Chloroquine retinopathy

Chloroquine Retinopathy is a medical condition characterized by damage to the retina of the eye that occurs as a side effect of long-term or high-dose use of chloroquine, a medication commonly used for the treatment of malaria, rheumatoid arthritis, and lupus erythematosus. This condition is a form of toxic retinopathy, where the toxicity of a drug leads to retinal damage, potentially resulting in permanent vision loss if not identified and managed promptly.

Causes and Risk Factors

Chloroquine retinopathy is primarily caused by the accumulation of chloroquine in the retinal pigment epithelium (RPE), which leads to damage of the photoreceptor cells in the retina. The risk of developing this condition increases with the total cumulative dose of chloroquine. Other risk factors include long-term use of the drug (typically over five years), higher daily doses, and the presence of pre-existing retinal disease. Kidney or liver dysfunction, which can affect the metabolism and excretion of the drug, may also increase the risk.

Symptoms

The initial symptoms of chloroquine retinopathy may be subtle and not immediately noticeable to the patient. Early signs include difficulty in reading and seeing in low light conditions. As the condition progresses, patients may experience a reduction in their central vision, development of blind spots (scotomas), and changes in color vision. Without intervention, the condition can lead to significant vision loss and even blindness.

Diagnosis

The diagnosis of chloroquine retinopathy involves a comprehensive eye examination, including a review of the patient's medical history, particularly their use of chloroquine. Diagnostic tests may include:

• Visual field test to detect any blind spots in the vision.
• Optical coherence tomography (OCT) to obtain detailed images of the retina, allowing for the identification of any structural changes.
• Fundus autofluorescence (FAF) imaging to assess the health of the retinal pigment epithelium.
• Electroretinogram (ERG) to measure the electrical responses of the retina's light-sensitive cells.

Prevention and Management

Preventing chloroquine retinopathy involves careful management of chloroquine dosage and duration of therapy, taking into account the patient's body weight and overall health status. Regular eye examinations are crucial for early detection of retinal changes, ideally before the onset of symptoms. Once chloroquine retinopathy is diagnosed, the most effective management strategy is to discontinue or reduce the use of chloroquine, if medically feasible, to prevent further retinal damage. However, it is important to note that some retinal changes may be irreversible, and discontinuation of the drug does not guarantee improvement of vision.

Treatment

There is no specific treatment for reversing the damage caused by chloroquine retinopathy. Management focuses on stopping the progression of the disease by discontinuing or adjusting the dosage of chloroquine. Patients with chloroquine retinopathy should be closely monitored by an ophthalmologist, and supportive treatments may be recommended to help manage symptoms and maintain the best possible vision.

Conclusion

Chloroquine retinopathy is a serious and potentially vision-threatening condition that underscores the importance of regular eye examinations for patients undergoing long-term chloroquine therapy. Early detection and appropriate management are key to preventing significant vision loss.