Hypothyroid Myopathy Very common (up to 80% ) in patients with hypothyroidism Pathophysiology: • T4 deficiency leads to abnormal glycogenotysis & mitochondrial oxidative metabolism which impairs musde function • Selective atrophy of fast-twitching Type II fibers (glycolysis dependent) and hypertrophy of slow-twitching Type I muscle fibers Spectrum of Clinical Manifestations Asymptomatic CK Elevations → Myalgias (common) → Symmetric, proximal myopathy → Muscle hypertrophy → Rhabdomyolysis (rare) #Hypothyroid #Myopathy #pathophysiology #signs #symptoms #endocrinology
