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

• Retinochoroiditis due to Toxoplasma
• Toxoplasmic Retinochoroiditis
• TRC (Toxoplasma Retinochoroiditis)

What is Toxoplasma Retinochoroiditis? (Definition/Background Information)

• Retinochoroiditis is an eye condition that results in the inflammation of both the retina and the choroid. The terminology retinochoroiditis indicates that the retina is involved first (causing retinal hemorrhages), with subsequent involvement of the choroid
• It can be caused by both infectious and non-infectious factors and any individual may be affected, particularly those with poor immunity. When retinochoroiditis develops from exposure to the pathogen Toxoplasma gondii, it is known as Toxoplasma Retinochoroiditis (TRC)
• The condition 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, Toxoplasma Retinochoroiditis may present severe signs and symptoms. In general, the signs and symptoms may include reduced eye pain, blurred vision, floaters in the eye, sensitivity to light, and vision loss. 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 exams, eye exams, and various blood tests to diagnose Retinochoroiditis due to Toxoplasma. Upon diagnosis, treatment options involving anti-parasitic medication and steroids may be used
• The treatment also depends on whether the condition is acute (termed Acute TRC) or chronic and relapsing (termed Chronic Relapsing TRC). Additionally, treatment for any underlying condition causing weak immunity is provided
• Toxoplasma Retinochoroiditis 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 Toxoplasma Retinochoroiditis depends on the severity of the signs and symptoms and may be assessed on a case-by-case basis. With appropriate early treatment, the prognosis is generally good. However, the condition may recur and hence, periodic checkups are advised
• Almost 25% of the individuals with Toxoplasma Retinochoroiditis have some form of permanent vision impairment due to recurrences. However, the incident rate of recurrence is observed to generally decrease with time (over several years and decades)

Who gets Toxoplasma Retinochoroiditis? (Age and Sex Distribution)

• Toxoplasma Retinochoroiditis can affect individuals of any age and gender, especially those with poor immune systems. However, the condition is relatively rare
• Congenital Toxoplasma Retinochoroiditis may be manifested within a year of birth or even after several years to decades following reactivation of T. gondii
• Both males and females are affected
• 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. In USA, the incidence of the condition is about 1 in 165 (0.6%) among the carrier population of toxoplasmosis pathogen

What are the Risk Factors for Toxoplasma Retinochoroiditis? (Predisposing Factors)

The risk factors for Toxoplasma Retinochoroiditis 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 Toxoplasma Retinochoroiditis? (Etiology)

Toxoplasmic Retinochoroiditis occurs from exposure of the body to the protozoan parasite Toxoplasma gondii, when the parasite travels to the eye. Retinochoroiditis results from an inflammation of the retina, followed by the choroid due to the infection. It is reportedly the most common cause of infectious retinochoroiditis. 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). A majority of congenital toxoplasmosis cases are known to exhibit retinochoroiditis
• 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 conditions weaken the immune system

What are the Signs and Symptoms of Toxoplasma Retinochoroiditis?

The signs and symptoms of Toxoplasma Retinochoroiditis may vary between individuals and may include:

• Blurred or hazy vision
• Eye floaters with sudden onset; the individuals experience illusions that some small objects such as spots, hairs, or strings are moving in the eye
• Light-sensitivity (photophobia) and blurred vision
• Impaired color vision
• Eye pain
• Decrease in visual acuity
• Loss of vision
• The condition may affect only one eye or both the eyes; congenital Toxoplasmic Retinochoroiditis affects bilaterally (involvement of both eyes) in a majority of the cases; while in many acquired cases, only one eye is affected (unilateral involvement)

Associated presentations of the underlying toxoplasmosis infection causing the eye infection may be observed; although, in most cases, systemic signs and symptoms are absent. In some, mild flu-like symptoms that include fever, swollen lymph nodes, and general weakness may be noted.

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 Toxoplasma Retinochoroiditis Diagnosed?

A healthcare professional may diagnose Toxoplasma Retinochoroiditis using the following tests and procedures:

• Physical examination and analysis of previous medical history
• Eye examination by an eye 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); a lot of retinal hemorrhages that appear superficial is noted
• 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

A differential diagnosis may be undertaken to eliminate the following conditions:

• Acute retinal necrosis
• Candida endophthalmitis
• Cytomegalovirus retinitis
• HIV retinitis
• Multifocal choroiditis
• Presumed ocular histoplasmosis
• Sarcoidosis
• Serpiginous choroiditis
• Syphilis
• Toxocariasis
• Tuberculosis

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 Toxoplasma Retinochoroiditis?

The complications of Toxoplasma Retinochoroiditis may include:

• Uveitic 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
• Epiretinal membrane: Development of scar tissue over the surface of the macula
• Optic nerve atrophy: A permanent visual impairment that occurs when the optic nerve is damaged
• Choroidal neovascularization: It can result in loss of vision and occurs during the later stages of the condition
• 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: Retinochoroiditis can lead to permanent blindness, if it is left untreated
• Eye complications in congenital cases include cross-eye (strabismus), abnormally-small eye (microphthalmia), and involuntary eye movements (nystagmus). Often, with systemic congenital toxoplasmosis, severe neurological manifestations, premature growth, enlargement of liver and spleen, skin rashes, large-sized head (hydrocephalus), and other findings may be noted
• Complications that arise from underlying toxoplasmosis in an immunocompromised host (especially patients with HIV infection or AIDS) include severe necrotizing chorioretinitis, toxoplasmic encephalitis, and/or brain abscess with associated neurological symptoms
• 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; some reports indicate that nearly 25% of the patients may experience some form of adverse reaction from the medication

How is Toxoplasma Retinochoroiditis Treated?

Early diagnosis and treatment of Toxoplasma Retinochoroiditis 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 and it depends on the type of Toxoplasma Retinochoroiditis - whether it is acute type or chronic/relapsing type:

• 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; this may be essential for both immunocompetent and immunocompromised individuals, based on the healthcare provider’s assessment

Patients with severe immunodeficiencies often require aggressive and lifelong medication/supportive therapy.

How can Toxoplasma Retinochoroiditis be Prevented?

The risks for Toxoplasma Retinochoroiditis 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

Infants with congenital toxoplasmosis may be prescribed medication (antibiotics) for a period of 12 months to reduce the risk for retinochoroiditis (into the future).

What is the Prognosis of Toxoplasma Retinochoroiditis? (Outcomes/Resolutions)

• The prognosis of Toxoplasma Retinochoroiditis generally varies between individuals and depends on a variety of 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
• Toxoplasma Retinochoroiditis can frequently result in visual field loss, and even 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 Toxoplasma Retinochoroiditis:

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

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