Dogs can have bloody stools or blood near the rectum for many reasons, from straining to defecate to intestinal tumors. A visit to your vet is necessary to diagnose your pet and implement treatment.
Impacted Anal Glands
Dogs have two anal glands or sacs just inside of the anus on each side of it. Secretions in the glands are thick and oily and smell fishy. Many dogs can empty the anal glands just by walking around and through normal defecation, though some are unable to express the liquid themselves. Anal glands can become impacted, and your dog will scoot his rear end on the ground trying to empty the glands. If the gland is impacted it can form an abscess that breaks through the skin and bleeds. Your dog will need veterinary attention for treatment with antibiotics.
The most common areas for malignant intestinal tumors in canines are the colon and the rectum. A benign form is polyps in the rectum as an abnormal growth of tissue. Older collies and German shepherds between 6 and 9 years of age are predisposed to these conditions. Symptoms include weight loss, diarrhea, anorexia and vomiting with a maroon stool containing blood. Diagnosis may include a complete blood count, physical examination, chemistry profile, X-rays, endoscopy and laparoscopy. The tumors are generally removed by surgery. Benign rectal tumors may be removed through transrectal endoscopy.
When a dog swallows a sharp object such as a needle or bone rectal tears, or fissures, can occur in the rectum or anus. The tear may be partial through the surface layers of skin or a complete tear though all layers of skin. Signs of rectal tears are rectal bleeding, straining to defecate and reluctance to defecate. Your veterinarian needs to see your pet to close the wound and prevent infection with antibiotics. He may also prescribe stool softeners to alleviate the pain associated with defecation after the surgery.
Colitis and Proctitis
Canine ulcerative colitis is a bowl disease that causes thickening of the colon and ulcers to appear in the lining. An inflamed colon leads to a reduction in water absorption needed to store feces and leads to frequent diarrhea with blood or mucus. Proctitis is the inflammation of a dog's anus and the rectal lining. Each stool evacuation can irritate the inflamed colon and rectum tissue and cause it to tear. The irritation can lead to vomiting and weight loss from lack of appetite. Both colitis and proctitis can be caused from parasites in the rectum or intestines; a bacterial, fungal or algae infection; or from eating an abrasive object that causes intestinal trauma. Treatment may include hospitalization of your pet to rehydrate him if he is dehydrated from excessive diarrhea. If the inflammation is sudden and severe, food may be withheld for 24 to 48 hours so the colon can relax. If your veterinarian discovers scar tissue with an X-ray, he will surgically remove the worst scarred segments of the colon.
Dogs with constipation may whimper or cry during defecation and strain to defecate with either a hard or bloody stool including mucous. You need to take your pet to the vet for a diagnosis and treatment program. The vet will likely do a physical exam, a complete blood count, an electrolyte panel, a urinalysis and a blood chemical profile. Your vet may also do an ultrasound or use X-rays to see inside of the intestines. Your veterinarian may prescribe antibiotics, anti-inflammatory medications and laxatives depending on the cause of constipation.