Muscular pseudohypertrophy associated with Hashimoto - thyroiditis (Hoffmann syndrome) - first familial case report

Abstract

Hypothyroidism is a frequently diagnosed endocrine disorder that has characteristic clinical signs and symptoms. The frequency of myopathy in hypothyroidism ranges from 30 to 80%. The major symptoms related are: weakness, muscular cramps and myalgia. The pseudohypertrophic form is called Hoffman's syndrome and is quite rare, reassign diagnosis difficulties both to endocrinologists and neurologists. The pathogenesis of this form of myopathy is still unclear. We report the case of two patients, daughter and father with pseudohypertrophic myopathy and hypothyroidism by Hashimoto's thyroiditis. The two were previously treated for hyperthyroidism: first by antithyroid drugs and secondary by surgery (the daughter) and radioiodine (the father). Both developed iatrogenic hypothyroidism that vas treated by thyroxin replacement therapy. The muscular symptoms: progressive proximal weakness, muscle hypertrophy accompanied by stiffness, spontaneous muscular pain, muscular cramps and fatigue during mild exercise have developed during the year before admittance. In both patients Hashimoto's thyroiditis was revealed by the high level of TPO antibodies and the thyroid appearance in sonography. Hormonal dosages confirmed hypothyroidism. Elevated values of CPK and electromyography established the diagnosis of thyroid myopathy. Muscular symptoms were improved but not remitted by the thyroxin replacement therapy in adequate doses, but CPK normalized. It is the first time that a familial case of Hoffmann syndrome is described, suggesting a genetic susceptibility to the development of the syndrome.