Why are steroids not contraindicated in schistosomiasis like they are in strongyloidiasis?

From the Guidelines

Steroids are not contraindicated in schistosomiasis and can be beneficial in reducing the duration of symptoms, as evidenced by the most recent guidelines 1. The life cycles and pathophysiology of schistosomiasis and strongyloidiasis differ significantly, which explains the different approaches to steroid use in these conditions. In strongyloidiasis, steroids can trigger hyperinfection syndrome by accelerating the autoinfection cycle of Strongyloides stercoralis, leading to massive parasite proliferation and potentially fatal dissemination throughout the body. In contrast, schistosomiasis has no autoinfection cycle within humans, as Schistosoma species require an intermediate snail host to complete their life cycle, so they cannot multiply within the human body regardless of immune status. Some key points to consider when treating schistosomiasis include:

• The use of steroids, such as 30 mg prednisolone daily for 5 days, as recommended by expert opinion 1
• The potential interaction between dexamethasone and praziquantel, which may result in reduced praziquantel levels due to increased metabolism 1
• The proposed combination therapy with artemisinin derivatives, which has been suggested to have a greater impact on immature schistosomulae, although there is no clinical trial evidence to support this 1
• The importance of using antiparasitic therapy, such as praziquantel, alongside steroids to kill the adult worms and address the parasitic infection 1. Overall, the use of steroids in schistosomiasis is supported by the most recent guidelines and evidence, and can be a beneficial addition to antiparasitic therapy in reducing the duration of symptoms and improving patient outcomes.

From the Research

Difference in Treatment Approach

• The use of steroids in schistosomiasis is not contraindicated like it is in strongyloidiasis, due to the different nature of the diseases and their treatments 2, 3.
• Schistosomiasis is a tropical parasitic disease caused by blood-dwelling worms of the genus Schistosoma, and its treatment relies on microscopic examination of stools or urine, serologic tests, and imaging, with praziquantel being the drug of choice 4.
• In contrast to strongyloidiasis, where steroids can exacerbate the infection, steroids have been used in combination with schistosomicides to treat acute schistosomiasis, with studies showing a synergistic effect between the two 3.

Mechanism of Action

• The exact mechanisms of action of praziquantel, the primary drug used to treat schistosomiasis, are not fully understood, which makes it difficult to determine the mechanisms of drug resistance in schistosomes 5.
• Research has shown that combining praziquantel with steroids can inhibit the fecundity of S. mansoni, reducing egg counts and liver pathology, which has implications for the treatment of Katayama syndrome 3.

Treatment Options

• Praziquantel is the most studied and widely used drug for treating urinary schistosomiasis, with a strong evidence base supporting its efficacy 6.
• Other drugs, such as metrifonate, artesunate, and mefloquine, have been evaluated for their antischistosomal properties, but the evidence is inconsistent and more research is needed to determine their effectiveness 6.
• Potential strategies to improve future treatments for schistosomiasis include combining praziquantel with other drugs, such as metrifonate or antimalarial drugs with antischistosomal properties 6.