Immune-Mediated Necrotizing Myopathy: An Often Misdiagnosed Entity

Immune-mediated necrotizing myopathies (IMNM) are recognized as a subgroup of idiopathic inflammatory myopathies (IIM). IMNM are defined based on a combination of clinical presentation and laboratory studies, requiring a specific myopathological pattern on muscle biopsy for diagnosis. The authors describe a case of a patient with necrotizing myopathy, thought to be immune mediated, highlighting the challenge of its differential diagnosis. As clinical assessment and diagnostic tools sometimes fail to determine whether a necrotizing myopathy is immune mediated, leading to misdiagnosis and a compromise of the optimal therapeutic approach, distinguishing between IMNM and other myopathies is crucial.

Anti-Signal Recognition Particle Myopathy in a Geriatric Patient

Anti-signal recognition particle (SRP) myopathy is a rare idiopathic inflammatory myositis that usually affects middle-age women, and is characterized by rapidly progressive proximal and symmetrical muscle weakness, elevated creatine kinase levels, severe necrotizing immune-mediated myopathy, presence of anti-SRP autoantibodies and poor response to steroid therapy. We report a geriatric case of a previously independent patient, presenting with slow onset of proximal paraparesis, myalgia and severe gait impairment. The patient was treated with steroid and azathioprine, with laboratory and pain response but modest muscle strength improvement. The clinical presentation of this unusual patient was atypical, which hampered the correct diagnosis.

Severe Statin-induced Rhabdomyolysis following Cholestatic Hepatitis induced by Amoxicillin-clavulanate

We report the case of an 86-year-old man with a past history of coronary disease admitted to our internal medicine department for severe asthenia and weakness due to rhabdomyolysis. Three days earlier, he had been discharged from a gastroenterology unit with a diagnosis of amoxicillin–clavulanate-induced acute cholestatic hepatitis. A review of his drugs revealed that he had taken atorvastatin 10 mg daily in the previous six years, without clinical or laboratory signs of myopathy. Atorvastatin was therefore stopped, with gradual improvement of the rhabdomyolysis. All concomitant drug therapy needs to be reassessed in elderly patients, especially when they become acutely ill.