Explainers

Crohn’s Disease


Crohn’s disease is a chronic and lifelong gastrointestinal disorder that causes inflammation in the colon, rectum and GI tract.

It’s one of the two most common forms of inflammatory bowel disease (IBD)  – the other being ulcerative colitis – and although it can affect any part of the gut, it’s commonly the ileum or colon that are most affected.

The severity of the disease is unpredictable, but severe flares can lead to hospitalisation and possibly even surgery and a temporary or permanent stoma.

It’s this fluctuating nature of the condition that has the most impact on our patients, affecting their emotional, physical and social wellbeing, along with potentially life-threatening complications.

An Emerging Global Disease that Shows Little Sign of Slowing Down

According to the report Improving Inflammatory Bowel Disease Care Across Australia, 1 in 250 people aged between 5 and 40 are affected by IBD.

Indeed, Crohn’s disease is considered to be an emerging global disease, with Australia having one of the highest rates of prevalence in the world with more than 80,000 Australians living with inflammatory bowel disease (Crohns & Colitis Australia 2018).

The report also found that care for inflammatory bowel disease is inconsistent and inadequate despite vast amounts of money being spent on healthcare for the condition. In 2007 an average of $2.7 billion was spent on Crohn’s disease and Ulcerative Colitis.

As the number of patients with the condition is set to increase to 100,000 over the next 4 years, so will the cost of treating them.

It’s crucial to have an understanding of what it is, how to diagnose it and how it can impact on our patients.

What is Crohn’s Disease?

Crohn’s disease is where one or more patches of inflammation develop in parts of the gastrointestinal tract. Although any part of the gut can be affected, including the mouth, oesophagus and stomach, it’s typically the ileum where the disease begins.

The patches of inflammation can vary in size, and it’s not unusual for several patches to develop along the gut with normal sections in between.

In around 30% of cases, the inflammation is restricted to just the small intestine, in around 20% of cases the inflammation is in just the colon with the remaining 50% occurring in different places along the gastrointestinal tract.

The inflammation itself can penetrate all layers of the intestinal wall, not just the lining, which can lead to additional complications such as:

  • Abscesses and skin tags outside the anus.
  • Fissures – ulcerated tears/cracks in the lining of the anal canal.
  • Fistulae – abnormal channels connecting different loops of intestine together, or even to other body organs.
  • Intestinal obstruction or narrowing of the intestinal wall – known as strictures.
  • Malabsorption and malnutrition.

Symptoms of Crohn’s Disease

Crohn’s disease can affect people of all ages, although symptoms most commonly appear in childhood and early adulthood.

Actual symptoms can vary depending on which part of the gut has been affected by the inflammation, although commonly diarrhoea, abdominal pain and feeling unwell are present.

Diarrhoea is often the first symptom to appear and can vary from mild to severe. It’s often mixed with mucus, pus or blood and there is a strong feeling of urgency to pass a motion, though often there is nothing left to evacuate.

Abdominal pain and discomfort will occur in around 70% of cases, with the pain being located at the site of inflammation. It’s common for the pain to be on the lower right of the abdomen where the ileum is located, though for this reason the Crohn’s is often misdiagnosed as appendicitis until further tests have been carried out.

Weight loss is a common feature in Crohn’s as a result of the malabsorption and malnutrition, which can also lead to anaemia and vitamin deficiencies. Loss of appetite, fever, and fatigue are also frequently seen.

Some less common symptoms that may appear as a result of Crohn’s disease include:

  • Inflammation and pain in the joints;
  • Inflammation of the middle layer of the eye – uveitis;
  • Liver inflammation;
  • Skin rashes.

How Does Crohn’s Disease Typically Present in Patients?

Crohn’s is usually categorised according to the parts of the gut that are most affected by the inflammation.

Terminal ileal and ileocaecal – where the Crohn’s is affecting the end of the ileum and/or the beginning of the large bowel. One of the most common forms of the disease which typically causes pain in the lower right side of the abdomen, diarrhoea and weight loss.

Colonic – where the inflammation is found in the colon and is sometimes known as ‘Crohn’s Colitis’. The main symptom here is diarrhoea with blood and mucus. The colon can’t hold as much waste as usual due to the inflammation, and this causes frequent bowel movements.

Small bowel – where the Crohn’s is found here and may be referred to as ileitis or jejunoileitis dependent on which part of the small bowel is affected. Abdominal pain, diarrhoea and nutrient deficiencies are the common symptoms here, with this form of Crohn’s more commonly seen in children and teenagers.

Perianal – where inflammation is found in the anus. It’s common for perianal symptoms to develop before intestinal symptoms with this form of Crohn’s, such as anal tags, fissures and fistulas, haemorrhoids and abscesses.

Gastroduodenal – a much less common form of Crohn’s where the inflammation is found in the oesophagus, stomach or the duodenum. Typical symptoms include indigestion-type pain, nausea, vomiting, poor appetite, weight loss and anaemia.

Crohn’s Disease v Ulcerative Colitis

The key difference between Crohn’s disease and ulcerative colitis is that the latter only affects the colon, where ulcers and sores will develop. These can then produce mucous and pus, which leads to abdominal discomfort, frequent bowel movements and other symptoms.

The symptoms of both conditions are so similar that it can be difficult to diagnose from presentation alone, though as you can see from the types of presentation above, Crohn’s can cause nausea, vomiting, and perianal symptoms not found with Ulcerative Colitis.

Crohn’s Disease Causes

It’s unknown what causes Crohn’s disease, although it’s likely to include a number of factors such as: inheriting susceptible genes; a trigger to the immune system, such as antigens in the environment; or a bacteria or virus.

Current thinking is that both forms of IBD are triggered by the body’s immune system overreacting and mistaking the lining of the gut as a foreign object and setting off the inflammatory response.

Crohn’s Disease Diagnosis

Due to the similarities between Crohn’s disease and ulcerative colitis, it is important that tests are conducted for each condition to avoid misdiagnosis.

Endoscopy is the first step in diagnosis with an upper endoscopy used to assess the oesophagus, stomach, and the first part of the small intestine. A colonoscopy or sigmoidoscopy is used to examine the colon for inflammation. If inflammation is found outside the colon, it cannot be ulcerative colitis.

It’s usual for biopsies to be taken from infected areas of the gut to determine between IBD and other conditions, such as cancer.

Other tests used to distinguish between the two types of inflammatory bowel disease include x-rays of the upper and lower GI tract, chromoendoscopy, and other visual imaging methods.

Crohn’s Disease Treatment

There is no cure for Crohn’s disease although there are a variety of treatments that can be used to manage the condition and its symptoms. Typically, a holistic approach of medication, diet plans and surgery, where necessary, will be used.

A course of corticosteroids is often used to reduce the inflammation, and in around 70% of cases, symptoms are vastly improved within 4 weeks. The dose is then gradually reduced and stopped once symptoms have eased and the flare-up has settled.

Immunomodulators may also be used to modify and suppress the immune system. These tend to be used in more severe cases where steroids have failed to ease symptoms.

Monoclonal antibodies can also be used in patients with severe cases of Crohn’s disease where other medications have failed to make an impact. These are genetically engineered antibodies that block the action of a chemical called cytokine tumour necrosis factor alpha (TNF-α) which is involved in the inflammation process of Crohn’s disease, thereby suppressing the immune system’s response.

Crohn’s disease can cause loss of appetite, and although the food itself isn’t responsible for the condition, modifying what is eaten can be helpful in reducing and managing symptoms.

Individual meal plans are important as symptoms vary per patient according to where the inflammation is sited. An effective meal plan will ensure that essential nutrients aren’t being lost during flare-ups and that nutrition is adequate for the individual and their lifestyle.

As many as 8 in 10 people suffering from Crohn’s Disease require surgery at some stage in their lives from complications, with around 50% within the first 10 years of developing the condition (Tidy 2017).

The most common reason for surgery is to remove a stricture that has formed, although other complications that require surgery include perforation of the bowel, excessive bleeding and cancerous growths.

Symptoms of Crohn’s can be unpredictable, and a well-managed case can quickly turn into a severe flare-up of the disease. Frequent communication between the patient and their healthcare practitioners is essential in identifying early symptoms and making rapid referral when required.

Unresponsive abdominal symptoms are the first indicator that referral may be needed, along with vitamin and nutrient deficiencies, and unexplained weight loss. Emergency referral should be made where signs of blood loss are apparent, including tachycardia, weak pulse, shallow breathing and pale, clammy skin alongside abdominal symptoms.

Careful management is essential for this chronic condition

As Crohn’s disease is a chronic and lifelong condition, it requires careful management from the patient and a good working relationship with the health team around them. Unfortunately, with the unpredictable nature of flare-ups, many patients can feel disheartened and experience anxiety and depression alongside the condition preventing adequate care and maintenance.

This can particularly be the case with young patients, who, while suffering from relapse, reported a lower quality of life and had a higher depression score than those in remission according to Rowse et al. (2016).

It’s important to identify risk factors both pertaining to Crohn’s disease and co-morbidities that may develop over a patient’s lifetime to ensure that best care is delivered, and adverse complications are reduced and prevented wherever possible.

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