ABSTRACT
Hydroxyl-methyl-glutaryl-Co-A reductase (HMGCR) immune mediated necrotising myopathy (IMNM) is a rare autoimmune myositis that is thought to be triggered by statins and responds to immunomodulation. We report a case of a woman in her 30s with HMGCR IMNM without a history of statin exposure who had a clear flare of her myositis after beginning mushroom supplements. Mushrooms are natural HMGCR inhibitors, and this is the first case to demonstrate a flare triggered by mushrooms in a patient with known HMGCR IMNM. This case highlights the importance of reviewing diet and supplements in patients with IMNM. It also emphasises the importance of strict statin avoidance for patients with IMNM even when the myositis is under good control.
Subject(s)
Agaricales , Autoimmune Diseases , Dietary Supplements , Muscular Diseases , Adult , Autoantibodies/immunology , Autoimmune Diseases/chemically induced , Autoimmune Diseases/diagnosis , Autoimmune Diseases/immunology , Autoimmune Diseases/pathology , Dietary Supplements/adverse effects , Female , Humans , Hydroxymethylglutaryl CoA Reductases/adverse effects , Hydroxymethylglutaryl CoA Reductases/immunology , Hydroxymethylglutaryl-CoA Reductase Inhibitors/adverse effects , Muscle, Skeletal/immunology , Muscle, Skeletal/pathology , Muscular Diseases/chemically induced , Muscular Diseases/diagnosis , Muscular Diseases/immunology , Muscular Diseases/pathology , Myositis/chemically induced , Myositis/diagnosis , Myositis/immunology , Myositis/pathology , Necrosis/chemically induced , Necrosis/immunology , Phytotherapy/adverse effects , Symptom Flare UpABSTRACT
OBJECTIVE: Dermatomyositis (DM) patients typically present with proximal weakness and autoantibodies that are associated with distinct clinical phenotypes. We observed that DM patients with autoantibodies recognizing the nuclear matrix protein NXP-2 often presented with especially severe weakness. The aim of this study was to characterize the clinical features associated with anti-NXP-2 autoantibodies. METHODS: There were 235 DM patients who underwent testing for anti-NXP-2 autoantibodies. Patient characteristics, including muscle strength, were compared between those with and without these autoantibodies. The number of cancer cases observed in anti-NXP-2-positive subjects was compared with the number expected in the general population. RESULTS: Of the DM patients, 56 (23.8%) were anti-NXP-2-positive. There was no significant difference in the prevalence of proximal extremity weakness in patients with and without anti-NXP-2. In contrast, anti-NXP-2-positive patients had more prevalent weakness in the distal arms (35% versus 20%; P = 0.02), distal legs (25% versus 8%; P < 0.001), and neck (48% versus 23%; P < 0.001). Anti-NXP-2-positive subjects were also more likely to have dysphagia (62% versus 35%; P < 0.001), myalgia (46% versus 25%; P = 0.002), calcinosis (30% versus 17%; P = 0.02), and subcutaneous edema (36% versus 19%; P = 0.01) than anti-NXP-2-negative patients. Five anti-NXP-2-positive subjects (9%) had cancer-associated myositis, representing a 3.68-fold increased risk (95% confidence interval 1.2-8.6) compared to the expected prevalence in the general population. CONCLUSION: In DM, anti-NXP-2 autoantibodies are associated with subcutaneous edema, calcinosis, and a muscle phenotype characterized by myalgia, proximal and distal weakness, and dysphagia. As anti-NXP-2-positive patients have an increased risk of cancer, we suggest that they undergo comprehensive cancer screening.