The musculo-skeletal features of hypothyroidism.

DURING recent years it has become accepted that patients with hypothyroidism may present with a variety of rheumatic syndromes, sometimes well before the more obvious features of myxoedema have appeared, and these 'hypothyroid-rheumatic syndromes' will be described. This term is used in preference to 'myxoedematous arthropathy', because the patients in question are not frankly myxoedematous, myalgia is more frequent than arthralgia, and joint destruction is only an occasional feature. The various musculo-skeletal syndromes associated with hypothyroidism are of clinical interest because of the vast number of rheumatic conditions that may be simulated. For example, either osteoarthritis of peripheral joints or the spine, rheumatoid arthritis, atypical gout, or non-articular rheumatism may be initially suspected. However, since the above conditions occur much more frequently than the hypothyroid-rheumatic syndromes, every effort must be made to exclude them by clinical, radiological and laboratory investigations. Also, it must be remembered that osteoarthritis is very common in this age group, and that clinical gout may occur as a result of hyperuricaemia which may be associated with myxoedema, and consequently these conditions themselves can give rise to symptoms in addition to those features due to hypothyroidism. The 'hypothyroid-rheumatic syndromes' which have been documented are listed in Table 1. Mention must also be made of auto-immune thyroiditis (Hashimoto's disease) as a possible cause of rheumatic pain. It seems possible that aching and stiffness, particularly affecting the neck muscles, trapezii and upper dorsal muscles may be a feature of active auto-immune thyroiditis in the premyxoedematous stage. This has been commented TABLE 1. Hypothyroid-rheumatic syndromes