A 5 year-old boy was referred to our office for evaluation of white retinal spots noticed during a yearly examination. He was otherwise healthy and had been born full-term.
Visual acuity with myopic correction was 20/150 OU, improved with pinhole to 20/80 OS. The anterior segment was within normal limits. The posterior segment exam revealed diffuse peripheral chorioretinal coalescing atrophic lesions, symmetrical in both eyes, and some arterial attenuation (Figure 1 & 2)
Wide field fundus photographs showed the widespread presence of atrophic chorioretinal lesions in both eyes (Figures 1 & 2). Autofluorescence imaging confirmed diffuse peripheral RPE damage, with relative RPE preservation in the posterior pole (Figures 3 & 4).
Gyrate atrophy was thought to be the most probable diagnosis. To confirm the diagnosis, the patient underwent laboratory testing to measure serum ornithine levels, which were extremely elevated. He was thereafter referred to a hereditary disease specialist and a genetics specialist.
A few other chorioretinal dystrophies can present with a similar clinical picture:
- Cone-rod dystrohpies
- Retinitis pigmentosa
A wider differential diagnosis of somewhat similar fundus findings include:
- Toxic retinopathies (e.g. thioridazine)
- Infectious retinopathies (e.g. syphilis)
- Paraneoplastic/metastatic/autoimmune retinopathies
Gyrate atrophy is a rare autosomal recessive chorioretinal dystrophy resulting from the abnormal metabolism of ornithine and subsequent high serum ornithine levels. The usual symptoms are myopia and night blindness, presenting in childhood. It is characterized by the presence of sharply defined areas of chorioretinal atrophy, starting in the midperiphery, and progressively extending towards the macula and peripherally. Two other ocular conditions found more frequently in this disease are macular edema and early cateracts.
Two treatments have been described, with varying degrees of success: vitamin B6 supplementation and dietary arginine restriction through a low protein diet. Arginine restriction diets can be difficult to establish and maintain, especially in children, and vitamin B6 supplementation is generally better tolerated.
Agarwal, A. Gass’ Atlas of Macular Diseases. Edinburgh: Elsevier Saunders, 2012. Pg. 380-2