Chagas disease is an illness resulting from the Trypanosoma cruzi parasite. This parasite is primarily transmitted through the feces of triatomine bugs, insects commonly known as “kissing bugs” because they often bite people on the face. The disease is most prevalent in rural parts of Mexico, Central America, and South America. While the infection can impact various body systems, some of its earliest and most recognizable signs involve the eyes.
Acute Phase Eye Manifestations
The initial, or acute, phase of Chagas disease occurs within the first few weeks or months of infection. During this period, a highly characteristic sign known as Romaña’s sign may appear. This manifestation is a direct result of the T. cruzi parasite entering the body through the conjunctiva, the thin membrane covering the white part of the eye. People can become infected by unintentionally rubbing the insect’s feces into their eye.
Romaña’s sign presents as a painless, one-sided swelling of the upper and lower eyelids. This purplish swelling is an inflammatory response at the site where the parasite invaded, causing localized fluid accumulation and puffiness around the eye.
Accompanying the eyelid swelling, other ocular symptoms can arise. Conjunctivitis, which causes redness and irritation in the eye, is common. The swelling may also extend to the nearby preauricular lymph node, located just in front of the ear, as the body’s lymphatic system responds to the localized infection.
Chronic Phase Eye Complications
After the acute phase, Chagas disease can transition into a chronic phase that may last for decades. During this time, many individuals may not show any symptoms for years. Up to 30% of those with chronic infections, however, may eventually develop complications. These later-stage issues arise from the long-term presence of the parasite and the body’s persistent immune response.
Ocular problems in the chronic stage are often related to long-term inflammation. Conditions such as keratitis, which is the inflammation of the cornea, can develop. Another potential complication is uveitis, an inflammation of the uvea, the middle layer of the eye. These inflammatory responses can cause pain, light sensitivity, and blurred vision.
The persistent inflammation can also affect the glands responsible for tear production. This may lead to changes in the tear film’s composition and stability, resulting in dry eye syndrome. Nerve damage is another possible outcome in up to 10% of chronic cases, which could potentially alter eye muscle function or sensation.
Diagnosis and Treatment
Diagnosing Chagas disease involves a combination of clinical evaluation and laboratory testing. When a patient presents with symptoms like Romaña’s sign, an ophthalmologist will conduct a thorough eye examination to assess the extent of the ocular manifestations. However, a definitive diagnosis is made through blood tests designed to detect either the T. cruzi parasite itself or the antibodies the immune system produces to fight it.
Treatment for Chagas disease is twofold, addressing both the parasite and the symptoms it causes. Antiparasitic medications, specifically benznidazole and nifurtimox, are used to kill the T. cruzi parasite. This treatment is most effective when administered during the acute phase of the infection, as it can cure the disease and prevent it from progressing to the chronic stage.
For the associated eye conditions, management is focused on relieving symptoms. In the acute phase, anti-inflammatory eye drops may be prescribed to reduce the swelling and discomfort of Romaña’s sign and conjunctivitis. In the chronic phase, a patient experiencing dry eye syndrome might be advised to use artificial tears to maintain lubrication and comfort.