Thyroid : official journal of the American Thyroid Association
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Case Reports
Myopathy as the persistently isolated symptomatology of primary autoimmune hypothyroidism.
Although disorders of thyroid function may cause a wide range of muscle disturbances, an overt myopathy has been rarely reported as an isolated clinical presentation of hypothyroidism. We observed 10 patients (5 males and 5 females) who had been referred to the department of neurology because of muscular fatigability, myalgia, cramps, or proximal weakness. Laboratory investigation showed that all patients had hypothyroidism due to Hashimoto's thyroiditis (atrophic variant in 9/10). ⋯ Our observations suggest that an isolated myopathy as the sole manifestation of hypothyroidism is not a rare event. We postulate that our cases may constitute a peculiar subgroup of Hashimoto's thyroiditis patients: (1) the strikingly abnormal F/M ratio of 1:1; (2) the relatively younger age; (3) the rarity of the goitrous variant; (4) the unusual finding of antithyroglobulin (Tg-Ab) > antithyroid peroxidase (TPO-Ab). Thorough evaluation of thyroid function is appropriate in patients with myopathy of uncertain origin.