Cytomegalovirus Retinitis - Causes, Symptoms, Diagnosis, and Management

Introduction

As we all know, AIDS is a life-threatening condition caused by the dreadful human immunodeficiency virus (HIV). HIV infection is usually spread by sexual contact or contact with the infected saliva, body fluids, sharing razors, etc. It is considered life-threatening because it affects an individual's immune system and gives way to opportunistic infections. Cytomegalovirus retinitis is one such opportunistic infection of HIV infection. Many other immune weakening disorders can also cause it. However, the retinal layer of the eye is primarily affected. Cytomegalovirus is a type of herpes virus. In people with weak immune systems, like in an individual with HIV infection, the retinal layer of the eye gets infected by cytomegalovirus. As a result, the retina becomes necrosed, which results in detachment and tears. Cytomegalovirus retinitis infection is common among males and females aged 20 and 50.

Cytomegalovirus can get transmitted in various ways:

• From infected mother to child through the placenta. If the child escapes placental transmission, the child may acquire the virus from vaginal secretions during vaginal delivery.

• Through organ transplantations and blood transfusions.

• Through saliva by sharing food and drinks.

• In adult groups, sexual intercourse is the main mode of transmission.

• Transmission through the fecal-oral route is also possible, and cases are recorded.

What Are the Symptoms of Cytomegalovirus Retinitis?

CMV retinitis infection will show signs in one eye initially and then starts in the other eye. The most common signs and symptoms of cytomegalovirus retinitis are as follows.

• Floaters can be seen in the field of vision. Floaters can appear as a speck or a dot and cause disturbances in viewing things.

• Photosensitivity or light sensitivity can be noticed.

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• Pain in the eyes.

• Blind spots can be noticed in the center field of vision.

• Blurred vision will be present as the infection infects the retinal layer and damages the optic nerve responsible for sending vision signals to the brain.

• Shadows along the peripheral vision can be seen.

• In extreme cases, it can result in blindness too.

What Are the Causes of Cytomegalovirus Retinitis?

Cytomegalovirus retinitis is caused by cytomegalovirus, a type of herpes virus. Most human beings will come in contact with cytomegalovirus at least once in their lifetime. But only the ones with the weaker immune system will get infected severely and show signs and symptoms.

Conditions that weaken the immune system and give way to CMV infections like CMV retinitis are,

• Human immunodeficiency virus (HIV) infection or acquired immunodeficiency syndrome (AIDS).

• Bone marrow transplant patients will have a weaker immune system till three to twelve months after the procedure.

• Cancer patients undergoing chemotherapy will generally have a weak immune system.

• Even organ transplant patients will have a weak immune system.

• Certain drugs like Prednisone, Dexamethasone, Dapsone, Methotrexate, Sulfasalazine, and Hydroxychloroquine can suppress the immune system.

• Aplastic anemia.

HIV/AIDS is the most common cause of cytomegalovirus infection.

Who Is at Risk of Acquiring Cytomegalovirus Retinitis?

Those people with a weaker immune system are at higher risk for acquiring cytomegalovirus retinitis. People having the following conditions are more likely to develop CMV retinitis.

• Human immunodeficiency virus (HIV) infection and acquired immunodeficiency virus syndrome (AIDS).

• People undergoing chemotherapy to treat cancer or leukemia.

• People undergoing organ transplants or specifically bone marrow transplants.

What Are the Possible Differential Diagnosis of Cytomegalovirus Retinitis?

Some of the conditions that can be misunderstood in place of CMV retinitis are,

• HIV retinopathy - It is characterized by internal bleeding and a cotton wool appearance. Thus, it is often mistaken place of CMV retinitis. HIV retinopathy is more common in occurrence than CMV retinitis.

• Syphilis.

• Herpes zoster infection.

• Toxoplasmosis.

• Tuberculosis (TB).

• Behcet disease.

• Bacterial endophthalmitis.

• Intraocular lymphoma.

What Are the Complications Associated With Cytomegalovirus Retinitis?

If CMV retinitis is left untreated, it may progress to cause,

• Retinal detachment.

• Necrosis of the retina.

• Damages to the optic nerve.

• Blindness - Permanent or temporary.

What Are the Three Stages of Retinitis?

A retinitis condition shows three patterns in general, and they are:

• Hemorrhagic - Behind the necrotic retinal layer, large spots of hemorrhage can be seen.

• Brush Fire - It is characterized by yellow-white lines seen in the margins of a necrotizing retina.

• Granular - There will be hemorrhage spots present. Instead, white granular lesions can be seen along with the infected retinal layer of the eye.

How to Diagnose Cytomegalovirus Retinitis?

Diagnosis of CMV retinitis will include physical examination, lab tests, and imaging tests. The physical examination will include proper pupil dilation to study the retina clearly and find hemorrhagic spots, retinal detachments, etc. Imaging studies will include ultrasonography to study the severity of retinal detachment and fundus photography to assess the retinitis condition in general. Lab tests will include a polymerase chain reaction to detect the presence of cytomegalovirus.

How to Manage Cytomegalovirus Retinitis?

Managing the HIV infection (if it is the cause) is mandatory as a further decrease in the CD4 plus cells may cause CMV retinitis again and again. Before the advent of antiretroviral therapy, managing CMV retinitis was a task. But now, with appropriate treatment, it can be managed to a greater extent.

Antiretroviral drugs like Cidofovir, Foscarnet, and Valganciclovir can help manage the condition. These medicines can be taken as an oral pill, injection into the vein and eyes, or as an eye implant, giving out medicines at a particular pace. However, taking medications for a long time can make CMV resistant to drugs. Thus, the condition must be treated immediately without any delay.

How to Prevent CMV Retinitis?

The only way to prevent cytomegalovirus retinitis is by taking appropriate antiretroviral drugs in case of HIV infection. However, the condition may become severe if proper treatment is not undergone and give way to opportunistic infections like CMV retinitis.

Conclusion

CMV retinitis has immense potential to cause blindness that can be reversed with any treatment or medications. Thus, prevention is the only cure. However, taking appropriate measures to develop HIV infection or any immunosuppressive condition will help.