Ataxia in horses refers to a neurological condition characterized by a lack of coordination and balance, often manifesting as unsteady or abnormal gait. The condition can result from various underlying causes, including spinal cord compression, brain lesions, or peripheral nerve damage. Ataxia is typically classified into three types: cerebellar, vestibular, and proprioceptive, each associated with different parts of the nervous system. Diagnosis involves a combination of clinical examination, neurological assessment, and diagnostic imaging. This page compiles peer-reviewed research studies and scholarly articles that explore the causes, diagnostic approaches, and management strategies for ataxia in equine patients.
Rose PL, Abutarbush SM, Duckett W.Standing myelography in the horse has been previously described. In that study, metrizamide was used and significant complications were reported. In recent years, the introduction of less-toxic nonionic contrast media has reduced the incidence of complications. This study was undertaken to determine whether standing myelography using a nonionic contrast medium could provide a diagnostic study and be performed safely in the equine patient. Standing myelography was performed in eight horses. The contrast medium used was iohexol. In five horses a myelogram of diagnostic quality was achieved; in o...
Derossi R, Medeiros U, de Almeida RG, Righetto FR, Frazílio FO.The aim of the study was to evaluate and compare the effects of caudal epidural administration of meperidine (MP), lidocaine (LD), and a combination of the two (MPLD) in six mature saddle horses. Horses were randomly assigned to receive three treatments (MP 0.3 mg/kg; LD 0.2 mg/kg; and MPLD: MP 0.3 mg/kg and LD 0.2 mg/kg), with at least 1 week between treatments. Drugs were injected into the epidural space between the first and second coccygeal areas in conscious standing horses. Analgesia, ataxia, sedation, cardiovascular and respiratory effects, and rectal temperature were recorded at differ...
Aleman M, Magdesian KG, Peterson TS, Galey FD.A 4-month-old American Paint filly was evaluated because of sudden onset of ataxia that progressed to recumbency. Five additional horses from the same and neighboring premises developed signs of poor performance, generalized weakness, ataxia, and recumbency; 2 of those horses were also evaluated. A new batch of a commercial feed supplement had been introduced to the horses' diet on each farm within the preceding 3 days. Results: Other than recumbency, findings of physical and neurologic examinations of the foal were unremarkable. The other 2 horses had generalized weakness and mild ataxia, and...
Strobach A, Kotschwar A, Mayhew IG, Peham C, Licka T.Equine ataxia is routinely evaluated subjectively by clinicians; however, objective measurements of the movement and coordination of ataxic horses have not been reported. Objective: To document the movement pattern of ataxic horses and compare the results to the movement of neurologically sound horses with, and without, sedation. Methods: Seventeen ataxic horses were evaluated walking and trotting on a treadmill using a 3D high speed video system. From the horizontal movement of hoof markers the autocorrelation function (ACF) of the left forelimb and the cross correlation function (CCF) betwee...
Cassart D, Baise E, Cherel Y, Delguste C, Antoine N, Votion D, Amory H, Rollin F, Linden A, Coignoul F, Desmecht D.There is a lack of well documented studies about muscular lesions in equine atypical myopathy (EAM). Objective: To characterise morphopathological changes of striated muscles and myocardium, to progress understanding of this disease. Methods: Thirty-two horses age 0.5-7 years kept on pasture were referred for a sudden ataxia/myoglobinuria syndrome. Clinical examination (stiffness, muscle pain, muscle fasciculations, abnormal gait, recumbency, myoglobinuria, tachycardia, sweating) and plasma CPK, LDH and AST levels were consistent with extensive myonecrosis and, together with anamnestic data, w...
Sasaki N, Yamada M, Morita Y, Furuoka H, Itoh M, Satoh M, Yamada H.We report a case of EMND in a heavy horse that was bred and trained in Hokkaido, Japan. Clinical symptoms included severe ataxia of all four limbs, tilted head, lethargy, and flaccid lips. Numerous axonal degenerations and swellings were observed in nuclei, mostly in the cerebellar dentate nucleus and the nucleus of the hypoglossal nerve, and in the ventral horn of the spinal cord. In the ventral horn of the spinal cord, neuronal degeneration, swelling, and/or necrosis were observed sporadically. The case was diagnosed as EMND from the clinical symptoms and pathological findings.
Bryant UK, Lyons ET, Bain FT, Hong CB.A 13-week-old Thoroughbred colt from central Kentucky was euthanized after an acute onset of ataxia, blindness, head tremors, leaning to the right, recumbency, and seizures. Microscopically, there was a verminous meningoencephalitis characterized by an eosinophilic and granulomatous inflammatory reaction primarily affecting the cerebellum. Dispersed within regions of inflammation were numerous cross and longitudinal sections of intact and degenerative small nematodes. The nematodes had dorsoflexed ovaries and ventroflexed vulvas, which are distinguishing features of Halicephalobus gingivalis. ...
Snowden NJ, Helyar CV, Platt SR, Penderis J.Moxidectin is a macrocyclic lactone related to ivermectin used in horses and dogs for endoparasite treatment and prophylaxis. The clinical and neurological presentation of moxidectin toxicity in two dogs following inadvertent poisoning with a moxidectin-containing equine de-worming medication is reported here. In both the dogs, the predominant clinical signs were generalised tremors and ataxia. Moxidectin exerts its neurotoxic effects in mammals by potentiating the effect of gamma-aminobutyric acid and, consistent with this, both the dogs demonstrated a poor response to treatment with diazepam...
Finno C, Pusterla N, Aleman M, Mohr FC, Price T, George J, Holmberg T.A 4-month-old American Paint Horse colt was evaluated because of acute onset of ataxia, left-sided head tilt, and fever and a recently noticed heart murmur. Upper respiratory tract infection caused by Streptococcus equi subsp equi had been diagnosed at 3 months of age. Results: Hematologic abnormalities included leukocytosis, mature neutrophilia, monocytosis, and mild anemia. Analysis of a CSF sample revealed high total protein concentration and total nucleated cell count; nucleated cells consisted mainly of degenerate neutrophils. Results of a real-time PCR assay were positive for S equi subs...
Blanco A, Moyano R, Vivo J, Flores-Acuña R, Molina A, Blanco C, Monterde JG.Purkinje cerebellar cells were studied in three Arabian horses aged between 6 and 8 months with clinical disorders in their movements, tremors and ataxia; the occurrence of apoptosis in this cell population was investigated by the (terminal deoxynucleotidyl transferase biotin-dUTP nick-end labelling (TUNEL) method. Both optical and electron microscopical images showed a scant number of Purkinje cells, most of them with morphological features of apoptosis such as condensation of the nucleus and cytoplasm as well as segregation and fragmentation of the nucleus into apoptotic bodies. The TUNEL te...
Ward MP, Schuermann JA, Highfield LD, Murray KO.Equine West Nile virus (WNV) encephalomyelitis cases - based on clinical signs and ELISA serology test results - reported to Texas disease control authorities during 2002 were analyzed to provide insights into the epidemiology of the disease within a previously disease-free population. The epidemic occurred between June 27 and December 17 (peaking in early October) and 1,698 cases were reported. Three distinct epidemic phases were identified, occurring mostly in southeast, northwest and then central Texas. Significant (P<0.05) disease clusters were identified in northwest and northern Texas. M...
Sharkey LC, DeWitt S, Stockman C.A 23-year-old Thoroughbred gelding was referred for the evaluation of acute onset of ataxia and depression, and a 2-day history of fever. On physical examination, the gelding was profoundly depressed and 10-12% dehydrated. The horse appeared very unstable, with a wide-based stance in the hind limbs, severe symmetric ataxia in all 4 limbs, and proprioceptive deficits in both hind limbs. Nasogastric intubation produced 4 L of brown, fetid reflux, and rectal examination revealed mild small intestinal and cecal distention. Hematologic abnormalities included neutropenia with toxic change, compatibl...
Hubbell JA, Muir WW.The ability to shorten the duration of sedation would potentially improve safety and utility of detomidine. Objective: To determine the effects of tolazoline and atipamezole after detomidine sedation. Objective: Administration of tolazoline or atipamezole would not affect detomidine sedation. Methods: In a randomised, placebo-controlled, double-blind, descriptive study, detomidine (0.02 mg/kg bwt i.v.) was administered to 6 mature horses on 4 separate occasions. Twenty-five mins later, each horse received one of 4 treatments: Group 1 saline (0.9% i.v.) as a placebo control; Group 2 atipamezole...
Hughes KJ, Hodgson DR.The research article discusses the case of a 7-year-old Thoroughbred stallion presenting symptoms such as ataxia, a leftward head tilt and a cloudy left eye, revealing a diagnosis of temporohyoid […]
Rainger JE, Hughes KJ, Kessell A, Dart CM.A 3-year-old Thoroughbred colt was presented to the University Veterinary Centre Camden for evaluation of ataxia. The horse was anaesthetised to facilitate cervical radiography and myelographic examination of the spinal cord. Recovery from anaesthesia was uneventful. Five days after general anaesthesia the horse re-presented with pleuropneumonia. It was euthanased 24 hours after presentation on humane grounds. Necropsy revealed severe tracheal erosion over the middle third of the ventral surface of the trachea, pleuropneumonia and narrowing of the cervical cord between C4 and C6. It is postula...
Yamanaka T, Tsujimura K, Kondo T, Yasuda W, Okada A, Noda K, Okumura T, Matsumura T.Japanese encephalitis (JE) developed in an unvaccinated half-bred horse kept in Tottori Prefecture, Japan. The animal showed ataxia with pyrexia and low appetite, and ultimately died. A viral strain was isolated from the cerebrum of the horse and was identified as JE virus (JEV) by RT-PCR using JEV specific primers. The isolated JEV was classified into genotype I by nucleotide sequence analysis of the viral envelope gene. We believe that this is the first report of the genotype I strain being isolated from a horse.
Valverde A, Gunkelt C, Doherty TJ, Giguère S, Pollak AS.Lidocaine constant rate infusions (CRIs) are common as an intraoperative adjunct to general anaesthesia, but their influence on quality of recovery has not been thoroughly determined. Objective: To determine the effects of an intraoperative i.v. CRI of lidocaine on the quality of recovery from isoflurane or sevoflurane anaesthesia in horses undergoing various surgical procedures, using a modified recovery score system. Objective: The administration of intraoperative lidocaine CRI decreases the quality of recovery in horses. Methods: Lidocaine (2 mg/kg bwt bolus followed by 50 microg/kg bwt/min...
Pusterla N, Holmberg TA, Lorenzo-Figueras M, Wong A, Wilson WD.A 10-year-old Thoroughbred gelding was admitted to the Veterinary Medical Teaching Hospital of the University of California-Davis with a 2-week history of intermittent fever and acute onset of lethargy, anorexia, and ataxia. Although the clinical signs were nonspecific, the results of initial hematologic and biochemical analysis were consistent with a chronic inflammatory process. Thoracic radiographs revealed an increased fine reticulonodular interstitial opacity throughout the dorsal caudal lung fields. Cytologic examination of bronchoalveolar lavage (BAL) fluid showed mixed inflammation wit...
Pellegrini-Masini A, Bentz AI, Johns IC, Parsons CS, Beech J, Whitlock RH, Flaminio MJ.Three adult horses were evaluated for signs of musculoskeletal pain, dullness, ataxia, and seizures. A diagnosis of bacterial meningitis was made on the basis of results of CSF analysis. Because primary bacterial meningitis is so rare in adult horses without any history of generalized sepsis or trauma, immune function testing was pursued. Flow cytometric phenotyping of peripheral blood lymphocytes was performed, and proliferation of peripheral blood lymphocytes in response to concanavalin A, phytohemagglutinin, pokeweed mitogen, and lipopolysaccharide was determined. Serum IgA, IgM, and IgG co...
Pumarola M, Vidal E, Trens JM, Serafín A, Marquez M, Ferrer I.Neuronal intranuclear inclusion disease (NIID) is reported in a 16-year-old Pure Spanish breed female horse suffering from progressive ataxia and motor deficiencies. The neuropathological study revealed NIIs throughout the central nervous system, although mainly in the brain stem and spinal cord. This distribution did not correlate with neuron loss, which was marked in the hippocampus and moderate in the neocortex, particularly in the occipital cortex. As in humans, NIIs in the horse were hyaline autofluorescent inclusions composed of non-membrane-bound aggregates of filaments and fine granule...
Pusterla N, Fecteau ME, Madigan JE, Wilson WD, Magdesian KG.The medical records of 19 horses with acute hemoperitoneum were reviewed. The causes for the hemoperitoneum were idiopathic (8 horses), splenic hematoma with capsular tear (7), bleeding from the reproductive tract (3), multicentric hemangiosarcoma (1), and systemic amyloidosis (1). The affected horses were between 4 and 32 years of age (median 11.5 years). The most consistent findings on initial examination were depression, tachycardia, tachypnea, pale mucous membranes, prolonged capillary refill time, colic, and abdominal discomfort. Less common clinical signs included abdominal distention, p...
Parkinson TJ, Mogg TD, Dykgraaf S, Collett MG.An aged pony gelding presented with sudden onset of neck pain, depression and ataxia and weakness of the hindlegs, together with longer-term weight loss. Diagnostic procedures failed to isolate the cause of these signs and, despite symptomatic treatment, the animal's condition deteriorated until it required euthanasia. Unassigned: Post mortem examination revealed the presence of multiple splenic and hepatic haemangiosarcomata, with metastases to the lung and dorsal cervical muscles overlying C1 and C2 vertebrae. No lesions were present in the spinal cord, spinal column or brain. Conclusions: T...
Keegan KG, Arafat S, Skubic M, Wilson DA, Kramer J, Messer NM, Johnson PJ, O'Brien DP, Johnson G.Subjective neurological evaluation in horses is prone to bias. An objective method of spinal ataxia detection is not subject to these limitations and could be of use in equine practice and research. Objective: Kinematic data in the walking horse can differentiate normal and spinal ataxic horses. Methods: Twelve normal and 12 spinal ataxic horses were evaluated by kinematic analysis walking on a treadmill. Each body position signal was reduced to a scalar measure of uncertainty then fuzzy clustered into normal or ataxic groups. Correct classification percentage (CCP) was then calculated using m...
Ruszczyk A, Cywinska A, Banbura MW.The prevalence of Equine herpesvirus 2 (EHV-2) infections in the horse populations in Poland was investigated. Peripheral blood leukocytes (PBLs) of 139 horses were tested. The animals were divided into four groups: clinically healthy horses, horses suffering from respiratory disorders, mares with a recent abortion and horses with diagnosed ataxia. Thirty-four virus isolates were obtained from leukocytes of the tested animals by cocultivation with equine dermal cells and were identified as EHV-2 by PCR using primers for the gB gene of EHV-2 and/or primers for the sequence located upstream of t...
Fitzgerald SD, Braselton WE.Diagnostic evaluation of a mildly ataxic young gelding Quarterhorse included a contrast myelogram. Unfortunately, sodium diatrizoate was inappropriately administered by intrathecal injection resulting in severe unrelenting seizure activity and necessitated the destruction of the animal. The contrast agent was identified by analyzing cerebrospinal fluid by high-performance liquid chromatography and confirmed with probe mass spectrometric analysis. This contrast agent is highly ionic, has high osmolarity, and also blocks neurotransmission at specific receptors; for these reasons it is contraindi...
Audigié F, Tapprest J, Didierlaurent D, Denoix JM.Complications of cervical myelography arising from the puncture of the subarachnoid space to collect the cerebrospinal fluid and to inject the contrast medium have been described in humans and animals. In this study, 2 ultrasound-guided procedures were developed for puncture of the atlanto-occipital subarachnoid space, collection of cerebrospinal fluid, and injection of contrast medium. Myelography was performed on 6 ataxic horses using these procedures. The first attempt to puncture the subarachnoid space was successful in 5 horses and in one horse, a second attempt was necessary. Collection ...
Salazar P, Traub-Dargatz JL, Morley PS, Wilmot DD, Steffen DJ, Cunningham WE, Salman MD.To determine outcome of equids in the western United States with clinical signs of West Nile virus (WNV) infection and identify factors associated with risk of death in infected equids. Methods: Cross-sectional study. Methods: 484 equids in Nebraska and Colorado. Methods: Owners of 484 equids with laboratory-confirmed West Nile virus infection in Nebraska and Colorado were contacted by telephone, and a questionnaire was used to obtain information on signalment, management, clinical signs, date of disease onset, duration of disease, WNV vaccination status, and health status at the time of the i...
Ward MP, Levy M, Thacker HL, Ash M, Norman SK, Moore GE, Webb PW.To describe an outbreak of encephalomyelitis caused by West Nile virus (WNV) in horses in northern Indiana. Methods: Case series. Methods: 170 horses. Methods: Horses with clinical signs suggestive of encephalomyelitis caused by WNV were examined. Date, age, sex, breed, and survival status were recorded. Serum samples were tested for anti-WNV antibodies, and virus isolation was attempted from samples of brain tissue. Climate data from local weather recording stations were collected. An epidemic curve was constructed, and case fatality rate was calculated. Results: The most common clinical sign...
Nolen-Walston RD, D'Oench SM, Hanelt LM, Sharkey LC, Paradis MR.An 11-year-old Hanoverian-cross gelding was evaluated because of acute onset of ataxia, recumbency, and fever. At the stable, this and other horses had recently been infested with ticks. Results of analysis of a sample of CSF were within reference limits, but hematologic abnormalities included lymphopenia, thrombocytopenia, mild anemia, and intracytoplasmic inclusion bodies in neutrophils that were consistent with Anaplasma phagocytophilum (previously Ehrlichia equi). Results of serum biochemical analyses were characteristic of infection and included high, unconjugated bilirubin concentration....
Abutarbush SM, O'Connor BP, Clark C, Sampieri F, Naylor JM.Two horses had a history of ataxia and weakness or recumbency. One recovered and was diagnosed with West Nile virus (WNV) infection by serologic testing. The other was euthanized; it had meningoencephalomyelitis, WNV was detected by polymerase chain reaction. West Nile virus infection is an emerging disease. Year 2002 is the first year in which cases have been seen in Saskatchewan. Deux chevaux présentaient une histoire d’ataxie et de faiblesse ou de décubitus. Un cheval s’est rétabli et un diagnostic d’infection au virus du Nil occidental (VNO) a été posé par épreuve sérologiqu...
Baumgärtner W, Frese K, Elmadfa I.Neuroaxonal dystrophy and minimal diffuse degenerative myelopathy was diagnosed in two female full sibling, 1- and 2-year-old, Haflinger horses. Both animals developed slowly progressive ataxia from the age of 4 months. Clinical signs, which were more prominent in the hind legs, included hypermetria and dysmetria. Histological examination revealed neuroaxonal dystrophy characterized by spheroid formation, vacuolation, astrogliosis and lipofuscin pigment deposition in macrophages and neuronal perikarya. These changes were restricted to the gracilis and cuneate nuclei, nucleus of the solitary tr...
Falco MJ, Whitwell K, Palmer AC.Sixty-seven TB horses in Britain suffering from clinical wobbler disease were divided into 5 groups, based on the presence or absence of pathological lesions and their nature. These groups were compared genetically with a control group of 67 TBs known not to exhibit signs of wobbling. Though analysed for both simple and complex modes of inheritance no evidence of a genetic basis was found in any group. The high breed incidence in TBs may be real or apparent. Considerably more male than female wobblers are reported. Other forms of possibly inherited ataxia in equidae are reviewed and reference ...
Khan SA, Kuster DA, Hansen SR.Moxidectin is a macrolide endectocide available as a 2% equine oral gel in the US. This report presents clinical signs of moxidectin toxicosis and its treatment in equines as reported to the ASPCA Animal Poison Control Center (APCC) from January 1998 to December 2000. Nine cases of moxidectin overdose in equines occurred: 5 had signs of toxicosis such as coma, dyspnea, depression, ataxia, tremors, seizures, or weakness. The approximate dose of moxidectin at which these signs were observed ranged from 1.0 to 5.1 mg/kg. The 4 equines that ingested moxidectin between 0.9 mg/kg to 1.7 mg/kg did no...
Dória RG, Valadão CA, Duque JC, Farias A, Almeida RM, Netto AC.To evaluate the cardiorespiratory and behavioural effects of epidural xylazine (XYL) or clonidine (CLO) in horses. Methods: Blinded, randomized experimental study. Methods: Twelve healthy Arabian yearling horses weighing 117-204 kg were randomly allocated into two groups: XYL (n = 6) and CLO (n = 6). Methods: An epidural catheter was inserted and a facial arterial catheter was placed and the next day the horses were restrained in stocks. Baseline values for heart (HR) and respiratory (RR) rates, arterial pressure and behavioural responses were evaluated before (T0) and 10, 20, 30, 45, 60, 90 a...
Finno CJ, Johnson AL.Neuroaxonal degenerative disease in the horse is termed equine neuroaxonal dystrophy (eNAD), when pathologic lesions are localized to the brainstem and equine degenerative myeloencephalopathy (EDM) and degenerative changes extend throughout the spinal cord. Both pathologic conditions result in identical clinical disease, most commonly characterized by the insidious onset of ataxia during early development. However, later onset of clinical signs and additional clinical features, such as behavior changes, is also observed. A definitive diagnosis of eNAD/EDM requires histologic evaluation of the ...
Lorenzett MP, Pereira PR, Bassuino DM, Konradt G, Panziera W, Bianchi MV, Argenta FF, Hammerschmitt ME, Caprioli RA, de Barros CSL, Pavarini SP....Trema micrantha is a tree widely distributed throughout the Americas. The tree produces highly palatable leaves that have been associated with natural poisoning in goats, sheep and horses, in which hepatic necrosis and hepatic encephalopathy have been observed. Objective: This study describes malacia and haemorrhage in the central nervous system (CNS) due to T. micrantha consumption, with minimal to absent hepatic lesions. Methods: Retrospective case series. Methods: A total of 14 horses with a history of neurological signs and spontaneous consumption of T. micrantha leaves were submitted to...
Gericota B, Aleman M, Kozikowski TA, Pesavento P, Bollen AW, Madigan JE, Higgins RJ.A 4-year-old Dutch warmblood mare was presented with a 10-month history of ataxia and proprioceptive deficits. Computed tomography defined a large, non-contrast enhancing mass in the left cerebral hemisphere. Necropsy examination revealed a tumour that effaced much of the piriform and temporal lobes. Microscopically the lesion was classified as a grade IV glioblastoma with an oligodendroglial component (GBM-O). The tumour was composed of highly pleomorphic cells organized in different patterns within a fibrillary stroma. There were multiple foci of necrosis. At the periphery of the tumour neop...
Tomizawa N, Nishimura R, Sasaki N, Hayashi Y, Senba H, Hara S, Kadosawa T, Takeuchi A.Morphological differences between cervical vertebrae were statistically analyzed in ataxic foals to clarify abnormal structural factors in the pathogenesis of this problem. At first, multiple regression analysis and cluster analysis were performed with 28 variables in C3-C7 of 39 control foals without lameness. As a result, there were no sex differences in the growth of all cervical vertebral sites, and the most suitable categorization of the age of the foals was 3 clusters of 8 months old or younger, 9-12 months old and 13 months old or older in any sites in the cervical vertebrae. Twenty-eig...
Bak EJ, Jean YH, Woo GH.Four thoroughbred horses showing lameness, ataxia, circling, depression, recumbency, and seizures, were examined. The horses had gross, pale- to dark-red manifestations and foci in the central nervous system (CNS). Multifocal to coalescing eosinophilic necrotizing encephalomyelitis was observed histologically in the CNS along with intact or degenerated nematodes. Nematodes had polymyarian-coelomyarian musculature, a smooth thin cuticle, and intestines lined by multinucleated cells with microvilli. These traits suggested the nematodes belonged to the family Protostrongylidae, which includes Par...
Carter SW, Robertson SA, Steel CJ, Jourdenais DA.Six healthy foals underwent instrumentation for measurement of the cardiopulmonary effects of sedation with 1.1 mg/kg bodyweight xylazine hydrochloride given intravenously. Responses to xylazine in foals at 10 and 28 days of age were not significantly different. Foals became sedate and markedly ataxic, and four of the six foals became recumbent. Heart rate decreased significantly but no arrhythmias were detected. Arterial blood pressure increased initially and then fell significantly below pre-injection values. Changes in respiratory airflow, upper airway obstruction and respiratory noise were...
Rainger JE, Hughes KJ, Kessell A, Dart CM.A 3-year-old Thoroughbred colt was presented to the University Veterinary Centre Camden for evaluation of ataxia. The horse was anaesthetised to facilitate cervical radiography and myelographic examination of the spinal cord. Recovery from anaesthesia was uneventful. Five days after general anaesthesia the horse re-presented with pleuropneumonia. It was euthanased 24 hours after presentation on humane grounds. Necropsy revealed severe tracheal erosion over the middle third of the ventral surface of the trachea, pleuropneumonia and narrowing of the cervical cord between C4 and C6. It is postula...
Diamond MJ, Young LE, Bartram DH, Gregg AS, Clutton RE, Long KJ, Jones RS.Romifidine, 100 micrograms/kg administered by intravenous injection, was evaluated as a premedicant to ketamine/halothane anaesthesia in 60 horses. Sedation developed within one to two minutes. In three cases mild staggering occurred within two minutes. Anaesthesia was induced after five minutes by the intravenous administration of ketamine (2 to 2.2 mg/kg). A mean time of 79 seconds elapsed before lateral recumbency was adopted. Fifty-four of the horses sank smoothly to the floor, with occasional steps sideways. Jaw tone, limb rigidity and mild muscle tremors often persisted for short periods...
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...
Nannarone S, Giannettoni G, Laurenza C, Giontella A, Moretti G.While butorphanol is the most commonly used opioid in horses, methadone is not licensed in most countries. Our aim was to compare the effects of both drugs, combined with romifidine, regarding the quality of sedation and induction in horses undergoing elective surgery. Results indicate the suitability of both methadone and butorphanol in this patient population. Animals were scored 10 min after intravenous injection of sedatives. Despite lower overall sedation (OS) score in horses receiving methadone (p = 0.002), the quality and time of induction and intubation remained unchanged. None of the ...
Noiva R, Ruivo P, de Carvalho LM, Fonseca C, Fevereiro M, Carvalho P, Orge L, Monteiro M, Peleteiro MC.Halicephalobus gingivalis is a small saprophytic rhabditid nematode, represented only by females with a typical rhabditoid oesophagus and one egg in the uterus, capable of infecting vertebrates. This opportunistic parasite present in the soil, manure and decaying humus, is thought to penetrate through previous injuries to the mouth, eyes and skin of horses and migrate to various organs. The brain is one such organ, where the females lay their eggs, leading to malacia and causing a sudden onset of neurological signs, such as anorexia, ataxia, urinary incontinence, blindness, decreased menace an...
Slone DE, Bergfeld WA, Walker TL.A filly with ataxia and splinting and crepitation in the neck was found to have atlantoaxial subluxation. Radiographic diagnosis was based on the same criteria as those used in other species, ie, increased distance between the atlas and spine of the axis and increased distance between the dens and floor of the atlas. Extensive hemilaminectomy was performed to decompress the spinal cord. Stabilization was not attempted. Immediate postoperative response was encouraging, but the untimely death of the filly prevented further evaluation of the procedure.
Spehar AM, Hill MR, Mayhew IG, Hendeles L.Pharmacokinetic characteristics of the anticonvulsant phenobarbital were studied in seven pony and two Thoroughbred foals aged between four and 10 days. A single, 20 mg/kg bodyweight (bwt) dose of phenobarbital was given intravenously over 25 mins and the serum concentrations of the drug were measured using an EMIT AED assay (coefficient of variation 1.37 per cent at 30 micrograms/ml, n = 7). Phenobarbital elimination was found to follow first order kinetics. The mean (+/- sd) peak phenobarbital serum concentration was 18.6 +/- 2.1 micrograms/ml at 1 h after initiation of infusion with a mean ...
van Loon JP, Menke ES, Doornenbal A, Back W, Hellebrekers LJ.The objective of this study was to evaluate the safety and efficacy of low dose lumbosacral epidural ropivacaine in ponies. Antinociceptive effects of epidural ropivacaine were evaluated by means of mechanical nociceptive thresholds (MNTs) at several spinal levels in conscious ponies. The effects of ropivacaine on nociceptive afferent transmission to the spinal cord were also assessed by measuring spinal cord somatosensory evoked potentials (SSEPs) in anaesthetised ponies. Ataxia scores were determined in conscious ponies to assess the effects on motor function. A randomised, placebo controlle...
Medeiros LQ, Gozalo-Marcilla M, Taylor PM, Campagnol D, de Oliveira FA, Watanabe MJ, de Araujo Aguiar AJ.Dexmedetomidine (DEX) alone, or combined with butorphanol (BUT), may be administered by constant rate infusions (CRIs) in standing horses. This blinded, randomised, crossover study in six healthy adult horses aimed to determine the sedative and cardiopulmonary effects of DEX (dexmedetomidine (3.5 µg/kg+5 µg/kg/hour CRI) and DEX/BUT (dexmedetomidine (3.5 µg/kg+3.5 µg/kg/hour CRI) and butorphanol (20 µg/kg+24 µg/kg/hour CRI)). Head height above ground (HHAG), ataxia, responses to tactile/auditory stimuli and cardiopulmonary variables were recorded before, at 5/15/30/60/90 min...
Liu SK, Dolensek EP, Adams CR, Tappe JP.Degenerative myelopathy was diagnosed in six Mongolian wild horses. Three of the horses had a history of ataxia dating from birth to 3 months of age. The clinical signs were uncoordinated movement of the hindlimbs and an abnormally wide-based gait and stance. The other 3 horses had mild ataxia. There were no gross lesions in the brain, vertebrae, or spinal cord. Histologic examination revealed degeneration of the neural processes in the ventral and lateral funiculi of all 6 horses. Myelin sheaths were dilated and vacuolated, and there were swollen, fragmented, or lysed axons. Neuronal degenera...
Journée SL, Journée HL, Reed SM, Berends HI, de Bruijn CM, Delesalle CJG.Adhesive surface electrodes are worthwhile to explore in detail as alternative to subcutaneous needle electrodes to assess myogenic evoked potentials (MEP) in human and horses. Extramuscular characteristics of both electrode types and different brands are compared in simultaneous recordings by also considering electrode impedances and background noise under not mechanically secured (not taped) and taped conditions. Methods: In five ataxic and one non-ataxic horses, transcranial electrical MEPs, myographic activity, and noise were simultaneously recorded from subcutaneous needle (three brands) ...
Finno CJ, Kaese HJ, Miller AD, Gianino G, Divers T, Valberg SJ.A pigment retinopathy has been reported in adult horses with equine motor neuron disease (EMND) arising from chronic α-tocopherol (α-TP) deficiency. A pigment retinopathy has not been identified in horses with neuroaxonal dystrophy/equine degenerative myeloencephalopathy (NAD/EDM) that affects genetically susceptible young horses with α-TP deficiency. The objective of this report is to describe, for the first time, a pigment retinopathy in a family of α-TP-deficient Warmbloods (WB) with clinically apparent NAD/EDM or EMND. Unassigned: Twenty-five WB horses from one farm underwent complete ...
Gangl M, Grulke S, Detilleux J, Caudron I, Serteyn D.Forty-eight horses subjected to elective surgery were randomly assigned to three groups of 16 horses. After premedication with 0.1 mg/kg acepromazine intramuscularly and 0.6 mg/kg xylazine intravenously, anaesthesia was induced either with 2 g thiopentone in 500 ml of a 10 per cent guaifenesin solution, given intravenously at a dose of 1 ml/kg (group TG), or with 100 mg/kg guaifenesin and 2.2 mg/kg ketamine given intravenously (group KG), or with 0.06 mg/kg midazolam, and 2.2 mg/kg ketamine given intravenously (group KM). Anaesthesia was maintained with isoflurane. The mean (sd) end tidal isof...
Dyson S, Quiney L, Phillips K, Zheng S, Aleman M.Radiological observations at the cervicothoracic junction in horses with or without related clinical signs have not been comprehensively described. The aim was to evaluate the seventh cervical (C7) to second thoracic (T2) vertebrae in horses with neck-related clinical signs (neck pain and/or stiffness, neck-related forelimb lameness, or general proprioceptive [spinal] ataxia) and control horses. This prospective analytical cross-sectional study included 127 control horses and 96 cases, examined using standardized clinical and radiological protocols. Univariable logistic regression was used to ...
Willems DS, Kranenburg LC, Ensink JM, Kummeling A, Wijnberg ID, Veraa S.Congenital portosystemic shunts in foals are rare and only a small number of cases have been described. Detailed description of the course of the shunt is lacking in earlier reports. This is the first detailed description of a computed tomography angiography (CTA) displaying an extra-hepatic splenocaval shunt. A 1-month old colt showing increasing signs of dullness, ataxia, circling, lip-smacking and coordination problems was presented. Hyperammonemia was detected and abdominal CTA revealed an extra-hepatic portocaval shunt. During surgery, ligation of the abnormal vessel could not be achieved...
Buonanno AM, Carlson GP, Kantrowitz B.Portosystemic shunt was diagnosed in a 6-month-old Quarter Horse filly with acute onset of apparent blindness and a 3-month history of depression, lethargy, and ataxia. Clinicopathologic test results indicated slightly high gamma-glutamyl transpeptidase activity and serum total bilirubin concentration. Sulfobromophthalein half time was prolonged, and plasma ammonia and serum bile acid concentrations were high as well. Histopathologic findings of percutaneous liver biopsy included widespread hepatocyte atrophy and numerous prominent small arterioles in the area of the portal triad. On the basis...
Dorman DC, Haschek WM.Toxicosis attributable to propylene glycol (1,2-propanediol) was suspected in an 8-year-old 450- to 500-kg male Quarter Horse. Clinical signs of toxicosis developed within 15 minutes of the accidental iatrogenic oral administration of 3.8 L of propylene glycol. Clinical signs of toxicosis included salivation, sweating, ataxia, and signs of pain. Additionally, at 24 hours after propylene glycol ingestion, the horse became increasingly atactic, had an abnormal breath odor, developed rapid shallow breathing, and was cyanotic. The horse died of apparent respiratory arrest 28 hours after the propyl...
