The effect of prior thecal puncture on cerebrospinal fluid analytes in normal adult horses

Comparison of atlantoaxial and lumbosacral cerebrospinal fluid centesis techniques in South American camelids

BACKGROUND

Iatrogenic blood contamination during cerebrospinal fluid (CSF) centesis is common, which can limit the diagnostic usefulness of the sample. A novel ultrasound-guided CSF collection technique is described in horses, by which CSF is obtained from the atlantoaxial (AA) space.

HYPOTHESIS/OBJECTIVES

To compare ultrasound-guided AA centesis with lumbosacral (LS) centesis in South American camelids (SAC). The hypotheses were that AA centesis would yield samples with less blood contamination although being technically more challenging than LS centesis.

ANIMALS

Eight clinically healthy adult SAC from a university-owned teaching herd.

METHODS

Single-blinded, randomized, 4-way, 4-period crossover study in which 2 veterinarians each performed both centesis techniques on each animal once. Cytological sample analysis was performed, and the technical difficulty of sample acquisition was assessed.

RESULTS

The CSF was collected successfully and without complications by either technique during all collection attempts. Aspects of technical difficulty and concentrations of CSF analytes did not vary significantly between techniques. Median total nucleated cell and red blood cell counts were 1/μL and 0.5/μL and 167.5/μL and 155/μL for AA and LS techniques, respectively. The median total protein concentration was 32.9 mg/dL and 38 mg/dL for AA and LS centeses. A median of 1 attempt was necessary for both centesis techniques and the median number of needle repositioning events was 1 for AA and 0 for LS.

CONCLUSION AND CLINICAL IMPORTANCE

Depending on clinical circumstances, ultrasound-guided AA centesis appears to be an acceptable alternative to other techniques for collection of CSF from SAC.

Dural and deep cervical musculature anesthetic blockade for atlantoaxial collection of cerebrospinal fluid in horses

The analysis of cerebrospinal fluid has diagnostic, prognostic, and therapeutic value in neurological illnesses in horses. There are different methods for obtaining cerebrospinal fluid, with the collection between the C1 and C2 vertebrae being a more recent methodology, which allows the procedure to be performed in standing patients, without the limitations of general anesthesia and with a low contamination of the sample with blood, presenting itself as a practical alternative. This study evaluated the efficacy and safety of a local dural blockade in healthy horses submitted to cerebrospinal fluid collection by atlantoaxial puncture and the quality of the samples obtained by this procedure, which were submitted to physical, chemical, and cytological analyses. The animals were evaluated considering aspects such as pain, sensitivity, the presence of edema, temperature variations, and ultrasonographic alterations post-collection. Discrete local changes were observed after the puncture, and the procedure was considered safe and simple to perform. Lidocaine blockade could reduce the reaction elicited by the needle passing through the dura mater, and the samples obtained showed satisfactory quality and laboratory results consistent with the values compiled in the literature. Transient hyperthermia was observed in 70% (7/10) of the animals in the dural blockade group, and 80%(8/10) of the patients from the control group, totalizing 75% of all individuals evaluated. The rectal temperature alteration was observed 4 to 12 hours after the procedure and was entirely resolved without intervention by the 24-hour evaluation.

Sequential Cerebrospinal Fluid Sampling in Horses: Comparison of Sampling Times and Two Different Collection Sites

Analysis of the cerebrospinal fluid (CSF) is important as a complementary test in horses with neurologic diseases, and sequential analysis may provide information about the treatment response or evolution and quantitative measures of the CSF drug concentration during treatment. The aim of this study was to compare erythrocyte and nucleated cell counts and protein concentration in multiple CSF samples obtained sequentially from two different puncture sites in clinically healthy horses. Eight and 12 horses, with no evidence of neurologic disease, were subjected to CSF collection from the atlanto-occipital (AO) and C1-C2 spaces, respectively. Cytologic and chemical analyses were performed on the CSF obtained at five sampling times (T1, T2, T3, T4, and T5). Repeated measures models were used to compare the mean erythrocyte count, nucleated cell count, and total protein concentration between the AO and C1-C2 groups at each sampling time. C1-C2 CSF had a significantly higher total protein concentration at T1 and T4 than that of AO CSF. All total protein concentration values remained within the reference interval (<90 mg/dL) for all sampling times and groups. No statistical difference was present between results at T2, T3, T4, and T5 and at T1 in both groups for all analyses. In conclusion, five consecutive AO or C1-C2 CSF collections with at least a 7-d interval did not result in alterations in the CSF erythrocyte and nucleated cell counts and total protein concentrations and did not interfere with the CSF analysis results.

The effect of prior thecal puncture on cerebrospinal fluid analytes in normal adult horses

Background

Serial cerebrospinal fluid (CSF) analysis might be required in clinical neurologic disease. The effect of lumbosacral (LS) or cervical (C1‐C2) centesis on subsequent CSF cytologic analyses has not been investigated in horses.

Objective

To evaluate the effect of thecal puncture on subsequent CSF analyses

Animals

Ten healthy adult horses.

Methods

Prospective study. Horses were randomly assigned to undergo CSF collection twice, 14 days apart, from either the C1‐C2 or LS space. After a 4‐month washout period, CSF collection was repeated from the alternate site. Continuous data were analyzed using linear mixed‐effects models and count data using mixed‐effects negative binomial regression. Statistical significance was set at P < .05.

Results

There was no significant effect of collection day (day 0 or day 14) for any CSF analytes, including protein concentration (C1‐C2: 45 [95% CI: 33‐57] mg/dL day 0 vs 49 [95% CI: 39‐62] mg/dL day 14, P = .12; LS: 64 [95% CI: 41‐100] mg/dL day 0 vs 83 [95% CI: 53‐129] mg/dL day 14, P = .37), or nucleated cell count (C1‐C2: 2 [95% CI: 1‐4] cells/μL day 0 vs 3 [95% CI: 1‐4] cells/μL day 14, P = .65; LS: 3 [95% CI: 2‐5] cells/μL day 0 vs 5 [95% CI: 3‐8] cells/μL day 14, P = .10). There was no significant difference in EPM titer or EPM serum : CSF ratio between days 0 and 14.

Conclusions and Clinical Importance

Repeat thecal puncture from the LS or C1‐C2 space 2 weeks apart does not appear to impact CSF analytes.