Teaching NeuroImages: Kearns-Sayre syndrome

A 19-year-old man presented 6 months postimplantation of permanent pacemaker for complete heart block with bilateral nonfatigable symmetric ptosis, diminished levator superioris function, and symmetric ophthalmoplegia (figure 1). Funduscopy revealed bilateral pigmentary retinopathy (figure 2). Skeletal muscle biopsy revealed presence ofragged-red fibers, consistent with Kearns-Sayre syndrome. This mitochondrial disorder is characterized by the triad of onset before age 20, chronic progressive external ophthalmoplegia, and pigmentary retinopathy. Other findings can include complete heart block, cerebellar ataxia, deafness, and endocrinopathies. CSF folate levels should be measured and supplemented if low. There is no definitive treatment but annual surveillance for comorbidities is required.(1,2</SUP)