Comparison of serum creatine kinase and aspartate aminotransferase activity in dogs with Neospora meningoencephalitis and noninfectious meningoencephalitis

Abstract

Background: Creatine kinase (CK) and aspartate aminotransferase (AST) activity can be increased with myositis associated with Toxoplasma and Neospora infection in dogs. Hypothesis/Objectives: Serum activity of CK and AST can be used as a rapid screen for predicting positive serology in meningoencephalitis caused by Toxoplasma gondii or Neospora caninum in dogs compared to dogs with noninfectious meningoencephalitis. Animals: Eighty dogs with meningoencephalitis based on magnetic resonance imaging and cerebrospinal fluid analysis. Methods: Retrospective case-control study. Serological cutoffs (≥1:800 immunofluorescence for Neospora and ≥1:400 IgG or ≥1:64 IgM or both for Toxoplasma) categorized dogs as infected (n = 21, all neosporosis) or noninfected (n = 59). Activities of CK and AST between infected and noninfected groups were compared using a Mann-Whitney U test and receiver operating characteristic curve analysis. Results: No dogs were diagnosed with toxoplasmosis. Serum CK and AST activities were significantly increased (P 99%. An AST cutoff of 57 U/L had 94.44% sensitivity and 85.71% specificity with an estimated negative predicative value of 99%. Conclusions and Clinical Importance: High serum CK and AST activity can increase suspicion for neosporosis while awaiting serological tests for dogs with meningoencephalitis.