Complications after colic
Most colic episodes will fully resolve with no long lasting consequences. However, if toxins are released into the abdominal cavity or bloodstream, or if colic surgery is required, the horse will be at risk for other problems.
Certain bacteria carry toxins. Many of these are found in the gut normally. If the toxin load overwhelms the usual defense mechanisms or if the gut is damaged and lets the toxins leak out, the horse can become ill. These horses may become shocky (poor blood flow causing an elevated heart rate and cool limbs), have reddened or purplish gums or red lines around the teeth, and may seem very depressed.
The toxins can cause laminitis, clotting problems, and damage to other organs (e.g., kidneys). When horses are stressed (like from colic surgery), their immune system can be weakened. Many horses carry organisms that can cause diarrhea, in particular Salmonella, but are usually unaffected. When stressed, the immune system can no longer keep these organisms under control and the horse develops diarrhea. This can be a severe complication of colic and can be difficult (and expensive) to treat. Many horses will have diarrhea following intestinal disturbances, so they will be closely monitored for salmonellosis.
If a horse has colic surgery, he will also be watched for incisional infections, infections within the abdominal cavity, and motility disturbances. Some horses will get motility problems following small intestinal surgery that can significantly prolong nursing care and hospital stays. Performing surgery also places a horse at risk for developing intestinal adhesions. Adhesions may make the intestines stick to each other or the body wall in abnormal positions. Some adhesions can cause repeated bouts of colic. In general, surgery for large colon problems has a greater success rate than surgery for small intestinal problems. Luckily the odds for both are improving all the time.