The Impact of Overt and Subclinical Hyperthyroidism on Skeletal Muscle
- 1 April 2006
- journal article
- research article
- Published by Mary Ann Liebert Inc in Thyroid®
- Vol. 16 (4) , 375-380
- https://doi.org/10.1089/thy.2006.16.375
Abstract
Objective: Patients with overt hyperthyroidism (OH) commonly have proximal limb muscle weakness that improves after correction of hyperthyroidism. It is unclear, however, if patients with milder degrees of hyperthyroidism (referred to as subclinical hyperthyroidism or SCH) may also have a degree of muscle weakness. This may have clinical relevance as SCH patients are often elderly and may therefore have concurrent sarcopenia of aging and would represent a previously unrecognized complication of SCH. Design: We measured both thigh strength and cross-sectional area in patients with OH (n = 30) or SCH (n = 24), both prior to treatment of hyperthyroidism and again at 6–9 months after the restoration of a euthyroid state. Euthyroid controls (n = 48) were studied at similar time intervals. Main outcome: Prior to treatment, both knee flexor and extensor muscle strength was reduced in both patients with OH and SCH compared to controls (p < 0.05). After treatment all strength measurements improved in the OH group (p < 0.01) while in the SCH group the majority of muscle strength measurements improved (p < 0.05). Midthigh muscle cross-sectional area was reduced in both the OH and SCH group at baseline (p < 0.05) compared to controls and increased significantly following treatment (p < 0.05). There were no significant changes in any parameter in the euthyroid control (EC) group during the study period. Conclusions: The finding that muscle strength and cross-sectional area are reduced in SCH and improved after treatment lends support for the clinical decision to treat rather than observe this condition. This may have particular relevance to certain SCH patient groups including the elderly who are prone to falls and athletically active younger patients who require optimal skeletal muscle function.Keywords
This publication has 28 references indexed in Scilit:
- Adverse effects of subclinical hyperthyroidismThe Lancet, 2001
- Effect of triiodothyronine on mitochondrial energy coupling in human skeletal muscleJournal of Clinical Investigation, 2001
- T3 increases mitochondrial ATP production in oxidative muscle despite increased expression of UCP2 and -3American Journal of Physiology-Endocrinology and Metabolism, 2001
- Thyroid (neuro) myopathyThe Lancet, 2000
- Neuromuscular findings in thyroid dysfunction: a prospective clinical and electrodiagnostic studyJournal of Neurology, Neurosurgery & Psychiatry, 2000
- Novel transitions in MHC isoforms: separate and combined effects of thyroid hormone and mechanical unloadingJournal of Applied Physiology, 1998
- Hyperthyroid Myopathy and the Response to TreatmentThyroid®, 1991
- Muscle strength in hyperthyroid patients before and after medical treatmentClinical Physiology and Functional Imaging, 1990
- Protein Metabolism in Skeletal Muscle Tissue from Hyperthyroid Patients after Preoperative Treatment with Antithyroid Drug or Selective β-Blocking Agent. Results from a Prospective, Randomized Study*Journal of Clinical Endocrinology & Metabolism, 1984
- MUSCLE DYSFUNCTION IN HYPERTHYROIDISMThe Lancet, 1966