Cytomegalovirus disease (CMV)

Summary

Cytomegalovirus disease (CMV) is a viral infection that can affect one part of the body, such as the eyes, or it can spread throughout the body. Before the advent of more effective anti-HIV drugs, it was common for people with AIDS to develop the infection. Today it is relatively rare: the number of new cases has dropped dramatically. People with HIV whose CD4 counts are below 50 are most at risk for developing this disease. Fortunately, treatment for CMV has improved dramatically in recent years.

What is CMV?

CMV is a serious infection caused by a virus called cytomegalovirus (CMV). This virus is related to the herpes viruses that cause chicken pox and mononucleosis (mono).

CMV is one of a number of infections that can develop in people who are living with HIV, called opportunistic infections. Opportunistic infections only occur if your immune system is quite weakened and your body becomes vulnerable to infections that would not otherwise affect you. Most adults carry the CMV virus but are unaware of it because the virus doesn’t make them sick. In people with severely weakened immune systems, CMV can make a person feel as though they have mono. CMV can also cause serious disease in different parts of the body (see Symptoms below).

Who is at risk for CMV?

People who have a weakened immune system, due to HIV, cancer, long-term use of corticosteroid drugs, or an organ or bone marrow transplant, are at risk of developing CMV.

People living with HIV most at risk of developing the disease are those who

• have a CD4 count below 50
• have a viral load over 100,000 copies/ml
• are not taking or do not respond to anti-HIV drugs
• have previously had CMV or other opportunistic infections

Symptoms

The most common sign of CMV is:

• retinitis—the death of cells in the back of the eye(s). Some people with CMV retinitis experience no symptoms at all or only mild symptoms. Others experience more severe symptoms. Retinitis can cause blurred vision, blind spots, light flashes, and dark specks that seem to float around in your field of vision, sometimes called “floaters.”

  Two thirds of people who are initially diagnosed with retinitis have the disease in just one eye; however, without anti-HIV drugs or anti-CMV treatment, most people develop retinitis in both eyes within 10 to 21 days of symptoms first appearing. When left untreated, retinitis leads to permanent blindness within three to six months.

Other illnesses and symptoms of CMV can include (but are not limited to):

• esophagitis—if CMV infects the esophagus (the passage that connects the mouth to the stomach). Symptoms include fever, nausea, painful swallowing and swollen lymph nodes.
• colitis—if CMV infects the colon (the longest part of the large intestine). Symptoms include fever, diarrhea, weight loss, pain in the abdomen (or belly) and malaise (a general feeling of unwellness or bodily discomfort).
• diseases of the central nervous system—if CMV infects the brain and spinal cord. Symptoms include confusion, fatigue, fever, seizures, weakness and numbness in the legs, and loss of bowel and bladder control.
• pneumonia—if CMV infects the lungs (rare).

CMV that has spread throughout the body can make a person feel as though they have mononucleosis. Symptoms include fatigue, weakness, malaise or a feeling of being generally unwell, stiff joints, aching muscles, fever, swollen lymph nodes, sore throat and loss of appetite.

Because CMV can be life-threatening if not treated early, it is important that you call your doctor as soon as possible if you have HIV and experience any of the symptoms of CMV, regardless of what your CD4 count is.

Diagnosis

Blood and urine tests are often used to detect and measure substances specific to CMV. A biopsy (a procedure that involves a doctor removing a small piece of tissue, which is then examined under a microscope for signs of disease) may be required to confirm a diagnosis of CMV, unless the disease is affecting the eyes or central nervous system.

If your doctor suspects CMV retinitis, he or she will refer you to an eye specialist (an ophthalmologist). The eye specialist will examine your eyes to check for CMV retinitis.

If you are pregnant and have CMV, your doctor may recommend that you have a test called an amniocentesis, to determine whether or not your baby has CMV. To perform an amniocentesis, a doctor inserts a long thin needle through the abdomen and into the womb, to collect a small amount of fluid from the amniotic sac surrounding the baby. CMV infection can harm the developing fetus. If the test shows that the fetus does have CMV, the doctor will examine your baby after birth to check for any birth defects or health problems, so that they can be treated if possible.

Treatment

Medications to treat CMV may be given by mouth (orally), through a vein (intravenously, or by IV) or locally (to the area affected)—for  example, in the case of CMV retinitis, after a local anesthetic is used, medication may be injected or surgically implanted directly into the eye, to control the disease. The choice of treatment depends on the location and severity of the CMV, the strength of your immune system, other medications you may be taking and other factors. Different forms of the drug ganciclovir (Cytovene) are often used to treat CMV infection.

Retinitis

For CMV retinitis, treatment can help restore a person’s vision and prevent the disease from causing blindness. No one medication has proven to be superior at protecting a person’s vision. Some HIV specialists recommend a combination of eye implants and valganciclovir (Valcyte) to treat patients with sight-threatening CMV. For smaller lesions in the eye, oral medication, such as valganciclovir alone may be prescribed. Some opthamologists recommend an initial injection of ganciclovir at the time CMV retinitis is first diagnosed, to deliver a concentrated dose of the drug directly to the eye as soon as possible, until a ganciclovir implant can be placed.

Colitis and esophagitis

For CMV colitis or esophagitis, most HIV specialists recommend that ganciclovir or foscarnet be given by IV (by injection) for 21 to 28 days or until the symptoms are gone.

Pneumonia

It is difficult to diagnose CMV disease in the lungs; however, if CMV is thought to be the cause of pneumonia, ganciclovir, foscarnet (Foscavir) or cidofovir (Vistide) by IV may be recommended.

Diseases of the central nervous system

For neurological infections, or infections that affect the brain and spinal cord, such as CMV encephalitis or neuropathy, it is important to start treatment as soon as possible. A combination of ganciclovir and foscarnet may be recommended as an initial treatment; however, there is a high rate of side effects to this treatment. Treatment and side effects should be monitored closely.

Anti-HIV drugs

If you are diagnosed with CMV retinitis, colitis, esophagitis or pneumonia and are not already taking anti-HIV drugs, it is recommended that you start. This should strengthen your immune system and help you fight off the infection. People with a disease of the central nervous system who are not already taking anti-HIV drugs should treat the CMV first and wait until their CMV symptoms improve before they start taking anti-HIV drugs. Talk to your doctor before starting or stopping any medication.

Preventing recurrence

Once the CMV has cleared up, your doctor will likely recommend that you take medication to prevent the infection from coming back. This medication should be taken until your CD4 count remains higher than 100 for at least three to six months as a result of taking anti-HIV drugs.

However, no CD4 count guarantees that the CMV won’t return. Even people whose immune systems recover and who are able to discontinue anti-CMV treatment can have a relapse. For example, retinitis can recur even when a person’s CD4 count is as high as 1250. For this reason, regular appointments should be scheduled with your opthamologist to have your eyes checked for CMV—ideally, every three months. Monitoring CMV viral load is not an effective way of predicting relapse and is not recommended.

Prevention

The best way to reduce the risk of CMV is to keep your CD4 count well above 100. Anti-HIV drugs can keep your CD4 count up and, if you’ve been exposed to the virus, keep the virus under control.

People living with HIV whose CD4 counts are below 100 should be examined regularly by an opthamologist for retinitis even if they don't have symptoms. If you notice an increase of “floaters” (dark specks that seem to float around in your eye), make an appointment to see your opthamologist and have it checked out.