FRI170 Ultrasound-Based Evaluation Of Muscles And Tendons In Patients With Cushing Syndrome

Disclosure: B. Bolayir: None. F. Gogus: None. B. Demir: None. M.M. Yalcin: None. J. Meray: None. A. Altinova: None. F.S. Toruner: None. M.Y. Akturk: None. Background: Myopathy, being induced by antianabolic and catabolic effects of excess corticosteroids is one of the characteristic features of Cushing Syndrome (CS). Muscle thickness which has been shown to be correlated with muscle cross sectional area can be used as an indicator of muscle mass. Although many studies have demonstrated effects of corticosteroids on collagen metabolism and case reports documented rupture of tendons in patients with chronic exposure to corticosteroids, tendon changes of patients with endogenous hypercortisolism have not been studied. Ultrasound, although not studied well in this group of patients, can be an alternative imaging method that provides information about muscle and tendon thickness. The aim of this study was to investigate muscle, tendon thicknesses and serum levels of myostatin in patients with CS. Methods: Twenty-two patients with CS and nineteen healthy control subjects similar for age, sex, height and weight were enrolled. Lower extremity tendon and muscle groups’ thickness were evaluated by ultrasound. Serum myostatin levels were measured by ELISA. Results: Age, height, weight and body mass index were similar between groups (p>0.05). The thicknesses of rectus femoris, vastus medialis, vastus lateralis, gastrocnemius medialis and gastrocnemius lateralis were lower in the CS group than control group (p≤0.001). However, thickness of soleus muscle was not significantly different between the groups (p > 0.05). No significant difference was revealed between groups in terms of Achilles and patellar tendon thickness (p>0.05). Median serum myostatin levels were found to be lower in the CS group than the control group (p<0.001).Conclusions: Ultrasound based measurement of muscle thickness can be used to assess and monitor steroid-induced changes of muscle mass. The fact that the thickness of the proximal muscles of lower extremity was found to be lower by ultrasound in patients with CS in our study supports the proximal myopathy feature of CS. Besides that, it was shown that the gastrocnemius lateralis and medialis thicknesses, which are the distal muscles of the lower extremity, were also shown to be lower in the Cushing group. On the other hand, CS might not affect the thickness of the lower extremity tendons. Moreover, the mechanism of the decrease in the level of myostatin, the negative regulator of muscle growth, in patients with needs to be elucidated with CS further studies. Presentation: Friday, June 16, 2023