A Case of Acromegaly With Progressed Diabetic Retinopathy and Sarcopenia Diagnosed Following the Onset of Severe Hypoglycemia

Abstract

Acromegaly is a rare disorder characterized by excessive production of growth hormone (GH) from a pituitary tumor, typically leading to elevated glucose levels due to increased insulin resistance; hypoglycemia is rare. However, the long-term effect of excess GH on the peripheral organs is still unclear. Here we present a 69-year-old man evaluated for the cause of a hypoglycemic episode. He was underweight (body mass index: 17.3 kg/m²) with sarcopenia, which potentially contributed to his hypoglycemia. Notably, he exhibited progressed proliferative diabetic retinopathy compared to other microvascular complications, leading to further endocrinological investigation. As a result, he was diagnosed with acromegaly showing elevated GH and insulin-like growth factor-1 (IGF-1) with a pituitary tumor. Opting against transsphenoidal surgery (TSS), the patient was treated with a somatostatin analog (SSA), achieving normalized IGF-1 levels with a monthly 120 mg lanreotide injection. In this case, acromegaly could lead to sarcopenia from GH-derived gluconeogenesis in the peripheral organs such as the reduction of muscle leading to reduced glucose reserves. Acromegaly in the elderly may present atypicality. Clinicians should be vigilant for unique manifestations such as advanced diabetic retinopathy, even in elderly patients with hypoglycemia.

Keywords: acromegaly; diabetic retinopathy; hypoglycemia; insulin autoimmune disease; sarcopenia.

Figure 1. Representative abdominal CT images of sarcopenia

Demonstrable axial CT images at the third lumbar vertebra region with highlighted skeletal muscles. The image was obtained from LightSpeed VCT Vision (GE Healthcare, Princeton, NJ, USA) and analyzed with Ziostation2 (Ziosoft, Tokyo, Japan). CT, computed tomography

Figure 2. An image of diabetic retinopathy in the right eye

Fundus photography of the present case was shown. Laser photocoagulation for proliferative diabetic retinopathy was repeated many times previously.

Figure 3. Images of acromegalic phenotypes

The phenotype led to suspicion of acromegaly. The facial features were prominent brow ridges (a), macroglossia, and thickened nose (b).

Figure 4. Images of the pituitary tumor

Non-contrast coronal and sagittal T2- (a and b) and T1-weighted (c and d) pituitary images with MRI are shown. White arrows indicate a mass. MRI, magnetic resonance imaging

Figure 5. Treatment time-course of the present case

Laboratory data and treatment time-course of the present case are shown. HbA1c, hemoglobin A1c; IGF-1, insulin-like growth factor-1; SD, standard deviation