Clinical And Pathological Analysis Of12Cases With Thyroid Myopathy

Background:Thyroid myopathy, attributed to autoimmune endocrine diseases related abnormal hormone levels leading to metabolic disorder, belongs to the endocrine myopathies, including:chronic thyrotoxic myopathy (CTM), acute thyrotoxic myopathy (ATM), myasthenia gravis with hyperthyroidism or hypothyroidism, thyrotoxic periodic paralysis (TPP), exophthalmic ophthalmoplegia (Graves’ ophthalmopathy, GO), and hypothyroidism myopathy (HTM). In these types of thyroid myopathy, CTM is the most common and TPP is the second, followed by the ATM at least. Because of various forms of thyroid myopathy, such as some patients with insidious onset, coexistent multiple types or superimposed clinical symptoms, these diseases have more difficulty and complex in diagnosis to result in delayed treatment.Objective:To analyze the clinical and pathological changes mechanism of thyroid myopathy and explore the clinical pathological features of all types of thyroid myopathy, in order to improve the diagnosis of these diseases.Method:The clinical data has been analyzed retrospectively for12patients with thyroid myopathy recorded in neuromuscular disease laboratory of Shandong University Qilu Hospital from September2000to June2011to detect and study the stained frozen muscle specimens by using light microscopic.Result:1. Twelve patients (7male and5female) had been diagnosed as thyroid myopathy, with age ranged from16to67years old (average43years). The disease process of myopathy thyroid was ranged from a month to13years, with an average of about2years. In all of12cases with thyroid myopathy,8cases was diagnosed as HTM including1patient with myositis occur,2cases was pure CTM and2cases was CTM combined with TPP.In this group,11patients made the vary degrees of muscle weakness as the first symptom, and another case with muscle swelling and pain starting had no obvious symptom with muscle weakness. In the11cases with muscle weakness,9cases had the performance of general weakness and2cases with myasthenia gravis patients showed that the proximal lower limbs weakness onset. In addition,3cases demonstrated the high metabolic syndrome accompanied by fever, sweating, food hyperactivity, palpitations and weight loss.By doing laboratory tests with T3, T4, FT3, FT4and TSH, these patients displayed the presence of abnormal thyroid function, diagnosed as typical hyperthyroidism or hypothyroidism. In these cases, the laboratory examination showed abnormal changes, including8HTM cases with CK increased up to5-30times for the normal high-value ranges,6cases with LDH increased,5cases with rapid erythrocyte sedimentation rate,4cases with ALT increased,3cases with AST increased. However,4cases with thyroid myopathy was hyperthyroidism followed with no significantly increasing of CK, LDH, ALT and AST, including1case with only TG increased.2. The results of electromyography used to exam a total of7patients were as follows:2HTM cases were presented with peripheral neuropathy,3HTM cases were normal EMG,1CTM cases was myogenic pattern damage and1CTM cases was normal.3. By detected the muscle biopsy specimens taken from biceps with8cases, quadriceps with2cases, deltoid with1case and tibialis anterior muscle with1case, the results demonstrated that:8cases were diagnosed as HTM, including4cases with myogenic injury,1case with hypothyroidism associated with inflammatory myopathy,1case with selective type II fiber atrophy,1case with normal muscle tissue;4cases were diagnosed as thyrotoxic myopathy, including3case with nonspecific myogenic pathological changes,1CTM and TPP patient with only lipid increased mild in some of the muscle fibers.Conclusion:1. The result demonstrated thyroid myopathy patients with hypothyroidism heve a certain correlation with the level of serum CK and erythrocyte sedimentation rate for hint significance. However it can be easily confused with inflammatory myopathy. Based on the different characteristics of the muscle pathology, muscle biopsy is a useful method for diagnosis.2. Muscle biopsies of thyroid myopathy patients showed no apparent specific changes.3. The results of HTM electromyography demonstrated that the clinical symptoms can be caused by myogenic or neurogenic changes at the same stage, and it also means both peripheral nerve and muscle can be affected.