Muscle ultrasound to identify prednisone-induced muscle damage in adults with nephrotic syndrome

Abstract

Steroid myopathy is a non-inflammatory toxic myopathy that primarily affects the proximal muscles of the lower limbs. Due to its non-specific symptoms, it is often overshadowed by patients’ underlying conditions. Prolonged or high-dosage use of glucocorticoids leads to a gradual decline in muscle mass. There are no tools available to identify the course of steroid myopathy before the patient displays substantial clinical symptoms. In this study, we investigated individuals with nephrotic syndrome receiving prednisone who underwent muscle ultrasound to obtain cross-sectional and longitudinal pictures of three major proximal muscles in the lower limbs: the vastus lateralis, tibialis anterior, and medial gastrocnemius muscles. Our findings revealed that grip strength was impaired in the prednisolone group, creatine kinase levels were reduced within the normal range; echo intensity of the vastus lateralis and medial gastrocnemius muscles was enhanced, the pennation angle was reduced, and the tibialis anterior muscle exhibited increased echo intensity and decreased thickness. The total dose of prednisone and the total duration of treatment impacted the degree of muscle damage. Our findings indicate that muscle ultrasound effectively monitors muscle structure changes in steroid myopathy. Combining clinical symptoms, serum creatine kinase levels, and grip strength improves the accuracy of muscle injury evaluation.