Cytomegalovirus retinitis, also known as CMV retinitis, is an inflammation of the

retina The retina (; or retinas) is the innermost, photosensitivity, light-sensitive layer of tissue (biology), tissue of the eye of most vertebrates and some Mollusca, molluscs. The optics of the eye create a focus (optics), focused two-dimensional ...

of the

eye An eye is a sensory organ that allows an organism to perceive visual information. It detects light and converts it into electro-chemical impulses in neurons (neurones). It is part of an organism's visual system. In higher organisms, the ey ...

that can lead to

blindness Visual or vision impairment (VI or VIP) is the partial or total inability of visual perception. In the absence of treatment such as corrective eyewear, assistive devices, and medical treatment, visual impairment may cause the individual difficul ...

. Caused by

human cytomegalovirus Human cytomegalovirus (HCMV), also called human herpesvirus 5 (HHV-5), is a species of virus in the genus ''Cytomegalovirus'', which in turn is a member of the viral family known as ''Herpesviridae'' or herpesviruses. It is also commonly call ...

, it occurs predominantly in people whose

immune system The immune system is a network of biological systems that protects an organism from diseases. It detects and responds to a wide variety of pathogens, from viruses to bacteria, as well as Tumor immunology, cancer cells, Parasitic worm, parasitic ...

has been compromised, including 15-40% of those with AIDS.

Signs and symptoms

PMID20029144 06 cytomegalovirus retinitis - pizza pie

The symptoms of cytomegalovirus retinitis have it usually starting in one eye (and also have the possibility of retinal detachment), presenting as: *

Blurred vision Blurred vision is an ocular symptom where vision becomes less precise and there is added difficulty to resolve fine details. Temporary blurred vision may involve dry eyes, eye infections, alcohol poisoning, hypoglycemia, or low blood pressur ...

* Blind spots * Specks in your vision

Cause

Cytomegalovirus (a type of

herpes Herpes simplex, often known simply as herpes, is a viral infection caused by the herpes simplex virus. Herpes infections are categorized by the area of the body that is infected. The two major types of herpes are oral herpes and genital herp ...

virus) is what causes cytomegalovirus retinitis. Other types of herpes viruses include

herpes simplex Herpes simplex, often known simply as herpes, is a viral disease, viral infection caused by the herpes simplex virus. Herpes infections are categorized by the area of the body that is infected. The two major types of herpes are Cold sore, ora ...

viruses and Epstein-Barr virus. Once an individual is infected with these viruses they stay in the body for life. What triggers the virus to reactivate are the following (though CMV can also be congenital).. *

Leukemia Leukemia ( also spelled leukaemia; pronounced ) is a group of blood cancers that usually begin in the bone marrow and produce high numbers of abnormal blood cells. These blood cells are not fully developed and are called ''blasts'' or '' ...

AIDS The HIV, human immunodeficiency virus (HIV) is a retrovirus that attacks the immune system. Without treatment, it can lead to a spectrum of conditions including acquired immunodeficiency syndrome (AIDS). It is a Preventive healthcare, pr ...

* Immunosuppressive chemotherapy

Mechanism

Human cytomegalovirus Human cytomegalovirus (HCMV), also called human herpesvirus 5 (HHV-5), is a species of virus in the genus ''Cytomegalovirus'', which in turn is a member of the viral family known as ''Herpesviridae'' or herpesviruses. It is also commonly call ...

(HCMV or CMV) is a

DNA virus A DNA virus is a virus that has a genome made of deoxyribonucleic acid (DNA) that is replicated by a DNA polymerase. They can be divided between those that have two strands of DNA in their genome, called double-stranded DNA (dsDNA) viruses, and t ...

in the family ''

Herpesviridae ''Orthoherpesviridae'', previously named and more widely known as ''Herpesviridae'', is a large family of DNA viruses that cause infections and certain diseases in animals, including humans. The members of this family are commonly known as herp ...

'' known for producing large cells with nuclear and cytoplasmic inclusions, CMV infects around 40% of the population worldwide. Those areas infected by cytomegalovirus have cells evolve to

necrosis Necrosis () is a form of cell injury which results in the premature death of cells in living tissue by autolysis. The term "necrosis" came about in the mid-19th century and is commonly attributed to German pathologist Rudolf Virchow, who i ...

, though inflammation within the retina is not great. Rhegmatogenous retinal detachments can occur following the development of holes in areas of healed retinitis (retina may be atrophic). Proliferative vitreoretinopathy has been observed in cases of retinal detachment.

Diagnosis

The diagnosis of CMV retinitis can be done via the following: * Ophthalmic screening frequency is based on CD4 count,(CD4 < 50 cells/mL, 0- 35% possibility of CMV retinitis) * BUN * CD8+ T-lymphocyte count * CMV

DNA Deoxyribonucleic acid (; DNA) is a polymer composed of two polynucleotide chains that coil around each other to form a double helix. The polymer carries genetic instructions for the development, functioning, growth and reproduction of al ...

capture ( polymerase chain reaction (PCR) test) * DNA PCR ( ocular fluids) *

Viral load Viral load, also known as viral burden, is a numerical expression of the quantity of virus in a given volume of fluid, including biological and environmental specimens. It is not to be confused with viral titre or viral titer, which depends on the ...

* Complete blood count

Treatment

In terms of the treatment of cytomegalovirus retinitis, oral valganciclovir, intravenous ganciclovir, IV

foscarnet Foscarnet (phosphonomethanoic acid), known by its brand name Foscavir, is an antiviral medication which is primarily used to treat viral infections involving the Herpesviridae family. It is classified as a pyrophosphate Structural analog, analog ...

, and IV

cidofovir Cidofovir, brand name Vistide, is a topical or injectable antiviral medication primarily used as a treatment for cytomegalovirus (CMV) retinitis (an infection of the retina of the eye) in people with AIDS. Cidofovir was approved for medical ...

are all efficient in the treatment of this condition. Also intravitreal injections, an injection of medicine into the vitreous near the retina, of

in concomitance with oral valganciclovir can be used for treatment as well. Often individuals with CMV retinitis will need surgery for either

retinal detachment Retinal detachment is a condition where the retina pulls away from the tissue underneath it. It may start in a small area, but without quick treatment, it can spread across the entire retina, leading to serious vision loss and possibly blindness. ...

or intravitreal instillation of ganciclovir. Retinal detachment occurs in up to 29% of affected eyes, repair being most effective with endolaser and

silicone oil A silicone oil is any liquid polymerized siloxane with organic side chains. The most important member is polydimethylsiloxane. These polymers are of commercial interest because of their relatively high thermal stability and their lubricating prop ...

endotamponade. Intravitreal ganciclovir implant has the benefit of less systemic toxicity. An adverse effect of this is retinal detachment (and vitreous hemorrhage), also there is no systemic beneficial effect for cytomegalovirus organ disease.

References

External links

* {{Authority control HIV/AIDS Cytomegalovirus-associated diseases Disorders of choroid and retina