Prevalence and significance of extracellular myelin-like material in canine cerebrospinal fluid.
BACKGROUND
Myelin-like material in canine cerebrospinal fluid (CSF) specimens has been attributed to demyelinating or myelomalacic conditions. In our experience, myelin-like material is observed frequently, especially in lumbar samples, and in a variety of disease conditions.


OBJECTIVE
The objective of this study was to determine if there are associations between the presence of myelin-like material and CSF collection site, body weight, underlying disease, and patient outcome.


METHODS
Wright-Giemsa-stained cytocentrifuged specimens of CSF from the cerebellomedullary cistern (n=51) and lumbar cistern (n=47) of 98 dogs with neurologic disease were evaluated retrospectively for the presence and amount of extracellular myelin-like material. Results were compared based on collection site, body weight, type of neurologic disease, and outcome.


RESULTS
Myelin-like material was observed in 20/98 (20%) samples and was more frequently observed in lumbar (17/47, 36%) than cerebellomedullary samples (3/51, 6%) (P=.0028). Samples from dogs <10 kg were more likely to contain myelin (14/36, 39%) compared with dogs > or =10 kg (5/60, 8%) (P=.0052). Larger amounts of myelin-like material were observed in CSF from dogs with intervertebral disk disease compared with other diseases (P=.045). No association was found between myelin-like material and outcome.


CONCLUSIONS
The association of extracellular myelin-like material in canine CSF samples with sampling site and body weight suggests it is more often an artifact of collection technique and anatomy rather than the result of neurologic disease. Myelin-like material in CSF is not associated with a poorer prognosis.
Veterinary Medical Teaching Hospital, University of CaliforniaDavis, Davis, CA, USA.
Shanon M
SM
Zabolotzky
Karen M
KM
Vernau
Philip H
PH
Kass
William
W
Vernau
D000818:Animals; D001835:Body Weight; D002555:Cerebrospinal Fluid / Q000737:chemistry*; D004283:Dog Diseases / Q000134:cerebrospinal fluid*; D004285:Dogs; D009186:Myelin Sheath / Q000737:chemistry*; D009422:Nervous System Diseases / Q000134:cerebrospinal fluid / Q000662:veterinary*