What is Cytomegalovirus Colitis (CMV colitis)?
Cytomegalovirus (CMV) is a type of virus that belongs to the herpes virus family. It’s a common infection, affecting up to 100% of people worldwide, depending on their age and ethnicity. The virus itself is quite large and contains about 200 genes. When healthy people get infected with CMV, they often don’t have any symptoms or they might have short-lived symptoms. However, this virus can cause a long-term infection in some people or make them lifetime carriers of the virus which can reactivate occasionally.
This virus is also known to get active again frequently in individuals suffering from a serious condition called ulcerative colitis that is resistant to treatment with corticosteroids. However, researchers are still figuring out whether CMV worsens the symptoms of ulcerative colitis, or if its presence doesn’t contribute to the condition’s severity.
CMV infection in the colon, known as CMV colitis, typically shows up as common symptoms such as diarrhea, stomach pain, fever, bleeding from the rectum, and weight loss. Patients most frequently report blood in the stool and diarrhea.
Because these symptoms can indicate other diseases as well, it’s essential to carry out laboratory tests to diagnose CMV colitis accurately. Various methods can be used for this, including checking for antigens in the blood, performing endoscopies, examining biopsy tissue under a microscope, culturing the CMV virus, and using a test called PCR to measure the amount of virus in the tissues.
When tissue samples from the colon are stained with a particular dye and looked at under a microscope, they may show a feature called “owl eye appearance” which is typical of CMV infection. Despite this, staining is not always the most reliable method. That’s why a technique known as immunohistochemistry is considered the best for diagnosing CMV colitis.
Given the potential severity of the disease, it is usually recommended to diagnose and manage CMV colitis promptly, particularly in those who are critically ill.
What Causes Cytomegalovirus Colitis (CMV colitis)?
Cytomegalovirus colitis, an inflammation of the colon, often happens in people whose immune systems are weakened. These could be people living with AIDS, those who’ve received organ transplants, or those undergoing cancer treatment.
However, even healthy people without immune deficiencies can develop this condition. They’re usually around the age of 68 and may experience symptoms like diarrhea, stomach pain, and blood in their stool. In around a quarter of these cases, the inflammation goes away on its own without needing antiviral treatment.
In a study, certain risk factors for cytomegalovirus colitis were observed in healthy individuals. These included kidney disease, brain disorders, rheumatic diseases, or being in intensive care. People who took antibiotics, antacids, or corticosteroids, or had a blood transfusion one month before being diagnosed with colitis were also at risk. Of these risk factors, using corticosteroids and having a blood transfusion within a month were found to be key risk factors for immunocompromised individuals.
Cytomegalovirus colitis should therefore be considered in diagnosis for both immunocompromised and healthy patients, particularly older individuals presenting with blood in their stool who have co-existing health conditions, are in intensive care, or are undergoing corticosteroid treatment or blood transfusion. This condition is also typically related to severe ulcerative colitis (a type of inflammatory bowel disease), especially in those treated with high doses of corticosteroids.
Finally, cytomegalovirus colitis is a major concern for patients who have undergone solid organ or stem cell transplants.
Risk Factors and Frequency for Cytomegalovirus Colitis (CMV colitis)
Cytomegalovirus (CMV) is very common, with around 70% of adults having it. The prevalence is even higher, reaching 100%, in less privileged communities and developing countries. Around 21% to 34% of people suffering from severe acute colitis have a CMV infection. CMV reactivation is observed in 4.5% to 16.6% of patients with critical ulcerative colitis, and this figure can reach up to 25% in those requiring colectomy. When diagnosed using antigenemia and tissue biopsy examination, CMV infection rate in people battling severe, corticosteroid-resistant ulcerative colitis is observed to be between 20% and 40%.
- 70% of adults generally have the Cytomegalovirus (CMV).
- Prevalence of CMV rises to 100% in underprivileged communities and developing countries.
- 21% to 34% people with severe acute colitis are found to have CMV.
- CMV reactivation is seen in 4.5% to 16.6% of severe ulcerative colitis patients, which can reach 25% in patients undergoing colectomy.
- The infection rate of CMV is estimated to be between 20% to 40% in people with severe, corticosteroid-resistant ulcerative colitis when diagnosed with antigenemia and tissue biopsy examination.
Signs and Symptoms of Cytomegalovirus Colitis (CMV colitis)
Cytomegalovirus (CMV) infection often doesn’t show any symptoms in patients with a strong immune system. However, patients with compromised immune systems might experience symptoms, although they can be quite general and not specific to CMV infection. These symptoms can include:
- Diarrhea
- Abdominal pain
- Fever
- Tiredness
- Bleeding from rectum
- Weight loss
In confirmed cases of CMV infection in the colon (CMV colitis), the most common symptoms are bleeding from the rectum and diarrhea.
Interestingly, these symptoms can often seem like a flare-up of inflammatory bowel disease, making it hard to tell the difference between ulcerative colitis and CMV colitis based on symptoms alone.
Testing for Cytomegalovirus Colitis (CMV colitis)
To diagnose CMV colitis, doctors use blood tests and tissue samples taken during an endoscope procedure.
Blood Tests
The antibodies IgG and IgM tests can show exposure or reactivation of the CMV virus but can’t directly diagnose CMV colitis. A CMV antigenemia test, another type of blood test, can potentially predict outcomes of CMV colitis and sometimes diagnose it earlier, although it’s not always sensitive enough for diagnosis.
Endoscopy
During an endoscopy, a tube with a light and camera is used to look inside the body. Some key signs of CMV colitis that can be seen during this procedure are punched-out looking ulcers, which occur in 70-80% of cases. Sometimes, the ulcers might have an irregular, cobblestone-like appearance. Specific features like an ulcer in the cecum (part of the large intestine), particularly in patients with graft-versus-host disease, can also indicate CMV colitis.
One of the ways to diagnose CMV colitis is by identifying the “owl-eye” viral inclusions seen in stained tissue samples taken during the endoscopy. But if these are negative and CMV colitis is still suspected, additional staining methods, like immunohistochemistry (IHC), can be employed, which is often considered the gold standard.
Real-time PCR Test
This specialized DNA test can be used alongside the findings obtained from an endoscopy. However, it’s important to note that even with this method, only 50% of patients with CMV colitis have tested positive.
CMV Culture
This highly sensitive and specific test can be very helpful in diagnosing CMV colitis. It involves growing the virus in the laboratory from a patient’s samples. However, one major disadvantage is that it can take a significant amount of time to get the result, which could delay treatment.
Treatment Options for Cytomegalovirus Colitis (CMV colitis)
Most people with CMV (cytomegalovirus) colitis who have a healthy immune system may not need antiviral treatment. Antiviral medications like ganciclovir can come with severe side effects such as bone marrow suppression, liver damage, kidney damage, and neurological disorders. Current evidence suggests that using these medications doesn’t significantly change the outcomes for these patients. But, for males over the age of 55 who have severe CMV colitis and other health conditions like diabetes or chronic kidney disease, antiviral treatment might be necessary. They can take ganciclovir orally or through an IV.
People who experience CMV reactivation, which often happens in serious or steroid-resistant inflammatory bowel disease, might not require antiviral treatment either. This is because the virus usually doesn’t cause disease, and antivirals might not be beneficial. However, some conditions might call for antiviral treatment. These include situations where CMV reactivation leads to CMV colitis, histological reviews show high CMV density in tissue, patients with low CMV density are steroid-dependent or have steroid-resistant disease, or when large ulcers appear through endoscopy. These could all indicate the need for antiviral therapy.
However, it is noteworthy that there is limited low-quality data on antiviral treatment of CMV colitis and its impact on the need for colectomy (removal of the colon) and death rates. In order to identify the groups that would most benefit from treatment, more comprehensive research and bigger randomized trials are needed. In patients with ulcerative colitis and CMV reactivation, it might be worth considering the use of anti-TNF (a type of medication used to control the immune response) along with antiviral therapy. An example where antiviral treatment has proved effective is in preventing and treating CMV disease in patients who have undergone bone marrow transplants. Currently, research is being conducted to figure out how to identify high-risk groups, and the potential benefits of preventive therapy.
What else can Cytomegalovirus Colitis (CMV colitis) be?
- Stomach flu caused by viruses or bacteria
- A group of chronic conditions known as inflammatory bowel disease
- Colorectal cancer, which affects the colon or rectum
- Toxic megacolon, a life-threatening condition that causes the large intestine to rapidly expand
- Diverticulitis, an inflammation or infection of small pouches in the digestive tract
- Irritable bowel syndrome, a common disorder that affects the large intestine
- Celiac disease, which affects the body’s ability to process gluten
- Graft-versus-host disease, a complication that can occur after a stem cell or bone marrow transplant
What to expect with Cytomegalovirus Colitis (CMV colitis)
The overall outlook for CMV colitis is typically very good. However, there are some factors that can make it more serious or increase the chance of death. Patients who are generally healthy see their outlook change based on age. Those over 55 years of age face a slightly increased risk of death. The outlook is worse for patients needing surgery. Some research also suggests that men with CMV colitis face a higher risk of death.
Diagnosing and treating CMV colitis quickly can significantly improve the outlook for patients with weaker immune systems. If patients with a reactivated CMV colitis also have ulcerative colitis, the outlook is often poor. However, quick treatment can greatly improve their prospects.
Possible Complications When Diagnosed with Cytomegalovirus Colitis (CMV colitis)
Complications can result from CMV, a type of virus. These can range from long-lasting inflammation to bowel perforation and extreme colon enlargement (known as toxic megacolon). Other potential issues include pseudo-membrane formation and the emergence of ischemic colitis, a condition where parts of the large intestine receive insufficient blood. Patients suffering from inflammatory bowel disease may experience severe bleeding or bowel perforation due to CMV colitis.
- Chronic inflammation
- Bowel perforation
- Toxic megacolon
- Pseudo-membrane formation
- Development of ischemic colitis
- In patients with inflammatory bowel disease, severe bleeding, or bowel perforation due to CMV colitis
Preventing Cytomegalovirus Colitis (CMV colitis)
Preventing CMV colitis, a kind of gut infection, is critical in patients with weakened immune systems who are receiving organ transplants. Ways to prevent this infection have been developed and new treatments are being studied. However, there is no universal rule on how to prevent the infection. Treatments depend on individual patients and local factors.
The Third International Consensus Guidelines on Managing Cytomegalovirus, a virus often seen in organ transplant recipients, suggest the following methods for preventing the disease:
- They strongly recommend either a universal preventive treatment or an early treatment strategy for all organ transplant recipients.
- For kidney, liver, heart, and pancreas transplant recipients, doctors are strongly suggested to use preventive treatments for 3 to 6 months.
- They also encourage the use of blood products from donors who either have a reduced number of white blood cells or who have never had a CMV infection in patients at the highest risk.
- They suggest not to routinely use secondary preventive treatments after treating a CMV infection.
- They also recommend the use of drugs called mTOR inhibitors in patients who received kidney, liver, heart, and lung transplants and who have had a CMV infection.