Extended durotomy to treat severe spinal cord injury after acute thoracolumbar disc herniation in dogs.

OBJECTIVE: To report recovery of ambulation of dogs treated with extended thoracolumbar durotomy for severe spinal cord injury caused by intervertebral disc herniation. STUDY DESIGN: Descriptive cohort. ANIMALS: Twenty-six consecutive paraplegic dogs presented with loss of deep pain sensation after acute thoracolumbar intervertebral disc herniation. METHODS: Each dog underwent routine diagnostic assessment and surgery for removal of extradural herniated intervertebral disc, followed by a four-vertebral body length durotomy centered on the herniated disc. Each dog was followed up until it was able to walk 10 steps without assistance or until 6 months after surgery. RESULTS: Sixteen of 26 dogs recovered to walk unaided (all but one also recovered fecal and urinary continence), and six dogs did not; four dogs were lost to follow-up. One dog was euthanized because of signs consistent with progressive myelomalacia. There was no evidence of detrimental effects of durotomy within the period of study. Using Bayesian analysis, we found a point estimate of successful outcome of 71% with 95% credible interval from 52% to 87%. CONCLUSION: Extended durotomy seemed to improve the outcome of dogs in our case series without increase in morbidity. CLINICAL SIGNIFICANCE: Extended durotomy appears safe and may improve the outcome of dogs with severe thoracolumbar mixed contusion and compressive injuries associated with acute intervertebral disc extrusion.

Selected Clinical Features of Coccidioidomycosis in Dogs.

Canine coccidioidomycosis, a systemic fungal infection endemic to arid and semiarid regions of North, Central, and South America, is commonly diagnosed in dogs living in or traveling through lower Sonoran life zones in the states of California and Arizona. Canine and human cases have geographic overlap. Similarities between clinical coccidioidomycosis in dogs and humans include asymptomatic infection, primary respiratory disease and disseminated disease. Differences include a high rate of dissemination in dogs, differences in predilection of dissemination sites, and a granulomatous or diffuse meningoencephalopathic form in the canine central nervous system (CNS) without the obstructive component seen in humans. Dogs presenting with CNS coccidioidomycosis most commonly experience seizures. Prior disease history and serology are unreliable indicators of CNS coccidioidomycosis. Magnetic resonance imaging (MRI) is advantageous for diagnosis of CNS coccidioidomycosis in dogs. Long-term administration of antifungal medication is promoted for treatment of both primary and disseminated coccidioidomycosis in dogs. Supportive treatment addressing pain, fever, inappetance, coughing, and other clinical signs improves patient care. Glucocorticoids and or anticonvulsants are also recommended for canine disseminated CNS disease. Protracted treatment times, lack of owner compliance, failure of the disease to respond to the first antifungal drug selected, and high cost are challenges of successfully treating dogs.

Shunt tube placement for amelioration of cerebrospinal fluid flow obstruction caused by spinal cord subarachnoid fibrosis in dogs.

OBJECTIVE: To describe a novel technique for ameliorating cerebrospinal fluid flow obstruction secondary to pia-arachnoid fibrosis in dogs and report outcome. STUDY DESIGN: Descriptive report and retrospective case series. ANIMALS: Dogs with cerebrospinal fluid (CSF) flow obstruction (n = 7). METHODS: Medical records were searched for dogs that had a subarachnoid-subarachnoid shunt placed for treatment of CSF flow obstruction. Data collected included age, sex, breed, clinical signs and duration of signs prior to examination, neurologic status and localization prior to surgery, pre-surgical diagnostics, surgical technique, histopathology, postoperative neurologic examination, time to discharge from hospital, and outcome. RESULTS: All dogs were diagnosed at surgery with a fibrotic adhesion between the arachnoid and pia mater. A subarachnoid shunting tube was implanted to allow CSF flow across the lesion site. Five dogs showed improvement of clinical signs, 3 of which showed complete recovery and 2 of which showed improvement without resolution of all clinical signs. Two dogs showed no change at 7 and 24 months postoperatively. CONCLUSION: Bridging a region of pia-arachnoid fibrosis with a tube placed in the subarachnoid space can ameliorate or prevent progression of associated clinical signs.

The effects of topical oxygen therapy on equine distal limb dermal wound healing.

Topical oxygen therapy (TOT) has been used in human medicine to promote healing in chronic wounds. To test the efficacy and safety of TOT in horses, an experimental wound model was created by making 1 standardized dermal wound on each limb of 4 healthy horses (n = 16). Each wound was fitted with an oxygen delivery cannula and covered with a bandage. One limb of each front and hind pair was randomly assigned to the treatment group (fitted with an oxygen concentrator device), with the contralateral limb assigned to the control group (no device). Wound area, epithelial area, and contraction were measured every 3 to 4 d. Biopsy samples and culture swabs were taken on days 16 and 32 to evaluate angiogenesis, fibroplasia, epithelial hyperplasia, inflammation and bacterial growth. Mean healing time in treated wounds (45 d, range: 38 to 52 d) was not significantly different from that in the paired control wounds (50 d, range: 38 to 62 d). Topical oxygen therapy had little effect on dermal wound healing in this experimental wound model in healthy horses.

Effets de la thérapie à l'oxygène topique sur la guérison des blessures cutanées des membres distaux équins. La thérapie à l'oxygène topique (TOT) a été utilisée en médecine humaine pour traiter les blessures chroniques. Afin de tester l'efficacité et l'innocuité de la TOT chez les chevaux, un modèle de blessure expérimental a été créé en pratiquant une blessure cutanée normalisée chez 4 chevaux en santé (n = 16). Chaque blessure a été équipée d'une canule de distribution d'oxygène et couverte d'un pansement. Une jambe avant et une jambe arrière ont été assignées au hasard au groupe de traitement (équipée d'un dispositif de concentration d'oxygène) et la jambe controlatérale a été assignée au groupe témoin (aucun dispositif). La région de la blessure, la région épithéliale et les contractions ont été mesurées tous les 3 ou 4 jours. Des biopsies et des écouvillons pour culture bactérienne ont été prélevés aux jours 16 et 32 afin d'évaluer l' angiogenèse, la fibroplasie, l'hyperplasie épithéliale, l'inflammation et la croissance bactérienne. La durée moyenne de guérison des blessures traitées (45 jours, écart : de 38 à 52 jours) n'était pas significativement différente de celle des blessures témoins (50 jours, écart : de 38 à 62 jours). La thérapie à l'oxygène topique a eu peu d'effet sur la guérison des blessures dans ce modèle de blessure expérimentale chez des chevaux en santé.(Traduit par Isabelle Vallières).

Syringohydromyelia in horses: 3 cases.

Syringomyelia and hydromyelia are cavitary lesions of the spinal cord that may be acquired or congenital. These lesions are not frequently reported in large animal species. The presenting complaints, clinical, gross pathological, and histopathologic findings of 2 cases of syringomyelia and 1 case of hydromyelia in horses are described.

The utility of Coccidioides antigen and antibody detection in cerebrospinal fluid in the diagnosis of canine central nervous system coccidioidomycosis.

OBJECTIVE: To evaluate the utility of enzyme immunoassays (EIAs) for the detection of Coccidioides antigen and antibody in CSF in the diagnosis of CNS coccidioidomycosis in dogs. ANIMALS: 51 dogs evaluated for CNS disease in a single specialty center in Tucson in 2016. PROCEDURES: Excess CSF after routine analysis was banked after collection from dogs presented to the neurology service. Samples were tested by EIA for presence of Coccidioides antigen and antibody. Clinical data were collected from medical records retrospectively. RESULTS: 22 dogs were diagnosed with CNS coccidioidomycosis (CCM) or another neurologic disease (non-CCM). These groups of dogs overlapped in the presenting complaints, MRI results, and routine CSF analysis results. Four dogs, all with CCM, had positive antigen EIA results. With clinical diagnosis used as the reference standard, CSF antigen testing had low sensitivity (20%) but high specificity (100%) for diagnosis of CCM. Ten dogs with CCM and 4 dogs with other diagnoses had antibody detected in CSF by EIA. Sensitivity of CSF antibody testing was 46%, specificity was 86%, and positive and negative predictive values for the study population were 71% and 68%, respectively. CLINICAL RELEVANCE: Diagnosis of CNS coccidioidomycosis in dogs in an endemic region was hampered by overlap of clinical signs with other neurologic disorders and the low sensitivity of confirmatory diagnostics. The evaluated Coccidioides-specific EIAs performed on CSF can aid in the diagnosis. A prospective study is warranted to corroborate and refine these preliminary findings.

Physiologic effects of nasopharyngeal administration of supplemental oxygen at various flow rates in healthy neonatal foals.

OBJECTIVE: To evaluate the effects of various flow rates of oxygen administered via 1 or 2 nasal cannulae on the fraction of inspired oxygen concentration (FIO2) and other arterial blood gas variables in healthy neonatal foals. ANIMALS: 9 healthy neonatal (3- to 4-day-old) foals. PROCEDURES: In each foal, a nasal cannula was introduced into each naris and passed into the nasopharynx to the level of the medial canthus of each eye; oxygen was administered at 4 flow rates through either 1 or both cannulae (8 treatments/foal). Intratracheal FIO2, intratracheal end-tidal partial pressure of carbon dioxide, and arterial blood gas variables were measured before (baseline) and during unilateral and bilateral nasopharyngeal delivery of 50, 100, 150, and 200 mL of oxygen/kg/min. RESULTS: No adverse reactions were associated with administration of supplemental oxygen except at the highest flow rate, at which the foals became agitated. At individual flow rates, significant and dose-dependent increases in FIO2, PaO2, and oxygen saturation of hemoglobin (SaO2) were detected, compared with baseline values. Comparison of unilateral and bilateral delivery of oxygen at similar cumulative flow rates revealed no differences in evaluated variables. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that administration of supplemental oxygen via nasal cannulae appeared to be a highly effective means of increasing FIO2, PaO2, and SaO2 in neonatal foals. These findings may provide guidance for implementation of oxygen treatment in hypoxemic neonatal foals.

Baseline plasma cortisol and ACTH concentrations and response to low-dose ACTH stimulation testing in ill foals.

OBJECTIVE: To evaluate baseline plasma cortisol and ACTH concentrations and responses to low-dose ACTH stimulation testing in ill foals. DESIGN: Cross-sectional study. ANIMALS: 58 ill foals. PROCEDURES: Baseline cortisol and ACTH concentrations and cortisol concentrations after administration of a low dose of cosyntropin were determined within 6 hours after admission. Foals were assigned to 4 groups on the basis of age (

Multinodular pulmonary fibrosis in five horses.

CASE DESCRIPTION: 5 horses were evaluated because of decreased appetite, weight loss, fever, cough, tachypnea, and respiratory distress. CLINICAL FINDINGS: Tachycardia, tachypnea, increased respiratory effort, lethargy, fever, poor body condition, and nasal discharge were detected in various combinations on initial physical examination. Evaluation of the lower portion of the respiratory tract via radiography and ultrasonography revealed a severe nodular interstitial pattern. Histologic examination of lung tissue revealed interstitial expansion of alveolar parenchyma with collagen, intraluminal accumulation of neutrophils and macrophages within the alveoli, and occasional intranuclear inclusion bodies within alveolar macrophages. Equine herpesvirus type 5 was detected in samples of lung tissue, bronchoalveolar lavage fluid, or both via polymerase chain reaction assay in all cases. A diagnosis of equine multinodular pulmonary fibrosis (EMPF) was established. TREATMENT AND OUTCOME: Horses were provided supportive treatment and were administered a variety of medications including corticosteroids and acyclovir. Two horses survived and returned to their previous level of activity. Three horses were euthanized because of either deterioration of clinical condition (n=2) or failure to improve within 4 weeks of initiation of treatment (1). CLINICAL RELEVANCE: EMPF should be considered as a differential diagnosis for adult horses with interstitial pneumonia and should be suspected on the basis of characteristic radiographic, ultrasonographic, and histopathologic findings. Equine herpesvirus type 5 is found in association with EMPF; although the exact pathogenic role this virus plays in EMPF is unknown, equine herpesvirus type 5 may be an etiologic agent or cofactor in the development of EMPF.

The Association of Specific Constituents of the Fecal Microbiota with Immune-Mediated Brain Disease in Dogs.

Meningoencephalomyelitis of unknown origin (MUO) is a common, naturally-occurring, clinical disease of pet dogs. It is an immune-mediated condition that has many similarities with experimental autoimmune encephalitis (EAE) in rodents and so investigation of its pathogenesis may aid in understanding factors that contribute to development of multiple sclerosis in people. Gut microbiota are known to modulate immune responses that influence susceptibility to immune-mediated brain disease. In this study we aimed to compare abundance of specific constituents of the fecal microbiota, namely Faecalibacterium prausnitzii and Prevotellaceae, between dogs diagnosed with MUO and matched controls. Fecal samples were obtained from 20 dogs diagnosed with MUO and 20 control dogs matched for breed, age and gender. Bacterial abundance was measured using qPCR and 16S rRNA sequencing. We found that Prevotellaceae were significantly less abundant in cases compared with controls (p = 0.003) but there was no difference in abundance of F.prausnitzii. There was no evidence of other differences in gut microbiota between groups. These data, derived from this naturally-occurring canine clinical model, provide strong corroborative evidence that high abundance of Prevotellaceae in the gut is associated with reduced risk for developing immune-mediated brain disease.

Factors associated with recovery from paraplegia in dogs with loss of pain perception in the pelvic limbs following intervertebral disk herniation.

OBJECTIVE: To investigate associations between recovery of locomotion and putative prognostic factors in dogs with loss of deep pain perception in the pelvic limbs caused by intervertebral disk herniation (IVDH). DESIGN: Prospective cohort study. ANIMALS: 78 client-owned dogs evaluated for IVDH that underwent spinal decompression surgery. PROCEDURES: Dogs with complete loss of deep pain perception in the pelvic limbs and tail underwent routine examinations, advanced imaging, and spinal decompression surgery in accordance with standards of practice and owner consent. For each dog, information was prospectively collected on duration of clinical signs prior to onset of paraplegia; delay between onset of paraplegia and initial referral evaluation; date of recovery of locomotion, death, or euthanasia (3-month follow-up period); and whether dogs had received corticosteroid drugs before surgery. Severity of spinal cord compression at the lesion epicenter was measured via CT or MRI. RESULTS: 45 of 78 (58%) of dogs recovered the ability to ambulate independently within 3 months after spinal decompression surgery. No evidence of prognostic value was identified for any of the investigated factors; importantly, a greater delay between onset of paraplegia and referral evaluation was not associated with a poorer prognosis. CONCLUSIONS AND CLINICAL RELEVANCE: In this group of dogs with IVDH, immediacy of surgical treatment had no apparent association with outcome. The prognosis for recovery may instead be strongly influenced by the precise nature of the initiating injury.

Macrophage effector responses of horses are influenced by expression of CD154.

Reactive intermediates contribute to innate immunity by providing phagocytes with a mechanism of defense against bacteria, viruses and parasites. To better characterize the role of CD154 in the production of reactive intermediates, we cloned and expressed recombinant equine CD154 (reqCD154) in Chinese Hamster Ovary (CHO). In co-culture experiments, CHO cells ectopically expressing reqCD154 elicited superoxide production in monocyte-derived macrophages (MDM). Collectively, our results indicate that regulation of CD154 expression plays a role in innate host defenses.

Effects of intravenous administration of polymyxin B in neonatal foals with experimental endotoxemia.

OBJECTIVE: To evaluate the effect of IV administration of polymyxin B on clinical and serum biochemical variables in foals with experimental endotoxemia. DESIGN: Prospective experimental study. ANIMALS: 14 healthy neonatal foals. PROCEDURES: Foals were randomly assigned to a treatment or control group and were administered a single dose of lipopolysaccharide (0.5 µg/kg [0.23 µg/lb]) IV over 30 minutes. The treatment group received polymyxin B (6,000 U/kg [2,727 U/lb], IV) immediately after completion of lipopolysaccharide infusion; the control group was administered an equal volume of saline (0.9% NaCl) solution. Subsequent doses of polymyxin B or saline solution were administered IV at 8 and 16 hours. Blood was collected at various time points, and outcome variables, including heart rate, respiratory rate, rectal temperature, attitude score, WBC count, neutrophil count, lymphocyte count, monocyte count, platelet count, Hct, blood lactate concentration, blood glucose concentration, serum tumor necrosis factor-α concentration, and plasma thromboxane B2 concentration, were measured. Urine was collected prior to and after experimentation to determine whether nephrotoxicosis was associated with treatment. RESULTS: The treatment group had significantly lower blood lactate concentration and serum tumor necrosis factor-α and plasma thromboxane B2 concentrations and had higher blood glucose concentrations and better attitude scores, compared with the control group, at various time points during the study. No other significant differences and no evidence of overt nephrotoxicosis were detected. CONCLUSIONS AND CLINICAL RELEVANCE: Administration of polymyxin B IV in healthy neonatal foals challenged with lipopolysaccharide attenuated some clinical and serum biochemical derangements associated with endotoxemia.

Alloimmune neonatal neutropenia and neonatal isoerythrolysis in a Thoroughbred colt.

A 3-day-old Thoroughbred colt was originally presented for treatment of neonatal isoerythrolysis, which was treated with a blood transfusion. However, persistent neutropenia was observed despite the absence of detectable infection. Subsequently, a granulocyte agglutination test was performed by incubating the colt's neutrophils with the mare's serum; results were positive, leading to a clinical diagnosis of alloimmune neonatal neutropenia. The diagnosis was further supported via flow cytometric analysis. The colt was hospitalized and treated prophylactically with antimicrobials and 4 separate doses of recombinant human granulocyte colony-stimulating factor (rhG-CSF; 1.4-3.5 µg/kg, subcutaneously) in attempts to maintain the neutrophil count within reference intervals over a 4-week period. The colt's neutrophil count increased after administration of rhG-CSF and eventually stabilized within reference intervals by day 20. The colt maintained normal neutrophil counts after discharge and was reportedly healthy at 6 months of age. Alloimmune neonatal neutropenia should be considered in foals with persistent neutropenia in the absence of infection. Alloimmune neonatal neutropenia can be treated with prophylactic antimicrobials combined with rhG-CSF with a favorable outcome.

Agreement between arterial partial pressure of carbon dioxide and saturation of hemoglobin with oxygen values obtained by direct arterial blood measurements versus noninvasive methods in conscious healthy and ill foals.

OBJECTIVE: To determine agreement between indirect measurements of end-tidal partial pressure of carbon dioxide (PetCO(2)) and saturation of hemoglobin with oxygen as measured by pulse oximetry (SpO(2)) with direct measurements of PaCO(2) and calculated saturation of hemoglobin with oxygen in arterial blood (SaO(2)) in conscious healthy and ill foals. DESIGN: Validation study. ANIMALS: 10 healthy and 21 ill neonatal foals. PROCEDURES: Arterial blood gas analysis was performed on healthy and ill foals examined at a veterinary teaching hospital to determine direct measurements of PaCO(2) and PaO(2) along with SaO(2). Concurrently, PetCO(2) was measured with a capnograph inserted into a naris, and SpO(2) was measured with a reflectance probe placed at the base of the tail. Paired values were compared by use of Pearson correlation coefficients, and level of agreement was assessed with the Bland-Altman method. RESULTS: Mean ± SD difference between PaCO(2) and PetCO(2) was 0.1 ± 5.0 mm Hg. There was significant strong correlation (r = 0.779) and good agreement between PaCO(2) and PetCO(2). Mean ± SD difference between SaO(2) and SpO(2) was 2.5 ± 3.5%. There was significant moderate correlation (r = 0.499) and acceptable agreement between SaO(2) and SpO(2). CONCLUSIONS AND CLINICAL RELEVANCE: Both PetCO(2) obtained by use of nasal capnography and SpO(2) obtained with a reflectance probe are clinically applicable and accurate indirect methods of estimating and monitoring PaCO(2) and SaO(2) in neonatal foals. Indirect methods should not replace periodic direct measurement of corresponding parameters.

Anaphylaxis and systemic inflammatory response syndrome induced by inadvertent intravenous administration of mare's milk in a neonatal foal.

OBJECTIVE: To describe the diagnostic procedures, therapeutic management and successful outcome of a case of anaphylaxis induced by the inadvertent intravenous (IV) administration of mare's milk to a neonatal foal. CASE SUMMARY: A 3-day-old Thoroughbred colt was presented for treatment of bilateral flexural limb deformities of the forelimbs. Because the foal was unable to ambulate initially, mare's milk was administered via nasoesophageal tube feedings during treatment of the musculoskeletal disorder. Anaphylaxis resulted after unintentional administration of a bolus of 150mL of mare's milk through a jugular catheter. Aggressive therapy for anaphylaxis and careful monitoring resulted in the successful recovery of the foal after 9 days of intensive care. NEW OR UNIQUE INFORMATION PROVIDED: This case is the first published report to describe the effects of accidental IV administration of mare's milk to a neonatal foal. Medical errors are commonly reported in pediatric medicine; the intent of this report is to raise awareness of medical errors and student education in equine medicine as well as describe the therapy and outcome of anaphylaxis induced by IV administration of mare's milk in a neonatal foal.

Adrenocorticotropic hormone stimulation tests in healthy foals from birth to 12 weeks of age.

The purpose of this study was to investigate total baseline plasma cortisol and adrenocorticotropic hormone (ACTH) concentrations, and ACTH-stimulated cortisol concentrations in foals from birth to 12 wk of age. Plasma (baseline) cortisol and ACTH concentrations were measured in 13 healthy foals at birth and at 1, 2, 3, 4, 5, 7, 10, 14, 21, 28, 42, 56, and 84 d of age. Each foal received cosyntropin (0.1 microg/kg) intravenously. Plasma cortisol concentrations were measured before (baseline), and 30, and 60 min after cosyntropin administration at birth and at 3, 5, 7, 10, 14, 21, 28, 42, 56, and 84 d of age. Compared with baseline, cortisol concentration increased significantly 30 min after administration of cosyntropin on all days. Cortisol concentration was highest at birth, measured at 30 and 60 min after cosyntropin administration, compared with all other days. With the exception of birth measurements, cortisol concentration was significantly higher on day 84, measured at 30 and 60 min after cosyntropin administration, when compared with all other days. Baseline plasma ACTH was lowest at birth when compared with concentrations on days 2, 3, 4, 5, 7, 10, 14, 42, 56, and 84. Administration of 0.1 microg/kg of cosyntropin, IV, reliably induces cortisol secretion in healthy foals. Differences in the magnitude of response to cosyntropin are observed depending on the age of the foal. These data should serve as a reference for the ACTH stimulation test in foals and should be useful in subsequent studies to evaluate the hypothalamic-pituitary-adrenal axis in healthy and critically ill foals.