59 | Help, we’ve chopped out too much intestine! The VN’s guide to short bowel syndrome

PodcastGastroenterology
Written By Laura Jones

I remember the first time I ever saw a patient with short bowel syndrome.

 

I was a relatively new medicine nurse working in my first medicine referral role. Our patient, a gorgeous staffy who had a foreign body removed a few days before, came in with a septic abdomen.

Cue some rapid stabilisation and a trip to theatre, and he came back to us missing over a third of his small intestine. His GI tract was so unhappy that our surgeon had no choice but to remove his entire ileum and attach his jejunum directly to his colon.

He was a challenge like I hadn’t encountered before - needing parenteral nutrition and intensive care in the hospital, and then really intensive nutritional and medical management support after he was discharged. And while he was a real test, it was the skills and experience of our nursing team and the intensive care he received that made all the difference to his recovery.

In this episode of the medical nursing podcast we’re diving in to what short bowel syndrome is, how it impacts our patients, and the skills we can use to care for them.

So what is short bowel syndrome, and what problems does it cause?

Short bowel syndrome, or SBS, occurs when a significant portion of the small intestine is missing. This is usually due to surgical removal, following an intestinal foreign body, intussusception, volvulus, or neoplasia. 

We can also see it due to congenital defects, where patients are born missing significant portions of their intestine; however, this is more common in humans.

Regardless of the cause, the result for our patients is the same—without enough intestine, our patients can’t digest and absorb nutrients, water, and electrolytes.

Let’s look at the GI tract for a second…

It wouldn’t be an episode of the medical nursing podcast without a quick trip to A&P land, but I promise we’ll only be there for a minute. To appreciate WHY short bowel syndrome is such a problem for our patients, we need to take a second and think about how the GI tract works.

The small intestine extends from the pylorus (the exit from the stomach) to the ileocolic valve, where it joins the large intestine (colon) and the caecum. It is three and a half times as long as our patient’s body - around 1m long in cats and between 2 and almost 5m long in dogs!

The small intestine is broken down into three sections - the duodenum is the proximal section, the jejunum is the middle section, and the ileum is the distal section. Each of these sections has slightly different functions: 

  • Food is broken down via bile and digestive enzymes in the duodenum

  • Protein, carbohydrates, fats, vitamins and water are mainly absorbed in the jejunum

  • Bile acids and vitamin B12 are absorbed in the ileum, and certain hormones are also secreted from this portion of the small intestine.

Together, these sections (and our small intestine as a whole) digest food, absorb nutrients, absorb water and electrolytes, and produce hormones and enzymes that regulate the GI tract.

So, if our patient is missing a chunk of their small intestine, these functions are significantly impaired.

This means our patients have:

  • Reduced levels of digestive enzymes,

  • Impaired digestion and transport of carbohydrates, proteins and fats

  • Insufficient absorption of amino acids, glucose, vitamins and other trace elements (which can cause additional complications for our patients, such as problems with calcium balance in the body due to vitamin D deficiency).

On top of all this, their intestinal transit time speeds up because there’s less intestine for the food to move through. This worsens malabsorption and causes diarrhoea because those nutrients are in contact with the small intestine for less time.

As the GI tract is also responsible for absorbing water and electrolytes, diarrhoea isn’t the only issue in these patients—we also see dehydration, electrolyte imbalances, and acid-base imbalances.

And, if the patient’s ileo-colic junction is removed, they are at risk of developing intestinal dysbiosis, where the population of ‘normal’ bacteria become imbalance and patients develop antibiotic-responsive diarrhoea. This occurs because we have slight differences in our ‘normal’ bacteria in different areas of the intestines - and if the colon joins to the small intestine directly, these populations can mix and change.

Okay, so we know that SBS is bad news. But what signs do we see in these patients?

Well, usually, we have an idea that SBS is coming because we’ve had to chop out a significant chunk of intestine.

These patients will have presented initially with signs consistent with intestinal obstruction (such as vomiting, anorexia and dehydration).

After their surgery, signs suggestive of SBS include diarrhoea, malabsorption, weight loss (which is usually severe) and electrolyte imbalances.

Watery diarrhoea is the most common and severe clinical signs and typically begins soon after surgery. Acute weight loss can be seen due to dehydration, alongside skin tenting, dry or tacky mucous membranes and sunken eyes.

Persistent diarrhoea, ongoing weight loss, steatorrhea (fatty faeces) and other evidence of malnutrition are also seen. 

Depending on the type, severity and duration of electrolyte abnormalities, signs such as weakness (due to hypokalaemia) and neuromuscular signs or osteopenia can be seen (due to hypocalcaemia).

Though these patients may initially have anorexia as they recover from gastrointestinal surgery, they will become polyphagic as they try to compensate for their reduced ability to digest and absorb nutrients from food (similar to patients with exocrine pancreatic insufficiency, as we discussed in episode 58).

After their initial recovery from surgery (assuming they are well hydrated and have no complications, such as surgical site breakdown), these patients are usually bright and alert. However, they will require intensive long-term medical care.

Over time, their intestine will compensate for its reduced volume by becoming hyperplastic (thickened and enlarged). These changes will help the patient’s signs somewhat, though they’ll still have some diarrhoea, weight loss and water loss without appropriate treatment.

And how do we diagnose these patients?

In the majority of cases, a diagnosis is made based on compatible clinical signs and examination findings in a patient who has had significant intestinal resection.

Initial diagnostic tests to investigate an intestinal obstruction are performed prior to surgery, as we discussed in episode 54 on GI foreign bodies. These include abdominal radiographs or ultrasound in addition to routine bloodwork.

Patients with short bowel syndrome will show evidence of malabsorption on bloodwork. Vitamin B12 levels will be low, and folate levels may be increased or decreased. 

Biochemistry typically reveals hypoalbuminaemia alongside evidence of electrolyte abnormalities such as hypokalaemia and hypocalcaemia where present, and anaemia may be seen on haematology.

Ok, so we think our patient has SBS - how will we treat and nurse them?

We can divide the care we give our SBS patients into two main sections - acute post-surgical care and long-term (outpatient) care.

Let’s start by looking at postop care

Patients with SBS need aggressive supportive care. These patients are often not just dealing with the consequences of their intestinal resection - many of them have concurrent complications like septic peritonitis due to intestinal perforation, meaning they need even more intensive treatment and nursing care.

In the immediate postoperative period, our focus needs to be on:

  • Fluid balance

  • Electrolyte balance

  • GI motility and managing any postoperative ileus present

  • Nutrition

  • Pain and analgesia

  • Elimination management

  • Monitoring carefully for early signs of surgical site breakdown

  • Nausea and vomiting

These patients are often significantly dehydrated and at risk of electrolyte abnormalities, so appropriate fluid therapy should be provided, with supplementation as needed. We need to keep a close eye on their hydration and perfusion status and adjust their fluids accordingly.

Many of these patients require partial parenteral nutrition in hospital, to deliver sufficient nutrition. Parenteral nutrition is the delivery of a specialised intravenous glucose, amino acid, electrolyte and lipid solution; it is not without risk, and is only performed in 24/7 intensive care settings. It also needs to be delivered through a central venous catheter - and placing and managing these is a great advanced nursing skill for us to use with these patients.

It is important to deliver some enteral nutrition alongside this - firstly, as this is the preferred method of feeding all of our patients (the old saying ‘if the gut works, use it!’ is VERY true, even in patients with GI disease) but also because the GI tract trying to digest and absorb will help those compensatory changes kick in. So if you can, get *something* in via the GI tract - even if they can only tolerate small amounts.

Aside from this, most of the initial management of these cases is the same for intestinal foreign body patients - monitoring for complications after enterectomy, pain scoring and providing appropriate analgesia, and providing supportive care.

And then there’s long-term management

Without appropriate medical management and dietary modifications, these patients will never be able to significantly improve their body condition and nutritional status - and this means that our nursing doesn’t stop when the patient is discharged after surgery.

Long-term treatment of these patients includes:

  • Nutritional support

  • Vitamin B12 supplementation (alongside supplementation of other vitamins as required depending on the individual patient)

  • Appropriate antibiotics if the patient has antibiotic responsive diarrhoea (such as metronidazole or tylosin)

  • Antacids to minimise excess secretion of gastric acid, which can occur secondary to short bowel syndrome.

And what should we feed these patients?

The general recommendation when feeding a short bowel syndrome patient is to feed small volumes of low-residue, moderate-to-high-fat, energy-dense foods with low-to-moderate fibre content. Depending on the individual, supplementation of deficient micronutrients (such as calcium, magnesium, or zinc) and fat soluble vitamins may also be required.

Many patients also require pancreatic enzyme supplementation with their food, just like a patient with exocrine pancreatic insufficiency (episode 58).

And just like our EPI cases, ongoing nutritional assessment, bodyweight and body condition scoring is absolutely essential - and is a great area for nurses and technicians to get involved in. These patients will always have significant risk of malnutrition and require careful monitoring and ongoing care, so regular examination, advice and support is needed.

Whilst we don’t see short bowel syndrome often, they are often SO challenging to manage that I wanted to make sure you had a resource to use in case you ever see a case. If you’ve got a really challenging foreign body patient or septic abdomen and your vet needs to resect a lot of intestine, make sure you keep a close eye on their fluid and electrolyte balance, eliminations and nutrition - and keep assessing them regularly, even once they’ve been discharged.

Did you enjoy this episode? If so, I’d love to hear what you think. Take a screenshot and tag me on Instagram (@vetinternalmedicinenursing) so I can give you a shout-out and share it with a colleague who’d find it helpful!

Thanks for learning with me this week, and I’ll see you next time!

References and Further Reading

Laura Jones
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