Discussion:
Statins are very commonly prescribed for dyslipidemia and coronary artery disease. They have anti-inflammatory properties and other properties that are beneficial in treatment of a wide range of cardiovascular diseases (5). The side effect profile of statins is very good, with only mild side effects in most cases. Musculoskeletal side effects are among the more commonly reported side effects, but recent studies have shown that most of these complications are a nocebo effect.
Statin use can be associated with SANAM, which is a much more serious complication. Only a small proportion of patients with SANAM improve spontaneously, and even with treatment the outcomes can be poor. With SANAM, prompt and immediate discontinuation of the statin drug is required if the patient is still being treated with it. Following discontinuation of the statin, aggressive immunosuppressive treatment is needed though a clinical response is not always noted. In some cases, the patients continue to deteriorate. There have being no clinical trials on treatment protocols for SANAM and clinical and therapeutic decision is based on case reports, cohort studies and clinical experience and expertise. Oral prednisone at a dose of 1 mg per kilogram of body weight per day is usually the initial therapy, with methotrexate, azathioprine, or mycophenolate mofetil being added as steroid sparing agents (2). Other therapies such as intravenous immune globulin or rituximab may be needed if there is persistent muscle enzyme elevation. Continued muscle weakness may not indicate ongoing muscle disease as fatty replacement of muscle tissue develops and can cause ongoing weakness.
Our case is a typical presentation as statin-associated necrotizing myopathy and also features its poor response to therapy. SANAM must be considered in the right clinical scenario and if the patients do not respond as expected. Given the uniqueness and specificity of the Anti-HMGCR Ab (6), screening patients with this antibody test may prevent the need for more invasive testing. SANAM is likely to become less common following the development of monoclonal antibody therapies that lower cholesterol. This newer class of medication is highly effective in reduces LDL cholesterol and becoming more commonly prescribed. Given the current ubiquitous use of statins, SANAM is a disease entity that all physicians should be aware of, as early diagnosis allows for early and aggressive treatment that improved the likely outcomes for the patient.