While on this website, we provide educational resources with a focus on IBS (irritable bowel syndrome), it is also important to introduce IBD (irritable bowel disease) to avoid potential misdiagnosis. This article describes the key differences between the two commonly mistaken bowel disorders.
What is IBD?
IBD is a bowel disease characterised by abdominal pain with frequent loose stools and fatigue. In some cases, bloody diarrhea may be seen. There are two types of IBD:
- Ulcerative colitis – a disorder that involves inflammation and ulcers along the lining of the colon
- Crohn’s disease – disorder with inflammation in the lining of the digestive tract, primarily the small intestine
How is IBD diagnosed and treated?
The first clues of IBD are chronic diarrhea, blood in the stool, and abdominal pain. It is also associated with fatigue, weight loss, and nausea. Several diagnostic methods may be used including blood tests, X-rays, or colonoscopy. The doctor needs to rule out other conditions, including IBS. The treatments include:
- diet and lifestyle changes
- over-the-counter medications for symptom management
- anti-inflammatory drugs
- immunosuppressants
- surgery might be necessary in severe cases
What is IBS?
IBS is an umbrella term that covers many different chronic bowel symptoms including constipation, not only diarrhea. Symptoms of IBS include abdominal pain, bloating, diarrhea/constipation, or a mix of both. Learn more about the symptoms of IBS. These symptoms the normal bowel function leading to chronic digestive issues.
How is IBS diagnosed and treated?
There is no straightforward diagnostic method for IBS. It is diagnosed using different methods to exclude other potential causes of the symptoms. One of the diagnostic methods used is the Rome IV criteria. For the treatment of IBS, several approaches may be considered:
- diet and lifestyle changes
- antidepressants
- over-the-counter medications for symptom management
How are they similar?
- IBD, IBS with diarrhea (IBS-D), and Post-infectious IBS (PI-IBS) share common symptoms, diarrhea, abdominal pain, and bloating.
- Worsening symptoms seem to be triggered by stress or other psychological factors like mental health disorders or traumatic life events.
- One of the causes of both of these conditions is dysbiosis (imbalance) between good and bad bacteria in the gut. Both may benefit from a low-FODMAP diet.
How are they different?
- The main difference between IBS-D and IBD in symptoms is that rectal bleeding or bloody diarrhea is not a common symptom of IBS-D.
- Colonoscopy results for IBS often reveal normal mucosa (protective layer lining the intestine) with an increased number of white blood cells, esp. in PI-IBS. Mucosa is typically more visibly disrupted in IBD.
- Calprotectin (protein found in some white blood cells) can be used to distinguish IBS and IBD. Increased levels of calprotectin are associated with IBD.
- IBD is much less common (1-3% of the population) than IBS (10-15% of the population).
- IBD may be genetic since there are some genes associated with the disease while with IBS it is still unclear. The genes for IBD are less common which could explain why IBD is generally less common than IBS.
References
Spiller, R., & Major, G. (2016). IBS and IBD — separate entities or on a spectrum? Nature Reviews Gastroenterology & Hepatology, 13(10), 613–621. https://doi.org/10.1038/nrgastro.2016.141