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.