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Thursday, April 30, 2009

Cool Recent Abstracts


Intracranial Arachnoid Cysts in Dogs

from Compendium by Curtis W. Dewey - Veterinary Answers Consultant, Peter V. Scrivani, Ursula Krotscheck, Sofia Cerda-Gonzalez, Kerry Smith Bailey, Dominic J. Marino

Intracranial arachnoid cyst (IAC) is an infrequently reported developmental disorder seen primarily in small-breed dogs. It usually occurs in the caudal fossa, in the region of the quadrigeminal cistern. Although still considered uncommon, IAC is being recognized more frequently in veterinary medicine, coinciding with the increased availability of magnetic resonance imaging. In this article, clinical information from previously reported cases of canine IAC is combined with additional case information from our hospitals. Similar to IAC in people, it is thought that canine IAC is often an incidental finding. When IAC is responsible for neurologic disease in dogs, generalized seizures and cerebellovestibular dysfunction are the most common clinical presentations. Medical therapy of IAC focuses on management of increased intracranial pressure and seizures, if the latter are part of the clinical complaints. Surgical therapy of IAC involves either cyst fenestration or shunting the excess fluid to the peritoneal cavity.

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

from JVIM by I. Aroch, G. Segev, E. Loeb, Y. Bruchim

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. Peripheral NRBC are common in dogs with heatstroke and have prognostic significance. Forty client-owned dogs with naturally occurring heatstroke. 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. 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[ndash]124) and 1.48 × 103/[mu]L (range 0.0[ndash]19.6 × 103/[mu]L), 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. 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.

Relationships between Low Serum Cobalamin Concentrations and Methlymalonic Acidemia in Cats

from JVIM by C. G. Ruaux, J. M. Steiner, D. A. Williams

Serum cobalamin concentrations below reference range are a common consequence of gastrointestinal disease in cats. Serum cobalamin [le] 100 ng/L is associated with methylmalonic acidemia. To determine the prevalence of cobalamin deficiency, defined by elevated serum methylmalonic acid (MMA), in cats with serum cobalamin [le] 290 ng/L, and the optimum serum cobalamin concentration to predict cobalamin deficiency in cats. Residual serum samples (n = 206) from cats with serum cobalamin [le] 290 ng/L. Retrospective, observational study. Serum cobalamin and folate were measured with automated assays. Serum MMA was determined by gas chromatography-mass spectrometry. Cobalamin deficiency was defined as serum MMA > 867 nmol/L. Sensitivity and specificity of serum cobalamin concentrations [le]290 ng/L for detecting MMA > 867 nmol/L were analyzed using a receiver-operator characteristic curve. There was a negative correlation between serum cobalamin and MMA concentrations (Spearman's r=[minus]0.74, P < 0.0001). The prevalence of MMA [ge] 867 nmol/L in cats with serum cobalamin [le] 290 ng/L was 68.4%. Serum cobalamin [le] 160 ng/L had a 74% sensitivity and 80% specificity for detecting MMA > 867 nmol/L. No significant difference in serum folate concentrations was detected between affected and unaffected cats. Elevated MMA concentrations, suggesting cobalamin deficiency, are common in cats with serum cobalamin [le] 290 ng/L. Cobalamin deficiency is clinically significant, and supplementation with parenteral cobalamin is recommended for cats with gastrointestinal disease and low serum cobalamin concentrations.

For more on MMA in human beings, click here.

Small Mammals
Single- and multiple-dose pharmacokinetics of marbofloxacin after oral administration to rabbits

From AJVR by James W. Carpenter, MS, DVM; Christal G. Pollock, DVM (VETERINARY ANSWERS CONSULTANT); David E. Koch, MS; Robert P. Hunter, PhD

Objective—To determine the pharmacokinetics of marbofloxacin after oral administration every 24 hours to rabbits during a 10-day period.

Animals—8 healthy 9-month-old female New Zealand White rabbits.

Procedures—Marbofloxacin (5 mg/kg) was administered orally every 24 hours to 8 rabbits for 10 days. The first day of administration was designated as day 1. Blood samples were obtained at 0, 0.17, 0.33, 0.5, 0.75, 1, 1.5, 2, 3, 4, 5, 6, 8, 12, and 24 hours on days 1 and 10 of marbofloxacin administration. Plasma marbofloxacin concentrations were quantitated by use of a validated liquid chromatography–mass spectrometry assay. Pharmacokinetic analysis of marbofloxacin was analyzed via noncompartmental methods.

Results—After oral administration, mean ± SD area under the curve was 10.50 ± 2.00 μg·h/mL and 10.90 ± 2.45 μg·h/mL, maximum plasma concentration was 1.73 ± 0.35 μg/mL and 2.56 ± 0.71 μg/mL, and harmonic mean terminal half-life was 8.0 hours and 3.9 hours for days 0 and 10, respectively.

Conclusions and Clinical Relevance—Marbofloxacin administered orally every 24 hours for 10 days appeared to be absorbed well and tolerated by rabbits. Administration of marbofloxacin at a dosage of 5 mg/kg, PO, every 24 hours is recommended for rabbits to control infections attributable to susceptible bacteria.

Risk Factors for Equine Postoperative Ileus and Effectiveness of Prophylactic Lidocaine

from JVIM by S. Torfs, C. Delesalle, J. Dewulf, L. Devisscher, P. Deprez
Postoperative ileus (POI) is a frequent and often fatal complication of colic surgery. Reliably effective treatments are not available. To determine risk factors and protective factors associated with POI, and to assess the effect of lidocaine IV on short-term survival. One hundred and twenty-six horses that underwent small intestinal colic surgery and that survived for at least 24 hours postoperatively. Retrospective cross-sectional study. The association of 31 pre-, intra-, and postoperative variables with POI and the association of lidocaine treatment with short-term survival were investigated. Associations were evaluated with univariable logistic regression models, followed by multivariable analysis. Significant associations of high heart rate (odds ratio [OR] = 1.05, 95% confidence interval [CI] 1.03[ndash]1.08), the presence of more than 8 L of reflux at admission (OR = 3.02, 95% CI 1.13[ndash]8.02) and the performance of a small intestinal resection (OR = 2.46, 95% CI 1.15[ndash]5.27) with an increased probability of POI were demonstrated. Prophylactic lidocaine treatment was significantly associated with a reduced incidence of POI (OR = 0.25, 95% CI 0.11[ndash]0.56). Lidocaine treatment was also significantly associated with enhanced short-term survival (OR = 0.30, 95% CI 0.09[ndash]0.98). The variables associated with an increased risk of POI can be useful in identifying horses at risk of POI and in providing a more accurate prognosis. The results are supportive for lidocaine IV as an effective prokinetic treatment after small intestinal colic surgery.

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