Rare serological overlap of anti-HMGCR and anti-SRP antibodies in immune-mediated necrotising myopathy presenting with dysphagia

A woman in her 60s was referred to the gastroenterology outpatient service with a 6-month history of progressive global muscle weakness, 4 kg unintentional weight loss and new-onset oropharyngeal dysphagia. Laboratory testing revealed a markedly elevated serum creatine kinase (CK) level (5070 U/L). MRI femur demonstrated symmetrical muscle oedema in thighs, proximal calves and short adductor muscles consistent with an inflammatory myositis. Myositis antibody panel was positive for anti-HMG-CoA reductase, anti-signal recognition particle and anti-cytosolic 5’-nucleotidase 1A (cN1A) antibodies. CT chest, abdomen and pelvis revealed small-volume lymphadenopathy, but biopsy showed no evidence of malignancy or active inflammation. Oesophagogastroduodenoscopy revealed gastritis only while barium swallow confirmed mild aspiration. The patient was diagnosed with an autoantibody-positive immune-mediated inflammatory myopathy presenting predominantly with dysphagia. Treatment with oral prednisolone 40 mg daily, tapered over time, led to substantial improvement in muscle strength and a fall in CK to 445 U/L. Methotrexate was commenced as a steroid-sparing agent alongside vitamin D, folate and bisphosphonate therapy. This case highlights an inflammatory myopathy as an uncommon but important cause of dysphagia and demonstrates the importance of early recognition and timely initiation of immunosuppressive treatment.