A series of case reports in BMC Opthalmology on patients with both myasthenia gravis (MG) and autoimmune retinopathy (AIR) highlights the importance of eye disease screening and care among patients with MG.
AIR is a group of rare eye diseases where the body’s immune system causes damage to the retina. AIR can lead to progressive vision loss and blind spots; treatment can help slow its progression but can’t reverse the damage, making early diagnosis important.
Yet diagnosing AIR in people with MG carries an extra challenge: Since MG can impact the eyes, doctors may not realize a patient’s symptoms are due to AIR, not MG. “Ocular manifestations of MG may divert attention from ocular symptoms and hinder early recognition of AIR,” noted the authors.
One of the case reports detailing a 65-year-old woman with MG and AIR illustrates the challenges. After diagnosis in 2006, she underwent thymectomy (the surgical removal of the thymus gland in the neck) and took oral steroids. Testing of the removed thymus confirmed that the patient had thymoma, which is a cancerous tumor.
Despite MG treatment, her vision became progressively poorer over the following years. She developed significant deterioration in at least two components of her vision: decreased central visual acuity and central visual field defect. She underwent cataract surgery, but her vision problems remained. The patient was thought to have a hereditary eye condition known as retinitis pigmentosa, but genetic testing proved otherwise.
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A series of highly-specific eye tests were carried out, finally leading to a diagnosis of AIR. When her diagnosis of thymoma was additionally taken into consideration, the patient was mores specifically diagnosed with cancer-associated retinopathy, a type of AIR that occurs when there is cancer elsewhere in the body.
In January 2018, the patient had a thymoma recurrence, resulting in a second thymectomy. While her MG symptoms improved, her vision continued to deteriorate; upon last follow-up, she was only able to to perceive the difference between light and darkness in both eyes.
While it is common for patients with MG to also have other autoimmune diseases, the co-occurrence of AIR is relatively rare. Hence, there are no detailed diagnostic and management guidelines on how to deal with AIR associated with MG. Nevertheless, patients with MG should be screened for this condition if they present with vision problems as this may allow doctors to initiate the necessary treatments as early as possible.
“In conclusion, AIR concurrent with MG is rare, and the diagnosis can be challenging due to combined ocular symptoms from MG and AIR,” the authors of the report wrote. “MG patients with vision loss should undergo a comprehensive ocular examination to make a definitive diagnosis of AIR as soon as possible for early treatment.”
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