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Figure 1. This external photograph demonstrates the 15-year-old patient’s bilateral ptosis. He also reported experiencing progressive vision loss in both eyes for 16 months.
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Figure 2. (A) This ultra-widefield fundus photograph shows peripheral pigmentary changes in the patient’s right eye. (B) A fundus autofluorescence of the right eye displays scattered peripheral hypoautofluorescence. Findings were similar in the patient’s left eye.
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Figure 3. Spectral domain optical coherence tomography imaging shows bilateral outer retinal atrophic changes and photoreceptor disruptions in the patient’s right eye. Findings were similar in his left eye.
A 15-year-old boy with a history of ptosis, intermittent exotropia, and myasthenia gravis (MG) presented to the eye clinic with blurry vision. The patient was followed by neurology and had been previously treated with pyridostigmine for MG with minimal benefit.
The patient reported progressive vision loss in both eyes for 16 months. He denied flashes, floaters, or eye pain. When performing physical activity, he did not have fatigability, but did have muscle soreness persisting for multiple days after exertion.
On examination, the patient had short stature and was underweight. His Snellen visual acuities were 20/40 OD and 20/30 OS. Pupillary exam and intraocular pressures (IOP) were normal. Ocular motility was abnormal with -4 limitation of elevation, abduction, and adduction, and -3.5 limitation of depression in both eyes. External examination was notable for bilateral ptosis worse on the left. Dilated fundus exam was notable for bilateral peripheral retinal pigmentary changes and atrophic changes in the macula, and autofluorescence imaging showed scattered peripheral hypoautofluorescence (Figure 1A and 1B). Optical coherence tomography (OCT) was notable for bilateral outer retinal atrophic changes (Figure 2).
On review of records the previous MG antibody panel, electromyogram, and chest magnetic resonance imaging (evaluating for thymoma) were negative 7 years prior.
The clinical findings of a peripheral pigmentary retinopathy on dilated fundus examination combined with ptosis, ophthalmoplegia, and delayed muscle soreness after exertion led to reconsideration of the initial diagnosis of myasthenia gravis. The patient underwent an electroretinogram (ERG) that showed...
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The clinical findings of a peripheral pigmentary retinopathy on dilated fundus examination combined with ptosis, ophthalmoplegia, and delayed muscle soreness after exertion led to reconsideration of the initial diagnosis of myasthenia gravis. The patient underwent an electroretinogram (ERG) that showed smaller than average detectable stimuli in scotopic and photopic conditions. Mitochondrial DNA (mtDNA) genetic sequencing from blood revealed a 7.9 kb deletion confirming the diagnosis of Kearns-Sayre syndrome (KSS).
Due to high energy demand and abundant mitochondria in the extraocular muscles, ophthalmic signs are usually the initial manifestation of KSS. Ptosis is the most common presentation, followed by ophthalmoplegia and pigmentary retinopathy, and less commonly, vision loss.1 In contrast to MG, Kss patients may not have muscle fatigability. The pigmentary retinopathy may vary from subtle changes to extensive pigment atrophy similar to retinitis pigmentosa.2 The primary affected retinal cell layer in KSS is thought to be the retinal pigment epithelium (RPE), with changes between the photoreceptors and RPE visible on OCT.3
Regular follow-up with a multidisciplinary team is the mainstay of management in KSS. When needed, surgery for ptosis or strabismus as well as prism glasses can be considered. It is also crucial to monitor cardiac activity with an electrocardiogram initially and at least every year, as cardiac conduction abnormalities can be a life-threatening feature of KSS.
Dr Hoyek is a postdoctoral research fellow in Ophthalmology at Massachusetts Eye and Ear and Harvard Medical School, Boston.
Dr Sokol is a Resident in Ophthalmology at Massachusetts Eye and Ear and Harvard Medical School, Boston.
Dr Patel is an Instructor of Ophthalmology at Massachusetts Eye and Ear and Harvard Medical School and Director of Pediatric Retina at Boston Children’s Hospital, Boston.
References
1. Khambatta S, Nguyen DL, Beckman TJ, Wittich CM. Kearns-Sayre syndrome: a case series of 35 adults and children. Int J Gen Med. 2014;7:325-332. doi:10.2147/IJGM.S65560
2. Padhy SK, Kumar V, Mandal S. Pigmentary retinopathy in Kearns-Sayre syndrome. Case Reports. Published online October 2, 2018. doi:10.1136/bcr-2018-2273943.
3. Birtel J, Landenberg C von, Gliem M, et al. Mitochondrial retinopathy. Ophthalmol Retina. 2021;6(1):65-79. doi:10.1016/j.oret.2021.02.017
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