german shepherd DOG ENTEROPATHY

German shepherd dogs appear to be predisposed to an increased incidence of GI diseases such as IBD and SIBO. Practitioners who see German shepherds with any frequency no doubt recognize that these dogs have an increased incidence of diarrhea and sometimes weight loss and other symptoms.

^• Genetic susceptibility, as a result of major his­tocompatibility complex class II antigens

^• A breakdown in immunologic tolerance to endogenous bacterial components

^• Mucosal permeability and brush border enzyme defects, which may allow increased antigen exposure to the mucosal immune system

^• Underlying selective IgA deficiency— German shepherd dogs with small intestinal disease have been shown to have a relative deficiency of IgA secretion from the small intestinal mucosa

^• IBD in German shepherd dogs is accompa­nied by marked disturbances in inflamma­tory cell populations and the cytokine profile

It is possible that IBD and SIBO in German shepherds are part of a single disease syndrome. It is also possible, given that SIBO is more com­mon in young animals and IBD is more common in older dogs, that SIBO can predispose to IBD. There is currently no substantiation of this hypothesis, but studies are ongoing.

Clinical signs in German shepherds are vari­able. The most common signs of SIBO are diar­rhea and weight loss or failure to thrive. Signs of IBD are more variable and in addition to diarrhea and weight loss may include vomiting, flatulence, decreased appetite, and other signs. German shep­herd dogs with GI signs should be investigated in the same manner as has been described for intes­tinal disease earlier in this chapter.

Treatment

If it is thought that the problem is limited to SIBO and/or IBD, it is generally recommended that antibiotics alone be used initially, unless there is a moderate or of course severe degree of IBD pres­ent, in which case immunosuppressive therapy is also indicated. Antibiotics may include oxytetra­cycline, metronidazole, or tylosin. Initially a course of 4 to 6 weeks is prescribed, and then if there has been a good response, the medication can be dis­continued. The dog is then observed for relapse, and if this occurs, the antibiotic therapy should be reinstituted. Again, it is important that other causes of diarrhea be ruled out, if they have not been already, and an effort to look for evidence of CPE must be made. CPE sometimes responds to metronidazole and more consistently, especially in chronic cases, to tylosin. Fiber supplementation is also very beneficial in management of CPE. For SIBO and IBD, a highly digestible low-residue diet is generally preferred, so dietary trials may be necessary, along with a thorough diagnostic effort, to determine which type of diet is most indicated. If there is an excellent response to antibiotics and the diarrhea recurs when they are discontinued, antibiotics can be used either continuously on a low-dose basis (I prefer to use tylosin in this situ­ation as a first choice and metronidazole as a sec­ond choice), or pulse therapy may be used, in which case antibiotics are administered once daily two to three times a week. In some dogs this is sufficient to maintain control.

If IBD is present and not responsive to antibi­otics and dietary management, immunosuppressive drugs are used following the guidelines described earlier in this chapter. In general I rarely find it necessary to use a prednisone dose greater than 0.5 mg/lb per day in German shepherd dogs.