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Chorioretinitis

Choroiditis

Chorioretinitis is an inflammatory process that affects both the choroid and the retina of the eye.


Presentation

Chorioretinitis is a condition that causes non-specific ocular symptoms, such as blurred or otherwise impaired vision, photosensitivity, pain in the eye or redness, as well as ocular exudate [8]. The findings during fundoscopy are particularly useful in order to definitely diagnose such a condition and further examinations will help to reveal the underlying infection that initially caused chorioretinitis.

Blurred Vision
  • An immunodeficient patient, 34 years old, receiving systemic antifungal treatment for 1 month for invasive aspergillosis with necrotizing pneumonia and brain metastasis, who presented with blurred vision in his left eye.[ncbi.nlm.nih.gov]
  • Chorioretinitis causes manifestations such as blurred vision or dark spots in one's visual field, sensitivity to light, red and puffy eyes.[symptoma.com]
  • It is characterized by blurred vision, photophobia, and distorted images. cho·ri·o·ret·i·ni·tis ( kōr'ē-ō-ret'i-nī'tis ) Inflammation in the choroid and retina with its origin in the choroid. chorioretinitis Any inflammatory process involving the CHOROID[medical-dictionary.thefreedictionary.com]
  • Symptoms [ edit ] Symptoms may include the presence of floating black spots , blurred vision, pain or redness in the eye, sensitivity to light, or excessive tearing. [2] Causes [ edit ] Chorioretinitis is often caused by toxoplasmosis and cytomegalovirus[en.wikipedia.org]
Flank Pain
  • Hereinafter we describe a case of an immunocompetent 56 years old woman, presenting with flank pain and shivering. The diagnosis turned out to be difficult due to initially negative urine culture.[ncbi.nlm.nih.gov]

Workup

The first step towards a successful diagnosis is a thorough medical history and physical exam. Patients with chorioretinitis usually present, if they are symptomatic, with acute symptomatology that includes pain in the eye, blurred vision, the sensitivity of the eye to light, or dark spots that float in their visual field. The pupil may display irregular borders and the vitreous membrane may be clouded. Loss of vision of the one eye is the ultimate stage, which indicates an irreversible condition.

Fundoscopy is an extremely useful tool towards the diagnosis of chorioretinitis. Tissues may appear blurred and the retina is expected to be considerably hyporeflective. The observation of the vascular network can also reveal a hemorrhagic tendency, vasculitis, and exudate. When the condition is progressing, the involvement of the anterior segment can lead to various pathological alterations, such as miosis, corneal edema, cataract, and hypopyon.

Except for the examination of the eye and retina, the diagnosis of chorioretinitis needs to be accompanied by the defining of etiology. Therefore, blood laboratory testing is mandatory, in order to pinpoint the cause of infection. More specifically:

  • Routine blood testing is used to detect pathological levels of erythrocytes, white blood cells, and platelets. It is a first step that can direct the physician towards the accurate diagnosis.
  • Liver function tests: SGOT/SGPT, ALP, γ-GT, bilirubin, albumin and protein levels are paramount in order to evaluate the condition of the liver, whose functionality is in many instances impaired by congenital infections.
  • Renal function.
  • Possible immunosuppression: An individual that may be affected by chorioretinitis due to an undiagnosed HIV infection requires testing. The PCR method can be used to accurately diagnose the disease in newborns; other than that, affected individuals may have decreased levels of CD4+ T cells and hypergammaglobulinemia.

As far as imaging modalities are concerned, they are employed depending on the suspicions that exist for each patient. Every imaging modality can contribute to the diagnosis of an underlying pathology in an individual, including chest radiographs and computerized tomography scans for a tuberculosis infection, a magnetic resonance imaging scan or an ultrasonographic scan in the case of a potential congenital infection, etc. A skin biopsy can also be useful to detect blueberry muffin infant syndrome in cases of babies with a possible underlying toxoplasmosis.

Treatment

Treatment of chorioretinitis comprises various pharmaceutical and invasive options aimed at the eradication of the underlying cause. Corticosteroids, antimicrobial agents and antiviral medications can all be used selectively, depending on the actual cause of chorioretinitis. Treating the underlying disease is paramount, in order to avoid considerable loss of vision that might occur if the infection remains untreated.

Specifically, medication options are individualized depending on the type of infection present and may include the following:

  • Ganciclovir, foscarnet, valganciclovir, and cidofovir are employed in cases of an underlying CMV infection. Various other agents, such as maribavir, are being currently tested for their potential use against some strains of CMV [9].
  • Fomivirsen is used to treat CMV chorioretinitis in an immunodeficient person who is affected by the acquired immunodeficiency syndrome (AIDS).
  • Pyrimethamine, prednisone, sulfadiazine and folinic acid are useful medications against toxoplasmosis. Note that the folinic acid is not an antiparasitic drug itself, but it is used to prevent bone marrow toxicity, caused by pyrimethamine. Because of their potential toxicity, pyrimethamine and sulfadiazine levels need to be monitored regularly, via high-performance liquid chromatography testing of the plasma.

Except for the medications that can be used to effectively remove the agent causing the original infection, various other invasive techniques may be required under some circumstances. Vitrectomy is reserved for those individuals who are diagnosed with fibrosis of the vitreous membrane and it is usually a second-line treatment that ensues, after the failure of pharmaceutical therapy.

Prognosis

Chorioretinitis is not a fatal disease and is curable if the appropriate treatment is administered. The extent of the residual damage it may lead to greatly depends on the exact location of the lesion and the existence of timely workup and treatment. In general, the presence of a lesion on the retina implies that a scar will definitely form, but peripheral scars usually cause no visual impairment. Centrally located retinal lesions will cause a visual impairment of different extent, depending on lesion characteristics.

The timely diagnosis and treatment of congenital conditions such as a CMV infection or toxoplasmosis reduce the possibilities of extensive residual damage to the retina and, subsequently, to an individual's vision.

Etiology

Chorioretinitis is usually caused by an infection with an agent that is vertically passed from mother to child during pregnancy or childbirth. Toxoplasmosis and cytomegalovirus are the primary culprits behind the inflammatory, infectious process, while other parasites and fungi could also lead to such ocular manifestations [1] [2]. During the course of an individual's postnatal life, various other pathogens could infect the eye area and lead to the disorder. Only on rare occasions have non-infectious inflammatory diseases been incriminated for causing chorioretinitis, both in newborns and adults.

Epidemiology

The exact prevalence of chorioretinitis has not been established; however, it is known that congenital toxoplasmosis (CTP) is one of its leading causes. Congenital toxoplasmosis is not so common amongst newborns in the United States, due to maternal care, monitoring, and informative campaigns: it is believed that approximately 2,000 cases occur annually [3]. Other countries, primarily European, perform screening tests for the disease and report higher frequencies of CTP [4] [5].

If left untreated, congenital toxoplasmosis is expected to cause chorioretinitis in a 20% of the children affected by it by the age of 5 or 6 years old, with the majority of the children experiencing impaired vision unilaterally [6].

Sex distribution
Age distribution

Pathophysiology

The uveal tract comprises the choroid, ciliary body, and iris. Each ocular condition is defined according to the structure mainly affected by it and an infection leading to inflammation of the posterior uveal tract is usually referred to as choroiditis. The retina rarely remains unaffected, which is the reason why the term chorioretinitis is used interchangeably with choroiditis [7].

Not every pathogen causes inflammation of the same extent; individuals affected by toxoplasmosis are usually diagnosed with panuveitis or bilateral regional or widespread chorioretinitis. Toxocara canis leads to isolated choroidal lesions and vascular damage. An interesting fact is that although the lesions caused by a CMV infection may be indistinguishable from those caused by toxoplasmosis, the retinal inflammation remains clinically stable and is usually not progressive in the case of CMV.

Prevention

Chorioretinitis is a condition that is caused by an infection, either localized or systemic. Therefore, preventive measures include following basic hygienic guidelines and maintaining good health, so that the organism will be able to fight infections. Specifically, otherwise healthy individuals are advised to consult an ophthalmologist any time they experience ocular symptoms, such as blurred vision, red or edematous eyes. Patients affected by diseases or conditions that greatly affect their immune system are particularly advised to follow their physician's advice closely, with regard to their protection against possible infections.

Summary

Chorioretinitis is an inflammation of the retina and choroid, as opposed to the term choroiditis which implies an inflammation restricted to the choroid alone. The condition usually develops as a result of an infection, either localized to the ocular area or even systemic. Congenital toxoplasmosis, cytomegalovirus, other parasites and viruses, and fungi can cause various types of infection that may ultimately lead to an inflammatory response of the eye and, subsequently, chorioretinitis.

Congenital chorioretinitis is often diagnosed in newborns and may produce no symptomatology; nevertheless, it can occur at any age, both in immunocompetent and immunocompromised patients. The vitreous membrane is a structure that may as well be affected by the inflammatory process. The symptoms occurring as a result of chorioretinitis are non-pathognomonic and comprise distortion of vision, erythematous eyes, excessive exudate and sensitivity to light. A careful and thorough medical history, physical examination and eye examination including fundoscopy are indispensable so that an accurate diagnosis can be reached. Upon diagnosing chorioretinitis, the underlying cause must be detected and further laboratory tests and imaging modalities are implemented towards this target.

Chorioretinitis requires immediate ophthalmological consultation and proper treatment because persistent inflammation might interfere with retinal function and endanger retinal perfusion, thus leading to impaired vision, depending on the expansion of the lesion. Each case of chorioretinitis is individualized, and various types of drugs may be used in order to treat the underlying cause including antiviral and antiparasitic agents.

Patient Information

Chorioretinitis is an inflammation of the choroid and retina of the eye. The choroid is the layer of the eye that contains the vessels and the retina is the inner coat of the eye, which is extremely photosensitive. The inflammation is, in the majority of the cases, a result of an infection or, rarely, it might be caused by an inflammatory process that affects the organism, without the involvement of an infectious microorganism.

The two types of infection that most commonly lead to chorioretinitis are congenital toxoplasmosis and CMV infection. These infections could be passed down from the infected mother to the fetus during pregnancy. Other than these, the West Nile virus, fungi, and some parasites can also lead to the same inflammatory process. Chorioretinitis causes manifestations such as blurred vision or dark spots in one's visual field, sensitivity to light, red and puffy eyes.

An ophthalmologist needs to be consulted once an individual experience symptoms that could be related to chorioretinitis, because prolonged inflammation can lead to partial or total loss of vision, depending on the damaged ocular region. Various medications are used to treat the underlying infection, such as antiviral and antiparasitic drugs.

References

Article

  1. Koevary SB. Ocular involvement in patients infected by the West Nile virus. Optometry. 2005;76(10):609-612.
  2. Zinkernagel MS, Bolinger B, Krebs P, Onder L, Miller S, Ludewig B. Immunopathological basis of lymphocytic choriomeningitis virus-induced chorioretinitis and keratitis. J Virol. 2009;83(1):159-166.
  3. Lopez A, Dietz VJ, Wilson M, Navin TR, Jones JL. Preventing congenital toxoplasmosis. MMWR Recomm Rep. 2000;49:59-68.
  4. Elsheikha HM. Congenital toxoplasmosis: priorities for further health promotion action. Public Health. 2008;122(4):335-353.
  5. Rothova A. Ocular manifestations of toxoplasmosis. Curr Opin Ophthalmol. 2003;14(6):384-388.
  6. Freeman K, Tan HK, Prusa A, et al. Predictors of retinochoroiditis in children with congenital toxoplasmosis: European, prospective cohort study. Pediatrics. 2008;121(5):e1215-1222.
  7. Greydanus DE, Noble KG, Hofmann AD. Chorioretinitis in the adolescent: two case presentations with discussion. Pediatrics. 1977;60(6):884-892.
  8. Kasper; et al., eds. Harrison's Principles of Internal Medicine (16th ed.). New York: McGraw-Hill. pp. 959, 1038; 2005.
  9. Johannessen JK, Christiansen I, Schmidt DR, Petersen E, Hansen SH. Simultaneous determination of pyrimethamine, sulfadiazine and N-acetyl-sulfadiazine in plasma for monitoring infants in treatment of congenital toxoplasmosis. J Pharm Biomed Anal. 2005;36(5):1093-1098.

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Last updated: 2018-06-22 09:10