Common causes of Hematochezia

Parvo This is a serious disease often found in puppies. Black and tan breeds such as Rottweilers, German Shephards and Dobermans are more prone. Typically, a puppy with Parvo will exhibit vomiting, diarrhea, lethargy, loss of appetite and blood in stools. Because this disease can be deadly, puppies suspected of having Parvo should be seen by a vet promptly.

Parasites Usually, this is the most common cause of blood in the stool. The most common parasites that cause blood in the stool are hookworms, whipworms, and roundworms. Protozoans such as coccidia may also cause bloody stools. With appropriate identification of the offending parasites, a veterinarian will prescribe specific dewormers to help get rid of these annoying beings.

Dietary Indiscretions Over eating or dietary indiscretion may irritate a dog's intestines, causing vomiting, diarrhea and bloody stools. Dogs must be switched to new foods gradually. If a diet change is done too sudden vomiting and diarrhea may take place. Other causes may be eating spoiled foods or food intolerance and allergies.

HGE Hemorrhagic gastro-enteritis involves copious blood in stools along with vomiting and diarrhea. Often the cause cannot be found, but your dog may need intravenous fluids and proper medications to let this condition subside.

Rectal Injury Dogs that ingest sticks or bones or anything that is sharp may eventually scrape a bit the lower intestinal lining or the rectum as they make their way out through the feces. Often such sharp items may be seen in the feces protruding out. In such cases the blood is bright red and will eventually stop. Avoid giving cooked bones and sticks to play with. Also check the rectal area for any rectal injuries especially involving the anal glands. Hematochezia should not be confused with Melena.

Melena is the passage of old, digested blood making the stools appear black and tarry. Melena develops when bleeding occurs into the stomach or small intestines. The bleeding must be high in the intestinal tract in order for the blood to be digested and become discolored. Melena may represent a severe, life-threatening illness, and should not be ignored. It must especially be addressed if it persists or worsens.

Common causes of Melena

Use of NSAIDS If your dog is on aspirin or some type of NSAID (Non Steroidal Anti-Inflammatory Drug), it may develop ulcers from its use. Dogs with bleeding ulcers will typically have black, tarry stools meaning digested blood coming from the stomach. Inform your vet promptly and if your dog is on such medication, discontinue and keep a watchful eye on the stools.

Pepto-Bismol If you have recently given Pepto Bismol to your dog, consider that it may turn his stools black. It states so on the bottle. Discontinue use and the stools should return to normal colour.

Ingestion of Blood A dog's stool may also appear black and tarry from ingesting blood. For instance, your dog may have licked a bloody wound or he may have had a mouth injury causing him to swallow blood.

Blood Clotting Disorders There are several canine conditions that may cause blood clotting disorders and bleeding. Affected dogs may also exhibit other symptoms other than black tarry stools such as purple tinted skin suggesting bleeding under the skin. Rat poison may also cause blood clotting disorders and bleeding and it may manifest as dark tarry stools. If you think this may be a possibilty have your dog seen A.S.A.P.

Post Surgery Complication If your dog has recently had surgery and is showing black stools, call your vet immediately. There may be internal bleeding somewhere. Possible complication may display up to 72 hours post surgery.

Tumors/Cancers Any time your dog presents dark, blackish stools, have your dog seen by a qualified vet. You want to rule out the possibility of tumors such as polyps or cancer.

While these are just some causes, there may be several more such as bloat or intestinal obstructions. Also, some of the causes above may both cause melena or hematochezia. Whichever the cause, if your dog has bloody stools, make sure you collect a fecal sample so your vet can rule out parasites and protozoans. The stool sample needs to be no longer than 12 hours old to grant testing accuracy.

The above info is in part by Alexadry

Some viral infections can temporarily irritate the walls of the small intestine and make it bleed. Blood in the stool can also be a sign of colitis, an inflammation of the large intestine. Also types of food poisoning or other intestinal infections are associated with bleeding. The main bacteria and parasites that can cause bloody diarrhea are Salmonella, Shigella, invasive E. Coli 0157, Campylobacter, Yersinia, and Entaomeba histolytica.

Finally, bleeding may be caused by an infection of the anal sacs. The anal sacs are on either side of the anus that contain a strong liquid pets use to mark their territory. These sacs normally empty whenever your pet has a bowel movement. When the sacs are infected however, they don't empty the way they should, causing them to swell. Having a bowel movement can irritate the area, causing blood to flow.

See Your Vet If...

  • The surface of your pet's stool has spots or smears of blood

  • His stool is dark and tarry-looking

  • Pushing on your pet's belly causes him pain

  • He hasn't eaten for 24 hours or more

  • His abdomen appears bloated

  • He has eaten rodent poison, antifreeze, houseplants, or other harmful substances

  • He has been vomiting for more than a day or is vomiting blood

  • There are worms or other parasites in his stool

  • He has had diarrhea for 24 hours or more

  • There is blood in his stool or it looks dark and tarry

  • He is scooting across the floor, or the anal area looks swollen

  • He has gained or lost substantial amounts of weight

  • Has side effects from medication, like appetite loss or vomiting

  • There are growths in the anal area

  • There is a bulge in his throat

  • He is drooling much more than usual

  • He vomits shortly after eating

  • Has pale gums

  • Is lethargic

What You Can Do for Your Pet

There is no reason to panic at the first sign of blood. Even though it looks scary, it usually isn't serious, anymore than a bloody nose is. "If you see just a few specks of red blood, I wouldn't worry about it," says Dr. Brothers. In most cases, the problem will be minor, and the bleeding will stop in a day or two.

In fact, you can often prevent bleeding by taking simple precautions. For starters, skip the bones, says David Tayman, D.V.M., a veterinarian in private practice in Columbia, Maryland. No matter how much your pet loves them, bones generally do more harm than good. As pets crunch them into small bits, the bones often get sharp edges that can damage the intestine.

Reducing your pets' exposure to parasites can be very helpful for preventing bleeding. One way to do this is simply to stop your pets from sniffing (or, worse, eating) other pets' stools. "Most parasites are contracted by sniffing the stool of other pets," says Howard Rothstein, D.V.M., a veterinarian in private practice in Saugerties, New York.

It is a good idea to clean the yard after every bowel movement and to scoop out the litter box every time it has been used. "That way they can't reinfect themselves," says Dr. Rothstein.

If you live in the country or go for hikes in the woods with your pet, pack enough water for the day -- for you and him -- since streams and ponds are common sources of parasites. Even stagnant water in your yard, under a rainspout, for example, may harbor parasites.

Even though blood in the stool usually indicates a minor problem, sometimes it is a serious warning sign. Don't take chances if there is a lot of blood or if the stool looks dark and tarry. Take a stool sample when you notice the problem, and make an appointment to see your vet as soon as possible, says Karen Mateyak, D.V.M., a veterinarian in private practice in Brooklyn New York. It's best if the sample is less than 24 hours old at the time of your appointment, she adds.

Other Causes of Blood in Stool 

A few common causes of digestive problems are exocrine pancreatic insufficiency, hair balls, intestinal obstructions, pancreatitis, parasites, and parvovirus. Learn more about these common conditions now.

Exocrine Pancreatic Insufficiency

The pancreas is a small, complex organ that produces powerful chemicals that dogs and cats (and humans) need to survive. One part of the pancreas secretes insulin, the hormone that helps the body absorb the sugars found in foods. The rest of the pancreas secretes enzymes that are shipped to the intestines to aid in digestion.

When the pancreas doesn't produce enough of these digestive enzymes (a condition called exocrine pancreatic insufficiency), food will pass through the intestines without being broken down and absorbed. Pets with this condition will be hungry all the time. They will also lose weight and pass large amounts of soft, poorly formed stools. The stools may look greasy because of the large amounts of undigested fats they contain.

Without treatment, this is an extremely serious condition. Once it has been diagnosed, however, it is very easy to manage. Generally, all you will need to do is add a pancreatic replacement enzyme, such as Viokase or Prozyme, to your pet's food each time she eats, says Grant Nisson, D.V.M., a veterinarian in private practice in West River, Maryland.