Idiopathic eosinophilic meningoencephalitis in a Dutch Warmblood gelding

An increased content of eosinophils in cerebrospinal fluid (CSF) and eosinophilic infiltration of brain tissue are observed in eosinophilic meningoencephalitis (EME). After exclusion of various infectious diseases and further known causes of EME in other species, the diagnosis idiopathic EME was made at necropsy in the case reported here. To the authors' knowledge, this is the first report of idiopathic EME in a horse similar to the disorder occurring in dogs.     

Cytologic interpretation of canine cerebrospinal fluid samples with low total nucleated cell concentration,with and without blood contamination

Background: Cerebrospinal fluid (CSF) is potentially altered by iatrogenic blood contamination at the time of sampling due to the addition of blood‐associated leukocytes and protein. Objectives: The objective of this study was to assess whether protein concentration, neutrophil percentage, and the presence of activated macrophages, reactive lymphocytes, or eosinophils in CSF samples with low total nucleated cell concentration (TNCC) are affected by blood contamination or associated with central nervous system (CNS) disease. Methods: Case records from the Royal Veterinary College Diagnostic Laboratory were searched retrospectively for dogs with CSF having ≤5 TNCC/μL. TNCC, RBC, and protein concentrations; neutrophil percentage; and the presence of activated macrophages, reactive lymphocytes, and eosinophils were recorded. Results of magnetic resonance imaging (MRI) also were recorded as a marker of CNS disease. Results: Of 906 cases evaluated, 106 (12%) had blood contamination (>500 RBCs/μL) in CSF. Protein concentration and neutrophil percentage were significantly higher and the presence of eosinophils was more likely in blood contaminated vs noncontaminated samples. Non‐blood‐contaminated samples with activated macrophages or reactive lymphocytes had higher protein concentrations and neutrophil percentages, and those with activated macrophages were more likely to have a positive finding on MRI. Conclusions: Protein concentration, neutrophil percentage, and the presence of eosinophils are significantly affected by blood contamination in canine CSF having low TNCC. Activated macrophages and reactive lymphocytes are not affected by blood contamination, however, and may be useful in identifying dogs with CNS abnormalities.     

Cerebrospinal Fluid Analysis and Clinical Outcome of Eight Dogs With Eosinophilic Meningoencephalomyelitis

Eight dogs, 14 weeks to 5.5 years of age, had signs of diffuse or multifocal meningoencephalomyelitis. The total white cell counts of the cerebrospinal fluid (CSF) ranged from 11 to 5,550 cells/microliters; the percentage of eosinophils ranged from 21% to 98%. The total CSF protein content range was 19 to 1,430 mg/dl. On necropsy, two dogs had granulomatous encephalomyelitis due to protozoan infection. The other six dogs, of which three were Golden Retriever dogs, appeared to have an idiopathic eosinophilic meningoencephalitis; four of these dogs recovered. The significance of eosinophils in CSF and the possible emergence of a new encephalitic syndrome of dogs involving a hypersensitivity to an unknown agent is also discussed.     

Concentrations of acute-phase proteins in dogs with steroid responsive meningitis-arteritis

Background: Measurement of concentrations of acute-phase proteins (APPs) is used as an aid in the diagnosis of a variety of diseases in animals.
Objective: To determine the concentration of APPs in dogs with steroid responsive meningitis-arteritis (SRMA) and other neurologic diseases.
Animals: One hundred and thirty-three dogs with neurologic diseases, 6 dogs with sepsis, and 8 healthy dogs were included in the study. Thirty-six dogs had SRMA (31 of which had monitoring), 14 dogs had other meningoencephalitides (ME), 32 had disk disease (IVDD/DLSS), 26 had tumors affecting the central nervous system (TCNS), and 25 had idiopathic epilepsy (IE).
Methods: Prospective, observational study: C-reactive protein (CRP), α₂-macroglobulin (AMG), and albumin concentrations were determined in the serum or plasma. CRP was also measured in the cerebrospinal fluid.
Results: Serum CRP was significantly higher in dogs with SRMA (     = 142 μg/mL ± 75) and sepsis (     = 114 μg/mL ± 67) in comparison with dogs with other neurologic diseases (     = 2.3–21 μg/mL; P < .001). There was no significant difference detected in AMG between groups. Serum albumin concentration was significantly lower ( P < .01) in dogs with SRMA (     = 3.2 g/dL ± 0.41) than in other groups (     = 3.6–3.9 g/dL). Serum CRP concentration of SRMA dogs correlated with alkaline phosphatase levels ( r = 0.515, P = .003).
Conclusions and Clinical Importance: CRP concentrations in serum are useful in diagnosis of dogs with SRMA. Serum CRP could be used as a monitoring parameter in treatment management of these dogs.     

Clinical Evaluation of a Novel Liquid Formulation of L-Thyroxine for Once Daily Treatment of Dogs with Hypothyroidism

Background: A liquid solution of levothyroxine (L-T4) is available for treatment of canine hypothyroidism.
Hypothesis: Once daily oral administration of a liquid L-T4 solution is effective and safe for controlling hypothyroidism in dogs.
Animals: Thirty-five dogs with naturally occurring hypothyroidism.
Methods: Dogs received L-T4 solution PO once daily at a starting dosage of 20 μg/kg body weight (BW). The dose was adjusted every 4 weeks, based on clinical signs and peak serum total T4 (tT4) concentrations. Target peak serum tT4 and thyroid stimulating hormone (TSH) concentrations, 4–6 hours posttreatment, were 35–95 nmol/L and < 0.68 ng/mL, respectively. Dogs were followed for up to 22 weeks after establishment of the maintenance dose.
Results: Clinical signs of hypothyroidism improved or resolved in 91% of dogs after 4 weeks of L-T4 treatment at 20 μg/kg once daily. The maintenance dose was established in 76, 94, and 100% of dogs after 4, 8, and 12 weeks of treatment, respectively. This was 20 μg L-T4/kg BW for 79% of the dogs, 30 μg/kg BW for 15%, and 10–15 μg/kg BW in the remaining 6%, once daily. Thereafter, median peak tT4 and TSH concentrations were 51 nmol/L and 0.18 ng/mL, respectively, and remained stable during the 22-week follow-up; clinical signs did not recur.
Conclusions and Clinical Importance: All of the hypothyroid dogs had rapid clinical and hormonal responses to supplementation with the PO-administered L-T4 solution. The starting dosage of 20 μg L-T4/kg BW once daily was suitable for 79% of dogs.     

Significance of surface epithelial cells in canine cerebrospinal fluid and relationship to central nervous system disease

Background: The term “surface epithelium” is used to describe cells, including meningeal, choroid plexus, ependymal, and endothelial cells, that are found in human cerebrospinal fluid (CSF) and are difficult to distinguish cytologically. We hypothesized that the presence of surface epithelial cells in canine CSF was associated with specific diseases of the central nervous system (CNS). Objectives: In this retrospective study the frequency of surface epithelial cells in CSF from dogs with neurologic disease was investigated along with the potential association with age, specific type of CNS disease, and CSF total nucleated cell count (TNCC) and protein concentration. Methods: The frequency of surface epithelial cells in 359 canine CSF samples was analyzed for 5 disease groups: CNS neoplasia, CNS compression, CNS inflammation, idiopathic epilepsy, and miscellaneous diseases. Groups were also combined into those with and without expected meningeal involvement. Association of the presence of surface epithelial cells in CSF with age, disease type, and CSF TNCC and protein concentration was investigated. Results: Surface epithelial cells were found in 27 of 359 (7.5%) CSF samples: CNS neoplasia 2/30 (6.7%), CNS compression 7/64 (10.9%), CNS inflammation 1/39 (2.6%), idiopathic epilepsy 8/124 (6.5%), and miscellaneous diseases 9/102 (8.8%). Significant associations between surface epithelial cell presence in CSF and age, disease type, CSF TNCC, and CSF protein concentration were not found. Conclusions: The presence of surface epithelial cells was not related to a specific disease group or CSF changes in the studied population. Thus, the presence of surface epithelial cells should be interpreted carefully, as it could represent an incidental finding in CSF specimens.     

Thyroid testing in Sloughis

Background: Thyroid hormone concentrations were found to be different in Greyhounds and Whippets compared with nonsight hound dogs.
Hypothesis: In Sloughis, thyroid hormone concentration is lower than in nonsight hounds and comparable to Greyhounds.
Animals: Fifty-one Sloughis with no evidence of disease and a mean age of 4 years (range, 1–12 years).
Methods: Thyroid profiles consisting of total thyroxine (tT4), free thyroxine (fT4), free thyroxine after equilibrium dialysis (fT4 after ED), canine thyroid stimulation hormone (cTSH), and thyroglobulin antibodies as well as CBC and serum biochemistry results of Sloughis were compared with those of normal dogs. In 8 Sloughis, TSH stimulation tests were performed.
Results: In Sloughis, tT4 concentrations and fT4 concentrations measured by chemiluminescence were lower than those of controls (1.13 ± 0.65 μg/dL compared with 2.9 ± 0.8 μg/dL, P < .0001 and 11 ± 4.3 pmol/L compared with 16.7 ± 5.2 pmol/L, P < .0001, respectively). Concentrations of fT4 after ED and TSH were increased in Sloughis, when compared with controls (41.3 ± 26.9 pmol/L compared with 20.98 ± 10.29 pmol/L, P < .0001 and 0.22 ± 0.15 pmol/L compared with 0.15 ± 0.13 pmol/L, P = .0138, respectively). T4 concentration after TSH stimulation increased from 1.5 μg/dL (range, 0.2–2.7 μg/dL) to 2.7 μg/dL (range, 1.2–4.7 μg/dL); the recommended post-TSH T4 concentration was achieved by only 3 of 8 Sloughis. Hemoconcentration was found in 84.3% and hypoglobulinemia in 80.3%.
Conclusions and Clinical Importance: When evaluating Sloughis for hypothyroidism, veterinarians should be aware that these dogs have different thyroid hormone concentrations than nonsight hound dogs.     

Prothrombotic and Inflammatory Effects of Intravenous Administration of Human Immunoglobulin G in Dogs

Background: Intravenous administration of human immunoglobulin G (hIVIgG) has been suggested to potentiate thromboembolism in dogs, but supportive scientific reports are lacking.
Objectives: To determine if hIVIgG therapy promotes hypercoagulability and inflammation in dogs.
Animals: Twelve healthy Beagle dogs.
Methods: Prospective, experimental trial. An hIVIgG/saline solution was infused IV at 1 g/kg BW over 8 hours to 6 dogs, and physiological saline was infused to the other 6 dogs. Blood samples were drawn before, during, and after infusion for serial measurement of indicators of coagulation and inflammation. Data were analyzed by 2-way repeated measures analysis of variance.
Results: Dogs administered hIVIgG developed mildly decreased blood platelet concentrations without thrombocytopenia (median, 200 × 10³/μL; range, 150–302 × 10³/μL; P < .01), leukopenia (median, 3.5 × 10³/μL; range, 20–62 × 10³/μL; P < .001), and mildly increased plasma total protein concentrations (median, 6.3 g/dL; range, 5.6–6.7 g/dL; P < .001). Administration of hIVIgG was also associated with increases in fibrin/fibrinogen degradation products in all dogs (either 5 μg/mL or 10 μg/dL), thrombin-antithrombin III complexes (median, 7.2 ng/mL; range, 4.9–14.2 ng/mL; P < .001), and C-reactive protein concentrations (median, 2.5 mg/dL; range, 0.5–4.3 mg/dL; P < .01).
Conclusion and Clinical Importance: Administration of hIVIgG to dogs promotes hypercoagulability and an inflammatory state. This should be further evaluated and considered when using hIVIgG in dogs with IMHA or other prothrombotic conditions.     

Choroid plexus tumors in 56 dogs (1985-2007)

Background: Choroid plexus tumors (CPTs) comprise approximately 10% of all primary brain tumors in dogs. The clinical utility of magnetic resonance imaging (MRI), cerebrospinal fluid (CSF) analysis, or both in the presumptive diagnosis of CPTs has not been determined.
Objectives: To report MRI and CSF findings in dogs with CPT and determine if there are distinguishing features that allow clinical discrimination between the tumor grades.
Animals: Fifty-six client-owned dogs with naturally occurring CPT.
Methods: Retrospective case series. The inclusion criterion was histologically confirmed CPT. Blinded review of cranial MRI and cisternal CSF analysis was performed.
Results: Thirty-six of 56 dogs had a choroid plexus carcinoma (CPC) and 20 had a choroid plexus papilloma (CPP). Golden Retrievers were overrepresented compared with the hospital population (frequency 3.7 times that expected, confidence interval 95%= 2.0–6.7, P < .0002). Median CSF protein concentration in CPCs (108 mg/dL, range 27–380 mg/dL) was significantly higher than in CPPs (34 mg/dL, range 32–80 mg/dL) ( P = .002). Only dogs with CPCs had a CSF protein concentration >80 mg/dL. Cytological evidence of malignancy in CSF was seen in 7 of 15 CPCs. Only CPCs had evidence of intraventricular or subarachnoid metastases on MRI.
Conclusions and Clinical Importance: MRI, CSF analysis or both can help to differentiate between CPPs and CPCs, and may provide valuable prognostic and pretreatment information.     

Association of cerebrospinal fluid analysis findings with clinical signs and outcome in acute nonambulatory thoracolumbar disc disease in dogs

Background: Cerebrospinal fluid (CSF) pleocytosis recently was associated with the severity of neurologic signs in dogs with intervertebral disc disease (IVDD). Hypothesis/Objectives: To look for an association among CSF cell counts, total protein concentration, and severity of neurologic signs at presentation with outcome in dogs with acute thoracolumbar IVDD. Our hypothesis was that CSF total nucleated cell count (TNCC) and percentage cell types would be associated with the severity of spinal cord damage and therefore with both the presenting clinical signs and the prognosis of affected dogs. Animals: Fifty‐four dogs with acute nonambulatory thoracolumbar IVDD were evaluated. Methods: Retrospective study. Signalment, neurologic grade, CSF TNCC, protein concentration, red blood cells count and differential cell percentages, and short‐ and long‐term outcomes were evaluated. Results: CSF pleocytosis (>5 cells/μL) was present in 54% of dogs and was positively associated with neurologic grade at presentation and with postoperative time to regaining ambulation. Neutrophils were observed most frequently. The percentage of CSF macrophages and macrophage to monocyte ratio were higher (P= .001, for both) in dogs presented without deep pain sensation (DPS) that did not regain ambulation. Receiver operator characteristics curve analysis yielded a cut‐off point of 13% macrophages with a sensitivity and specificity of 100 and 83%, respectively, for prediction of a negative outcome. Conclusions and Clinical Importance: CSF pleocytosis is positively associated with the severity of spinal cord damage in dogs with thoracolumbar IVDD. The percentage of CSF macrophages can be used as a prognostic indicator for regaining ambulation in dogs that have lost DPS.     

Glutathione, Cysteine, and Ascorbate Concentrations in Clinically Ill Dogs and Cats

Background: Oxidative stress plays a role in the pathogenesis of many systemic diseases. Hospitalized human patients are glutathione, cysteine, and ascorbate deficient, and antioxidant depletion has been correlated with poor clinical outcome. To date little is known about antioxidant concentrations in hospitalized veterinary patients. The purpose of this study was to determine whether ascorbate, cysteine, or glutathione depletion is present in ill dogs and cats compared with healthy controls.
Hypothesis: Clinically ill dogs and cats would be antioxidant depleted, and depletion would correlate with illness severity and clinical outcome.
Animals: Clinically ill client-owned dogs (n = 61) and cats (n = 37), healthy control dogs (n = 37) and cats (n = 33).
Methods: Prospective, observational, case control study. Erythrocyte reduced glutathione, plasma cysteine, and plasma ascorbate were quantified using high-performance liquid chromatography.
Results: Clinically ill dogs had significantly lower erythrocyte glutathione concentrations (1.22 mM, range 0.55–3.61) compared with controls (1.91 mM, range 0.87–3.51; P = .0004), and glutathione depletion correlated with both illness severity ( P = .038) and mortality ( P = .010). Cats had higher ascorbate concentrations when ill (10.65 μM, range 1.13–25.26) compared with controls (3.68 μM, range 0.36–13.57; P = .0009).
Conclusions and Clinical Importance: Clinically ill dogs had decreased erythrocyte glutathione concentrations, which could be a marker of illness severity and prognostic of a poor outcome. Clinically ill cats had an unexpectedly high plasma ascorbate, which could represent a unique species response to oxidative stress.     

The effects of L-659,066, a peripheral alpha2-adrenoceptor antagonist, on dexmedetomidine-induced sedation and bradycardia in dogs

Objective  To investigate the influence of L-659,066, a peripheral α2-adrenoceptor antagonist, on dexmedetomidine-induced sedation and reduction in pulse rate (PR) in dogs.
Study design  Randomized, cross-over.
Animals  Six healthy laboratory Beagles.
Methods  All animals received dexmedetomidine (5 μg kg⁻¹ IV, DEX) alone or in combination with L-659,066 (250 μg kg⁻¹ IV, DEX + L) with a 7-day rest period between treatments. Sedation was assessed using a composite sedation score and PRs were recorded. Atipamezole (50 μg kg⁻¹ IM, ATI) was administered to reverse the sedation. Overnight Holter-monitoring was carried out to obtain a minimum heart rate (MHR) at rest.
Results  Bioequivalence was shown for clinical sedation between DEX and DEX + L. Heart rate was significantly higher with DEX + L during the period of sedation. Bioequivalence was demonstrated between MHR and PR in the DEX + L group during the period of sedation. Recoveries after ATI were uneventful.
Conclusions  L-659,066 did not affect the quality of dexmedetomidine-induced sedation whilst it attenuated the reduction in PR. Thus, L-659,066 could prove a useful adjunct to reduce the peripheral cardiovascular effects attributed to dexmedetomidine in dogs.
Clinical relevance  The clinical safety of α2-adrenoceptor agonists could be markedly improved with less peripheral cardiovascular effects.     

Beta-2-microglobulin levels in the cerebrospinal fluid of normal dogs and dogs with neurological disease

BACKGROUND: Cerebrospinal fluid (CSF) analysis is the basis for establishing a diagnosis of central nervous system (CNS) inflammation. However, the information provided by routine CSF analysis is limited. Determination of CSF beta-2-microglobulin (beta2m) concentration has been used diagnostically in humans to identify inflammatory CNS disease; we hypothesized that it may have similar value in dogs. OBJECTIVES: The objective of this study was to measure (beta2m concentration in the CSF of clinically healthy dogs and compare the values to those observed in dogs with inflammatory CNS disease and intervertebral disc disease (IVDD). METHODS: CSF was collected from 10 clinically healthy laboratory dogs and 11 dogs each with inflammatory CNS disease and IVDD. Routine CSF analysis was performed, and (beta2m concentration was measured by ELISA. CSF (beta2m concentration and CSF:serum (beta2m ratio were compared between groups by ANOVA. Linear relationships between CSF total nucleated cell count (TNCC), RBC count, total protein concentration, and (beta2m concentration were assessed by regression analysis. RESULTS: The mean (+/- SD) CSF (beta2m concentration in clinically healthy dogs was 0.36 (+/- 0.05 microg/mL (cisternal) and 0.40 (+/- 0.07 microg/mL (lumbar). Median CSF (beta2m concentration in dogs with IVDD (0.46 microg/mL) and inflammatory CNS disease (0.85 microg/mL) differed from that of controls (0.36 microg/mL; P=.002). The concentration also differed between the 2 disease groups (P=.01). Five dogs with inflammatory CNS disease had CSF:serum (beta2m ratios >1. A correlation was identified between TNCC and (beta2m concentration (r=0.69, P=.0003). CONCLUSIONS: CSF (beta2m concentration is higher in dogs with IVDD and inflammatory CNS disease, with highest values seen with inflammatory disease. This may be attributed in part to the correlation between CSF (beta2m concentration and TNCC, but also may reflect intrathecal immune activation.     

Peripheral Nucleated Red Blood Cells as a Prognostic Indicator in Heatstroke in Dogs

Background: Heatstroke in dogs is often fatal and is associated with a high prevalence of secondary complications. Peripheral nucleated red blood cells (NRBC) occur in dogs with heatstroke, but their association with complications and the outcome is unclear.
Hypothesis: Peripheral NRBC are common in dogs with heatstroke and have prognostic significance.
Animals: Forty client-owned dogs with naturally occurring heatstroke.
Methods: Prospective, observational study. Dogs were followed from presentation to discharge or death. Serum biochemistry and coagulation tests were performed at presentation. CBC and evaluation of peripheral blood smears were performed at presentation and every 12 hours. The relative and the absolute NRBC numbers were calculated.
Results: Presence of NRBC was observed in 36/40 (90%) of the dogs at presentation. Median relative and absolute NRBC were 24 cells/100 leukocytes (range 0–124) and 1.48 × 10³/μL (range 0.0–19.6 × 10³/μL), respectively. Both were significantly higher in nonsurvivors (22) versus survivors (18) and in dogs with secondary renal failure and DIC versus those without these complications. Receiver operator curve analysis of relative NRBC at presentation as a predictor of death had an area under curve of 0.92. A cut-off point of 18 NRBC/100 leukocytes corresponded to a sensitivity and specificity of 91 and 88% for death.
Conclusions and Clinical Importance: Relative and absolute numbers of peripheral NRBC are clinically useful, correlate with the secondary complications, and are sensitive and specific markers of death in dogs with heatstroke, although they should never be used as a sole prognostic indicator nor should they replace clinical assessment.     

Antitumor Activity of Mycobacterial Cell Wall‐DNA Complex (MCC) Against Canine Urinary Bladder Transitional Cell Carcinoma Cells

Introduction:  Mycobacterial cell wall‐DNA complex (MCC) is a bifunctional anticancer agent that induces cancer cell apoptosis and stimulates cytokine synthesis by immune cells. Intravesical MCC is currently being evaluated in humans with high‐grade urinary bladder cancer. Evaluation of MCC in dogs with transitional cell carcinoma (TCC) will allow mechanistic studies in a natural animal model of TCC, and a potentially beneficial therapy for dogs with this cancer. In this study, we have determined the anticancer activity of MCC against canine TCC cells in vitro .
Methods:  Canine TCC cells (K9TCC cell line) were incubated with MCC (0.05–100 μg/ml, 0.5–72 hours). Cellular proliferation was measured by MTT reduction. Cell cycle was analyzed by flow cytometry with propidium iodide. Apoptosis was identified by flow cytometry using anti‐active‐caspase‐3/PE and anti‐cleaved‐PARP/FITC antibodies. Apoptosis‐inducing activity of 100 μg/ml MCC in combination with piroxicam (0.1–1.0 uM) was evaluated.
Results:  MCC inhibited K9TCC cell proliferation in a concentration‐dependent manner (maximal activity – 45% at 100 μg/ml MCC) in association with the presence of activated caspase‐3 and cleaved PARP. Inhibition of proliferation and apoptosis‐inducing activities of MCC were independent of cell cycle phase. A thirty‐minute exposure of MCC was sufficient for optimal activity. Piroxicam (0.5 uM) enhanced apoptosis‐inducing activity of MCC.
Conclusions:  MCC induces apoptosis in K9TCC cells. This activity is potentiated by piroxicam. Following positive results in vitro , in vivo studies have been initiated. One dog, treated to date, has had a minor reduction in tumor volume following the first course of treatment with no treatment‐related toxicity.     

Comparison of 2 Doses of Recombinant Human Thyrotropin for Thyroid Function Testing in Healthy and Suspected Hypothyroid Dogs

Background: Various protocols using different doses of recombinant human thyrotropin (rhTSH) in TSH stimulation testing have been described. However, the influence of TSH dosage on thyroxine (T4) concentration has not yet been evaluated in suspected hypothyroid dogs.
Objective: To evaluate the effectiveness of 2 doses of rhTSH.
Animals: Fifteen dogs with clinical signs consistent with hypothyroidism and abnormal stimulation results with 75 μg rhTSH and 18 clinically healthy dogs.
Methods: All dogs were stimulated with 75 and 150 μg rhTSH IV in a 1st and 2nd stimulation test, respectively. Blood samples were taken before and 6 hours after rhTSH administration for determination of total T4 concentration.
Results: Using the higher dose led to a normal test interpretation in 9 of the 15 dogs, in which stimulation had been abnormal using the lower dose. Based on follow-up information, hypothyroidism was excluded in 7 of these 9 dogs. In all 6 dogs with a blunted response to the higher dose, hypothyroidism could be confirmed. Healthy dogs showed significantly higher post-TSH T4 concentrations with the higher compared with the lower dose. Post-TSH T4 concentrations after TSH stimulation were not related to dogs' body weight in either healthy or diseased dogs.
Conclusions and Clinical Relevance: TSH dose significantly influenced test interpretation in suspected hypothyroid dogs. Differentiation between primary hypothyroidism and nonthyroidal disease was improved with 150 μg rhTSH. Because this effect was independent of the dogs' body weight, the higher dose is recommended in dogs that have concurrent disease or are receiving medication.     

Blood Lactate Concentrations in Anesthetized Dogs with Intracranial Disease

Background: The importance of blood lactate concentrations in dogs with intracranial disease has not been established, despite frequently observed hyperlactatemia in dogs undergoing general anesthesia for advanced imaging, surgery, or both.
Hypothesis: Blood lactate concentrations are elevated in anesthetized dogs with intracranial disease, compared with dogs with intervertebral disc disease (IVDD).
Animals: Eighty-five hospitalized dogs undergoing advanced imaging, surgery, or both for primary neurologic disease; 30 with intracranial disease; 55 with IVDD.
Methods: Retrospective study. Age, breed, neurologic diagnosis, time from anesthesia induction to measurement of blood lactate, blood lactate concentration under anesthesia, and concurrently measured heart rate, mean arterial pressure, PCV, arterial hemoglobin oxygen saturation, and arterial partial pressure of oxygen were included in a multivariable linear regression analysis.
Results: Dogs with meningioma (adjusted mean lactate 2.99 mmol/L, 95% CL 2.21–4.05, P < 0.0001) and hydrocephalus (adjusted mean lactate 1.5 mmol/L, 95% CL 0.99–2.27, P = 0.003) had higher blood lactate concentrations compared with dogs with IVDD (adjusted mean lactate 0.79 mmol/L, 95% CL 0.6–1.04). Only dogs with meningioma had clinically important hyperlactatemia (>2.5 mmol/L).
Conclusions: Prospective studies are warranted to determine the degree and clinical importance of high blood lactate concentrations in dogs with intracranial disease.     

Idiopathic Eosinophilic Masses of the Gastrointestinal Tract in Dogs

Background: Eosinophilic inflammation of the gastrointestinal tract of dogs occurs in numerous disorders, typically resulting in diffuse intestinal thickening. Rarely, eosinophilic masses have been reported.
Objective: Describe a series of dogs with 1 or more idiopathic eosinophilic gastrointestinal masses (IEGM) to better characterize the clinical features, treatment, and prognosis.
Animals: Seven dogs with 1 or more gastrointestinal masses composed primarily of eosinophilic infiltrates for which no underlying cause was found.
Methods: Retrospective case series.
Results: Rottweilers and purebred, large breed dogs predominated. Dogs were middle-aged and typically had chronic signs of upper or lower gastrointestinal disease. Decreased appetite, vomiting, and evidence of gastrointestinal hemorrhage were present in the majority of cases. An abdominal or rectal mass was frequently noted on physical examination. Common laboratory abnormalities included peripheral eosinophilia, mature neutrophilia, hypoproteinemia, and hypocholesterolemia. The masses were histologically composed of moderate to severe eosinophilic infiltrates, which were often transmural and accompanied by fibrosis. All dogs treated with surgery alone died of complications of their disease. Treatment with corticosteroids and ivermectin improved clinical signs, caused resolution of eosinophilic infiltrates, and prolonged survival in most dogs treated medically.
Conclusions and Clinical Importance: These findings suggest that the prognosis for dogs with IEGM may be good when recognized and managed appropriately. When surgery is performed, medical treatment should also be added.     

Effect of Thyroxine Supplementation on Glomerular Filtration Rate in Hypothyroid Dogs

Background: Glomerular filtration rate (GFR) is decreased in humans with hypothyroidism, but information about kidney function in dogs with hypothyroidism is lacking.
Hypothesis: Hypothyroidism influences GFR in dogs. The objective of this study was to assess GFR in hypothyroid dogs before implementation of thyroxine supplementation and after re-establishing euthyroidism.
Animals: Fourteen hypothyroid dogs without abnormalities on renal ultrasound examination or urinalysis.
Methods: Blood pressure and GFR (measured by exogenous creatinine clearance) were measured before treatment (T0, n = 14) and at 1 month (T1, n = 14) and at 6 months (T6, n = 11) after beginning levothyroxine supplementation therapy (20 μg/kg/d, PO). The response to therapy was monitored at T1 by measuring serum total thyroxine and thyroid stimulating hormone concentrations. If needed, levothyroxine dosage was adjusted and reassessed after 1 month. Statistical analysis was performed using a general linear model. Results are expressed as mean ± standard deviation.
Results: At T0, the average age of dogs in the study group was 6.3 ± 1.4 years. Their average body weight decreased from 35 ± 18 kg at T0 to 27 ± 14 kg at T6 ( P < .05). All dogs remained normotensive throughout the study. GFR increased significantly with levothyroxine supplementation; the corresponding results were 1.6 ± 0.4 mL/min/kg at T0, 2.1 ± 0.4 at T1, and 2.0 ± 0.4 at T6 ( P < .01).
Conclusion: GFR was <2 mL/min/kg in untreated hypothyroid dogs. Re-establishment of a euthyroid state increased GFR significantly.     

Sparing effect of a low dose of intrathecal morphine on fentanyl requirements during spinal surgery: a preliminary clinical investigation in dogs

Objective— To evaluate the effect of preoperative intrathecal administration of a low dose of morphine on intraoperative fentanyl requirements in dogs undergoing cervical and thoracolumbar spinal surgery.
Study Design— Prospective randomized clinical study.
Animals— Dogs (n=18) matched by surgical procedure administered intrathecal morphine (MG) or no-treatment (control group, CG).
Methods— After premedication with romifidine (4 μg/kg, intravenously) and induction with propofol, anesthesia was maintained with sevoflurane in oxygen. Intrathecal morphine 0.03 (0.023–0.034) mg/kg was administered at lumbar level 41 (25–65) minutes before surgery in MG. Ketamine (0.5 mg/kg) was administered hourly, starting before incision. Fentanyl infusion (1.2 and 4.2 μg/kg/h in MG and CG, respectively) was administered after a loading dose (5 and 10 μg/kg in MG and CG, respectively), and boluses were given if an increase >20% in heart rate and arterial blood pressure was observed. Total amount of fentanyl administered was recorded, to calculate hourly requirements and predict plasma concentration using a computer simulation.
Results— Hourly fentanyl consumption and predicted plasma concentrations at the time of response to surgery were significantly lower in MG compared with CG.
Conclusions— Preoperative administration of a low dose of intrathecal morphine has a sparing effect on intraoperative fentanyl requirements.
Clinical Relevance— Preoperative intrathecal administration of a low dose of morphine at the lumbar level represented a safe and effective mean of providing intraoperative analgesia in dogs undergoing cervical and thoracolumbar spinal surgery.