Statin-Associated Immune-Mediated Necrotising Myopathy With Troponin Elevation Without Cardiac Involvement in an Octogenarian

Immune-mediated necrotising myopathy (IMNM) is a rare autoimmune muscle disease characterised by progressive proximal weakness, markedly elevated muscle enzymes, and necrotising changes on biopsy with minimal inflammation.The anti-HMGCR (anti-3-hydroxy-3-methylglutaryl coenzyme A reductase) subtype is strongly associated with statin exposure, and symptoms frequently persist despite discontinuation, often requiring immunosuppressive therapy.Although cardiac involvement is uncommon, the interpretation of raised troponin can be challenging, as regenerating skeletal muscle may express foetal troponin isoforms, creating diagnostic uncertainty.We report a rare case of statin-associated IMNM in an octogenarian who developed progressive proximal weakness and sustained biochemical evidence of muscle injury after long-term statin use.The persistence of her symptoms and enzyme elevation despite statin withdrawal, together with an unexpectedly raised troponin in the context of exertional breathlessness, prompted comprehensive evaluation to clarify the underlying cause and exclude alternative pathology.The subsequent identification of strongly positive anti-HMGCR antibodies supported the diagnosis of statin-associated IMNM, and she improved following immunosuppressive therapy.This case highlights the importance of recognising statin-associated IMNM in older adults on statins presenting with persistent weakness and persistent elevated muscle enzymes.Awareness of the diagnostic pitfall, particularly in the coexistence of raised creatine kinase and troponin, along with early antibody testing and careful cardiac evaluation, can help avoid misinterpretation and facilitate timely treatment.The case reinforces the need for clinical vigilance when assessing unexplained weakness in later life and underscores the value of considering this condition even when initial investigations are inconclusive.