Stories from My Diary-rrhea (part II): Acute Small Intestinal Diarrhea

by Dr. Laci, aka, Dr. Poop
Acute small intestinal diarrhea forms the majority of all the cases of smooth mooves that I see in the hospital.

The main function of the small intestine is to continue digestion of food stuff from the stomach, and absorb fluids and electrolytes. 

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

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), if your dog is ever unsupervised and given the opportunity to get him or herself into this kind of trouble, medication history, progression of the 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 the 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, meaning the GI contents continues to pass along, missing out on crucial absorption.  Make more sense?

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 panty hose (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 pet's is at risk for developing an intussusception, a potentially fatal condition where part of the intestine invaginates into another part of the intestine, usually 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 panty hose 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, so her owners were not overly concerned about her loose business, but after a couple 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, 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."

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, and 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, but 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.

Let's review some of the common features of acute small intestinal diarrhea that apply here: weight loss, markedly watery stool, increased frequency of defection, 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 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:
A Tale of Many Tails—and What Came Out From Underneath Stories from My Diary-rrhea (part I)
Acute Small Intestinal Diarrhea
Acute Large Intestinal Diarrhea (Acute Colitis)
hronic Large Intestinal Diarrhea
Chronic Small Intestinal Diarrhea

Laci Schaible has always been an animal lover and wanted to be a veterinarian since the third grade. Eager to actualize her dreams, she left home and started college with a full scholarship at the age of 16. She graduated with honors at the age of 19, and then became one of the youngest U.S. trained veterinarians in history when she graduated with her D.V.M. at the age of 23 from Texas A&M University.

After practicing as an associate at an emergency / referral and general practice small animal hospital, she was anxious to lead and manage her own hospital, which she successfully did for years. Performing surgeries with her husband Jed (also a vet) is one of her favorite aspects of practice.

Together, after losing their beloved family dog Madison to terminal cancer, Laci and Jed realized the need for pet owners to have affordable unbiased guidance for their pet's health care beyond their veterinarian with office hours. 

Jed's entrepreneurial genes and Laci's creative passion motivated them to fill this need, and was born.  Check out their blog for a mix of pet health advice, funny stories from the vet perspective, and even cool video blogs from Dr. Jed!

You can also follow Dr. Laci on Twitter  or VetLive on Twitter  or Facebook.


  1. You found a picture! Haha, love it! Thanks again for sharing Jana!

  2. You explained it so well. So many times my vet does not have the time or take the time to explain causes and effects to me. The RedRum experience must have been quite an ordeal. Hope Jack didn't appear with an ax later on. Great idea your website.

  3. I'm happy to help! Sometimes it is difficult as a vet to even remember to explain, especially when we get very busy. Haha, yes the RedRum was quite the messy experience--not the first and most definitely not the last!

  4. I had never imagined that things like this really happen. What a profession. Thanks for putting this to us in such a "Shining" way.

  5. I have never imagine many things actually happen. Then I learned otherwise.

    Once talked to a vet a our holiday location when I was concerned about a tick bite Jasmine had in her ear. He said: "Not all the bad things always happen, and if they do they don't happen to the same dog."

    Well, he can explain that to Jasmine, as she is clearly not aware of that rule.

  6. Jana, haha! I know, some of my favorite and sweetest patients have the worst luck. Very sad actually.

  7. Very sad and seems to be the rule :-(


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