Acute Small Intestinal Diarrhea in Dogs: Stories from My Diary-rrhea

Acute small intestinal diarrhea forms the majority of all the cases of “smooth mooves” that I see in the hospital.

Acute Small Intestinal Diarrhea in Dogs: Stories from My Diary-rrhea (part II)
Photo from “The Shining”

The primary function of the small intestine is to

  • continue the digestion of foodstuff from the stomach, and
  • absorb fluids and electrolytes.

When it is not functioning properly, the amount of stool produced is going to increase drastically.

The stool will also be really wet.  Hand-in-hand, or gut-to-butt, (technically, the small intestines does not go to the butt, but humor me) while losing so much nutrition, the dog may often lose weight as the nutrition is not being fully absorbed.

This is more often seen with chronic small intestinal diarrhea, but can also be seen with acute.

Diagnosing acute small intestinal diarrhea

Thorough history

The initial step your vet will take involves the thorough history I repeatedly endorse.

Things that should be discussed include: 

  • diet change
  • foreign object ingestion
  • other edible no-nos (chocolate, spoiled foods, random poop left on the sidewalk)
  • medication history
  • progression of diarrhea, and
  • contact with other animals, ie, exposure to infectious creepy crawlies.

Gathering this information immediately may directly lead us to the cause of the diarrhea.

Is your dog taking any new meds?  You may be at the emergency vet, and forget to mention the meds for his skin infection.  Or your vet may be having one of those days and forget that he or she prescribed meds in the first place.

You are your best friend’s best advocate!

Antibiotics that are administered orally may alter the flora of the GI tract or even increase the movement of ingesta through the GI tract.  It may be as simple as that!

Next is detailed physical examination

Your vet will be assessing whether Fido is bright, healthy, and alert versus clinically ill, dehydrated, or even shocky (from loss of fluids or even sepsis, for example). 

If the dog has a painful or tense abdomen, diagnostic tests are indicated. X-rays are fine to start with, but, unfortunately, can’t always rule out a foreign body).

How does a foreign body cause diarrhea?

It likely is not a complete blockage and is almost certainly rubbing and damaging the lining of the small intestine. 

When the absorption structures on the inside of the small intestine (small finger-like projections called villi) are damaged or knocked out entirely, the surface area responsible for absorption is decreased. As a result, the GI contents continues to pass along, missing out on crucial absorption.  Make more sense?

Oral and rectal exam

Physical exam should also include checking out both ends of your pooch, an oral exam, and the dreaded rectal exam.

You or your pet may not appreciate it, but skipping these steps could be deadly.

For instance, it is possible your dog ate a linear object, such as pantyhose (I have seen this multiple times), and there is part of the hose that is caught on the inside of their mouth, preventing the hose from passing throughout the GI tract. 

All of a sudden, your dog is at risk for developing an intussusception. Intussusception is a potentially fatal condition where part of the intestine invaginates into another part of the intestine. This usually happens because the body can’t effectively move a foreign object any further.

Helpful hint 

Think about the collapsing components of a telescope.  Linear foreign objects are more often associated with cats, but tasty long treats like pantyhose are too tempting for some pooches to pass on.  It doesn’t mean they are perverts, just the things that smell most strongly like you (panties, hose, shoes) are super yummy!  It’s a compliment, really.

Sophie’s story and summary.

Take Sophie, a four-year-old female Rottweiler: 

Sophie’s diarrhea had started a day or two prior to when her parents brought her to see me.  She was energetic and still had her voracious appetite. That’s why her owners were not overly concerned about her loose business. However, after a couple of days of cleaning up horrifically smelling messes, they decided to have her checked out.

Normal enough in presentation, diarrhea in an adult dog with a two-day duration. Sophie’s parents claimed she was current on her vaccines (I was not her regular vet),

She might have gotten into something (she is known to eat “love-overs” out of the garbage when mom and dad aren’t looking), but no tell-tale exam signs, and nothing alarming in the history
Then she stayed with us (in our isolation ward, no worries) to run some tests and have an IV placed for fluid replacement therapy and it happened. 

REDRUM!  It came pouring out from underneath the door like the blood gushing down the hall in “The Shining.”

Oh, crap.  In it’s worst form.  The all-too memorable smell filled the air. Upon seeing the dark jammy digested blood in the copious relentless pools of liquid poo, I knew what we had on our hands– and feet and gloves.

Time to break out the bleach because this was a case of parvovirus.

I am certain if you are reading this you have heard of parvo.  Most people think that parvovirus just affects young puppies. I want to make it known that the virus does not discriminate against age.

Sophie stayed with us for a week and had many ups and downs, but she pulled through.

Common features of acute small intestinal diarrhea

  • weight loss
  • markedly watery stool
  • increased frequency of defecation
  • stool volume increased enough to resemble a scene from “The Shining,” and a clinically ill patient—although the last is not always present.

I tell you about Sophie because I do have an ulterior motive. A friendly reminder in the times of vaccine controversy, parvovirus is a deadly and real disease. I lose patients, and patience, every year to this deadly virus.

When your vet asks for proof of vaccines or titers, it is nothing personal; keeping up with our own tetanus info is challenging enough, and pet parents, just like vets, make mistakes.  Please make every effort still to ensure your dog, puppy or adult, is protected for this deadly virus—please.

Some take homes about acute small intestinal diarrhea

Common causes of acute small intestinal diarrhea in dogs are

  • parasites, (such as roundworms and Strongyloides)
  • dietary problems (such as abrupt diet change or allergies)
  • viral or bacterial infection (parvovirus, coronavirus, Salmonella, E. coli)
  • abrupt deficiency in glucocorticoids (either from too quick of withdrawal of oral steroids or from an endocrine disease like Addison’s disease–a far too comprehensive disease to approach today)
  • poisoning (Salmon poisoning, toxin ingestion from spoiled food, heavy metal poisoning), and finally Hemorrhagic gastroenteritis.

Withhold food and ensuring hydration alone may be therapeutic. Remember, if your dog has black, red or maroon specs in the stool, seek veterinary care. Also, if your puppy has diarrhea and is less than 12 – 14 weeks of age, is underweight or under 5 pounds, don’t wait. Go to the vet now, and diagnostics will be necessary, including monitoring blood glucose levels as these small guys don’t have nutritional reserves. Lethargic or patients that are warm or running a fever (the average dog temp is around 101.5 F) are also indicators to not ride it out.

Related articles:
Symptoms to Watch for In Your Dog: Diarrhea
A Tale of Many Tails—and What Came Out From Underneath 
Acute Small Intestinal Diarrhea
Acute Large Intestinal Diarrhea (Acute Colitis)
Chronic Large Intestinal Diarrhea
Chronic Small Intestinal Diarrhea

Further reading:
Dog Diarrhea (All You Need To Know)

  1. Very interesting post. Happy to hear Sophie survived Parvo. I’m lucky my two cats haven’t really had a bad case of diarrhea, but when they do have it, it can usually be traced to a new food or treat.

  2. FiveSibesMom

    Excellent information, as always! I have had a Husky with IBS and had mild bouts of HGE (scary)…and I have a Husky now who has pudding like poo quite often. She does love to lick dirt, grab blades of grass as we are walking by…so I’m not too surprised. Thankfully, with meds, she is fine!

    • HGE is scary for sure. With the pudding poop, licking dirt and grass eating … I would not consider the bad poop result of licking dirt, if it is a consistent behavior. Rather, I’d want to know what might be causing both.

  3. I had no idea that a small object could cause irritation and bring on such drama. Once you tell us it becomes obvious and I shake my head at my own lack of knowledge. I am glad you explained what a vet is looking for. It is things like that that make sure a vet visit includes an informed dog owner not a totally panicked one.

  4. Our girl Daviana lost a lot of weight and was diagnosed with IBD. Her intestines weren’t absorbing nutrients, as you described. As a result, her weight was dropping and fast! She lost approximately 20 lbs in a month and she didn’t have 20 lbs to lose!

  5. My Shadow cat used to get diarrhea at the slightest provocation. The poopoclypse is a good word for it. Eventually he was diagnosed with IBS.

  6. I have lived through quite a few incidents like this but am blessed that I can immediately email my vet to discuss it and they normally reply within a couple of hours, if they think it is necessary they will tell me to bring her in but we have been lucky up till now.

  7. I’ve lived through a few incidents of poopocalypse. It’s often been overeating or that bad bacteria stuff. My first dog caught giardia once and, boy, was that messy.

  8. I was so glad to read that Sophie survived her bout of parvo! I get so paranoid when either of my dogs get diarrhea, I usually end up taking them to the vet for it even though, thus far, it’s never been caused by anything too serious. My senior dog especially has a notoriously sensitive stomach. He’s also VERY food driven, a combo, you can imagine, that lands him in the vets office more often than I’d like.

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