Toxoplasmic chorioretinitis

Illness description

This is an inflammation of the choroid (Latin chorioidea – choroid) and retina (retina – retina) caused by Toxoplasma gondii. It is the most common cause of posterior segment inflammation (posterior uveitis) in developed countries. Cats are the primary hosts of Toxoplasma. The parasite is found in cat feces, and humans can become infected directly or by consuming undercooked meat. Toxoplasma can also be transmitted transplacentally, meaning that if a pregnant woman becomes infected, the fetus can be harmed – it may either die in the womb or be born with congenital anomalies. Adults infected with Toxoplasma often do not experience any symptoms – the disease is asymptomatic. However, individuals with weakened immune systems may develop an acute systemic disease.

Symptoms

If the course of the disease is symptomatic, there may be general weakness, sweating, a slight fever (rarely high), headaches/muscle/joint pain, swollen neck and occipital lymph nodes. Sometimes the liver and spleen enlarge, and in rare cases, hepatitis or myocarditis may develop. If the infection reaches the brain, it can cause encephalitis (inflammation of the brain) or meningitis (inflammation of the meninges). Posterior uveitis manifests as decreased vision, floating spots in front of the eyes (floaters), and a visible haze. There is no eye pain, redness, or sensitivity to light.

Diagnosis of the disease

Specific anti-Toxoplasma antibodies are detected, and their titers increase when retested after 3-4 weeks. During pregnancy, the fetus’s amniotic fluid is tested for the virus’s DNA (amniotic fluid is taken by amniocentesis from the 16th week of pregnancy). Eye damage – chorioretinitis – is diagnosed by ophthalmoscopy: lesions of damage are detected.

Eye damage often reoccurs during adolescence. Patients complain of floating spots in their eyes, merging of vision. Signs of chorioretinitis (pale spots with sharp borders) are detected at the fundus of the eye during ophthalmoscopy.

Treatment

In adolescence, if there is a reactivation of the disease and immunological tests are negative (50% of infected individuals test positive, so the most important factor in diagnosing the disease are clinical symptoms and ophthalmoscopy data), the risk of chorioretinitis is unlikely, so treatment is usually not prescribed.

In other cases, treatment involves steroids and antibiotics (clindamycin, sulfonamide, pyrimethamine).

Source | Author Doctor Nikas Samuolis, reviewed by Prof. Virginijus Šapoka | Vilnius University | Faculty of Medicine | Head of the Department of Internal Medicine, Family Medicine, and Oncology