Research Update: Identifying biochemical markers in abdominal effusions

In this prospective clinical study from a university teaching hospital, 15 dogs with abdominal effusion were evaluated in an attempt to identify biochemical markers of malignancy in the abdominal fluid. Abdominal fluid (3 ml) was collected by paracentesis, stored at room temperature, and analyzed within 10 minutes of sample collection. The fluid was analyzed for pH; lactate, urea nitrogen, creatinine, total bilirubin, and glucose concentrations; alkaline phosphatase, alanine transaminase, gamma-glutamyltransferase, amylase, and lipase activities; specific gravity and total protein concentration; and nucleated and red blood cell counts. Dogs were divided into neoplastic (eight dogs) and nonneoplastic (seven dogs) groups based on the cause of the abdominal effusion.

Compared with dogs in the nonneoplastic group, dogs in the neoplastic group had significantly lower glucose (mean = 72.6 vs. 110 mg/dl) and higher lactate (mean = 3.8 vs. 1.7 mmol/L) concentrations in their abdominal fluid. According to the authors, these findings were caused by preferential use of glucose and increased metabolism by neoplastic cells. Additionally, neoplastic cells use anaerobic glycolysis for energy, producing increased concentrations of lactate in the effusion. The authors recommended further studies with increased patient numbers to validate their findings and establish the specific diagnostic value of these markers in identifying malignant effusions.

Nestor DD, McCullough SM, Schaeffer DJ. Biochemical analysis of neoplastic versus nonneoplastic abdominal effusions in dogs. J Am Anim Hosp Assoc 2004;40:372-375.

COMMENTARY

Abdominal effusions are common in dogs and are often caused by hepatic disease, neoplasia, trauma, peritonitis, and coagulopathies. Diagnosis is based on physical examination and imaging and paracentesis results; prognosis is based on identifying the cause of the effusion. In this study, the authors identified biochemical markers that should help clinicians treat dogs with abdominal effusion. The authors described several studies in people in which other markers such as pH and albumin and cholesterol concentrations were used to characterize specific abdominal effusions. More veterinary cases are needed to support the authors’ findings and possibly identify more distinguishing features of neoplastic effusion.

The information in "Research Updates" was provided by Veterinary Medicine Editorial Advisory Board member Joseph Harari, MS, DVM, DACVS, Veterinary Surgical Specalists, 21 E. Mission Ave., Spokane, WA 99202.

Joseph Harari, MS, DVM, DACVS