Cerebrospinal Fluid

Abstract

It is hoped that we have demonstrated that collection, handling, and limited analysis of CSF samples from the dog and cat are relatively simple. No special equipment or handling is required, and the procedures are within the capabilities of any veterinarian interested in performing them. In addition, although this article was not intended to present a detailed discussion on the interpretation of the analysis of CSF, we have demonstrated some very practical interpretations to the various aspects of a routine CSF analysis. When combined with a signalment, complete history, and thorough general physical and neurologic examination, CSF analysis can prove invaluable in the workup of an animal with a neurologic disorder. Relatively simple laboratory procedures can be helpful in differentiating peripheral blood contamination from true intrathecal hemorrhage, in identifying an active inflammatory process, in potentially characterizing an etiologic agent, and, on rare occasions, in identifying primary or metastatic neoplastic disease involving the CNS. In many cases, the above is not directly possible, because the changes observed in our routine analysis are nonspecific. Yet, documenting and following these "nonspecific" alterations are helpful in determining if there is progression or regression of the disease process. In turn, these changes or lack of changes are helpful in identifying if the proper therapy has been instituted and if additional or different therapy is required.

Cerebrospinal fluid analysis

“…A small aliquot of the obtained sample must be saved separately in sterile plastic vials for microbiological testing (culture and sensitivity) if an infectious disorder is suspected. It has been anecdotally stated that cytological evaluation of CSF samples should be done within 30 minutes from collection, as subsequent cell degeneration associated with its low protein content (Cook and DeNicola, 1988;Oliver and Lorenz, 1993). More recent studies on the effects of time, composition and addition of stabilizing agents have concluded that CSF samples have to be processed as soon as possible, however delayed (from 4 up to 8 hours) analysis may not alter clinical interpretation significantly (Fry et al, 2006).…”

“…The latter is an uncommon cause of CSF red coloration because free erythrocytes start to degenerate within 1-4 hours in the subarachnoid space and fluid collection rarely coincides with their presence. In this case, sample centrifugation results in the formation of a erythrocyte "pellet" at the bottom of the tube while the supernatant remains clear (Cook and DeNicola, 1988). The presence of pink or reddish, "thread-like" swirls during CSF flow into the sampling vial suggest iatrogenic blood contamination (Levine and Levine, 2012).…”

“…Yellow and yellow-orange CSF discoloration (xanthochromia) is the result of hemoglobin degradation within the subarachnoid space or secondary to an increase of total protein concentration, hyperbilirubinemia, CNS neoplasia and inflammation (Kjeldsberg and Knight, 1986;Cook and DeNicola, 1988). In subarachnoid hemorrhage xanthochromia persists for 24 hours after the event and subsequently dissipates within the next 4-8 days, while erythrophagocytosis may also be detected in microscopic examination of the CSF sediment (Jamison and Lumsden, 1988;Levine and Levine, 2012).…”

“…Increased TNCC (pleocytosis) may be scored as mild (less than 25 cells/ μl), moderate (26-100 cells/ μl) and marked (more than 100 cells/ μl) (Cook and DeNicola, 1988). The scoring of pleocytosis does depend on the severity of the inciting cause, as well as other factors (CSF collection site, lesion proximity to the subarachnoidal space etc).…”

“…Regardless of the methodology used, slides are then air dried and stained with a Romanowsky stain (Wright Giemsa, Diff Quick). Special staining techniques may be applied if specific pathogens are suspected (Cook and DeNicola, 1988).…”