Search Results

You are looking at 1 - 7 of 7 items for

  • Author or Editor: Thomas D. Brown x
  • Refine by Access: All Content x
Clear All Modify Search

Abstract

Case Description—A 2-year-old spayed female domestic shorthair cat was examined because of bilateral thoracic limb weakness of acute onset.

Clinical Findings—Clinical signs included muscle atrophy, paresis, depressed spinal reflexes, hyperesthesia of the thoracic limbs, and reduced jaw muscle tone. Pelvic limb reflexes were normal. Results of a neurologic examination were suggestive of multifocal lesions involving both brachial plexuses and the trigeminal nerves. Abnormal nerve conduction across the brachial plexus and delayed late potentials were found on electrodiagnostic testing, and diffuse subclinical involvement of other regions of the peripheral nervous system was confirmed on the basis of abnormal electromyographic findings for the masticatory muscles and conduction block of the peroneal nerve.

Treatment and Outcome—No specific treatments were given, and neurologic signs resolved within a month. A relapse occurred 2 months after the first episode, with clinical signs affecting both the pelvic and the thoracic limbs on this occasion. Again, the condition resolved without specific treatment, and 13 months after the initial episode, the cat reportedly was normal.

Conclusions and Clinical Relevance—Findings suggested that brachial plexus neuropathy can be a multifocal disease in cats, even if clinically apparent neurologic deficits are initially subtle or absent, and that electrodiagnostic techniques can be used to identify subclinical involvement of the peripheral nerves.

Restricted access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine the effects of syringomyelia on electromyography (EMG) findings, somatosensory-evoked potentials (SEPs), and transcranial magnetic motor-evoked potentials (TMMEPs) in Cavalier King Charles Spaniels (CKCSs).

Animals—27 client-owned CKCSs that underwent prebreeding magnetic resonance imaging screening or investigation of clinical signs consistent with syringomyelia.

Procedures—In dogs with (n = 11) and without (16) magnetic resonance imaging-confirmed syringomyelia, the median nerve in each thoracic limb was stimulated and SEPs were recorded over the C1 vertebra; onset latency and latency and amplitude of the largest negative (N1) and positive (P1) peaks were measured. The TMMEPs were recorded bilaterally from the extensor carpi radialis and tibialis cranialis muscles; onset latencies in all 4 limbs were measured. Bilateral systematic needle EMG examination was performed on the cervical epaxial musculature, and the number of sites with spontaneous activity was recorded.

Results—In dogs with syringomyelia, amplitudes of N1 and P1 and the amplitude difference between P1 and N1 were significantly smaller than those recorded for dogs without syringomyelia (approx 2-fold difference). No difference in SEP latencies, TMMEP latencies, or the proportion of dogs with > 2 sites of spontaneous activity detected during EMG examination was detected between groups.

Conclusions and Clinical Relevance—Results indicated that SEP amplitude at the C1 vertebra was a more sensitive measure of spinal cord function in CKCSs with syringomyelia, compared with results of EMG or TMMEP assessment. Measurement of SEP amplitude may have use as an objective assessment of the evolution and treatment of this disease.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To characterize the temporality of dates of breeding and abortion classified as mare reproductive loss syndrome (MRLS) among mares with abortions during early gestation.

Animals—2,314 mares confirmed pregnant at approximately 28 days after breeding from 36 farms in central Kentucky, including 515 mares that had earlyterm abortions.

Procedure—Farm veterinarians and managers were interviewed to obtain data for each mare that was known to be pregnant to determine pregnancy status, breeding date, last date known to be pregnant, and date of abortion.

Results—Mares bred prior to April 1, 2001, appeared to be at greatest risk of early-term abortion, both among and within individual farms. Mares bred in mid-February appeared to be at greatest risk of abortion, with an estimated weekly incidence rate of abortion of 66% (95% CI, 52% to 80%).

Conclusions and Clinical Relevance—Mares in central Kentucky bred between mid-February and early March were observed to be at greatest risk of early-term abortion, and risk gradually decreased to a background incidence of abortion of approximately 11%. Mares bred after April 1, 2001, appeared to be at markedly less risk, indicating that exposure to the cause of MRLS likely occurred prior to this date. (Am J Vet Res 2005;66:1792–1797)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To estimate spatial risks associated with mare reproductive loss syndrome (MRLS) during 2001 among horses in a specific study population and partition the herd effects into those attributable to herd location and those that were spatially random and likely attributable to herd management.

Animals—Pregnant broodmares from 62 farms in 7 counties in central Kentucky.

Procedure—Veterinarians provided the 2001 abortion incidence proportions for each farm included in the study. Farms were georeferenced and data were analyzed by use of a fully Bayesian risk-mapping technique.

Results—Large farm-to-farm variation in MRLS incidence proportions was identified. The farm-to-farm variation was largely attributed to spatial location rather than to spatially random herd effects

Conclusions and Clinical Relevance—Results indicate that there are considerable data to support an ecologic cause and potential ecologic risk factors for MRLS. Veterinary practitioners with more detailed knowledge of the ecology in the 7 counties in Kentucky that were investigated may provide additional data that would assist in the deduction of the causal factor of MRLS via informal geographic information systems analyses and suggest factors for inclusion in further investigations. (Am J Vet Res 2005;66:17–20)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To compare signalment of horses with cervical vertebral malformation-malarticulation (CVM) with that of control horses and to describe results of clinical examination, diagnostic imaging and necropsy findings, and reported outcome in horses with CVM.

Design—Retrospective case-control study.

Animals—270 horses with CVM and 608 control horses admitted to 6 veterinary hospitals from 1992 through 2007.

Procedures—Medical records of participating hospitals were reviewed to identify horses with CVM (ie, case horses) and contemporaneous control (non-CVM-affected) horses that were admitted for treatment. Signalment was compared between case horses and control horses. Results of clinical examination, laboratory and diagnostic imaging findings, necropsy results, and outcome were assessed for horses with CVM.

Results—Case horses were younger (median age, 2 years) than were control horses (median age, 7 years). Thoroughbreds, warmbloods, and Tennessee Walking Horses were overrepresented in the CVM group. Gait asymmetry and cervical hyperesthesia were frequently detected in horses with CVM. Vertebral canal stenosis and articular process osteophytosis were commonly observed at necropsy; agreement between the results of radiographic or myelographic analysis and detection of lesions at necropsy was 65% to 71% and 67% to 78%, respectively. Of 263 horses with CVM for which outcome was recorded, 1 died and 172 (65.4%) were euthanatized.

Conclusions and Clinical Relevance—Odds of a diagnosis of CVM were greater in young horses and horses of specific breeds. Detection of gait asymmetry and cervical hyperesthesia were frequently reported in association with CVM. Accurate diagnosis of lesions associated with CVM by use of radiography and myelography can be challenging. (J Am Vet Med Assoc 2010;237:812-822)

Restricted access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To identify factors associated with abortions during early gestation classified as mare reproductive loss syndrome (MRLS).

Design—Case-control study.

Animals—324 broodmares from 43 farms in central Kentucky, including 121 mares from 25 farms that had early-term abortions (ETAs) associated with MRLS (case horses), 120 mares from the same farms but that did not abort, and 83 mares from 18 farms that were not severely impacted by MRLS.

Procedure—Farm managers were interviewed to obtain data on various management practices and environmental exposures for the mares. Data for case and control horses were compared to identify risk factors for mares having MRLS-associated ETAs.

Results—Several factors increased the risk of MRLS-associated ETAs, including feeding hay in pasture, greater than usual amounts of white clover in pastures, more eastern tent caterpillars in pastures, abortion during a previous pregnancy, and sighting deer or elk on the premises.

Conclusions and Clinical Relevance—Analysis indicates that certain characteristics of pastures predisposed mares to MRLS-associated ETAs. Methods for limiting exposure to pasture (keeping mares in stalls longer) during environmental conditions similar to those of 2001 (ie, sudden freezing in mid-April following warmer-than-usual springtime temperatures and larger-than-usual numbers of eastern tent caterpillars in and around pastures) should reduce the risk of mares having MRLS-associated ETAs. It was not possible to determine whether exposure to white clover or caterpillars were causal factors for MRLS or were merely indicators of unusual environmental conditions that resulted in exposure of mares to a toxic or infectious agent. (J Am Vet Med Assoc 2003;222:210–217)

Restricted access
in Journal of the American Veterinary Medical Association