Bacterial pneumonia associated with corticosteroid therapy in three horses.

This research article studies three cases of horses developing severe pulmonary infections from systemic corticosteroid therapy. The investigation reports on two horses with immune-mediated skin disease and one with chronic obstructive pulmonary disease, all leading to bacterial pneumonia and varying outcomes following infection by different bacteria types.

Overview of Cases

• The research discusses three instances where horses faced severe pulmonary infections while undergoing systemic corticosteroid therapy for different diseases. These diseases include two cases of immune-mediated skin disease, specifically pemphigus foliaceus, and a severe case of chronic obstructive pulmonary disease.

Details of First Case

• In the first case, the horse developed diffuse pneumonia, an infection characterized by widespread inflammation in the lung. The bacteria Streptococcus zooepidemicus and Bacteroides melaninogenicus were identified in this patient. The horse, however, responded positively to the administered antibiotic therapy, indicating a successful treatment strategy for this bacterial infection.

Details of Second Case

• The second horse experienced more severe symptoms, developing septicaemia, pulmonary thrombosis, and pneumonia in conjunction with an Escherichia coli infection. Unfortunately, the horse succumbed during a sudden peracute illness, characterised by a rapid onset and severe symptoms, with visible signs of disseminated intravascular coagulation – a serious condition that causes blood clots and bleeding simultaneously throughout the body. This case highlights the potential severity and deadly consequences of these infections, particularly if combined with other health complexities.

Details of Third Case

• The final case presented a horse that developed focal pneumonia, a localized infection within the lung, wherein the bacterium S zooepidemicus was isolated. This horse was euthanized at the owner’s request and did not receive treatment. While this case does not provide insight into potential treatment strategies or outcomes, it does provide further evidence of bacterial infections that can arise from systemic corticosteroid therapy in horses.

Implications of the Study

• While this study is centered on a small and specific set of cases, it raises crucial questions regarding the possible side effects of systemic corticosteroid therapy in horses, particularly regarding severe pulmonary infections. Further research should be conducted to deeply understand the risks involved and to develop treatment strategies to manage the resulting bacterial infections.