Introduction

Microscopic Colitis is a chronic inflammatory disease of the large bowel. It is a less common form of inflammatory bowel disease. Microscopic Colitis has long been considered an ailment of adults only, but a few cases have been recorded in children as well. Microscopic Colitis classically presents with persistent gastrointestinal discomfort, causing a negative impact on the quality of life in children. It is crucial to promptly diagnose and manage Microscopic Colitis in order to improve their quality of life. 

We will explore the details of what Microscopic Colitis is, and understand its diagnosis and management. Read on to equip yourself with the knowledge that may help you to recognise Microscopic Colitis in children.

Understanding Microscopic Colitis

Microscopic Colitis is a chronic inflammatory disease of the large bowel. Primarily, it causes inflammation of the inner mucosal lining of the colon.¹

Microscopic Colitis (crohnsandcolitis.org.uk) 

What causes Microscopic Colitis?

Researchers are still looking for the exact cause of Microscopic Colitis, however it’s suggested that it may occur due to a combination of genetic factors and external factors. Genetic factors include gender (more likely to occur in females), and predisposition to auto-immune disorders. There is strong evidence that Microscopic Colitis is frequently associated with autoimmune disorders.² External factors may include smoking, disrupted gut flora, or damage to the gut by medicine or pathogens.^1,3 These proposed mechanisms could explain why Microscopic Colitis occurs. 

Once triggered by these proposed mechanisms, the body’s defense system abnormally attacks and damages cells in the large bowel. The large bowel becomes inflamed due to the damage. When we hear the word ‘inflamed’, we may imagine a red, swollen and painful colon. However, as the name suggests, the damage to the cells in Microscopic Colitis can only be seen under a microscope.

Types of Microscopic Colitis

There are two types of Microscopic Colitis. Both present with similar symptoms, but can be differentiated under a microscope. 

1. Lymphocytic colitis: This type has increased lymphocytes in the inner layer of the colon. Lymphocytes cause swelling and inflammation of the tissues as a result of an abnormal response from the body’s immune system⁴ 
2. Collagenous colitis: This type of Microscopic Colitis presents with a thick layer of collagen in the wall of the colon. Some experts believe it may be the next stage of lymphocytic colitis, but evidence is lacking⁵ 

How does it affect the gut?

Normally, the large bowel absorbs leftover water from the food that’s being digested. However, this function is disrupted in Microscopic Colitis. The inflammation of the inner lining messes up the colon’s ability to absorb fluid, resulting in fluid buildup in the gut. Then, all the excess fluid comes out in the form of watery diarrhoea.³

What are the symptoms/ signs of Microscopic Colitis in children?

Microscopic Colitis classically presents with chronic (>12 weeks) watery diarrhoea. The diarrhoea is usually clear, with no blood or mucus. A study on Microscopic Colitis in children also documented abdominal pain, nausea, vomiting, flatulence, dehydration and fatigue. Weight loss and abdominal distension are less likely.⁶ The symptoms mentioned are not helpful in diagnosing Microscopic Colitis because they are observed in many other gastrointestinal disorders.

Diagnosis of Microscopic Colitis

It is hard to diagnose Microscopic Colitis without invasive tests. Delayed diagnosis can prolong the negative impact on a child’s quality of life and growth. So, let’s take a look at what can be done to promptly diagnose MC in children. 

Medical history and physical examination

If a child presents with persistent watery diarrhoea, it is important to take them to the doctor. The doctor will begin by taking a thorough medical history, like details about the symptoms and previous medical history. Next up, the doctor will do a physical examination. Signs of dehydration, abdominal tenderness and distention may be noted. In cases of Microscopic Colitis, history and physical examination are helpful to exclude other gastrointestinal disorders, but can’t be used to make a definite diagnosis.⁷ 

Non-invasive tests

After the initial check-up, the doctor may order some non-invasive tests e.g. complete blood count, stool culture, electrolytes, etc. These tests can help to identify any nutritional deficiencies, underlying diseases, dehydration and so on. However, non-invasive tests also can’t make a definitive diagnosis for Microscopic Colitis.⁷ 

Invasive tests

To make a definitive diagnosis, a colonoscopy with a biopsy is often required. A healthcare provider will use a slender, flexible tube equipped with a camera to examine the inner lining of the colon. Images will be captured to check for any physical irregularities. Subsequently, a tool will be passed through the tube to gather a small tissue sample from the colon wall, known as a biopsy, which will be analysed under a microscope for any abnormalities. Microscopic Colitis may be diagnosed if abundant lymphocytes or collagen are found under the microscope.⁸

Always remember to visit the doctor if experiencing diarrhoea!

Treatment for Microscopic Colitis

Management of Microscopic Colitis requires a combination of multiple treatment modalities. This includes medicine for symptoms, symptomatic therapy, anti-inflammatory medicine, treating the underlying cause, and lifestyle changes. The point of focus in children is to improve their quality of life and minimise side effects. 

In this article, our focus will solely be on treatments proven effective for children. Prior to initiating any treatment, it's crucial to consult your doctor for guidance.

Symptomatic therapy

The mainstay of symptomatic therapy in Microscopic Colitis is pain management and controlling the diarrhoea. 

Anti-diarrheals

Firstly, we need to control the persistent watery diarrhoea. Loperamide is commonly used to treat diarrhoea in children, and it’s even available over-the-counter in some countries. However, WHO discourages its use due to concerns over safety. Studies have shown that it can cause serious side effects in children with active infections and severe dehydration.⁹ Instead, Zinc supplements are preferred for treatment of diarrhoea in children. Zinc has shown to reduce the duration, severity and episodes of diarrhoea.¹⁰

Painkillers

The second most common symptom in Microscopic Colitis can be treated with painkillers like paracetamol. Paracetamol is the preferred painkiller for mild to moderate pain in children under 16 years.¹¹ 

Anti-inflammatory medication

Since the mechanism of Microscopic Colitis involves inflammation, anti-inflammatory medication is necessary to control the overall progression of the disease.

Aminosalicylic acid/ Mesalamine (5-ASA)

Aminosalicylic acid (5-ASA) medications have shown to be effective in treating Microscopic Colitis in children, whereas in adults it’s not been helpful. The good news is that 5-ASA can improve the condition and has fewer side effects than steroids. The bad news is that the symptoms may return after stopping the medication.^12,13,14 

Steroids

Studies suggest that budesonide is the superior steroid for treatment of Microscopic Colitis. It has fewer side effects than prednisolone, and is effective in resolving the symptoms.¹⁵ In a case study, a 4-year old girl with collagenous colitis was treated with budesonide for 6 months. The patient showed significant improvement of symptoms. Repeated biopsies also showed significant resolution of collagen formation in the colon. However, discontinuing budesonide resulted in relapse of watery diarrhea.¹⁶ Relapsing seems to be the main downside of budesonide. Lifelong maintenance treatment may be needed, but taking budesonide for a long time can slow down the growth and development of children.¹⁷ 

Sulfasalazine

Sulfasalazine is a disease-modifying anti-rheumatic drug (DMARD). It is commonly used to decrease inflammation in rheumatoid arthritis, but some studies have explored its use for Microscopic Colitis. In one study, sulfasalazine was able to improve the disease in a child.¹⁸ Further research is needed to assess the use of sulfasalazine in children. 

Lifestyle changes

Certain changes in diet can be helpful in relieving diarrhoea. Dietary changes are usually the first thing the doctor will ask you to try, but diet alone won’t stop progression of Microscopic Colitis. A low-fat and low-fiber diet may help control diarrhea briefly, along with limiting dairy products, gluten etc.⁸ Other changes like quitting smoking and alcohol may also be beneficial. Overall, lifestyle changes may minimize irritation of the large bowel. 

Treating underlying causes

As mentioned above, Microscopic Colitis can be caused by a number of things, like medications, infections, and other autoimmune conditions. Specific treatment of the underlying cause is necessary to treat Microscopic Colitis itself.

Summary

Microscopic Colitis is an inflammatory disease of the large bowel. Although rare, it can develop in children, classically presenting with chronic watery diarrhoea. It can have a significant impact on the quality of life, and definitive diagnosis can only be made through biopsy. Microscopic Colitis can be treated with medications like antidiarrheals, painkillers and anti-inflammatory drugs, along with lifestyle changes. Since the occurrence of Microscopic Colitis is rare in children, more research is needed to establish management guidelines for children.