What are the other Names for this Condition? (Also known as/Synonyms)

• Chorioretinitis due to Toxoplasma
• Toxoplasma Chorioretinitis

What is Toxoplasmic Chorioretinitis? (Definition/Background Information)

• Chorioretinitis is an eye condition that results in the inflammation of both the choroid and the retina. It can be caused by both infectious and non-infectious factors and any individual may be affected, particularly those with poor immunity
• When chorioretinitis develops from exposure to the pathogen Toxoplasma gondii, it is known as Toxoplasmic Chorioretinitis. In some literature, the condition is incorrectly referred to as ocular toxoplasmosis (that involves the entire eye)
• Toxoplasmosis may be congenital in nature, meaning the infection is passed on from the mother to a child during pregnancy; or, it can be acquired by consuming meat, raw vegetables, or water that is contaminated by the parasitic microorganism. Generally, acquired cases are more often noted than congenital cases
• In severely immunocompromised individuals, Toxoplasmic Chorioretinitis may present severe signs and symptoms. In general, the signs and symptoms may include reduced visual acuity in one eye, floaters in the eye, blurred vision, sensitivity to light, and partial vision loss; in a majority of cases, eye pain is not observed. In many, the involvement of both the eyes is noted, when the condition is transmitted via birth (prenatal infection)
• A healthcare provider may use physical exam, eye exam, and various blood tests to diagnose Chorioretinitis due to Toxoplasma. Upon diagnosis, treatment options involving anti-parasitic medication may be considered. Additionally, treatment for any underlying condition causing weak immunity is provided
• Toxoplasmic Chorioretinitis may be mild in immunocompetent individuals (those with good immune systems) and mostly self-resolving. The healthcare provider may follow a ‘wait and watch’ approach in such cases
• In those with weak immune system, the prognosis for Toxoplasmic Chorioretinitis depends on the severity of the signs and symptoms and may be assessed only on a case-by-case basis. With early and appropriate treatment, the prognosis is generally good. However, the condition may recur, and hence, periodic checkups are advised

Who gets Toxoplasmic Chorioretinitis? (Age and Sex Distribution)

• Toxoplasmic Chorioretinitis can affect individuals of any age and gender, especially those with poor and weak immune system
• Congenital Toxoplasmic Chorioretinitis may be manifested within a year of birth or even after several years to decades, following reactivation of T. gondii pathogen
• Both males and females are affected and no gender preference is observed
• Individuals of different racial and ethnic backgrounds may be affected and no particular preference is noted; the condition is mostly noted in Europe, Asia, Central America, and Caribbean regions
• According to literature, in USA, almost 25% of the posterior uveitis cases are due to toxoplasmic infection

What are the Risk Factors for Toxoplasmic Chorioretinitis? (Predisposing Factors)

The risk factors for Toxoplasmic Chorioretinitis may include:

• Congenital cases
  • Women, who are infected by toxoplasmosis, either shortly before or during their pregnancy, have a high risk of transmitting it to their unborn offspring
  • Pregnant women on immunosuppressant drugs for various reasons, might cause the protozoa that they carry to be reactivated and infect the baby in the womb
• Acquired cases
  • Individuals with decreased immunity due to a host of conditions such as HIV infection and/or AIDS, cancer or cancer therapy, organ transplant, or any other debilitating illness
  • Consuming contaminated meat, milk, and raw vegetables and fruits
  • Drinking untreated water
  • Exposure to cat feces; or, cat feces contaminated soil
  • Crowded neighborhoods and areas with poor sanitation facilities

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one's chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Toxoplasmic Chorioretinitis? (Etiology)

Toxoplasmic Chorioretinitis occurs from exposure of the body to the protozoan parasite Toxoplasma gondii; when the parasite travels to the eye; chorioretinitis results from an inflammation of the choroid and retina. It is reported that the most common cause of chorioretinitis is toxoplasmosis infection. The condition is usually noted in individuals with decreased immune system.

• Congenital transmission of the infection can take place from a mother to the infant child, in the womb (known as vertical transplacental transmission of infection). Almost all cases of congenital toxoplasmosis reportedly show chorioretinitis
• In acquired cases, the parasite infects the body mostly via gastrointestinal tract on consumption of raw milk, undercooked meat, using unclean and contaminated kitchen knives and cutting boards, eating raw fruits and vegetables, etc.
• Also, dormant pathogenic lesions may be reactivated in the retina to re-infect the individual, when certain health ailments cause a weakening of the immune system, resulting in Toxoplasmic Chorioretinitis

What are the Signs and Symptoms of Toxoplasmic Chorioretinitis?

The signs and symptoms of Toxoplasmic Chorioretinitis may vary between individuals and may include:

• Unilateral decrease in visual acuity; meaning the eye that is infected shows deficient vision clarity. It is the most common manifestation of Toxoplasmic Chorioretinitis
• Red eyes
• Tearing from the eye
• Eye floaters: The individuals experience illusions that some small objects such as spots, hairs, or strings are moving in the eye
• Presence of blind spots, or scotoma, causing partial vision loss
• Light-sensitivity (photophobia) and blurred vision
• Impaired color vision
• Eye pain, in some rare cases
• The condition may affect only one eye or both the eyes; congenital Toxoplasmic Chorioretinitis affects 65-85% of the individuals bilaterally (involvement of both eyes seen)

Associated presentations of the underlying toxoplasmosis infection causing the eye infection may be observed. Manifestation of congenital toxoplasmosis may occur during the fetal stage or shortly after the baby’s birth with systemic presentations including irregular head size, hearing and vision loss, and delayed growth.

How is Toxoplasmic Chorioretinitis Diagnosed?

A healthcare professional may diagnose Toxoplasmic Chorioretinitis using the following tests and procedures:

• Physical examination and analysis of previous medical history
• Eye examination by a specialist (ophthalmologists or retinal experts)
• Some healthcare providers conduct toxoplasmosis screening for women in the period immediately following a pregnancy (during the first few visits). The tests may include CBC, PCR, ELISA test for toxoplasma, cordocentesis, and testing of amniotic fluid and blood of the fetus
• Fundoscopic (ophthalmoscopic) examination by an eye specialist, who examines the back part of the eye (or the fundus)
• Visual acuity test using a special and standardized test chart (Snellen chart)
• Slit-lamp examination: Examination of the eye structure using a special instrument called a slit-lamp. In this procedure, the pupils are dilated and the internal eye structure is examined
• Tonometry: Measurement of intraocular pressure or eye fluid pressure, especially to detect conditions such as glaucoma
• Fundus fluorescein angiography (FFA): In this technique, the eye blood vessels are examined using a fluorescein dye
• Fundus autofluorescence (FAF): It is a non-invasive diagnostic technique to examine the fundus of the eye without using a fluorescent dye by a specialized fundus camera 
• Indocyanine green (ICG) angiography: It is used to examine the blood vessels of the choroid using a dye, called indocyanine green, particularly to study the choroid
• B-scan ultrasonography: Special ultrasound scan of the eye through a non-invasive diagnostic tool, to assess health of eye structures
• Electroretinogram (ERG): It is a technique to measure electrical activities in the retinal cells
• Optical coherence tomography (OCT) of eye: It is an ocular imaging technique to visualize the eye structure
• Blood tests:
  • To check for the presence of antibodies in blood
  • Blood culture for infections
  • Complete blood count (CBC) with differential
  • Erythrocyte sedimentation rate (ESR)
• Tests to determine toxoplasmosis infection
• Antibody titer in aqueous humor and vitreous humor fluid samples

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Toxoplasmic Chorioretinitis?

The complications of Toxoplasmic Chorioretinitis may include:

• Glaucoma: A condition that can cause blindness due to higher intraocular pressure
• Cataracts: When the lens of the eye becomes clouded and cause vision loss
• Retinal detachment: An eye condition wherein the retina gets separated from the eye structures that holds the retinal layers together
• Cystoids macular edema
• Optic nerve atrophy: A permanent visual impairment that occurs when the optic nerve is damaged
• Over time and due to a lack of proper treatment, the condition can affect other surrounding eye structures such as the lens, optic nerve, and vitreous fluid
• Vision loss: Chorioretinitis can lead to permanent blindness, if it is left untreated
• Complications that arise from underlying toxoplasmosis in an immunocompromised host
• The toxoplasma is retained in the body even after recovery. This may get reactivated when conditions are favorable and the infection can recur; sometimes, multiple recurrences have been noted
• Side effects of treatment medication

How is Toxoplasmic Chorioretinitis Treated?

Early diagnosis and treatment of Toxoplasmic Chorioretinitis is crucial in preventing complications that may result in irreversible damage to the eye. In general, the management would involve decreasing eye pain and inflammation, addressing other associated symptoms, and stopping progression of eye tissue damage with the goal of preserving vision.

The treatment may include the following measures:

• Anti-parasitic medication (pyrimethamine) and antibiotics (such as sulfadiazine) are the most common drug combinations used
• Eye drops and oral medications (including pain medications)
• Corticosteroids (prednisone) to control inflammation
• Dark glasses may be prescribed for light-sensitivity
• Pregnant women and infants may require medication and sometimes extensive treatment, if the infection is systemic
• Addressing underlying toxoplasmosis infection
• In case of chronic cases that fails to get better with medication, surgery (such as vitrectomy) to treat the condition may be considered
• Long-term follow-up and prophylactic treatment may be necessary to prevent recurrent infections, in some cases
• Patients with severe immunodeficiencies often require aggressive and lifelong medication therapy

How can Toxoplasmic Chorioretinitis be Prevented?

The risks for Toxoplasmic Chorioretinitis may be lowered through the following measures:

• To reduce the incidence of toxoplasmosis, proper precautions have to be taken to prevent transmission of the harmful protozoa via food and water
• Avoid taking raw, undercooked, or improperly cooked meat or vegetables and fruits
• Pregnant women have a high-risk of the infection being transmitted to their babies; hence, adequate prenatal care is to be ensured
• Avoiding or minimizing contact with individuals who have infections
• Washing hands frequently with suitable hand sanitizer
• Treating underlying infections, as early as possible
• Maintaining long-term follow-up to watch out for recurrence of the infection

What is the Prognosis of Toxoplasmic Chorioretinitis? (Outcomes/Resolutions)

• The prognosis of Toxoplasmic Chorioretinitis generally varies between individuals and depends on various factors. However, in many, the infection is self-limiting and resolves within a few weeks and no treatment may be necessary
• Individuals with poor immune system, those with severe symptoms and complications, and those who do not avail adequate treatment may have a poorer prognosis
• Toxoplasmic Chorioretinitis can result in permanent blindness in some cases. A total loss of vision is typically associated with location of the retinal scar, development of complications, and multiple recurrences
• Recurrence of the condition may be observed in individuals with both strong and healthy immune systems and those with weak immunity; although, the frequency of recurrence is lower for immunocompetent individuals

Additional and Relevant Useful Information for Toxoplasmic Chorioretinitis:

Please visit our Eye & Vision Health Center for more physician-approved health information:

http://www.dovemed.com/health-topics/vision-center/