Multifocal Choroiditis: Understanding Symptoms, Treatments, and Prognosis

Multifocal choroiditis (MFC) is a rare, chronic, inflammatory disease primarily affecting the choroid, a layer of tissue beneath the retina. This condition is often idiopathic, meaning the exact cause is not fully understood. Despite the availability of treatments that can suppress symptoms, MFC is not curable, as the disease tends to recur once medication is stopped.

Understanding Multifocal Choroiditis

MFC is an inflammation of the choroid, a network of blood vessels that nourish the retina. It is much more common in females and can lead to significant vision loss over time due to recurrent episodes. The condition involves a primary process at or near the retinal pigment epithelium (RPE) with or without photoreceptor outer segments and choriocapillaris (capillary network) involvement. The exact etiology remains unclear but is presumed to be either a vasculitic obstruction of the choriocapillaris leading to secondary infarction of the overlying RPE, or possibly an immunologic response directed at the RPE itself.

Primary Pathologic Process

The primary pathologic process in MFC occurs at or near the level of the retinal pigment epithelium, potentially leading to inflammation, fluid accumulation, and, in some cases, the formation of new blood vessels that can destroy the retina. This process often results in peripapillary atrophy with progressive subretinal fibrosis, leading to the enlargement of a blind spot in approximately 43% of patients. The disease also frequently leads to the formation of subretinal neovascular membranes, which is a primary cause of central visual loss in approximately 45% of cases, as opposed to cystoid macular edema, which is less common at 13%.

Treatment Options

The treatment of MFC is challenging due to its chronic and recurrent nature. The primary goal is to manage inflammation to preserve vision. Common treatments include:

Glucocorticoids: Steroid medications, both oral and intraocular, are often effective in suppressing inflammation and managing symptoms. However, the effect of these treatments may diminish with each recurrence of the disease. Immune-modulators: Azathioprine, methotrexate, and cyclosporine are used to modulate the immune response and prevent inflammation. These treatments have shown efficacy in controlling disease activity and preserving vision. Anti-VEGF Injections: Bevacizumab and similar drugs are injected into the eye to inhibit the formation of new blood vessels, reducing subretinal membrane formation and improving vision. Laser Coagulation: This procedure is used to prevent or treat the formation of neovascular membranes. Surgical Interventions: Limited macular translocation surgery has been considered in some cases to manage subretinal neovascular membranes.

While these treatments can provide temporary relief and help preserve vision, the outlook for MFC is generally poor. Recurrence is high, and visual prognosis remains poor, with approximately one-third of patients maintaining their initial visual acuity at onset, while another third can lose at least 2 Snellen lines in vision.

Conclusion

Multifocal choroiditis is a complex and challenging disease that requires a comprehensive approach to treatment. Despite advances in medical and surgical treatments, the disease remains difficult to cure, and patients often face significant vision loss due to recurrent inflammation and the formation of subretinal neovascular membranes. Close monitoring and a multidisciplinary approach to treatment are essential for managing MFC and preserving vision.