Pickering syndrome facilitated by seronegative immune mediated necrotizing myopathy: a case report.

Background: Immune-mediated necrotizing myopathies (IMNM) are rare types of idiopathic inflammatory myopathies characterized by severe proximal muscle weakness and muscle fibre necrosis with a paucity of inflammatory cells. Serologically, IMNM are further classified into three subtypes based on the presence or absence of two specific autoantibodies: the anti-3-hydroxy-3-methylglutaryl coenzyme A reductase and the anti-signal recognition particle. Especially the seronegative form exhibits a higher risk of various extra skeletal muscle involvement, including cardio-myositis. Nevertheless, severe cardiac involvement remains an extremely rare yet potentially life-threatening clinical manifestation of seronegative IMNM. Case summary: A 59-year-old male previously diagnosed with seronegative IMNM presented with severe hypertension and acute cardiac decompensation. On echocardiography, cardiac function was reduced with signs of eccentric left ventricular hypertrophy. Coronary angiography was normal, but cardiac magnetic resonance (CMR) found diffuse intra-myocardial oedema. The patient was suspected of having IMNM associated cardio-myositis and was started on heart failure therapy. In parallel, his immunosuppressive treatment was increased. Under this regiment, the patient rapidly developed acute renal failure caused by bilateral renal artery stenosis. After successful stenting of the stenotic arteries, cardiac and renal function significantly improved, and at 1-year follow-up, no more signs of myocardial oedema or inflammation were found on CMR. Discussion: Here, we describe a new case of acute congestive heart failure facilitated by severe reno-vascular hypertension in a patient with seronegative IMNM. This case highlights the importance of early recognition and treatment of hypertension in IMNM patients to avoid major adverse cardiac events.