Evaluation of Eosinopenia as a SIRS Biomarker in Critically Ill Horses

Abstract

Systemic inflammatory response syndrome (SIRS) is a very common finding in critically ill patients. To accurately identify patients with SIRS and those who need intensive care, several markers have been evaluated, including cortisol, WBC or lactate. It is widely known that a stress leukogram includes eosinopenia as one of its main markers (neutrophilia, eosinopenia, lymphopenia and mild monocytes). It is known that cortisol concentration in plasma is the main stress biomarker and is strongly correlated with the severity of disease in horses. However, it is not possible to measure this parameter routinely in clinical conditions. Hence, in this study it was hypothesized that the eosinophil count could be a reliable parameter to identify critically ill horses. Horses included in this study were divided into three groups: Group A (sick horses received at the Emergency Unit which did not fulfil the criteria for SIRS), Group B (horses that meet two or more criteria for inclusion in the definition of SIRS) and a control group of healthy horses. In this study, horses with SIRS showed lower eosinophil counts than healthy horses. Moreover, non-surviving horses exhibited lower eosinophil counts than survivors. Eosinopenia could be used to identify horses with SIRS and can be useful as a prognostic marker.

Association between Eosinophil Count and Cortisol Concentrations in Equids Admitted in the Emergency Unit with Abdominal Pain

“…Eosinophilia in horses is related to allergic airway disease, gastrointestinal helminth infections, allergic skin disease, multisystemic eosinophilic epitheliotropic disease, eosinophilic disease confined to the intestine, phycomycosis, and neoplasia [ 37 ]. Recently, the prognosis of eosinopenia as a biomarker in critically ill horses was described for the first time [ 3 ]. According to this result and those shown in human patients with gastrointestinal diseases, we found that EC in equids with acute abdominal pain are also lower in non-surviving patients.…”

“…Cortisol is the main stress biomarker, which is also strongly correlated with the severity of gastrointestinal disease in horses [ 2 , 3 ]. In horses with colic, cortisol measurement is a very useful marker of illness and severity, as acute abdominal pain leads to sympathetic nervous system activation [ 1 , 4 ].…”

“…White blood cell count (WBC) could indicate the severity of gastrointestinal disease; however, horses with acute abdominal pain may develop leucopenia, which can be hidden based on the stress leucogram, making it virtually impossible to establish a real relationship between cortisol and WBC count [ 3 ]. Eosinopenia has become an attractive biomarker in humans, offering a valuable tool for prognosis in critical conditions.…”

“…It represents a marker of acute inflammation [ 12 ], infection [ 13 ], sepsis [ 14 , 15 ], and mortality [ 16 ]. Recently, eosinophil cell count (EC) has also been pointed out as a valuable parameter for poor prognosis in critically ill horses [ 3 ]. In this report, horses admitted to the intensive unit with Systemic Inflammatory Response Syndrome (SIRS) showed lower eosinophil counts compared to healthy ones, and non-surviving animals presented the lowest EC.…”

“…This response is the body’s attempt to mitigate the damage, fight infection, and restore homeostasis. However, the inflammatory response can become dysregulated in severe colic cases, leading to SIRS [ 3 ].…”