BackgroundEquine neuroborreliosis (NB), Lyme disease, is difficult to diagnose and has limited description in the literature.ObjectiveProvide a detailed description of clinical signs, diagnostic, and pathologic findings of horses with NB.AnimalsSixteen horses with histologically confirmed NB.MethodsRetrospective review of medical records at the University of Pennsylvania and via an ACVIM listserv query with inclusion criteria requiring possible exposure to Borrelia burgdorferi and histologic findings consistent with previous reports of NB without evidence of other disease.ResultsSixteen horses were identified, 12 of which had additional evidence of NB. Clinical signs were variable including muscle atrophy or weight loss (12), cranial nerve deficits (11), ataxia (10), changes in behavior (9), dysphagia (7), fasciculations (6), neck stiffness (6), episodic respiratory distress (5), uveitis (5), fever (2), joint effusion (2), and cardiac arrhythmias (1). Serologic analysis was positive for B. burgdorferi infection in 6/13 cases tested. CSF abnormalities were present in 8/13 cases tested, including xanthochromia (4/13), increased total protein (5/13; median: 91 mg/dL, range: 25–219 mg/dL), and a neutrophilic (6/13) or lymphocytic (2/13) pleocytosis (median: 25 nucleated cells/μL, range: 0–922 nucleated cells/μL). PCR on CSF for B. burgdorferi was negative in the 7 cases that were tested.Conclusion and Clinical ImportanceDiagnosis of equine NB is challenging due to variable clinical presentation and lack of sensitive and specific diagnostic tests. Negative serology and normal CSF analysis do not exclude the diagnosis of NB.

This study provides a clearer appreciation of the clinical signs and variability of perennial ryegrass intoxication in horses.

BackgroundThe accuracy of the Lyme multiplex assay for the diagnosis of neuroborreliosis in horses is unknown.Hypothesis/ObjectivesTo describe Lyme multiplex results in horses with a postmortem diagnosis of neuroborreliosis. The hypothesis was that paired serum and cerebrospinal fluid (CSF) results and a CSF : serum ratio would allow differentiation of horses with neuroborreliosis from those with other neurologic diseases.AnimalsNinety horses that had neurologic examinations, serum and CSF Lyme multiplex analyses, and postmortem examination of the nervous system performed.MethodsRetrospective study. Data collected included signalment, ante‐ and postmortem diagnoses, and serum and CSF Lyme multiplex results. The CSF : serum ratio was calculated by dividing CSF median fluorescent intensity (MFI) by serum MFI for each result.ResultsTen horses had a final diagnosis of neuroborreliosis, 70 were diagnosed with other neurologic diseases, and 10 had no neurologic disease. Not all horses with neuroborreliosis had positive results: 4/10 had at least 1 positive serum result, 5/10 had at least 1 positive CSF result, and 3/10 had at least 1 CSF result 4‐fold higher than the corresponding serum result. Results were similar for the 70 horses with other neurologic diseases: 53% had at least 1 positive serum result, 50% had at least 1 positive CSF result, and 16% had at least 1 CSF result 4‐fold higher than the corresponding serum result.Conclusions and Clinical ImportancePositive Lyme multiplex results were common in horses with neurologic diseases and did not adequately differentiate horses with neuroborreliosis from horses with other disorders.

Background: Olfactory dysfunction (OD) is a common but underreported problem that can significantly impact a patient's quality of life. OD is prevalent in over 5% of the adult population and can be broadly categorised into conductive and sensorineural causes. Magnetic Resonance Imaging (MRI) can form part of the diagnostic work up, although its exact role is often debated. Objectives:The aim of this study was to evaluate the value of MRI in managing patients with OD.Design/Method: A retrospective analysis of the records of patients presenting to a national smell and taste clinic over a 5-year period was performed. Variables included demographics, endoscopic findings, final diagnosis, psychophysical smell test and imaging results.Results: A total of 409 patients, with an age range of 10-93 years, underwent clinical assessment and smell testing, of which 172 patients (42%) had MRI scans. Imaging in younger age-groups was associated with a higher rate of positive findings, however identifiable causes for OD were recorded across the range. MRI provided both diagnostic and prognostic information in those with idiopathic, traumatic and congenital causes of OD. For example, MRI provided information on the extent or absence of gliosis in those with a head trauma history allowing further treatment and prognosis. Conclusion:We recommend the adjunct use of MRI in patients with a clear history and examination findings of head injury, congenital cases and in apparent idiopathic cases. MRI should be requested to compliment clinical findings with a view to aiding decision-making on treatment and prognosis independent of patient's age.

Lolitrem B intoxication in horses may cause disruption to electrolyte handling in addition to neurological deficits.