Cerebrospinal fluid (CSF) is a clear, colorless fluid found within the central nervous system of horses, circulating around the brain and spinal cord. It serves multiple physiological functions, including cushioning the brain and spinal cord, maintaining intracranial pressure, and facilitating the exchange of nutrients and waste products. In equine medicine, CSF analysis is a valuable diagnostic tool for assessing neurological conditions, as changes in its composition can indicate the presence of diseases such as infections, inflammations, or trauma. This page compiles peer-reviewed research studies and scholarly articles that explore the composition, function, and clinical relevance of cerebrospinal fluid in horses.
Marsh AE, Barr BC, Madigan J, Lakritz J, Conrad PA.To identify Sarcocystis neurona-specific DNA sequences in the nuclear small subunit ribosomal RNA (nss-rRNA) gene that could be used to distinguish S neurona from other closely related protozoal parasites, and to evaluate a polymerase chain reaction (PCR) test, using broad based primers and a unique species-specific probe on CSF for detection of S neurona in equids. Methods: Sequencing of the nuclear small subunit ribosomal RNA gene from a new S neurona isolate (UCD 1) was performed. The sequence was compared with that of other closely related Sarcocystidae parasites. From this sequence, conse...
Giguère S, Sweeney RW, Bélanger M.To investigate the pharmacokinetics of enrofloxacin in adult horses. Methods: 2-dose oral and i.v. cross-over trial followed by multiple oral doses. Methods: 8 clinically normal adult horses. Methods: Enrofloxacin was administered at dosages of 2.5 mg/kg of body weight to 4 horses and 5.0 mg/kg to 4 other horses. Each dose was given by the intragastric and i.v. routes, using a cross-over design. After the first intragastric dose, 5 additional doses were administered at 12-hour intervals. Enrofloxacin concentrations were measured in serum, synovial fluid, peritoneal fluid, urine, CSF, and endom...
Dowling PM, Wilson RC, Tyler JW, Duran SH.The pharmacokinetics of ciprofloxacin was investigated in healthy, mature ponies. Ciprofloxacin was administered intravenously to six ponies at a dose of 5 mg per kg body weight. Seven days later, ciprofloxacin was administered orally to each pony at the same dose. Intravenous ciprofloxacin concentration vs. time data best fit a two-compartment open model with first-order elimination from the central compartment. Mean plasma half-life, based on the terminal phase, was 157.89 min (harmonic mean). Total body clearance of ciprofloxacin was 18.12 +/- 3.99 mL/min/kg. Volume of distribution at stead...
Jackson CA, deLahunta A, Dykes NL, Divers TJ.Cholesterinic granulomas have been previously reported as an incidental post mortem in horses. Three adult horses with diencephalic dysfunction due to cholesterinic granulomas are described. All the horses exhibited profound depression, somnolence and reluctance to move. One horse experienced generalised seizures. Cerebrosinal fluid was xanthochromic with an elevated total protein in two of the cases evaluated. The large cholesterinic granulomas caused expansion of the lateral ventricle and secondary hydrocephalus due to the build up of cerebrospinal fluid behind the mass. Cholesterinic granul...
Newton-Clarke MJ, Guffoy MR, Dykes NL, Divers TJ.A haemangiosarcoma in a horse resulted in ataxia affecting all four legs, a low head carriage and a reluctance to flex the neck. Ancillary diagnostic procedures included the analysis of cerebrospinal fluid, standing lateral cervical radiographs and a myelogram. Post mortem a tumour was found which involved the body of the second cervical vertebra and the associated hypaxial muscles, with secondary intravertebral extradural infiltration and focal compressive myelopathy. A histological examination showed that the tumour was a haemangiosarcoma.
Andrews FM, Geiser DR, Sommardahl CS, Green EM, Provenza M.Total protein (TP), albumin, and IgG concentrations were measured in CSF from the atlanto-occipital (AO) and lumbosacral (LS) sites and in serum of 15 clinically normal neonatal foals < or = 10 days old (mean, 7.0 days). The albumin quotient (AQ; CSF albumin/serum albumin x 100) and IgG index ([CSF IgG/serum IgG] x [serum albumin/CSF albumin]), indicators of blood-brain barrier permeability and intrathecal IgG production, respectively, were then calculated. Mean +/- SD values obtained from the foals of this study were: serum albumin, 2,900 +/- 240 mg/dl; serum IgG, 1,325 +/- 686 mg/dl; AO CSF ...
Furr MO, Bender H.To determine the effects of age on each analyte, CSF variables were evaluated in healthy foals from birth through 42 days of age. Cerebrospinal fluid was collected from 14 clinically normal, naturally delivered cross-bred foals and was analyzed for glucose, sodium, potassium, magnesium, and total protein concentrations, total and differential WBC counts, RBC count, and lactate dehydrogenase, aspartate transaminase, and creatine kinase activities. Samples were collected in 3 foals < 48 hours old, and at 11 to 14 days of age in 4 foals, 21 to 22 days of age in 3 foals, and 31 to 42 days of ag...
Johnson PJ, Lin TL, Jennings DP.Cholesterinic granulomas, commonly found at necropsy in aged horses, may cause neurologic signs by obstructing the interventricular foramina, resulting in hydrocephalus. Diffuse cerebral disease in horses may not always result in rapid progression of clinical signs. Intermittency of neurologic signs may be associated with intermittent increases in CSF pressure.
Cervantes CC, Brown MP, Gronwall R, Merritt K.Each of 5 healthy mares was given 5 consecutive IM injections of ceftiofur sodium (2 mg/kg of body weight; 50 mg/ml) at 12-hour intervals. Ceftiofur concentrations were measured serially in serum, synovial fluid, peritoneal fluid, and urine, and were measured in CSF and endometrial tissue after the fifth dose. Mean elimination rate constant was 0.354 +/- 0.101 h-1 and elimination half-life was 2.49 +/- 0.49 hour. Mean serum ceftiofur concentrations peaked approximately 1 hour after each injection. The highest mean ceftiofur concentration was 5.09 micrograms/ml at 1 hour after the fifth dose fo...
Moore RM, Trim CM.Facial artery pressure, central venous pressure, heart rate, and lateral ventricle cerebrospinal fluid (CSF) pressure (LV-CSFP) were measured in 10 pentobarbital-anesthetized horses at arterial partial pressure of carbon dioxide (PaCO2) values of 40, 60, and 80 mm Hg, produced by varying the inspired carbon dioxide concentration. Variables were recorded at 5-minute intervals for 15 minutes at each level of PaCO2. Arterial blood gas analysis was performed at the end of the 15-minute time period for each level of PaCO2. Lateral ventricle CSF pressure was significantly increased (p < .05) at a...
Clarke CR, MacAllister CG, Burrows GE, Ewing P, Spillers DK, Burrows SL.Pharmacokinetics, CSF penetration, and hematologic effects of oral administration of pyrimethamine were studied after multiple dosing. Pyrimethamine (1 mg/kg of body weight) was administered orally once a day for 10 days to 5 adult horses, and blood samples were collected frequently after the first, fifth, and tenth doses. The CSF samples were obtained by cisternal puncture 4 to 6 hours after administration of the first, third, seventh, and tenth doses. Pyrimethamine concentration in plasma and CSF was quantified by gas chromatography, and plasma concentration-time data were analyzed, using a ...
Lester GD, MacKay RJ, Smith-Meyer B.Primary meningeal lymphoma was diagnosed in an 18-year-old Morgan gelding. The horse was examined because of a 3-day history of progressive ataxia and weakness. The gait abnormalities were worse on the left side, and the pelvic limbs were more affected than the thoracic limbs. Additional findings included signs of depression, miosis of the left pupil, ptosis of the left upper eyelid, and areas of muscle atrophy on the left side of the neck and over the dorsal aspect of the left scapula. Inflammatory changes were evident in the CSF. At necropsy, there was diffuse and irregular thickening of the...
Specht TE, Brown MP, Gronwall RR, Rib WJ, Houston AE.Serum concentrations of metronidazole were determined in 6 healthy adult mares after a single IV injection of metronidazole (15 mg/kg of body weight). The mean elimination rate (K) was 0.23 h-1, and the mean elimination half-life (t1/2) was 3.1 hours. The apparent volume of distribution at steady state was 0.69 L/kg, and the clearance was 168 ml/h/kg. Each mare was then given a loading dose (15 mg/kg) of metronidazole at time 0, followed by 4 maintenance doses (7.5 mg/kg, q 6 h) by nasogastric tube. Metronidazole concentrations were measured in serial samples of serum, synovia, peritoneal flui...
Moore RM, Trims CM.Lumbosacral CSF pressure was measured in 6 horses via a catheter inserted through the lumbosacral space. Heart rate, facial artery pressure, central venous pressure, and CSF pressure were measured before IV injection of a saline solution control, for 15 minutes after saline solution injection, and for 60 minutes after the IV injection of 1.1 mg of xylazine/kg of body weight. Arterial pH and blood gases were analyzed before saline solution injection, 15 minutes after saline solution injection, and at 15, 30, and 60 minutes after xylazine injection. Constant craniocervical posture was maintained...
Green SL, Smith LL, Vernau W, Beacock SM.The records of 21 horses with rabies were reviewed. Results of fluorescent antibody testing for rabies antigen in brain tissue were positive in each case. According to the histories, 5 of the horses had been vaccinated for rabies between 4 to 24 months prior to the onset of the clinical signs. Bite wounds were not observed on any of the horses, and exposure to a suspected rabid animal was witnessed in only 5 cases. Clinical signs of disease at the time of initial examination included ataxia and paresis of the hindquarters (9/21, 43%), lameness (5/21, 24%), recumbency (3/21, 14%), pharyngeal pa...
Furr MO, Anver M, Wise M.Intervertebral disk prolapse was diagnosed in a mature horse with clinical signs of caudal ataxia. Radiography and myelography demonstrated a collapsed intervertebral space and loss of the dorsal and ventral dye columns. Results of CSF analysis were normal, as were a CBC and serum biochemical profile. High CSF WBC count and high CSF creatine kinase activity were noticed following acute neurologic deterioration. While common in certain breeds of dogs, intervertebral disk prolapse is rarely reported in horses. It should be considered in the differential diagnosis of horses with caudal ataxia.
Grabner A, Goldberg M.In a blind study serum and cerebrospinal fluid (CSF) of control horses and of horses in hepatic coma after chronic food intoxication with Senecio alpinus were collected simultaneously and the composition of free amino acids was determined. The hepatic encephalopathy index in serum (less than 1.65) and in CSF (less than 1.11) of liver patients was distinctly less than to the control values in serum (greater than 2.42) and in CSF (greater than 1.49). The serum concentrations of glutamic acid in hepatic coma were elevated five-fold in comparison to the controls. An indication of ammonia decontami...
Grabner A, Fischer A.In a retrospective study of 38 horses with Borna encephalitis which were clinically and histopathologically examined in the "I. Medizinische Tierklinik" in Munich between 1977 and 1990, the epidemiology, the clinical symptomatic and the diagnostic procedures available are presented. Indirect immunofluorescence showed antibodies in the serum of 12 out of 29 cases (41%) and in the cerebrospinal fluid (CSF) of 17 out of 28 cases (61%). The evaluation of 23 cases in which indirect immunofluorescence of serum and CSF, and also the post mortem virological and histopathological examination of the bra...
Furr MO, Tyler RD.The CSF creatine kinase (CK) activity was determined in 70 CSF samples from 69 horses with CNS disease. Abnormal values (greater than or equal to 1 IU/L) were determined from 32 CSF samples, and normal values (less than 1 IU/L) were found in 38 samples. Increased CK activity was most frequently associated with a diagnosis of equine protozoal myelitis; CK activity was not increased in 11 horses with cervical compressive myelopathy. Other diagnoses, in which CSF CK activity was increased included trauma (n = 1), idiopathic epilepsy (n = 2), botulism (n = 2), articular facet fracture (n = 1), int...
Green SL, Mayhew IG, Brown MP, Gronwall RR, Montieth G.Each of seven mares was given an intravenous (IV) injection of 40% dimethyl sulfoxide (DMSO) at a dosage of 1 g/kg, over 35 min, immediately followed by a single IV injection of a trimethoprim (TMP) and sulfamethoxazole (SMZ) combination (SMZ 83%, TMP 17%) at a combined dosage of 44 mg/kg (7.48 mg/kg TMP; 36.52 mg/kg SMZ). Each horse served as its own control and was alternately treated with an identical dose of TMP-SMZ treatment alone at least seven days following or preceding the DMSO and TMP-SMZ treatment. Serum and cerebrospinal fluid (CSF) concentrations of TMP and SMZ were measured over ...
Cullen LK, Steffey EP, Bailey CS, Kortz G, da Silva Curiel J, Bellhorn RW, Woliner MJ, Elliott AR, Jarvis KA.The effects of different arterial carbon dioxide tensions (PaCO2) on cerebrospinal fluid pressure (CSFP) and intraocular pressure (IOP) were studied in 6 male halothane-anesthetized horses positioned in left lateral recumbency. Steady-state anesthetic conditions (1.06% end-tidal halothane concentration) commenced 60 minutes following anesthetic induction with only halothane in oxygen. During atracurium neuromuscular blockade, horses were ventilated, and respiratory rate and peak inspiratory airway pressure were maintained within narrow limits. The CSFP and IOP were measured at 3 different leve...
Harkness RA, McCreanor GM, Allsop J, Snow DH, Harris RC, Rossdale PO, Ousey JC.1. Plasma hypoxanthine and xanthine concentrations are very low in the horse and low in rat, mouse and greyhound compared to concentrations in beagles, man, sheep and rabbit. 2. Activities in erythrocytes of the main enzyme metabolizing hypoxanthine, hypoxanthine phosphori-bosyltransferase, show a similar pattern (Tax et al., 1976, Comp. Biochem. Physiol. 54B, 209-212); thus low activities have been found where plasma concentrations were low. 3. Hypoxanthine phosphoribosyltransferase activities in horse tissue other than erythrocytes are similar to those in man and rabbit with high activities ...
Melrose PA, Walker RF, Douglas RH.Catecholamine concentrations (pg/ml) in the cerebrospinal fluid (CSF) of prepubertal (n = 9) and adult (n = 18) horses were determined by radioenzymatic assay. Norepinephrine was low or non detectable in all CSF samples. In contrast, measurable CSF dopamine concentrations were effected by age, reproductive status and exogenous steroid treatments. The concentration of dopamine in the CSF of prepubertal females (733 +/- 92) was greater (p less than 0.05) than the concentration in the CSF of prepubertal males (117 +/- 67). Prepubertal male horses which were treated with testosterone for 5 days (5...
Mück WM, Henion JD.The performance of microbore high-performance liquid chromatography and capillary zone electrophoresis, both equipped with on-line tandem mass spectrometric detection capability, was evaluated critically for the determination of endogenous amounts of leucine enkephalin and methionine enkephalin in equine cerebrospinal fluid. Using an identical sample clean-up and enrichment procedure, capillary zone electrophoresis-mass spectrometry is limited in its concentration detection capacity owing to its much smaller injection volume. Leucine enkephalin was identified in post-mortem equine cerebrospina...
Burbidge HM, Kannegieter N, Dickson LR, Goulden BE, Badcoe L.Iohexol, a water soluble non-ionic contrast agent, was evaluated for myelography in the horse. Both 300 and 350 mg iodine/ml iohexol gave diagnostic cervical myelograms. Pathological changes were limited to extradural oedema and an increase in the number of white blood cells and specific gravity in the cerebrospinal fluid two days after myelography. This increase in white blood cells in the cerebrospinal fluid was, however, much less than that recorded by other authors using metrizamide and iopamidol contrast media. These findings indicate that iohexol is a less irritant myelographic contrast ...
Prades M, Brown MP, Gronwall R, Houston AE.After single oral administration of ketoconazole (30 mg/kg bodyweight [bwt]) in 50 ml of corn syrup to a healthy mare, the drug was not detected in serum. Ketoconazole in 0.2 N HC1 was administered intragastrically to six healthy adult horses in five consecutive doses of 30 mg/kg bwt at 12 h intervals. Ketoconazole concentrations were measured in serum, synovial fluid, peritoneal fluid, cerebrospinal fluid (CSF), urine and endometrium. Mean peak serum ketoconazole concentration was 3.76 micrograms/ml at 1.5 to 2 h after intragastric administration. Mean peak synovial concentration was 0.87 mic...
Brown MP, Gronwall RR, Houston AE.Six healthy adult mares were each given an oral loading dose of ormetoprim(OMP)-sulfadimethoxine (SDM) at a dosage of 9.2 mg of OMP/kg and 45.8 mg of SDM/kg, followed by four maintenance doses of 4.6 mg of OMP/kg and 22.9 mg of SDM/kg, at 24 h intervals. Ormetoprim and SDM concentrations were measured in serum, synovial fluid, peritoneal fluid, cerebrospinal fluid, urine and endometrium. The highest mean serum OMP concentration was 0.92 micrograms/mL 0.5 h after the first dose; the highest mean SDM concentration was 80.9 micrograms/mL 8 h after the first dose. The highest mean synovial fluid c...
Vaughn DM, Smyth GB, Whitmer WL, Satjawatcharaphong C.Small volumes (0.05 ml) of cisterna magna cerebrospinal fluid (CSF) from 23 neurologically normal horses were analysed for the monoamine neurotransmitters dopamine, norepinephrine, epinephrine, serotonin and their metabolites using high pressure liquid chromatography and electrochemical detection. Two metabolites, homovanillic acid (HVA) and 5-hydroxyindoleacetic acid (5-HIAA) were present in all CSF samples. The deaminated and methylated metabolite of dopamine, HVA, was present at a mean concentration of 42.33 +/- 3.14 ng/ml of CSF. The deaminated metabolite of serotonin, 5-HIAA, was present ...
Vaughn DM, Smyth GB.The serotonin metabolite, 5-hydroxyindoleacetic acid (5-HIAA) and the dopamine metabolite, homovanillic acid (HVA) in the cerebrospinal fluid (CSF) of seven clinically normal horses were evaluated with reverse phase high pressure liquid chromatography and electrochemical detection. Comparisons of the neurotransmitter metabolite concentrations were made on CSF collected simultaneously from the atlanto-occipital and lumbosacral regions. There were significantly higher amounts of 5-HIAA and HVA in atlanto-occipital CSF than in lumbosacral CSF. Mean 5-HIAA concentrations in atlanto-occipital and l...
Moore RM, Trim CM.Facial artery pressure, central venous pressure, heart rate, and lateral ventricle cerebrospinal fluid (CSF) pressure (LV-CSFP) were measured in 10 pentobarbital-anesthetized horses at arterial partial pressure of carbon dioxide (PaCO2) values of 40, 60, and 80 mm Hg, produced by varying the inspired carbon dioxide concentration. Variables were recorded at 5-minute intervals for 15 minutes at each level of PaCO2. Arterial blood gas analysis was performed at the end of the 15-minute time period for each level of PaCO2. Lateral ventricle CSF pressure was significantly increased (p < .05) at a...
Watrous BJ.Head tilt in the horse is commonly a sign of either central or peripheral vestibular disease. The confirmation of vestibular disease is based on physical findings, including results of cranial-nerve function evaluation and observation of stance, posture, and gait. Further localization is made by ancillary tests such as cerebral spinal fluid analysis, electrodiagnostic testing, and radiography. The normal anatomy and physiology of the vestibular system, the abnormal clinical signs demonstrated during physical examination, and the various etiologies are discussed.
Bernardino PN, Pusterla N, Conrad PA, Packham AE, Tamez-Trevino E, Aleman M, James K, Smith WA.Among the recognized neurologic diseases in horses, equine protozoal myeloencephalitis (EPM) has been reported around the world and still presents challenges in diagnosis and treatment. Horses can present with clinical neurologic signs consistent with EPM while testing negative for the two main causative agents, Sarcocystis neurona or Neospora hughesi, and may still be clinically responsive to anti-parasitic drug therapy. This context led to our hypothesis that another protozoal parasite, Toxoplasma gondii, which is known to cause toxoplasmosis in other mammalian species, is a potential pathog...
Quattrini C, Scalco R, Vernau W, Dini P, Aleman M.Cerebrospinal fluid (CSF) is highly labile and delayed processing might alter results of analysis. Objective: To determine the effects of time and addition of autologous serum on cytological evaluation of CSF. Methods: Ten client-owned adult horses requiring euthanasia. Methods: Prospective study. Serum and CSF were collected from each horse before and within 10 minutes after euthanasia. CSF samples were divided into 15 aliquots (2 mL each); 1 aliquot was submitted for routine CSF analysis within 60 minutes of collection. Four drops of autologous serum were added to 7 of the aliquots, and ...
Adams SB, Steckel R, Blevins W.Diskospondylitis was diagnosed in 5 horses admitted to the Purdue University Large Animal Clinic during a 3-year period. Each horse had evidence of cervical pain. Clinical signs and radiography were useful for identifying the diskospondylitis. Cerebrospinal fluid was normal.
Ellison S, Witonsky S.Sarcocystis neurona is the principal etiologic agent of equine protozoal myeloencephalitis (EPM). An immunodominant protein of S. neurona, SnSAG-1, is expressed by the majority of S. neurona merozoites isolated from spinal tissues of horses diagnosed with EPM and may be a candidate for diagnostic tests and prophylaxis for EPM. Five horses were vaccinated with adjuvanted recombinant SnSAG1 (rSnSAG1) and 5 control (sham vaccinated) horses were vaccinated with adjuvant only. Serum was evaluated pre- and post-vaccination, prior to challenge, for antibodies against rSnSAG1 and inhibitory effects on...
Raphel CF.Three horses with brain abscesses had different clinical manifestations: 1 had a protracted clinical course whereas 2 had a short clinical course. Clinical signs in 2 horses (1 acute case, 1 chronic case) included unilateral loss of vision, head tilt, circling, abnormal mental status, and ataxia. The 3rd horse had bilateral loss of vision, altered mental status, and apparent deafness. Results of cerebrospinal fluid analysis were inconsistent. The horse with the protracted clinical course had paradoxic central vestibular disease.
Tokunaga S, Fujiki M, Yabuki A, Misumi K.Cartilage-derived retinoic acid-sensitive protein (CD-RAP)/melanoma inhibitory activity (MIA), which appears abundantly in hypertrophic cartilage at the stage of endochondral ossification, is also detected in cerebrospinal fluid (CSF) following spinal cord injury. In this study, the localization of the CD-RAP/MIA molecule in normal tissues of the spine and brain obtained from mice, rats, dogs, cattle and horses was examined using immunohistochemistry with a specific antibody. The positive signals of CD-RAP/MIA were found at nerve cells in the spinal cords of all species and were especially str...
Harkness RA, McCreanor GM, Allsop J, Snow DH, Harris RC, Rossdale PO, Ousey JC.1. Plasma hypoxanthine and xanthine concentrations are very low in the horse and low in rat, mouse and greyhound compared to concentrations in beagles, man, sheep and rabbit. 2. Activities in erythrocytes of the main enzyme metabolizing hypoxanthine, hypoxanthine phosphori-bosyltransferase, show a similar pattern (Tax et al., 1976, Comp. Biochem. Physiol. 54B, 209-212); thus low activities have been found where plasma concentrations were low. 3. Hypoxanthine phosphoribosyltransferase activities in horse tissue other than erythrocytes are similar to those in man and rabbit with high activities ...
Rossano MG, Kaneene JB, Schott HC, Sheline KD, Mansfield LS.Equine protozoal myeloencephalitis (EPM) is a neurological disease of equids that is caused by infection of the central nervous system with Sarcocystis neurona. Veterinarians diagnose EPM by performing a neurological examination and by ordering Western blot tests for antibodies to S. neurona in the blood and/or cerebrospinal fluid (CSF). The negative predictive value of the Western blot test is generally accepted to be high for both serum and CSF. If the agreement between serum and CSF test results is strong, serum tests could be used to substitute for CSF tests in some cases. The purpose of t...
Specht TE, Brown MP, Gronwall RR, Rib WJ, Houston AE.Serum concentrations of metronidazole were determined in 6 healthy adult mares after a single IV injection of metronidazole (15 mg/kg of body weight). The mean elimination rate (K) was 0.23 h-1, and the mean elimination half-life (t1/2) was 3.1 hours. The apparent volume of distribution at steady state was 0.69 L/kg, and the clearance was 168 ml/h/kg. Each mare was then given a loading dose (15 mg/kg) of metronidazole at time 0, followed by 4 maintenance doses (7.5 mg/kg, q 6 h) by nasogastric tube. Metronidazole concentrations were measured in serial samples of serum, synovia, peritoneal flui...
Luethy D, Colmer S, Jodzio D, Bender S, Porter E, Hemmen Z, Fultz L, Craft W, Walker R, Johnson A, Holbrook T.Ultrasound-guided cervical centesis has gained popularity as a method for collecting cerebrospinal fluid (CSF) from standing horses. There are anecdotal reports of neck stiffness, regional swelling, sensitivity to palpation, and fever after the procedure. We report 2 horses with complications that occurred within days of C1-C2 centesis and ultimately resulted in euthanasia. Both C1-C2 centesis were performed routinely, with CSF cytologic analysis providing no evidence of blood contamination. Post-mortem examination revealed equine degenerative myeloencephalopathy as the primary disorder causin...
Lindsay DS, Dykstra CC, Williams A, Spencer JA, Lenz SD, Palma K, Dubey JP, Blagburn BL.Equine protozoal myeloencephalitis (EPM) is a neurologic syndrome in horses from the Americas and is usually caused by infection with the apicomplexan parasite, Sarcocystis neurona. A horse model of EPM is needed to test the efficacy of chemotherapeutic agents and potential vaccines. Five horses that were negative for antibodies to S. neurona in their serum and cerebrospinal fluid (CSF) were injected in the subarachnoid space with living merozoites of the SN2 isolate of S. neurona. None of the horses developed clinical disease or died over a 132-day observation period. All five horses develope...
Orr JA, Busija DW.Unanesthetized ponies were given 4% CO2 (inspired CO2 pressure = 28 Torr) to breathe at two levels of arterial O2 pressure (PaO2): 1) near 75 Torr and 2) near 200 Torr. During 4% CO2 breathing, at either level of PaO2, the mean arterial CO2 pressure (PaCO2) was unchanged from control measurements (control measurements were made at the same PaO2, but with no CO2 in inspired air), suggesting that awake ponies can "clear" 4% CO2. The ability of individual ponies to clear 4% CO2 was quite variable: some ponies did not clear 4% CO2 and others cleared 4% CO2 on one day but not on the following day. ...
Vaughn DM, Smyth GB, Whitmer WL, Satjawatcharaphong C.Small volumes (0.05 ml) of cisterna magna cerebrospinal fluid (CSF) from 23 neurologically normal horses were analysed for the monoamine neurotransmitters dopamine, norepinephrine, epinephrine, serotonin and their metabolites using high pressure liquid chromatography and electrochemical detection. Two metabolites, homovanillic acid (HVA) and 5-hydroxyindoleacetic acid (5-HIAA) were present in all CSF samples. The deaminated and methylated metabolite of dopamine, HVA, was present at a mean concentration of 42.33 +/- 3.14 ng/ml of CSF. The deaminated metabolite of serotonin, 5-HIAA, was present ...
Gilliam LL, Holbrook TC, Dechant JE, Johnson BJ.A 6-year-old Quarter Horse stallion was referred to Oklahoma State University Veterinary Medical Teaching Hospital for evaluation of abdominal pain that developed after breeding activity earlier in the day. The horse developed diarrhea and progressively worsening neurologic signs (circling, ataxia, head pressing) within 22 hours of presentation and was subsequently euthanized due to severe self-destructive behavior. Antemortem biochemical and hematologic abnormalities included hypocalcemia but no evidence of hepatic disease. Idiopathic hyperammonemia and encephalopathy were suspected; cerebros...
Vickroy TW, Chang SK, Chou CC.The goals of this study were to elucidate the temporal and quantitative relationships between caffeine and its major bioactive metabolites in blood and cerebrospinal fluid (CSF) and to characterize the pharmacokinetic-pharmacodynamic relationship for caffeine-induced changes in spontaneous locomotor activity in the horse. We hypothesized that caffeine and its metabolites distribute efficiently into the CSF to antagonize adenosine A1 and A2a receptors and that spontaneous locomotor activity correlates well with caffeine and/or metabolite concentrations in CSF and blood. A microdialysis system w...
Cock G, Blakeney Z, Hernandez JA, DeNotta S.Atlantoaxial (AA) cerebrospinal fluid (CSF) collection in standing horses utilizes the controlled narcotic morphine, thereby limiting feasibility in field practice settings. Objective: To compare AA CSF collection time and reaction scores in horses sedated with morphine-containing and opioid-free sedation protocols: detomidine + morphine (DM), detomidine + xylazine (DX), detomidine + detomidine (DD), detomidine alone (D0); To develop a novel method for assessing sedation in standing horses using open-source motion-tracking software. Methods: Six healthy adult horses. Methods: Randomi...
Furr M, Pontzer C, Gasper P.The percentages of T-lymphocytes, lymphocyte subsets CD4+ and CD8+ T-cells, and lymphocyte adhesion molecule CD11a/CD18 were determined in the peripheral blood and cerebrospinal fluid (CSF) of seven normal horses and four horses with equine protozoal myeloencephalitis (EPM) using flow cytometry. There was a greater percentage of CD5+ cells in the CSF (79.0%) than in peripheral blood (67.0%), although this did not achieve statistical significance. Furthermore, the lymphocyte population in CSF comprises a significantly greater (P = .01) percentage of CD8+ T-cells, resulting in a decrease of the ...
Prades M, Brown MP, Gronwall R, Houston AE.After single oral administration of ketoconazole (30 mg/kg bodyweight [bwt]) in 50 ml of corn syrup to a healthy mare, the drug was not detected in serum. Ketoconazole in 0.2 N HC1 was administered intragastrically to six healthy adult horses in five consecutive doses of 30 mg/kg bwt at 12 h intervals. Ketoconazole concentrations were measured in serum, synovial fluid, peritoneal fluid, cerebrospinal fluid (CSF), urine and endometrium. Mean peak serum ketoconazole concentration was 3.76 micrograms/ml at 1.5 to 2 h after intragastric administration. Mean peak synovial concentration was 0.87 mic...
Njoku CJ, Saville WJ, Reed SM, Oglesbee MJ, Rajala-Schultz PJ, Stich RW.Equine protozoal myeloencephalitis (EPM) is a disease of horses that is primarily associated with infection with the apicomplexan Sarcocystis neurona. Infection with this parasite alone is not sufficient to induce the disease, and the mechanism of neuropathogenesis associated with EPM has not been reported. Nitric oxide (NO) functions as a neurotransmitter, a vasodilator, and an immune effector and is produced in response to several parasitic protozoa. The purpose of this work was to determine if the concentration of NO metabolites (NO(x)(-)) in the cerebrospinal fluid (CSF) is correlated with...
Pedrick TP, Moon PF, Ludders JW, Erb HN, Gleed RD.To describe the effects of tromethamine, a putative treatment for metabolic acidosis, and to compare its biochemical effects with those of sodium bicarbonate. Methods: Randomized intervention study with repeated measures. Methods: 16 healthy horses, 3 to 17 years old, weighing 391 to 684 kg. Methods: Ten horses received 3 mEq/kg tromethamine and six received 3 mEq/kg sodium bicarbonate. Samples of venous blood and cerebrospinal fluid (CSF) were collected at intervals before and after drug administration. Heart rate and breathing rate were also recorded at intervals. Results: Median standard ba...
Geiser DR, Andrews FM, Rohrbach BW, Provenza MK.To determine normal acid-base status of the CSF and to compare it with changes during acute hypercapnia in equine neonates. Methods: 10 clinically normal foals between 1 and 12 days old. Methods: CSF and arterial and venous blood samples were collected every 15 minutes during 45 minutes of normocapnia and 90 minutes of hypercapnia in isoflurane-anesthetized foals. CSF samples were collected via a subarachnoid catheter placed in the atlanto-occipital space. Results: Comparison of blood and CSF gases during normocapnia indicated that CSF was significantly more acidic than blood. The lower pH was...
Clarke CR, MacAllister CG, Burrows GE, Ewing P, Spillers DK, Burrows SL.Pharmacokinetics, CSF penetration, and hematologic effects of oral administration of pyrimethamine were studied after multiple dosing. Pyrimethamine (1 mg/kg of body weight) was administered orally once a day for 10 days to 5 adult horses, and blood samples were collected frequently after the first, fifth, and tenth doses. The CSF samples were obtained by cisternal puncture 4 to 6 hours after administration of the first, third, seventh, and tenth doses. Pyrimethamine concentration in plasma and CSF was quantified by gas chromatography, and plasma concentration-time data were analyzed, using a ...
Rivas LJ, Hinchcliff KW, Robertson JT.Cervical meningomyelocele, spina bifida, and hydrocephalus were diagnosed in a newborn miniature colt that was unable to stand and had a cystic mass in the caudal portion of the dorsal cervical region. Results of physical examination and ultrasonographic imaging of the brain supported the diagnosis of hydrocephalus. Results of radiographic evaluation of the vertebral column were consistent with spina bifida at C5-C6. Fluid aspirated from the cervical mass resembled CSF. Radiography of the cervical region after injection of iohexol into the mass revealed herniation of the spinal cord through a ...
Rossano MG, Schott HC, Kaneene JB, Murphy AJ, Kruttlin EA, Hines MT, Sellon DC, Patterson JS, Elsheikha HM, Dubey JP, Mansfield LS.To determine whether daily administration of pyrantel tartrate can prevent infection in horses experimentally challenged with Sarcocystis neurona. Methods: 24 mixed-breed specific-pathogen-free weanling horses, 10 adult horses, 1 opossum, and 6 mice. Methods: Sarcocystis neurona-naïve weanling horses were randomly allocated to 2 groups. Group A received pyrantel tartrate at the labeled dose, and group B received a nonmedicated pellet. Both groups were orally inoculated with 100 sporocysts/d for 28 days, 500 sporocysts/d for 28 days, and 1000 sporocysts/d for 56 days. Blood samples were collec...
Donaldson MT, Sweeney CR.To determine results of CSF analysis in horses with equid herpesvirus myeloencephalopathy (EHM) and to determine whether results of CSF analysis were associated with outcome. Methods: Retrospective study. Methods: 11 horses. Methods: Medical records of all horses admitted to the veterinary teaching hospital between February 1982 and March 1996 in which EHM was diagnosed were reviewed. Results: 7 horses were < or = 4 years old; 8 were admitted during January, February, or March. Six horses were febrile prior to admission, but none was febrile on the day of admission. Five horses had been sta...
Goehring LS, Kessels BG, van Maanen C, Voorbij HA, Sloet van Oldruitenborgh-Oosterbaan MM.The measurement of albumin concentrations in cerebrospinal fluid (CSF) and serum for albumin quotient (AQ) calculations in normal horses was performed by 2 methods: 1) total protein measurement, followed by electrophoresis of the samples to obtain an albumin percentage; and 2) albumin immunoprecipitation quantitated by nephelometry. The results of both methods correlated well, and nephelometry was chosen to determine the albumin concentrations in CSF samples obtained from an indwelling subarachnoidal catheter for daily sampling. Because the use of an indwelling catheter to collect repetitive C...
Cook AG, Maxwell VB, Donaldson LL, Parker NA, Ward DL, Morrow JK.To determine whether antibodies against Sarcocystis neurona could be detected in CSF from clinically normal neonatal (2 to 7 days old) and young (2 to 3 months old) foals. Methods: Prospective study. Methods: 15 clinically normal neonatal Thoroughbred foals. Methods: Serum and CSF samples were obtained from foals at 2 to 7 days of age and tested for antibodies against S. neurona by means of western blotting. Serum samples from the mares were also tested for antibodies against S. neurona. Additional CSF and blood samples were obtained from 5 foals between 13 and 41 days after birth and between ...
Garma-Aviña A.A cytologic study of the choroid plexi of animals and humans was carried out using impression smears (imprints, imp) to understand better the cellular changes that occur in the cerebrospinal fluid in the case of disease. The samples, totaling 756 imp were from 11 dogs (239 imp), 10 horses (219 imp), 1 mule (23 imp), 3 cattle (69 imp), 1 sheep (19 imp), 2 pigs (39 imp), 1 deer (20 imp), 4 monkeys (22 imp), and 7 humans (106 imp). The samples came from individuals clinically free of neurologic disease, as well as from a few abnormal cases. Six of the 7 humans had no history of neurologic disease...
