Clinical findings in 10 foals with bacterial meningoencephalitis

J Viu,C Cesarini,S Añor,L Monreal,E Jose‐Cunilleras,L Armengou

doi:10.1111/j.2042-3306.2011.00508.x

J Viu, C Cesarini + Show 4 more

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https://doi.org/10.1111/j.2042-3306.2011.00508.x

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Abstract

Bacterial meningoencephalitis is a severe complication in septic foals and there is scarce and often unclear information in the equine literature. To report the most frequent clinical signs, clinicopathological findings, causative agents, treatments given and outcome of a group of foals with confirmed bacterial meningoencephalitis. Foals aged < 6 months of age admitted to the Universitat Autonoma de Barcelona (2004-2009) with confirmed bacterial meningoencephalitis were retrospectively included in the study Diagnosis of bacterial meningoencephalitis was made by cerebrospinal fluid (CSF) culture, CSF analysis consistent with bacterial infection, observation of bacteria in CSF cytology or postmortem confirmation. Nine neonates and one 5-month-old foal were included. The most frequently observed clinical signs were alterations in mental status (10/10), recumbency (8/10), weakness (8/10), abnormal pupillary light reflexes (6/10), decreased suckling-reflex (6/9), seizures and/or nystagmus (4/10). Common clinicopathological alterations included hyperfibrinogenaemia (8/9), hyperlactataemia (7/7), and neutropenia (5/10) or neutrophilia (5/10). Most neonates (8/9) developed bacterial meningoencephalitis despite having a sepsis score near the cut-off value (median = 12). On CSF analysis, pleocytosis (9/9), increased total protein concentration (5/6) and intracellular bacteria (6/9) were detected. The most frequently isolated bacterium was Escherichia coil. Once bacterial meningoencephalitis was diagnosed, antimicrobial therapy was switched to third and fourth generation cephalosporins. The diagnosis of bacterial meningoencephalitis is established based on CSF analysis and culture. Clinical recognition of bacterial meningoencephalitis is difficult and can be easily overlooked. Moreover, severe sepsis is not necessary to develop bacterial meningoencephalitis. CSF analysis should be considered more often in sick newborn foals with signs indicative of central nervous system (CNS) involvement. Cerebrospinal fluid (CSF) cytology and culture would help to confirm or rule out unnoticed bacterial meningoencephalitis, and to choose appropriate antimicrobial therapy

Highlights

Bacterial infection of the equine central nervous system (CNS) is an uncommon condition and has been reported to affect 2.5% of horses with neurological disease (Furr 2008)
Information about bacterial meningoencephalitis in equine patients is scarce, and some authors consider that there is a lack of comprehensive case series of bacterial meningitis in these animals (Mitchell et al 2007)
Diagnosis of bacterial meningoencephalitis was confirmed by a board-certified neurologist and was based on either bacterial growth on cerebrospinal fluid (CSF) culture, consistent CSF analysis, or post mortem confirmation

Summary

Introduction

Bacterial infection of the equine central nervous system (CNS) is an uncommon condition and has been reported to affect 2.5% of horses with neurological disease (Furr 2008). Bacterial meningoencephalitis appears to be more frequent in neonatal foals. It is reported as a complication of sepsis in as many as 8–10% of septic foals (Koterba et al 1984; Brewer and Koterba 1990) and is associated with a high mortality rates (Koterba et al 1984; Brewer and Koterba 1990; Sanchez et al 2008). Reported clinical signs of bacterial meningoencephalitis, such as lethargy, weakness, fever and seizures (Pellegrini-Masini and Livesey 2006; Furr 2008) are nonspecific and frequently present in other common neonatal diseases. Clinical signs consistent with bacterial meningoencephalitis are often observed in many critically ill foals with other diseases, such as hypoxic-ischaemic encephalopathy (HIE). It is well known that meningitis can go unrecognised in septic neonates, so cerebrospinal fluid (CSF) is routinely collected in septic infants (Heath et al 2003)

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