Specific enzyme activities in bronchoalveolar lavage fluid as an aid to diagnosis of tracheobronchitis and bronchopneumonia in dogs

Lactate dehydrogenase (LDH), alkaline phosphatase (ALP), alanine aminotrans ferase and gamma-glutamyl transferase enzyme activities, and total protein (TP), calcium, inorganic phosphate. urea nitrogen (UN) and creatinine conce ntrations in bronchoalveolar lavage fluid were investigated for their relat ive importance in the diagnosis of respiratory diseases in dogs. Bronchoalv eolar lavage (BAL) fluid was obtained from 26 dogs (20 with respiratory dis eases and six controls) following anaesthesia with sodium pentothal. Enzyme activities and biochemical parameters were measured in BAL fluid. LDH and ALP levels were significantly increased in 12 dogs with bronchopneumonia, b ut not in eight dogs with tracheobronchitis. Insignificant and variable lev els of TP and UN concentrations were found in both groups. It was concluded that LDH and ALP enzyme activities could be considered as pointers to pulm onary inflammation and/or damage while TP and UN measurements in BAL fluid may have a place in the identification of changes in respiratory and vascul ar permeability. (C) 2001 Harcourt Publishers Ltd.