Equine multinodular pulmonary fibrosis and presumed corticosteroid‐induced side effects in a horse
Authors: Lauteri Eleonora, Tortereau Antonin, Peyrecave Xavier, Pin Didier, Desjardins Isabelle
Journal: Equine Veterinary Education
Summary
Equine multinodular pulmonary fibrosis (EMPF) is a progressive, often fatal fibrosing lung disease typically triggered by equine herpesvirus-5 infection, characterised by pyrexia, weight loss, respiratory distress and cough, with conventional treatment combining valacyclovir and corticosteroids showing limited success. This case report documents an 11-year-old gelding presenting with EMPF who, despite initial clinical improvement on antiviral and corticosteroid therapy, rapidly deteriorated and developed severe secondary complications including bacterial dermatitis, hepatic damage and pleural effusion; PCR analysis of liver biopsy confirmed EHV-5 infection, demonstrating the virus's ability to establish multisystem involvement beyond pulmonary tissue. The clinical trajectory raises important concerns about corticosteroid use in EMPF management, as immunosuppression may have exacerbated both disease progression and the horse's susceptibility to opportunistic infections rather than providing therapeutic benefit. Whilst antivirals remain potentially valuable, practitioners should exercise caution with corticosteroid administration in confirmed or suspected EHV-5-associated fibrosis, carefully weighing potential benefits against risks of HPA axis suppression, secondary infections and complications such as laminitis. This case emphasises the need for rigorous diagnostic confirmation of EHV-5 involvement and consideration of alternative or modified immunomodulatory approaches in what remains a condition with guarded to poor prognosis.
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Practical Takeaways
- •Corticosteroid therapy for EMPF carries significant risk of immunosuppression and secondary bacterial infections; consider risks versus benefits carefully in individual cases
- •EHV-5 can affect multiple organ systems beyond lungs; if treating EMPF cases, monitor liver function and skin integrity closely as potential complications
- •Poor prognosis typical for EMPF; realistic client communication needed regarding progressive respiratory decline despite antiviral and anti-inflammatory treatment
Key Findings
- •EHV-5 demonstrated multiple tissue tropism with PCR confirmation of virus in liver biopsy tissue
- •Corticosteroid treatment was suspected to exacerbate disease progression and increase susceptibility to secondary infections in EMPF
- •Horse treated with valacyclovir and corticosteroids showed initial transient improvement followed by rapid deterioration with severe complications