Advanced proliferative diabetic retinopathy and macular edema in acromegaly: a case report and literature review

We describe the multimodal management of a patient with proliferative diabetic retinopathy and diabetic macular edema associated with active acromegaly. A 61-year-old Japanese female who had had type 2 diabetic mellitus for > 10 years complained of deteriorated eyesight. She had distinct acromegalic features, and her visual acuity was 0.05 (right) and 0.4 (left) because of sub-capsular cataracts and proliferative diabetic retinopathy with macular edema. Anti-vascular endothelial growth factor treatments, cataract surgeries and retinal direct laser photocoagulation were performed together with gradual glycemic control with basal insulin to prevent worsening of the visual impairment. She was given an injection of a long-acting somatostatin analog (octreotide LAR) and began taking three bolus mealtime insulin shots with basal insulin beginning 1 month before undergoing a trans-sphenoidal adenomectomy. After this successful surgery, her blood glucose levels immediately decreased, and the rapid-acting insulin at mealtimes was discontinued with the observation of normal growth hormone and insulin-like growth factor (IGF)-1 levels, suggesting that her acromegaly was in remission. Her visual acuity improved without a worsening of diabetic retinopathy. Since the increased IGF-1 production in systemic circulation and local vitreous fluids may be one of the aggravating factors for diabetic retinopathy, our patient's acromegaly complicated with severe retinopathy presented an opportunity for multimodal management in close collaboration with an ophthalmologist, neurosurgeon, and endocrinologist. Our literature review revealed that the estimated prevalence of diabetic retinopathy in cases of acromegaly associated with diabetes mellitus is 12.5–42.9%.