C-reactive protein (CRP) a major acute phase protein in dogs has been evaluated in a variety of gastrointestinal diseases including inflammatory bowel disease (IBD), acute parvovirus infection and experimental models of ischaemic gut injury. In dogs with IBD CRP is useful for monitoring response to treatment but not severity of disease at initial presentation. There is little information available on CRP levels in dogs with chronic enteropathies other than IBD. As presenting clinical signs of the most common chronic canine gastrointestinal diseases are similar, an objective laboratory marker that could assist in differentiating potential causes would be valuable.

The aim of this study was to assess the utility of CRP as a marker of disease at initial presentation in dogs with chronic enteropathies. Fifty-one dogs referred to the University of Edinburgh Hospital for Small Animals for investigation of gastrointestinal disease of greater than three weeks duration were included in the study. Dogs with a final diagnosis of extra-intestinal disease were excluded. Faecal parasitology and culture was performed in all cases. Gastrointestinal biopsies were obtained from 45 dogs. Based on final diagnosis the dogs were divided into the following disease groups; IBD (n=22), enteric bacterial and/or parasitic infections (n=11), dietary responsive diarrhoea (n=9), gastrointestinal neoplasia (n=4), presumed motility disorder (n=2) and antibiotic responsive diarrhoea (ARD n=2).

Serum for CRP analysis was obtained at initial presentation and stored at -20oC before being assayed as a single batch using an immunoturbidimetric assay validated for canine CRP (normal reference range 0.001-4.415mg/L). CRP mean and standard deviations for each group are as shown in Figure 1.

The motility and ARD groups were excluded from further analysis as only two patients were included in each group. The other groups were compared using one-way analysis of variance with multiple comparisons performed using a Tukey test; p<0.05 was considered significant. There was no difference in CRP between the groups (F=0.57, P=0.64).

Although CRP was mildly elevated in most dogs with chronic enteropathies there was no difference between dogs with IBD, infectious, neoplastic or dietary responsive chronic gastrointestinal disease. CRP assessed at initial presentation does not appear to be useful in differentiating the cause of chronic gastrointestinal disease in dogs.

Figure 1.