Last week we learned about normal small intestinal function and that lots can go wrong here. Consumption of food contaminated with certain bacteria or toxins can lead to irritation of the intestinal lining. This irritation can cause more water to be secreted – diarrhea. It can also cause peristalsis (movement) to stop and thus cause cramping and the backing up of ingesta (contents) – vomiting. If the lining is badly damaged, as we can see with salmonella, parvovirus and others, bacteria can leak into the bloodstream and cause sepsis, or body-wide infection. If the intestine is blocked by an object (rock, ball, sock, small toy, etc.), a tumor, or even a twisting of the intestine, it means that the contents can no longer move towards the colon and anus.
Fluid and gas are still being produced upstream and pushed downstream, but nothing can pass. This leads to dilation of the gut which is very painful and will lead to vomiting (in essence pushing things back upstream!). Roundworms and hookworms are common parasites of the small intestine. They can upset intestinal function in youngsters and lead to poor nutrient absorption and even a complete blockage. One of the most common problems we see in pets is inflammatory bowel disease (IBD). This is complicated process, but it boils down to an infiltration of the intestinal wall with inflammatory cells. This reduces the intestinal lining ™s ability to absorb nutrients and water, and it diminishes peristalsis. Signs of IBD include vomiting, diarrhea and weight loss.

Diagnosis and treatment of intestinal disease can be simple or quite complex. Labwork, x-rays,
ultrasound, endoscopy, surgical biopsy, dietary trials, oral medications, or exploratory surgery may be required.

by Bonnie Markoff, DVM, ABVP