Brainstem and cranial nerve abnormalities: listeriosis, otitis media/interna, and pituitary abscess syndrome

Brain Abscesses in Domestic Ruminants: Clinicopathological and Bacteriological Approaches

Brain abscesses in ruminants often arise from primary infection foci, leading to an unfavorable prognosis for affected animals. This highlights the need for comprehensive studies on brain abscesses across different ruminant species. We retrospectively investigated medical records of epidemiological, clinical, neuroimaging, anatomopathological, and bacteriological findings in six ruminants (three goats, two cows, and one sheep) diagnosed with brain abscesses. All animals studied were female. Apathy (50%), compulsive walking (33%), decreased facial sensitivity (33%), head pressing (33%), seizures (33%), semicomatous mental status (33%), strabismus (33%), unilateral blindness (33%), and circling (33%) represented the most common neurologic signs. Leukocytosis and neutrophilia were the main findings in the hematological evaluation. Cerebrospinal fluid (CSF) analysis revealed predominant hyperproteinorrachia and pleocytosis. In three cases, computed tomography or magnetic resonance imaging were used, enabling the identification of typical abscess lesions, which were subsequently confirmed during postmortem examination. Microbiological culture of the abscess samples and/or CSF revealed bacterial coinfections in most cases. Advanced imaging examinations, combined with CSF analysis, can aid in diagnosis, although confirmation typically relies on postmortem evaluation and isolation of the causative agent. This study contributes to clinicopathological aspects, neuroimages, and bacteriological diagnosis of brain abscesses in domestic ruminants.

Intracranial inflammatory polyp with cerebellopontine compression and leptomeningitis secondary to chronic otitis in a red kangaroo

CNS lesions associated with chronic otitis have not been reported in red kangaroos (Macropus rufus), to our knowledge. Here we describe an intracranial inflammatory polyp secondary to chronic otitis in a 6-y-old female red kangaroo with right auricular discharge, loss of balance, and head tilt. Autopsy highlighted a pale-yellow, firm, intracranial polypoid growth that extended from the right tympanic cavity through the internal acoustic meatus and intracranially, with compression of the right cerebellopontine angle. Anaerobic bacterial culture yielded Bacteroides pyogenes from fresh brain and a right external ear swab. Histologically, the tympanic cavity was effaced by neutrophils and macrophages surrounded by lymphocytes and plasma cells, as well as edematous fibrovascular tissue. The epithelial lining of the mucoperiosteum was hyperplastic, with epithelial pseudoglands surrounded by fibrovascular tissue. Areas of temporal bone lysis and remodeling were associated with the inflammatory changes, which occasionally surrounded adjacent nerves. Fibrovascular tissue and inflammatory cells extended from the tympanic cavity through the internal acoustic meatus and into the intracranial cavity, forming the polypoid growth observed grossly; the polyp consisted of a dense core of fibrovascular tissue with scattered clusters of neutrophils and foamy macrophages. Lymphocytes and plasma cells surrounded the leptomeningeal perivascular spaces in the brainstem, cerebellum, and occipital lobe.

Risk factors associated with outcome in goats with encephalitic listeriosis: A retrospective study of 36 cases from 2008 to 2021

BACKGROUND

There exists a scarcity of information on risk factors associated with case outcomes in goats diagnosed with encephalitic listeriosis.

OBJECTIVE

Evaluate risk factors associated with outcomes in 36 cases of suspected encephalitic listeriosis in goats presented to a referral hospital.

ANIMALS

Thirty-six goats (26 does, 7 bucks, and 3 wethers) were presented to Auburn University Large Animal Teaching Hospital between 2008 and 2021 for treatment of neurologic disease diagnosed as encephalitic listeriosis based on any combination of clinical signs, cerebral spinal fluid (CSF) analysis, or postmortem examination.

METHODS

Retrospective study. Data were analyzed as binary and under a proportional odds model. The medical records were searched for presumptive encephalitic listeriosis in goats between 2008 and 2021. Data collected included signalment (sex, age, and breed), history, clinical signs, temperature, and ability to stand at presentation. Final diagnosis, CSF results, all treatments, outcomes, and results of necropsy were also collected for analysis.

RESULTS

Male goats were 14 (95% CI: 1.98-166.0) times more likely to be a non-survivor compared to females despite being presented with similar history, clinical signs, and treatments. Animals presented with circling or a history of circling were 6.24 (95% CI: 1.40-23.21) times more likely to be a survivor than a non-survivor. Other risk factors evaluated were not significantly associated with outcomes.

CONCLUSIONS AND CLINICAL IMPORTANCE

Few risk factors were associated with outcomes. Duration of clinical signs, antimicrobial or anti-inflammatory choices, or CSF results were not associated with outcome. Only sex and history or presence of circling were associated with case outcomes.

A novel machine learning-based web application for field identification of infectious and inflammatory disorders of the central nervous system in cattle

BACKGROUND

Central nervous system (CNS) infections in cattle are a major cause of economic loss and mortality. Machine learning (ML) techniques are gaining widespread application in solving predictive tasks in both human and veterinary medicine.

OBJECTIVES

Our primary aim was to develop and compare ML models that could predict the likelihood of a CNS disorder of infectious or inflammatory origin in neurologically-impaired cattle. Our secondary aim was to create a user-friendly web application based on the ML model for the diagnosis of infection and inflammation of the CNS.

ANIMALS

Ninety-eight cattle with CNS infection and 86 with CNS disorders of other origin.

METHODS

Retrospective observational study. Six different ML methods (logistic regression [LR]; support vector machine [SVM]; random forest [RF]; multilayer perceptron [MLP]; K-nearest neighbors [KNN]; gradient boosting [GB]) were compared for their ability to predict whether an infectious or inflammatory disease was present based on demographics, neurological examination findings, and cerebrospinal fluid (CSF) analysis.

RESULTS

All 6 methods had high prediction accuracy (≥80%). The accuracy of the LR model was significantly higher (0.843 ± 0.005; receiver operating characteristic [ROC] curve 0.907 ± 0.005 ) than the other models and was selected for implementation in a web application.

CONCLUSION AND CLINICAL IMPORTANCE

Our findings support the use of ML algorithms as promising tools for veterinarians to improve diagnosis. The open-access web application may aid clinicians in achieving correct diagnosis of infectious and inflammatory neurological disorders in livestock, with the added benefit of promoting appropriate use of antimicrobials.

Diagnostic and Therapeutic Evaluations of Computed Tomography in Three Calves with Unilateral Otitis Media Treated with Ventral Bulla Osteotomy

This case report describes the clinical utility of computed tomography (CT) in preoperative evaluation of otitis media in three calves, each exhibiting unilateral head tilt and ear droop. Of the three animals examined by CT, right-sided and left-sided involvements of this disease could be diagnosed in two animals and one animal, respectively, as represented by the accumulations of hyperattenuating contents within the extended tympanic bulla. These cases were treated with a ventral bulla osteotomy, which was conducted between the sternothyroid muscle and the omohyoid muscle via an incision made caudally to the area of the thyroid cartilage. The postoperative outcome was satisfactory in one case. However, the remaining two cases showed unsatisfactory outcomes; one calf died on the 10th postoperative day, as it was already seriously ill. The other animal died suddenly during surgery, potentially due to stimulation of the vagus nerve. The use of CT could allow effective visualization of unilateral lesions, proving helpful for the recommendation of surgical intervention. Based on the unfavorable results in two cases, we note that to prevent surgical complications, the clinical applicability of CT such as the creation of severity criteria and development of imaging-assist procedure should be advanced.

Listeria monocytogenes at the interface between ruminants and humans: A comparative pathology and pathogenesis review

The bacterium Listeria monocytogenes (Lm) is widely distributed in the environment as a saprophyte, but may turn into a lethal intracellular pathogen upon ingestion. Invasive infections occur in numerous species worldwide, but most commonly in humans and farmed ruminants, and manifest as distinct forms. Of those, neuroinfection is remarkably threatening due to its high mortality. Lm is widely studied not only as a pathogen but also as an essential model for intracellular infections and host-pathogen interactions. Many aspects of its ecology and pathogenesis, however, remain unclear and are rarely addressed in its natural hosts. This review highlights the heterogeneity and adaptability of Lm by summarizing its association with the environment, farm animals, and disease. It also provides current knowledge on key features of the pathology and (molecular) pathogenesis of various listeriosis forms in naturally susceptible species with a special focus on ruminants and on the neuroinvasive form of the disease. Moreover, knowledge gaps on pathomechanisms of listerial infections and relevant unexplored topics in Lm pathogenesis research are highlighted.

Intracranial abscess formation in an adult alpaca: a case report

Background

Intracranial abscess formation is an extremely rare and sporadically documented disease in South American Camelids (SACs). Herein we report the first case of otogenic brain abscess formation in this species.

Case presentation

A 4 years old female alpaca was presented to our veterinary hospital with a 6 month history of neurologic disorder symptoms, mainly head tilt to the right and emaciation. A comprehensive workup (ultrasound and computed tomography) revealed irreversible cranial nerve abnormalities, extensive lesions in the region of external, middle and internal right ear including destruction of bony structures (tympanic bulla, parts of temporal bone) and severe brain deformation caused by an intracranial abscess. The lesion was up to 6x7x4 cm and occupying almost 40% of the cranial cavity. No pathological findings were evident in other organs or structures. The late referral of the alpaca at this advanced stage of destructive disease precluded surgical intervention.

Conclusions

This case report describes the clinical signs, diagnostic procedures and pathological findings in an adult female alpaca suffering from cranial nerve abnormalities caused by a massive otogenic brain abscess. Camelids suffering from otitis may not present with clinical signs until the pathology is severe. The importance of considering intracranial abscess formation as differential diagnosis in SACs showing the merest hint of nerve deficits cannot be emphasized enough in order to diagnose such pathological processes at an early and treatable stage.

Pituitary Abscesses in Four Free-ranging White-tailed Deer ( Odocoileus virginianus)

Although intracranial abscesses are a well-recognized cause of morbidity and mortality in free-ranging white-tailed deer ( Odocoileus virginianus), reports of pituitary abscesses in this species are scarce. Pituitary abscesses were the cause of neurologic disease in four adult white-tailed deer from the southeastern US in 2013-15.

Diagnóstico diferencial das doenças neurológicas dos bovinos no estado do Paraná

RESUMO: O objetivo deste trabalho foi identificar as doenças neurológicas que acometeram bovinos no estado do Paraná entre os anos de 2009 e 2015. A investigação aconteceu, preferencialmente, nas propriedades rurais onde os casos ocorreram. Foram registradas as informações sobre a evolução das doenças nos bovinos afetados do rebanho, e os prováveis fatores de risco foram identificados. Todos os procedimentos de exame físico geral e neurológico foram realizados sistematicamente para a caracterização da síndrome neurológica presente. Amostras de sangue e de líquor foram colhidas para a realização de exames laboratoriais. De acordo com o tempo de evolução e com a gravidade dos sinais clínicos observados, os bovinos doentes eram mantidos vivos para acompanhamento da evolução ou da resposta ao tratamento, ou eram submetidos à eutanásia seguida de necropsia. Fragmentos do sistema nervoso e dos demais órgãos foram colhidos para exame histopatológico. O exame de imunofluorescência direta e a prova biológica em camundongos foram realizados em todos os bovinos que morreram, com a finalidade de confirmar ou descartar o diagnóstico de raiva. Métodos laboratoriais específicos das rotinas de virologia, bacteriologia e toxicologia foram empregados, como complementares, para o estabelecimento do diagnóstico diferencial. Foram investigados 236 bovinos com doença neurológica, sendo 85 casos de ocorrência individual e 151 casos distribuídos por surtos que ocorreram em 79 rebanhos. As encefalopatias (180/236; 76,2%) predominaram sobre as mielopatias (27/236; 11,4%). As doenças inflamatórias determinadas por infecções (98/236; 41,5%) e as doenças tóxicas (91/236; 38,6%) foram as principais, enquanto as causas degenerativas (10/236; 4,2%), metabólicas (9/236; 3,8%), físicas (9/236; 3,8%), neoplásicas (4/236; 1,7%), e os defeitos congênitos (1/236; 0,4%) ocorreram menos frequentemente. Os casos inconclusivos somaram 5,9% (14/236). A meningoencefalite por BoHV-5 e a raiva foram as doenças de frequência maior e podem ser consideradas as mais importantes. Dentre as causas tóxicas, as intoxicações por plantas se destacaram (63/91; 69,2%) e foram responsáveis por 26,6% de todos os casos. Destacaram-se ainda a polioencefalomalácia, a meningoencefalite trombótica por Histophilus somni e o botulismo. Essas informações contribuem para que os médicos veterinários adotem condutas mais efetivas de diagnóstico e de prevenção, e são valiosas para o sistema oficial de vigilância epidemiológica do estado.

Suppurative infectious diseases of the central nervous system in domestic ruminants

ABSTRACT: This study describes suppurative infectious diseases of the central nervous system (CNS) in domestic ruminants of southern Brazil. Reports from 3.274 cattle, 596 sheep and 391 goats were reviewed, of which 219 cattle, 21 sheep and 7 goats were diagnosed with central nervous system inflammatory diseases. Suppurative infectious diseases of the CNS corresponded to 54 cases (28 cattle, 19 sheep and 7 goats). The conditions observed consisted of listerial meningoencephalitis (8 sheep, 5 goats and 4 cattle), suppurative leptomeningitis and meningoencephalitis (14 cattle, 2 goats and 1 sheep), cerebral (6 cattle and 2 sheep), and spinal cord (7 sheep) abscesses, and basilar empyema (4 cattle and 1 sheep). Bacterial culture identified Listeria monocytogenes (9/54 cases), Escherichia coli (7/54 cases), Trueperella pyogenes (6/54 cases) and Proteus mirabilis (1/54 cases). All cases diagnosed as listeriosis through histopathology yielded positive immunostaining on immunohistochemistry, while 12/17 of the cases of suppurative leptomeningitis and meningoencephalitis presented positive immunostaining for Escherichia coli. Meningoencephalitis by L. monocytogenes was the main neurological disease in sheep and goats, followed by spinal cord abscesses in sheep. In cattle, leptomeningitis and suppurative meningoencephalitis was the most frequent neurological disease for the species, and E. coli was the main cause of these lesions. Basilar empyema, mainly diagnosed in cattle, is related to traumatic injuries, mainly in the nasal cavity, and the main etiologic agent was T. pyogenes.

Detection and DNA quantification of Enterococcus casseliflavus in a foal with septic meningitis

CASE DESCRIPTION A 3-month-old 180-kg (396-lb) Hanoverian colt was examined because of fever, lethargy, inappetence, drooping of the left ear, and stiff neck posture. Initial treatment included empirical antimicrobial treatment and NSAIDs. CLINICAL FINDINGS Initial findings were consistent with CNS anomalies. Endoscopy revealed hyperemia, ecchymosis, and some mucopurulent exudate in the right guttural pouch. Hematologic findings were consistent with neutrophilic inflammation. On the third day of hospitalization, severe neurologic signs were observed. Computed tomography of the skull revealed a comminuted fracture of the axial aspect of the right mandibular condyle. Examination of CSF revealed turbidity, xanthochromia, and intracellular and extracellular cocci, consistent with septic meningitis. After DNA extraction from blood and CSF, sequenced products from a PCR assay for the bacterial 16S rRNA gene were 99% identical to Enterococcus casseliflavus. Microbial culture of CSF and blood samples yielded bacteria with Enterococcus spp morphology; antimicrobials were selected on the basis of susceptibility testing that identified the isolate as vancomycin resistant. A quantitative PCR assay was used to estimate Enterococcus DNA concentrations in CSF and blood. TREATMENT AND OUTCOME Treatment for E casseliflavus meningitis, including trimethoprim-sulfadiazine and ampicillin sodium administration, resulted in resolution of clinical signs. Culture of CSF and blood samples after 12 days of the targeted treatment yielded no growth. CLINICAL RELEVANCE To the authors' knowledge, this was the first report of E casseliflavus meningitis in a horse. Treatment was successful; vancomycin-resistant enterococci can be a clinical problem and may potentially be zoonotic.

Hyponatremia as the Presenting Feature of a Pituitary Abscess in a Calf

A 2-month-old Simmental heifer presented for acute onset of neurological behavior. Laboratory tests confirmed the presence of hyponatremia, hypochloremia, and hypokalemia that improved with intravenous fluid therapy. Despite an initial cessation of neurological signs, symptoms re-emerged, and the heifer was euthanized due to poor prognosis. A pituitary abscess (Trueperella pyogenes) was observed on gross necropsy, suggesting that the effects of panhypopituitarism (inappropriate anti-diuretic hormone (ADH), adrenocorticotropic hormone (ACTH), and/or thyroid-stimulating hormone (TSH) secretion) may have resulted in the clinical findings. Pituitary abscess syndrome carries a poor prognosis due to the inability to penetrate the area with systemic antibiotic therapy. These findings highlight the unusual clinical presentations that may occur following pituitary abscess syndrome in cattle that practitioners need to consider when determining prognosis.

Brainstem and Cranial Nerve Disorders of Ruminants

Asymmetrical signs of brainstem disease occur relatively infrequently in ruminants. The most common differential diagnoses include listeriosis, otitis media/interna, and pituitary abscess syndrome. Although these conditions produce signs of brainstem dysfunction, the diseases can usually be differentiated based on historical findings and subtle clinical differences. Basic laboratory diagnostic tests are often not specific in the definitive diagnosis but may be supportive. Advanced imaging techniques have proven to be useful in the diagnosis of otitis media/interna. Presumptive clinical diagnosis is confirmed at necropsy. Treatment involves a prolonged course of antibiotic therapy but is unrewarding in cases of pituitary abscess syndrome.

[Pituitary syndrome caused by neoplasia in a 17-month-old Holstein Friesian heifer]

A 17-month-old Holstein Friesian heifer was presented after one day with dysphagia, slight paralysis of the tongue and swelling of the eyelids. Clinical examination of the animal revealed an extended posture of the head and neck, severely increased salivation, reduced lingual tone and mandibular paralysis with complete absence of the swallowing reflex. The right eye showed a drooping eyelid, mucopurulent discharge, exposure keratitis, corneal opacity and miosis. On the left side, a moderate exophthalmos and slight mucous discharge from the nostril were observed. Neurological examination revealed the absence of multiple cranial nerve reflexes suggesting a pituitary syndrome. On X-rays, a soft-tissue opacity with sharp margins and a diameter of approximately 5 cm was seen. It was located ventral to the ethmoid bone with possible intraneurocranial origin. Rhinoscopically, a mass located distal to the ethmoid bone with an uneven, slightly reddish surface partly covered by purulent exudate was visualised. Post-mortem examination of the euthanized animal confirmed neoplasia, which ranged from the fossa hypophysialis of the corpus ossis basisphenoidalis to the ethmoid bone. Histopathologic findings matched a small, round, blue cell tumour.

Clinical-pathological findings of otitis media and media-interna in calves and (clinical) evaluation of a standardized therapeutic protocol

Background

The aims of this field trial were to describe the clinical-pathologic findings in calves with otitis media (OM) and media-interna (OMI), to evaluate, through the development of a scoring system, the effectiveness of a standardized therapeutic protocol, and to identify the causative pathogens and their possible correlation with concurrent respiratory disease. All animals underwent physical and neurological examinations at three experimental time points: at diagnosis/beginning of treatment (T0), 1 week (T1) and 2 weeks (T2) after therapy was started, respectively. Follow-up telephone interviews with animal owners were conducted 1 month later. The therapeutic protocol consisted of tulathromycin (Draxxin®; Zoetis), oxytetracycline hydrochloride (Terramicina 100®; Zoetis), and carprofen (Rimadyl®; Zoetis).

Results

Twenty-two calves were enrolled. Physical and otoscopic examination at T0 revealed monolateral and bilateral otorrhea in 16 and 6 calves, respectively, with peripheral vestibular system involvement in calves presenting with neurological signs (n = 17; 77 %). A significant improvement of clinical and neurological scores was observed in 20 (90 %) calves, a full recovery in only 1 (5 %). One calf worsened between T0 and T1 and it was removed from the study. None of the other animals showed a worsening of clinical conditions and/or required further treatments at one month follow up. Mycoplasma bovis was isolated in 89 % of the affected ears either alone or together with P. multocida (n = 5), Streptococcus spp. (n = 1), Staphylococcus spp. (n = 1), and Pseudomonas spp. (n = 1). M. bovis either alone or together with these bacteria was also isolated from the upper and/or lower respiratory tract in 19 (86 %) calves.

Conclusions

This is the first prospective study to evaluate the effectiveness of a standardized therapeutic protocol for the treatment of OM/OMI in calves. The therapy led to clinical improvement in the majority of the calves. Persistence of mild clinical-neurological signs did not compromise productive performance. The numerical scoring system for clinical and neurological signs permitted objective evaluation of response to therapy. M. bovis was the pathogen most often isolated. This finding should be considered in the treatment of OM/OMI in calves. Moreover, respiratory tract infection should not be underrated, since it is one of the major risk factors for the development of OM/OMI.

Validation of an ultrasound imaging technique of the tympanic bullae for the diagnosis of otitis media in calves

Background

Otitis media is a common disease in calves that can be subclinical, making antemortem on‐farm diagnosis challenging.

Objectives

To evaluate the sensitivity and specificity of ultrasonography of tympanic bullae for the diagnosis of clinical and subclinical otitis media and to evaluate the reproducibility of the technique.

Animals

Forty calves 19–50 days of age were selected from a veal calf farm.

Methods

Prospective study. Ultrasonography was first performed on the farm by ultrasonographer A (US A). Ultrasonography was repeated by ultrasonographer A (US A') and another ultrasonographer (US B) at the Centre Hospitalier Universitaire Vétérinaire. Images were later reread by both examiners and a diagnosis was recorded. The calves were euthanized and submitted for necropsy, and histopathologic diagnosis was used as the gold standard.

Results

Forty‐five bullae were affected by otitis media and 35 bullae were normal. Sensitivity and specificity of the ultrasound technique ranged from 32 to 63% and 84 to 100%, respectively, depending on the examiner and classification of suspicious ultrasonography results. Kappa analysis to evaluate interobserver agreement between A' and B yielded a к value of 0.53. Agreement within the same examiner (A versus A') yielded a к value of 0.48, and real‐time ultrasound versus rereading of recorded images for A' and B yielded к values of 0.58 and 0.75, respectively.

Conclusions

Sensitivity and specificity of the ultrasound imaging technique are, respectively, low and high for diagnosis of clinical and subclinical otitis media in calves, with moderate reproducibility.

Bacterial meningitis after sinus surgery in five adult horses

OBJECTIVE

To report meningoencephalitis as a complication after paranasal sinus surgery in 5 horses.

STUDY DESIGN

Case series.

ANIMALS

Adult horses (n = 5).

METHODS

Medical records (2005-2010) of 5 horses that developed neurologic signs after sinus surgery were reviewed to identify potential risk factors, cause(s), or common pathways for infection.

RESULTS

Underlying diseases were primary (n = 1) and secondary sinusitis (4) because of apical dental infection (1), sinus cyst (2), or masses in the ethmoturbinate region (2). Horses were treated by conventional surgical approaches and aftercare including repeated sinus lavage. Four horses had undulating pyrexia postoperatively despite antimicrobial therapy. All horses developed neurologic signs, eventually unresponsive to treatment. Suppurative meningoencephalitis was diagnosed macro- and/or microscopically on necropsy in all horses.

CONCLUSION

Meningitis is a rare but fatal complication after sinus surgery in horses.

A retrospective study of brain lesions in goats submitted to three veterinary diagnostic laboratories

A retrospective study of brain lesions in goats was conducted to identify the range of lesions and diseases recognized and to make recommendations regarding the best tissues to examine and tests to conduct in order to maximize the likelihood of making a definitive diagnosis in goats that may have had clinical signs referable to the brain. One hundred thirty-nine goats with a brain lesion were identified. The most common lesion, in 52.5% of the goats, was suppurative inflammation. Approximately two-thirds of these goats had encephalitic listeriosis. Other goats were found to have suppurative inflammation in association with septicemia, pituitary abscesses, dehorning injury, and otitis. Thirty goats (21.6%) were diagnosed with polioencephalomalacia. Twenty-one goats (15.1%) were diagnosed with nonsuppurative inflammation. In more than half of these goats, no definitive diagnosis was made, while 8 were infected with Caprine arthritis encephalitis virus and 1 with Rabies virus. However, few goats were tested for rabies. Based on these findings, it is recommended that, in addition to appropriate handling of the brain, the head should be examined with attention paid to the sella turcica and the temporal bones for evidence of a pituitary abscess and otitis, respectively. Histologic examination should include multiple areas of the brain, including the brainstem, for lesions of encephalic listeriosis; the cerebral cortex, for lesions of polioencephalomalacia; and the hippocampus, for Negri bodies associated with Rabies virus infection. Consideration should be given to collecting samples of other tissues including, but not limited to, the spinal cord and liver for ancillary testing if warranted.

Diagnostic exercise: suppurative rhombencephalitis and meningitis in a goat

A 1-year-old female Boer goat was presented for necropsy following spontaneous death and history of acute recumbency, nystagmus, and sialorrhea. A swollen area was grossly observed in the brainstem at the level of the pons. On cut surface, the right cerebellar peduncles were expanded by a focal, pale, poorly demarcated, slightly depressed, and soft area of malacia. Microscopically, this area contained diffuse edema and necrosis, with microabscesses, neuronal necrosis, neuronophagia, axonal spheroids, vasculitis, and perivascular accumulations of lymphocytes, plasma cells, macrophages, and neutrophils. The diagnosis was based on the morphologic findings, fluorescent antibody test results, and special staining.

Neuropathology and diagnostics in food animals

Diseases of the central nervous system (CNS) are relatively common in food animals. Potential causes include infectious agents, nutritional deficiencies, metabolic disorders, genetic defects, toxins, and idiopathic causes. Determining the correct etiologic diagnosis often depends on a thorough postmortem examination and collection of samples. This article reviews some of the steps and procedures necessary to collect the necessary information on CNS diseases in food animals. Techniques for the examination of the CNS are briefly described, and some of the gross pathology likely to be encountered in a food animal practice is reviewed.

Síndrome do abscesso pituitário em bezerros na Região Centro-Oeste

A síndrome do abscesso pituitário é uma doença neurológica responsável por casos esporádicos e surtos, principalmente em bezerros, ocasionando alto índice de mortalidade. Descreve-se a ocorrência e os achados clínicos, laboratoriais e anátomo-patológicos em três bezerros com síndrome do abscesso pituitário no Centro-Oeste do Brasil. Os animais tinham 8-11 meses de idade e os sinais clínicos mais marcantes relacionaram-se aos sinais nervosos de origem cerebral e do tronco encefálico com evolução clínica de 7-20 dias. A hematologia revelou leucocitose por neutrofilia e hiperfibrinogenemia. A análise do líquido céfalo-raquidiano apresentou pleocitose neutrofílica. Arcanobacterium pyogenes foi isolado do líquido céfalo-raquidiano. Um dos bezerros apresentou recuperação após antibioticoterapia. A mortalidade foi de 66,6% (2/3). Os achados de necropsia consistiram em um único abscesso de localização parapituitária ou situado no parênquima da glândula; um dos bezerros apresentou rinite necrosante e outro, broncopneumonia abscedativa. O exame histológico do sistema nervoso central revelou ausência quase completa do tecido hipofisário normal, devido à necrose extensa e infiltrado inflamatório neutrofílico difuso concomitante. Reitera-se a importância da realização de práticas de manejo adequadas a fim de reduzir a incidência de inúmeras enfermidades, principalmente em bezerros, dentre elas a síndrome do abscesso pituitário.

Mycoplasma bovis Infections in young calves

Mycoplasma bovis has emerged as an important pathogen of young intensively reared calves in North America. A variety of clinical diseases are associated with M bovis infections of calves, including respiratory disease, otitis media, arthritis, and some less common presentations. Clinical disease associated with M bovis often is chronic, debilitating, and poorly responsive to antimicrobial therapy. Current control measures are centered on reducing exposure to M bovis through contaminated milk or other sources, and nonspecific control measures to maximize respiratory defenses of the calf. This article focuses on the clinical and epidemiologic aspects of M bovis infections in young calves.

Cerebrospinal fluid findings in cattle with central nervous system disorders: a retrospective study of 102 cases (1990-2008)

BACKGROUND

Cerebrospinal fluid (CSF) analysis is routinely used to aid in the diagnosis of central nervous system (CNS) disease in animals. There is little comprehensive information available on the diagnostic utility of CSF analysis in cattle.

OBJECTIVES

The purpose of this retrospective study was to review the characteristic CSF findings of specific CNS diseases in cattle.

METHODS

Medical records of cattle in which CSF analysis had been performed between 1990 and 2008 were reviewed. Cattle were included in the study if they had a confirmed diagnosis of CNS disease (based on clinical signs, laboratory testing, and/or histopathologic results). Cattle were categorized as having infectious or noninfectious causes of CNS disease and subgrouped based on specific disease diagnosis. CSF results were summarized and compared using nonparametric statistical tests.

RESULTS

Data from 102 cattle, mostly female Holsteins, were included in the study. Bacterial infections, particularly listeriosis and neonatal meningitis, were the most common cause of CNS disease. Neonatal meningitis was characterized by a marked, predominantly neutrophilic, pleocytosis. Mild mononuclear pleocytosis was typical of listeriosis, but was also seen with abscesses, viral infections, salt poisoning, and trauma. Variable CSF results were seen in cattle with otitis-related meningitis and thromboembolic meningoencephalitis. CSF results were usually normal with toxic, metabolic, degenerative, and neoplastic disorders.

CONCLUSIONS

CSF analysis is a useful adjunctive test for the diagnosis of CNS diseases in cattle. When interpreted together with signalment and clinical signs, CSF results can assist clinicians in the antemortem diagnosis of specific bovine CNS disorders.