Equine cerebrospinal fluid: reference values of normal horses

Area of Science:

• Equine Neurology
• Clinical Pathology
• Cerebrospinal Fluid Analysis

Background:

• Establishing reference ranges for cerebrospinal fluid (CSF) is crucial for diagnosing neurological conditions in horses and ponies.
• Previous studies have provided limited data on CSF composition in these animals, particularly concerning breed and anatomical site variations.

Purpose of the Study:

• To determine clinical reference values for CSF in clinically healthy horses and ponies.
• To compare CSF parameters between horses and ponies and between atlanto-occipital (AO) and lumbosacral (LS) collection sites.
• To report enzyme activities in equine CSF for the first time.

Main Methods:

• Collected CSF samples from the AO and LS subarachnoid spaces of 24 horses and 21 ponies.
• Analyzed CSF for physical properties, biochemical components (protein, glucose, electrolytes, cholesterol, urea nitrogen), cell counts, and enzyme activities.
• Compared obtained values with existing literature.

Main Results:

• Established reference ranges for CSF parameters, including white cell counts (0-6/microliters) and protein content.
• Observed wider protein content limits than previously reported, proposing the LS-AO difference as a clinical evaluation criterion.
• Found ponies had higher CSF protein than horses, and LS CSF had higher glucose than AO CSF.
• Reported CSF electrolyte composition similar to previous findings and presented novel data on CSF enzyme activities.

Conclusions:

• The study provides comprehensive reference values for equine CSF, accounting for breed and collection site.
• The LS-AO CSF protein difference is suggested as a valuable diagnostic tool.
• This research offers the first report on enzyme activities in equine CSF, expanding diagnostic capabilities.