Colon is a part of large intestine and beings from where the small intestine ends. Cecum is the sac that joins the colon to the small intestine. Colon ends at the point where the rectum begins. The colon serves as a temporary storage area where water and salt are extracted back from the waste. When the diameter of the colon becomes abnormally enlarged due to waste being retained in the colon, the condition is called Megacolon. Typically, it is associated with chronic constipation or obstipation that blocks the passage of gas as well as feces. The condition could be congenital or acquired. Dogs with congenital megacolon lack the normal smooth muscle function of the colon. Megacolon can also result due to feces being chronically retained; fecal water completely absorbed causing the feces to become solidified within the colon. If concreted feces remains lodged in the colon for a prolonged period of time it will cause distention of the colon resulting in irreversible colonic inactivity which means that the smooth muscles of the colon are no longer contracting or expanding to void feces.
Common symptoms demonstrated include:
Constipation: Feces trapped in the colon
Obstipation: Severe blockage that impedes both feces and gas, keeping them trapped in the colon
Infrequent defecation
Straining to defecate with small or no fecal volume
Small amount of diarrhea may occur after prolonged straining
Hard, dry feces
Hard colon felt on palpation
Fecal impaction can be felt in the rectum
Occasional vomiting, anorexia or depression
Weight loss
Dehydration
Scruffy, unkempt hair coat
