Successful reintroduction of statin therapy after myositis: was there another cause?

The Medical Journal of Australia ISSN: 0025-729X 3 May 2004 180 9 472-473 ©The Medical Journal of Australia 2004 www.mja.com.au Lessons from Practice STATIN-RELATED MUSCLE COMPLAINTS include myalgia, myositis and rhabdomyolysis.1 Hypothyroidism itself can cause musculoskeletal symptoms, including myalgia, Hoffmann’s syndrome (muscle stiffness, weakness and increased muscle mass, frequently with elevated creatine kinase [CK] level), Kocher–Debré–Sémélaigne syndrome (diffuse muscular hypertrophy and weakness in congenital hypothyroidism), a polymyositis-like syndrome (with proximal muscle weakness and markedly elevated CK level), and rhabdomyolysis.2 The coexistence of hypothyroidism and statin use may increase the risk of myopathy.3 Statin-induced myopathies tend to resolve within a few days to 1 month after ceasing statin use.4 Persistent elevation of CK level after stopping statin therapy has been reported, prompting further investigation and leading to the discovery of coexisting hypothyroidism. Thyroxine replacement therapy was reported as normalising CK and total cholesterol levels in these patients. However, to the best of our knowledge, ours is the first report of a patient with treated hypothyroidism in whom statin therapy was safely reintroduced after the resolution of myositis. While the exact aetiology of the myositis in our patient can not be proven, it seems most probable that it was precipitated by a combination of hypothyroidism and statin use. Full-dose statin therapy did not cause a recurrence of myositis once the hypothyoidism had been treated, implicating hypothyroidism as a contributing factor. However, it is uncertain whether the hypothyroidism would have resulted in myositis without coexisting statin therapy. The patient has mild asymptomatic elevation of CK level while taking simvastatin and with adequate thyroxine replacement. Such asymptomatic CK elevation is frequently seen in subjects during statin trials with both placebo and statin therapy, and continued treatment while asymptomatic and with CK levels up to 10 times the upper limit of normal has to date proven to be safe.6 As hypothyroidism can cause hyperlipidaemia, we suggest that thyroid function should be checked before commencing statin therapy, particularly if there are any clinical features to suggest its presence. We also suggest that patients who develop symptoms or signs suggestive of myopathy while taking statin therapy should be tested for hypothyroidism. As in our patient, it may be safe to cautiously reintroduce Successful reintroduction of statin therapy after myositis: was there another cause?