Interactive GI Cases: Common GI Diseases

Case 1: "Cindy" Willey - Helicobacter  gastritis 

Helicobacter spp. are a class of gram negative microaerophilic spiralshaped bacteria that are found in many places in the body. H. pylori has been identified as the underlying etiology for peptic ulcer disease in humans. Much study has been directed at the importance of Helicobacter-like organisms (GHLO’s) commonly found in dogs and cats. Lymphoid follicles may bee seen in dogs and cats that are not infected, but some suggest that those that are more heavily infected have more prominent follicular development and more severe inflammation. It is important to note that one significant difference from humans with H. pylori is that we do not see ulcer disease associated with infection in pets.
A number of diagnostic tests have been developed to diagnose GHLO’s. In a clinical setting, the last three are the most relevant. There are a number of rapid urease tests (e.g. the CLOtest). Cytology can be done on impression smears of gastric biopsies. Typically identification of GHLO’s occurs on histopathology of gastric biopsies. In dogs and cats the fundus is typically most heavily colonized. PCR is the most sensitive of all tests, and is most often indicated when trying to determine if infection has been eradicated.
When considering treatment, the first question we should ask is do we treat? Since infection is so prevalent, infection is not indication for treatment. I reserve treatment when vomiting is a prominent part of the presenting signs: 1) when colonization is very heavy; 2) when organisms are associated with regions of marked inflammation; or 3) when no other cause of vomiting can be identified.
A number of antibiotic combinations have been suggested for treatment of GHLO’s in people and animals. At present the most frequently recommended is a combination of amoxicillin (20 mg/kg BID), metronidazole (10-15 mg/kg BID) and clarithromycin (7.5 mg/kg BID) used ideally for 3 weeks. I often also add omeprazole (0.5-1 mg/kg QD) to help reduce clinical signs. This treatment is intended to reduce bacterial numbers- no antibiotic protocol has been show to completely clear infection based on PCR analysis of post-treatment biopsies. [...]