What Is Ischaemic Colitis

Ischaemic colitis (IC) is a frequently misdiagnosed condition; therefore, more attention should be paid to various signs and symptoms experienced, as it is fully treatable if caught in time and when the correct measures are taken. Symptoms are very similar to any gastrointestinal (GI) tract disorder; hence a good knowledge of the topic by the patient would be essential for the best outcome.

Ischaemic colitis, also known as a type of mesenteric colitis, is a condition that is the result of reduced blood flow to the large intestine due to different cofactors such as narrowing of the blood vessels (atherosclerosis), hernia, clot formation (obstructing the bowel), twisting of the bowel also known as volvulus, etc. Around 75% of the cases are considered reversible and mild, thus easily treatable with the right medication.

As IC is often misdiagnosed, educating patients about the symptoms related to the disease, people at risk, diagnosis procedures, different treatment options depending on the severity of the disease, and what to look out for, is of great importance for early detection.

Overview 

Ischaemia (reduced blood flow/supply); Colitis (inflammation of the large intestine/colon)

Ischaemic colitis (IC), also known as colonic ischaemia, is described as the inflammation of the large intestine/colon that results in reduced blood supply (ischaemia) to specific parts of the colon, causing a decreased metabolic function.¹ IC is the most common type of GI tract-related ischaemic injury, also known as mesenteric ischaemia (reduced or halted blood supply to the small or large intestine). It is a frequently misdiagnosed condition as symptoms are linked to abdominal pain and discomfort found in many other gastrointestinal tract disorders such as irritable bowel syndrome (IBS). There are two types of IC: 

• Mild/non-gangrenous (~75%)
• Severe/gangrenous (~25%) 

As a result, reversible or irreversible damage to the colon, either partially or fully, can occur. Two-thirds of the cases concern the upper left part of the colon, whereas the other one-third affects the right portion of the colon (more severe/gangrenous IC).

Causes of ischaemic colitis

A specific cause of IC has not been determined yet due to the large degree of misdiagnosis of the condition, together with many cases of mild IC going unrecorded. However, the main causes are thought to be:

•  Occlusive (formation of blockage/occlusion of blood vessels)
•  Non-occlusive

There are also some cofactors listed below that have been found to be linked in some way to the development of IC.² Non-occlusive causes are mainly found in young people. 

Signs and symptoms of ischaemic colitis

Symptoms vary depending on the time and severity of the disease. Many symptoms are fairly similar to those experienced in most other GI tract-related health conditions such as:

• Abdominal pain/tenderness and discomfort
• Diarrhoea
• Intestinal bleeding
• Bloody stools
• Nausea
• Fever

However, the right-side involvement of the colon, called isolated right colon ischaemia (IRCI), is associated with slightly different symptoms than left-side involvement. IRCI causes more abdominal pain without blood in the faeces and has a worse overall outcome.² 

Management and treatment for ischaemic colitis

As most cases are mild, they are easily treatable with medication, resulting in full recovery. However, this accounts mainly for the left-side involvement in IC. When the right side of the colon is affected, the degree of IC is considered more severe (gangrenous IC), and surgery may be required. Gangrenous means that there is tissue death in the specific region due to reduced blood flow. Different treatment options would be implicated depending on the severity and the progression of the disease.

Mild cases:

• Liquid diet
• Antibiotics
• Frequent observation of the current state of the condition by a doctor

Intermediate cases:

• Hospitalisation may be required for closer observation
• Antibiotics
• Stop the intake of medication that could be contributing to IC (listed below in Risk Factors)

Severe cases:

• Surgery
• Using IV for nutrition administration in patients not suitable for surgery
• Monitoring for necrosis (tissue death) of the affected area due to the reduced blood flow and oxygen supply required for normal tissue function
• Potential bowel resection (a surgical procedure where part of the intestine is removed)

Approximately 20% of patients diagnosed with IC require a surgical intervention, especially when the IC is considered gangrenous/severe.³

Diagnosis

The best diagnostic tool for detecting ischaemic colitis is via colonoscopy. However, there are some other analytical procedures that can help with assuring the diagnosis.⁴

• Laboratory assessment: blood tests (IC diagnosis can not be solely stated on blood tests)
• Colonoscopy: a medical procedure where a doctor uses a camera to look inside your rectum and colon
• Mesenteric angiopathy: an imaging test using X-ray and a type of dye that looks at the blood vessels supplying the small and large intestines
• Computed tomography: an imaging technique where a computer is used together with an X-ray to get different images of internal parts of the body

Risk factors

Risk factors are accompanying health conditions such as:

• Diabetes mellitus
• Hypertension
• Coronary artery disease
• Congestive heart failure
• Recent myocardial infarction/heart attack
• Chronic constipation
• Atherosclerosis (narrowing of the arteries due to fatty deposits and build-up)
• Small-vessel diseases, resulting in vessels narrowing or occlusion 
• Amyloidosis (build-up of amyloid protein in the blood vessels) 
• Major vascular surgical procedures
• Intake of various drugs including digoxin, diuretics, oestrogen, vasopressors, antibiotics, appetite suppressants (phentermine), chemotherapeutic agents (vinca alkaloids and taxanes), constipation-inducing medication, immunosuppressive agents, laxatives, nonsteroidal anti-inflammatory drugs (NSAIDs)⁵

The most susceptible age group in the general population is the elderly around 70 years of age, together with people assigned female at birth (AFAB). Also, patients who have been put on haemodialysis due to chronic renal failure have been found to have a higher incidence of developing right-side colonic ischaemic colitis.⁶

Complications

There are always possible complications with any disease. That is why early detection is vital for the prevention of further progression of the condition. Potential complications of ischaemic colitis are:

• Gangrene (tissue death due to reduced blood flow) 
• Bowel obstruction
• Perforation (hole formation) of the intestinal wall

FAQs

How can I prevent ischaemic colitis?

As there is no identified specific cause of IC, no certain way of prevention has been established. However, what you can always do is go for regular colonoscopies (once per year) in order to check your GI tract health. Also, you can prevent some of the risk factors associated with IC, such as blood vessel diseases like atherosclerosis, by liming your intake of high fatty foods (leading to fat build-up in the blood vessels), controlling your diet, exercising regularly and keeping active for better heart function and overall health.  

How common is ischaemic colitis?

No definitive answer can be given here due to frequent misdiagnosis of the disease, as well as many cases going undetected. However, there are some studies that have tried to identify the incidence in the general population, observing 4.5 to 44 cases per 100,000 persons per year, with people AFAB being more prone to IC.⁵

What can I expect if I have ischaemic colitis?

The main signs associated with ischaemic colitis are:

• Intense abdominal pain and tenderness
• Diarrhoea
• Lower GI tract bleeding
• Bloody faecal extensions
• Fever/nausea

If you present with any of these symptoms, do visit your GP for further consultation.

When should I see a doctor?

You should contact your GP if you:

• Have any symptoms linked to IC
• Are experiencing unusual, constant pain in your abdominal area that is not going away 
• Notice blood in your stool sample

This could indicate anything from tears in your anus, also called anal fissures, to more serious GI tract disorders. Your GP can arrange blood or faecal lab sample tests to help determine the cause of your symptoms. If necessary, you will be referred to a hospital where specialists can have a look at your condition.

Summary

Ischaemic colitis is the most common type of ischaemia in the GI tract. It is often misdiagnosed or undetected with most cases being mild/non-gangrenous ~75%. Symptoms range from abdominal pain, discomfort and diarrhoea to intestinal bleeding and bloody stools, where in two-thirds of cases, the left colon is affected. The usual recovery period for mild/acute IC is between 24-48 hours. The best approach for diagnosis would be a colonoscopy. People more prone to developing IC are the elderly population aged around 70, and people AFAB. Patients with accompanying diseases related to the blood supply and the cardiovascular system also have a higher incidence of IC. There are different treatment options depending on the severity and progression of the disease, therefore if experiencing any of the signs and symptoms, further consultation with your GP is highly recommended in order for correct diagnosis and discussion of further approaches.