Central changes in hypothyroid myopathy: A case report

Abstract

A muscle biopsy from a patient with hypothyroid myopathy showed striking central changes. "Cores" were seen in most type 1 fibers with oxidative enzyme preparations. Electron microscopy of these areas revealed Z disc streaming, myofilament disruption, and absent mitochondria. The myopathy rapidly improved with thyroxine treatment. This biopsy is of interest, as numerous "cores" have not previously been reported in hypothyroid myopathy.

Exercise-induced myalgia in hypothyroidism

“…Exercise-induced myalgias and recurrent rhabdomyolysis are uncommon signs of hypothyroid myopathy [2,6,7]. Three cases of rhabdomyolysis caused by hypothyroidism have been reported in the literature [3][4][5].…”

“…Myopathy is a widely recognized complication of hypothyroidism, with an estimated incidence of 30-80% in patients with myxedema [2,6,7]. Generally the severity of the myopathy parallels the duration and degree of the hypothyroidism.…”

“…Histological changes include type 1 fiber predominance, type 2 fiber atrophy, and increased numbers of central nuclei. Ultrastructural changes include excessive amounts of glycogen, lipid accumulations, abnormal mitochondria, dilated sarcoplasmic reticulum, and focal myofibrillar degeneration [2,6,7]. Magnetic resonance spectroscopy of hypothyroid muscle shows low intracellular pH in resting muscle and delayed glycogen breakdown in exercising muscle [8].…”

Hoffmann’s Syndrome: A Case Report

“…[1][2][3] Severity of myopathy generally correlates with the duration and the degree of thyroid hormone deficiency. 4,5 Serum CK (creatine kinase) elevation is usually observed even in the absence of overt muscle weakness. 4,6 .Although muscular symptoms may occur in many patients with hypothyroidism, muscular hypertrophy with muscle stiffness is reported in less than 10% of the patients.…”

“…4,5 Serum CK (creatine kinase) elevation is usually observed even in the absence of overt muscle weakness. 4,6 .Although muscular symptoms may occur in many patients with hypothyroidism, muscular hypertrophy with muscle stiffness is reported in less than 10% of the patients. 1 The adult and childhood forms characterized with increased muscle volume, slow movements and stiffness are known as Hoffmann's syndrome and Debre Kocher Semelaigne respectively.…”