Strongyloides Stercoralis Infection After the use of Emergency Corticosteroids

A Case Report on Hyperinfection Syndrome

George Vasquez-Rios; Roberto Pineda-Reyes; Eloy F. Ruiz; Angelica Terashima; Fernando Mejia


J Med Case Reports. 2019;13(121) 

In This Article


This case report presents a patient with symptoms related to bronchial hyperresponsiveness, presumed to be an asthma exacerbation complicated by pneumonia and sepsis. Mild or absent eosinophilia with severe obstructive respiratory symptoms may lead clinical judgment toward common etiologies. However, a high degree of suspicion along with consideration of this patient's epidemiologic background were vital for appropriate investigation of the presence of S. stercoralis in BAL and stool samples. Compared to previous literature, this is an unusual case of a patient who survived septic shock, Strongyloides HS, and high-dose steroid therapy.

Strongyloidiasis has become an emergent disease in developed countries because of immigration. Ostera et al. detected a prevalence of 4.2% among Latin American immigrants in Washington DC, USA.[34] More than half of the cases included in the literature review (Table 1) were reported in developed countries including the USA, England, France, and South Korea.[13–18,20,24] However, all the patients were exposed to endemic areas. This is an important finding, since the popularization of traveling and globalization could favor the presentation of Strongyloides in non-endemic areas, a trend noticed over the last 20 years.[2,5]

Clinical manifestations of S. stercoralis infection may range from asymptomatic to chronic symptoms, and Strongyloides HS with multiple systems involved.[2,4]Strongyloides HS is the result of the high replication and migration of the larvae, typically seen in patients with impaired cell-mediated immunity as in those with HTLV-1 infection, transplant recipients, or individuals on chronic or high-dose corticosteroids.[2,4,7,8] On the other hand, HIV has not been frequently associated with Strongyloides HS.[2,3] It usually presents with fever and GI complaints (for example, nausea, vomiting, abdominal pain, diarrhea, bleeding); however, extra-intestinal manifestations are also common, including dyspnea, wheezing, pulmonary infiltrates, or alveolar hemorrhage.[2–4]Strongyloides HS may be complicated with shock, disseminated intravascular coagulation, and respiratory failure.[2,4,7,8] Interestingly, the main presentation of Strongyloides HS noticed in the literature review, as well as in this case, was pulmonary involvement (64%) as opposed to the expected GI manifestation caused by helminths.

Strongyloides infection in healthy individuals characteristically produces marked eosinophilia.[2–5] In contrast, patients with Strongyloides HS may present with a higher number of larvae but few eosinophils.[2,5,8] Increased eosinophil count was observed in half of cases with available data (five out of ten patients); and it was present only in one third of patients who died. Our patient did not have eosinophilia. As stated before, corticosteroid therapy is one of the most frequent risk factors for Strongyloides HS in developed countries and may contribute to an adverse outcome.[5,7] Corticosteroids affect T-helper type-2 (Th2) response and eosinophil migration to the site of infection. Also, there is evidence suggesting that corticosteroids can play a role as molting signals for eggs, which enhances parasite production and promotes dissemination.[2–5]

Although malnutrition and HTLV-1 infection are strong risk factors for strongyloidiasis in developing countries,[2] this information was unavailable from the literature review. The patient had low albumin levels, probably reflecting his defective nutrition. He also tested negative for HIV and HTLV-1. The latter is especially important in Strongyloides HS, as it may induce a predominant Th1 cell response with high levels of interferon-γ (IFN-γ) and tumor necrosis factor-α (TNF-α). Furthermore, there is a decreased Th2 response that impairs the secretion of interleukin (IL)-4, IL-13, IL-5, and Ig E, which further reduces eosinophil recruitment and blunts the normal inflammatory response against the parasite.[3,5] Thus, investigation of HTLV-1 status is mandatory in patients with strongyloidiasis.

Examinations revealing larvae in bronchial fluids are an important criterion for confirming Strongyloides HS and dissemination.[5] Traditional stool-based techniques have low sensitivity (< 50%) for Strongyloidesdetection[35] and require multiple repeated examinations or concentration methods (such as Baermann) to increase its sensitivity.[2,3,7] However, it is hypothesized that in cases of Strongyloides HS, the larvae output is higher and the sensitivity of stool-based methods may increase.[2,3] In this review, one third of the cases had negative stool samples (4 out of 12), which could be explained by deficient sample collection in critically ill patients, insufficient number of stool samples provided for analysis, or lack of laboratory expertise. Molecular-based studies including enzyme-linked immunosorbent assay (ELISA) tests have the highest sensitivity (near 100%);[36] however, their availability, cost, and time-to-result may limit their role in an intensive care unit.

Suspicion of Strongyloides HS warrants immediate anti-parasitic treatment since mortality rates may be as high as 87%.[6] A recommended regimen is ivermectin 200 μg/kg per day for 2 days, repeated during the second and fourth week.[3] A single dose of ivermectin 200 μg/kg has been demonstrated to be superior to a 7-day course of albendazole 800 mg (93% versus 63% success rate).[37] In this review, three patients who received albendazole but not ivermectin ultimately expired. Two patients who did not receive any anti-parasitic drug also died. However, 100% of the individuals who received ivermectin alone or in combination with another anti-parasitic drug survived. Overall mortality rate was 46% in our patient cohort, which is concordant with the previously reported literature (15–87%).[5] There is limited evidence for the use of parenteral ivermectin and its use is restricted in clinical practice.