, due to increased parasite turnaround and dissemination, some patients with HS may only present with catastrophic clinical manifestations of shock or meningitis 7 9 16. It is therefore imperative that at-risk patients are appropriately screened for Strongyloides .…”

“…The presence of eosinophilia in patients who have lived or travelled to endemic areas should generate a high suspicion for strongyloidiasis,19 20 but eosinophilia is not always present 9. In this population, eosinophilia is not a strong predictor of strongyloidiasis 17.…”

“…Hyperinfection syndrome (HS) and disseminated strongyloidiasis (DS) can be fatal, and often occur in patients with impaired cell-mediated immunity, such as those with organ transplants and especially those on corticosteroid therapy 3 4 7. Steroids represent one of the main triggers predisposing patients to HS and DS by immediately increasing their risk of infection, which is sometimes directly dependent on the dose 9 14 15. Some authors have suggested that by suppressing eosinophilia and inducing apoptosis of lymphocytes, glucocorticoids can induce the parasite transformation from rhabditiform larvae to filariform larvae (the infective form within the host) leading to HS 7 8.…”

“…Occasionally, strongyloidiasis is associated with gut translocation of bacteria and subsequent bacteraemia. The migrating ability of the parasite across several organs/tissue promotes the distant dissemination of enteric pathogens and accompanying gram-negative bacteraemia, meningitis and sepsis 2 7 9 16. The most common organisms include E. coli and Streptococcus gallolyticus (previously bovis ),16 but other enteric pathogens may also be involved.…”

“…Fatalities have been reported following Strongyloides hyperinfection among patients receiving immunosuppressive treatment, including corticosteroids 7 8. Glucocorticoids may accelerate the replication of the parasite, leading to an increased risk for severe outcomes in asymptomatic patients due to their ability to acutely suppress both eosinophil levels (thereby masking eosinophilia) and lymphocyte activation 8–10. In immunocompetent patients, strongyloidiasis symptoms are often mild to severe diarrhoea 11.…”