Short Bowel Syndrome and Crohn’s Disease: What Is the Connection?

Crohn's disease and short bowel syndrome both affect your digestive system, but they are not the same condition. Crohn's disease is a type of inflammatory bowel disease. Short bowel syndrome happens when your small intestine cannot absorb enough nutrients from food. In some people with Crohn's disease, the 2 conditions become connected.¹

What is short bowel syndrome?

Short bowel syndrome develops when your small intestine is too short, or does not work well enough, to absorb nutrients from food. It most often happens after surgery to remove part of the small intestine, though it can also occur when the intestine is diseased, damaged, or shorter than typical at birth.^1,2

Chronic short bowel syndrome is rare, and experts are not sure how many people have it, since the intestine often heals and adapts over time.²

What is Crohn's disease?

Crohn's disease is a long-term condition that causes swelling and irritation in your digestive tract. It is one of the main types of inflammatory bowel disease and can affect any part of the tract, though it most often involves the small intestine and start of the colon.³

Common symptoms of Crohn’s disease include belly pain, ongoing diarrhea, fatigue, and unexpected weight loss, and over time it can make it harder for the body to absorb nutrients from food.³

How common are the 2 conditions?

Crohn's disease is one of the more common digestive conditions, affecting about 1.3 million adults in the United States. Short bowel syndrome is far less common and is considered rare, affecting between 10,000 and 20,000 adults and children.^3,4

Most people with Crohn's disease never develop short bowel syndrome. Research has found that short bowel syndrome develops in about 3.3 to 7.8 percent of people with Crohn’s, usually after repeated surgeries or serious complications.⁵

The risk of Crohn’s disease patients developing short bowel syndrome commonly increases at 15 to 20 years of living with the disease.⁵

How are short bowel syndrome and Crohn's disease connected?

Surgery is the most common point of connection between short bowel syndrome and Crohn's disease. Crohn's disease can severely damage the small intestine, causing blockages, abnormal connections called fistulas, and areas of infection that cannot always be managed with drugs alone. When this happens, a doctor may recommend surgery to remove the damaged intestine.^3,6

If enough intestine is removed, or a person needs repeat surgeries over the years, the remaining intestine may not absorb enough nutrients, which is how short bowel syndrome can develop in a person with Crohn's disease. In fact, Crohn's disease is one of the most common underlying causes of long-term intestinal failure, a condition closely related to short bowel syndrome.^1,5

Certain factors increase the chances that a person with Crohn's disease will develop short bowel syndrome, including receiving steroid treatments, recent weight loss, an abdominal abscess, and smoking.⁵

Symptoms that overlap between short bowel syndrome and Crohn's disease

Short bowel syndrome and Crohn's disease share several symptoms, which can make new digestive changes hard to sort out. Overlapping symptoms include:^1,3,6

• Diarrhea – Loose or watery stools occur with both conditions. Short bowel syndrome can also cause greasy, foul-smelling stools from unabsorbed fat.
• Fatigue – Unusual tiredness can come from a Crohn's disease flare or from nutrient losses caused by short bowel syndrome.
• Weight loss – Both conditions can make it hard to get enough calories and nutrients from food.
• Abdominal pain or bloating – Cramping, gas, and bloating can occur with either condition, or both together.

Warning signs of short bowel syndrome to watch for

If you have Crohn's disease, and especially if you’ve had intestinal surgery, it is important to know the specific signs that could point to short bowel syndrome rather than a typical flare. A few things to watch for include:^2,6-8

• Watery diarrhea that does not improve – Ongoing, high-volume diarrhea soon after bowel surgery can mean your remaining intestine is not absorbing enough fluid.
• Signs of dehydration – Dark urine, extreme thirst, dizziness, or sunken eyes and cheeks can mean your body is losing more fluid than it can replace.
• Unexplained weight loss – Continued weight loss despite eating enough food can point to malabsorption.
• Signs of a vitamin or mineral deficiency – Numbness or tingling, hair loss, unusual bruising, or mouth sores can develop when your body cannot absorb enough vitamin B12, iron, zinc, calcium, or magnesium.

Talk to your doctor

If you have Crohn's disease and notice any of these warning signs, especially after bowel surgery, tell your doctor. Short bowel syndrome can often be managed with nutrition support, diet changes, and close monitoring from your care team, though some people need long-term nutrition through an IV.^7,8

Short bowel syndrome and Crohn's disease affect everyone differently, and treatment works differently for each person. Your doctor can help build a plan that fits your needs, and you are not alone in managing these conditions.