[Hypothyroid hypertrophic myopathy following mantle irradiation for Hodgkin's disease. A case]

Hypothyroid myopathy: A peculiar clinical presentation of thyroid failure. Review of the literature

Abnormalities in thyroid function are common endocrine disorders that affect 5-10 % of the general population, with hypothyroidism occurring more frequently than hyperthyroidism. Clinical symptoms and signs are often nonspecific, particularly in hypothyroidism. Muscular symptoms (stiffness, myalgias, cramps, easy fatigability) are mentioned by the majority of patients with frank hypothyroidism. Often underestimated is the fact that muscle symptoms may represent the predominant or the only clinical manifestation of hypothyroidism, raising the issue of a differential diagnosis with other causes of myopathy, which sometimes can be difficult. Elevated serum creatine kinase, which not necessarily correlates with the severity of the myopathic symptoms, is certainly suggestive of muscle impairment, though it does not explain the cause. Rare muscular manifestations, associated with hypothyroidism, are rhabdomyolysis, acute compartment syndrome, Hoffman's syndrome and Kocher-Debré-Sémélaigne syndrome. Though the pathogenesis of hypothyroid myopathy is not entirely known, proposed mechanisms include altered glycogenolytic and oxidative metabolism, altered expression of contractile proteins, and neuro-mediated damage. Correlation studies of haplotype, muscle gene expression and protein characterization, could help understanding the pathophysiological mechanisms of this myopathic presentation of hypothyroidism.

Hoffman's syndrome: pseudohypertrophic myopathy as initial manifestation of hypothyroidism. Case report

The frequency of myopathy in hypothyroidism ranges from 30 to 80%. The major symptoms related are weakness, muscular cramps and myalgia. The pseudohyperthrophic form is called Hoffman's syndrome. The electrophysiological study reveals myopathy, neuropathy or mixed pattern. Laboratorial investigation generally shows increased levels of muscle enzymes and low serum thyroid hormones, with thyrotrophic-stimulating hormone (TSH) elevated. The treatment consists in hormone replacement and the prognosis is good in most of the cases. We report an adult male who developed muscular cramps, myalgia, weakness, pseudohyperthrophy, associated with facial edema and alteration of his voice. The muscle enzymes were increased and T4 was undetectable with a raised level of TSH. The myopathy was the initial manifestation of hypothyroidism in this case.

[Hypothyroid hypertrophic myopathy in adults related to chronic lymphocytic thyroiditis. A case]

The authors report a case of hypothyroid hypertrophic myopathy which reveal chronic lymphocytic thyroiditis. This entity est uncommon, can be the most important sign of hypothyroidism and cure after the institution of thyroid hormone replacement therapy. The E. M. G. is usually myopathic and serum muscle markers (myoglobin and enzymes) increased. Pathologic studies of muscle show caracteritic but non specific and inconstant abnormalities. Hypothyroid myopathy could be caused by a mitochondrial oxidative phosphorylation deficiency or changes in muscle contractile properties (both in fibre type proportion and in the properties of the muscle contractile proteins).