A review of equine sepsis

Abstract

Summary Sepsis is defined as an exaggerated, systemic inflammatory response to infection and is a common condition in horses. Systemic inflammatory response syndrome (SIRS) associated with bacterial infection is a hallmark of sepsis. Sepsis in neonatal foals is a common sequela of failure of passive transfer and, in addition to development of SIRS, may be characterised by bacteraemia, pneumonia, enterocolitis, omphalophlebitis, meningoencephalitis or arthritis. Sepsis in mature horses is most commonly observed secondary to gastrointestinal lesions that result in disrupted mucosa and bacterial translocation into circulation (endotoxaemia). Pleuropneumonia and metritis may also cause sepsis in mature horses. Diagnosis of sepsis is based on SIRS criteria as well as suspected or confirmed infection. Due to the relatively low sensitivity of microbial culture and the subjectivity of sepsis scoring, many sepsis biomarkers are being studied for their usefulness in diagnosis and prognostication of sepsis in horses. Treatment of sepsis requires an intensive care approach that includes antimicrobial drug administration, fluid resuscitation and pressure support, and treatment for inflammation, endotoxaemia and coagulopathy. Early recognition of sepsis and prompt antimicrobial drug treatment are critical for a successful outcome. Multiple organ dysfunction syndrome may occur in severe cases of sepsis, with common manifestations including laminitis and coagulopathies. Although prognosis for septic mature horses depends highly on the primary disease process, the overall survival rate in septic neonatal foals ranges from 26 to 86%, with most studies indicating a survival rate of 45–60%.

Expression of von Willebrand factor, pulmonary intravascular macrophages, and Toll-like receptors in lungs of septic foals

“…Foals, especially those with failure of passive transfer of maternal antibodies, are highly susceptible to bacterial infections and endotoxemia; however, the mechanisms underlying such susceptibilities are not fully understood [1925]. Non-specific intestinal absorption, hypoglycaemia, omphalophlebitis, unsanitary environmental conditions, and abnormal gestational lengths are common factors that predispose foals to further complications following birth, including septicaemia [162025].…”

“…Non-specific intestinal absorption, hypoglycaemia, omphalophlebitis, unsanitary environmental conditions, and abnormal gestational lengths are common factors that predispose foals to further complications following birth, including septicaemia [162025]. Sepsis is a systemic bacterial invasion that commonly results in systemic inflammatory response syndrome, which can lead to numerous sequelae such as coagulopathies and immune system dysfunction [25]. Indeed, septic shock can result in hypotension, organ hypoperfusion, and multiple organ dysfunction syndrome, which may lead to death of foals, especially neonates [1920].…”

“…Indeed, septic shock can result in hypotension, organ hypoperfusion, and multiple organ dysfunction syndrome, which may lead to death of foals, especially neonates [1920]. Mortality rates of septic neonatal foals generally range from 40 to 55% [25]. …”

“…Indeed there is very little data available regarding lung injury and inflammation in foals suffering from sepsis [16182025]. Because of the increased awareness of acute lung injury in veterinary species, a consensus statement was released to establish a veterinary specific definition [29].…”

“…A fifth optional factor is evidence of diffuse pulmonary inflammation seen on radiographs [29]. While septicaemic foals are commonly diagnosed with pulmonary inflammation, most clinical attention has focused on sequelae other than lung inflammation, such as haemostasis, arthritis, or organ dysfunction involving mainly the liver, spleen, and gastrointestinal tract [192526]. Previously, pneumonia was diagnosed either clinically or at post-mortem in 28 to 50% of septic foals [20].…”