Cytomegalovirus colitis (CMV colitis) is an inflammation of the
colon.
Causes
The infection is spread by saliva, urine, respiratory droplets, sexual contact, and blood transfusions. Most people are exposed to the virus in their lifetime, but it usually produces mild or no symptoms in healthy people.
However, serious CMV infections can occur in people with weakened immune systems. This includes patients receiving chemotherapy for cancer and patients on immune-suppressing medicines following an organ transplant.
In rare instances, more severe CMV infection involving the gastrointestinal tract has been reported in people with a healthy immune system.
Risk factors
The systemic use of
corticosteroids
Corticosteroids are a class of steroid hormones that are produced in the adrenal cortex of vertebrates, as well as the synthetic analogues of these hormones. Two main classes of corticosteroids, glucocorticoids and mineralocorticoids, are in ...
in the context of
inflammatory bowel disease
Inflammatory bowel disease (IBD) is a group of inflammatory conditions of the colon and small intestine, Crohn's disease and ulcerative colitis being the principal types. Crohn's disease affects the small intestine and large intestine, as wel ...
can promote CMV infection in the colon.
[ The corticosteroids used as a primary treatment for flare-up events of inflammatory bowel disease reduce the autoimmune activity of the T lymphocytes and monocytes that contribute to the inflammation of the colon and small intestine. By inhibiting the function of these leukocytes, corticosteroids reduce the inflammation caused by IBD, but this immunosuppression enables CMV to infect the colon. Similarly, use of the ]immunosuppressive drug
Immunosuppressive drugs, also known as immunosuppressive agents, immunosuppressants and antirejection medications, are drugs that inhibit or prevent activity of the immune system.
Classification
Immunosuppressive drugs can be classified into ...
that is required to decrease risk of rejection in patients who received transplant as Liver transplantation
Liver transplantation or hepatic transplantation is the replacement of a diseased liver with the healthy liver from another person ( allograft). Liver transplantation is a treatment option for end-stage liver disease and acute liver failure, ...
or Kidney transplantation
Kidney transplant or renal transplant is the organ transplant of a kidney into a patient with chronic kidney disease, end-stage kidney disease (ESRD). Kidney transplant is typically classified as deceased-donor (formerly known as cadaveric) or li ...
is a risk factor for CMV infection.
Diagnosis
CMV colitis may be clinically manifested with diarrhea (usually non-bloody), abdominal pain, weight loss and anorexia. The diagnosis of CMV colitis is based on serology
Serology is the scientific study of serum and other body fluids. In practice, the term usually refers to the diagnostic identification of antibodies in the serum. Such antibodies are typically formed in response to an infection (against a given ...
, CMV antigen
In immunology, an antigen (Ag) is a molecule or molecular structure or any foreign particulate matter or a pollen grain that can bind to a specific antibody or T-cell receptor. The presence of antigens in the body may trigger an immune response. ...
testing and colonoscopy
Colonoscopy () or coloscopy () is the endoscopic examination of the large bowel and the distal part of the small bowel with a CCD camera or a fiber optic camera on a flexible tube passed through the anus. It can provide a visual diagnosis ( ...
with biopsy
A biopsy is a medical test commonly performed by a surgeon, interventional radiologist, or an interventional cardiologist. The process involves extraction of sample cells or tissues for examination to determine the presence or extent of a d ...
. CMV colitis usually occurs in immunocompromised patient and is much rarer in immunocompetent patients. Although it is known that CMV colitis is almost always caused by reactivation of latent CMV infection in immunocompromised patients, new infection of CMV or reinfection of different strain of CMV can cause colitis in immunocompetent hosts. Because asymptomatic CMV viremia and viruria is common and about 1/3 of symptomatic CMV infection is caused by reinfection of different strain of CMV, the diagnosis of CMV colitis needs more direct causality. It is practically achieved by colonoscopy or sigmoidoscopy tissue sampling and pathological evidence of CMV infection under microscope, more specifically macroscopic picture will show many ulcers that appear on the mucous membrane and microscopically the biopsy will show intranuclear and cytoplasmic inclusion bodies. Positive CMV IgG doesn't necessarily mean that it is reactivation of latent infection because of the possibility of reinfection of different strain.
Treatment
The usual treatment is antivirals, specifically ganciclovir or valganciclovir.colectomy
Colectomy ('' col-'' + '' -ectomy'') is bowel resection of the large bowel ( colon). It consists of the surgical removal of any extent of the colon, usually segmental resection (partial colectomy). In extreme cases where the entire large intesti ...
.
See also
* Crohn's disease
Crohn's disease is a type of inflammatory bowel disease (IBD) that may affect any segment of the gastrointestinal tract. Symptoms often include abdominal pain, diarrhea (which may be bloody if inflammation is severe), fever, abdominal distension, ...
* Kidney transplantation
Kidney transplant or renal transplant is the organ transplant of a kidney into a patient with chronic kidney disease, end-stage kidney disease (ESRD). Kidney transplant is typically classified as deceased-donor (formerly known as cadaveric) or li ...
References
{{Viral systemic diseases
HIV/AIDS
Cytomegalovirus-associated diseases
Colitis