Introduction

What is crohn’s disease?

Crohn’s disease (CD) is a long-term condition where the immune system’s reactions are abnormal, causing inflammation in the digestive tract, most commonly affecting the small intestine and the start of the large intestine. However, it can affect any part of the digestive tract (from the mouth to the anus).

CD is a type of inflammatory bowel disease (IBD), a term for diseases that cause chronic inflammation in the intestines or irritation. CD is one of two common types of IBD, and there are ways, such as Endoscopy, that can contribute to CD diagnosis and can differentiate between CD and UC.

Role of endoscopy

Endoscopy is an imaging technique that examines structures of the body through the insertion of an endoscope, a long, thin tube, into the body to the required area or organ needed for examination.

It plays an important role in the diagnosis, management and treatment of IBD. It allows us to distinguish between CD and the other type of IBD, ‘Ulcerative Colitis’ (UC), monitor the activity of the disease and treatment response, and assess and treat complications.¹

Endoscopy is the most accurate method for CD diagnosis and to eliminate other health issues.²

In paediatric patients, endoscopy allows doctors to see the gastrointestinal mucosa (mucous lining) of the gastrointestinal (GI) tract and biopsy abundant sites.³

Types of endoscopic procedures

Upper endoscopy - The Doctor uses an endoscope with a camera attached to see the lining of the upper GI tract. This includes the mouth, oesophagus, stomach and small intestine.

Ileocolonoscopy - a test to look at the end of the small bowel and colon (large bowel) for anything abnormal. This is used for confirmation on ruling out a condition or diagnosis. 

Capsule Endoscopy (small bowel) - This is also known as a ‘pillcam’ and includes ingesting a capsule, which helps to find abnormalities within the small bowel. This is part of the GI tract, between the stomach and large bowel.

(Device-assisted) Balloon-assisted enteroscopy - Insertion of a long endoscope with attached camera and light, to analyse the oesophagus, stomach and deep small intestine, allowing for diagnosis and treatment. It also allows, in the small intestine, bowel and relevant areas to introduce air inside to allow for dilation of the area for a better view. Furthermore, it allows water for clearing the intestine or instruments for other procedures.

Endoscopic ultrasound (rare in paediatrics) - A Combination of an ultrasound and an endoscope to look at the upper GI tract. The endoscope has an ultrasound probe on its end. Ultrasound scans use high-frequency sound waves to create an image of the body and the area being examined.

In endoscopies, the endoscope can be inserted orally, via rectum/anus or through an incision made in the body.⁴

When is an endoscopy needed?

When to perform

• When concerning symptoms arise, which may include: abdominal pain, bloody diarrhoea, weight loss and/or positive serum inflammatory markers: C-CRP and/or ESR and/or high faecal calprotectin levels.⁵ These inflammatory markers are found to be high⁶
• Positive family history of IBD or extraintestinal symptoms⁷eg. perianal disease/abscess

If any symptoms or signs indicative of Crohn's disease are experienced, it is best to get medical attention. 

Symptoms of paediatric Crohn’s disease

Symptoms can appear unexpectedly or have been ongoing and build over time. These may be due to trauma, illness or stress, but sometimes in CD they do not have a start source that triggered the onset. 

Symptoms may include:

• Cramping 
• Abdominal pain 
• Ongoing watery diarrhoea, which can contain blood 
• Some may experience an urgency to move their bowels 
• Feeling tired
• Fever
• Nausea 
• Loss of appetite
• Some children may experience failure to gain weight and grow
• Malnutrition due to lower calorie consumption 
• Malabsorption - difficulty of the intestines absorbing nutrients
• Delay in starting/experiencing puberty 
• May develop anaemia(low levels of red blood cells) 
• Bleeding in children from the gastrointestinal system which is not seen by the naked eye¹²

At diagnosis

In suggestion to CD in paediatrics, endoscopy can support diagnosis confirmation as it may highlight the presence of deep ulcers, aphthous ulcers, nodules and strictures, which can be found in presentation of CD. There may also be involvement of the oesophagus. Ulcers are open sores that arise due to inflammation. Those in CD are deep lines that grow outwards through the intestinal wall.⁸

Many studies have shown that upper GI endoscopy helps to differentiate between CD and UC. Therefore, it is currently recommended for routine upper endoscopy at the early stage evaluation for suspected IBD in paediatrics.³ Therefore, endoscopy is needed and a crucial part for diagnosis as well as for monitoring the condition over time. 

In CD, lesions can appear anywhere in the GI tract, but aphthae and linear ulcers are usually found in the ileum or colon. Usually for paediatric CD, endoscopic results show aphthous ulcers and tortuous ulcers/dieulafoy lesion⁹, this creates and is known as having a cobblestone appearance,¹⁰ a narrowing of intestinal tract, anal lesions (anal fissures, abscesses, anal stenosis, anal canal ulcers, inflammation of the hilum), skip lesions (patchy inflammation or wound resulting usually from intestinal damage from CD) and ulcers in the small intestine-mainly in the jejunum and ileum.

In CD that affects only the colon (colonic CD) this can be identified from UC due to the presence of skip lesions, lesions in the upper GI tract, cobblestone appearance, aphthous ulcers and GI stenosis.¹¹

Severity

A severity assessment should be conducted, and an endoscopy is needed to undergo this, alongside diagnostic evaluation in support of paediatric CD diagnosis and monitoring. However, for children, there is no specific ‘endoscopic severity assessment’, but there are scoring systems instead to check severity. These include: Simple Endoscopic Score for CD and CD Endoscopic Index of Severity. Number and scoring systems allow healthcare professionals to understand the severity of CD and/or UC.¹¹  

Evaluation 

Endoscopy is also needed for the evaluation of the intestinal mucosa (inner intestinal lining) to ensure mucosal healing in clinical recovery and during the treatment process. This is to check for any success from management and treatments, or for any further complications that may have arisen. 

After a bowel resection, surgery for the removal of damaged, diseased or blocked intestine, an endoscopy for mucosal healing review and inspection should be carried out six to twelve months later for check-ups and evaluation during post post-surgery period. High-risk CD, onset at a younger age, severe disease, previous drug unresponsiveness and any other complications can require evaluation of the mucosa after six months. Levels of faecal calprotectin may affect the timing of these follow-up procedures.

Overall, endoscopy should be used initially before any treatment or management methods in order to exclude any other conditions and to diagnose any complications.⁵

Mucosal healing 

Endoscopy can check for mucosal healing. This is when the intestinal lining has or is in the process of returning to normal, and reduced/no endoscopic lesions are present, as due by signs relevant to CD, including but not restricted to ulcers and cobblestone appearance.¹³ Yet still, it can be scored, contributing to checking the severity and condition of CD. Mucosal healing is a target as it shows good management and treatment of CD.¹⁴

Summary 

To summarise, CD is a condition where there are abnormal reactions of the immune system that cause inflammation in the digestive tract. It is important to receive medical attention for diagnosis and confirmation of CD and to rule out any other conditions or complications.

An endoscopy is usually performed and is a great way to assess for CD and work towards diagnosis, alongside other clinical and laboratory findings, e.g presence of high and/or positive biomarkers: faecal calprotectin, C-CRP and/or ESR. Endoscopy findings allow us to differentiate between types of IBD due to their presentations in the GI tract/area. Not only for diagnosis, but endoscopy plays an important role in being completed upon and through treatment and management processes to check for mucosal healing, linings in the GI tract and intestines, whether any success or for complications post and throughout treatment and management. It is also needed to check the severity level of CD in patients. As endoscopy provides a view of internal structures, this can be done.