P52 Two pathologies one heart: life-threatening lupus myocarditis in a patient with pre-existing dilated cardiomyopathy

Abstract

Abstract Background Acute myocarditis is a life-threatening complication of systemic lupus erythematosus (SLE) often indicative of severe multisystem disease. Treatment of lupus myocarditis (LM) is well described in the literature with high-dose corticosteroids and cyclophosphamide providing the backbone of induction therapy. Less commonly reported are outcomes of patients with SLE and pre-existing structural heart disease. Methods We present a case of acute LM occurring in the context of established non-ischaemic dilated cardiomyopathy (DCM) presenting a significant diagnostic challenge. Results A 45-year-old woman from Afghanistan with known SLE presented with acute chest pain and dyspnoea. She had a previous mild SLE disease course limited to her skin and joints and was historically non-compliant with immunosuppressive treatment. She also had non-ischaemic DCM diagnosed six years prior to presentation with non-progressive imaging over this time. Upon acute assessment at the referring centre a widespread livedoid rash and cool peripheries were noted. Initial investigations revealed an elevated Troponin-I of 111ng/L and Brain Natriuretic Peptide (BNP) of 4497ng/L. An electrocardiogram revealed no acute ischaemic changes whilst her chest radiograph revealed features in keeping with pulmonary oedema. Transthoracic echocardiogram (TTE) demonstrated a dilated left ventricle with severe global systolic impairment. Her left ventricular ejection fraction (LVEF) was visually estimated at 10-15%, significantly reduced from her last recorded LVEF of 52% on a cardiovascular magnetic resonance (CMR) scan 18-months previously. Intravenous (iv) methylprednisolone, iv diuresis and B-cell depletion therapy were commenced prior to transfer to our department. Once transferred, a CMR scan confirmed an ejection fraction of only 12%. Septal mid-wall delayed enhancement was seen consistent with a non-ischaemic DCM, however, subepicardial delayed enhancement was visualised inferolaterally on native T1-mapping in keeping with perimyocarditis. Additional results on admission were supportive of a multisystem SLE flare. She was lymphopaenic (1.0x109/L), thrombocytopaenic (66x109/L), hypocomplimentaemic (C3 0.33g/L, C4 <0.03g/L), and had elevated dsDNA antibodies (83unit/mL). Serum creatinine had risen from a baseline of 47µmol/L to 110µmol/L and her urine protein: creatinine ratio (414mg/mmol) raised the suspicion of lupus nephritis (LN). Renal biopsy was not performed due to thrombocytopaenia. An MDT discussion with the cardiology, CMR imaging and renal teams took place with CMR imaging proving pivotal in establishing new LM on a background of established DCM. The decision to treat with intravenous (iv) cyclophosphamide was made and repeat TTE at 14 days revealed a significant improvement in LVEF to 25-30%. Conclusion CMR imaging was crucial in delineating acute and potentially reversible myocarditis on a background of chronic cardiomyopathy. This finding supported the escalation in immunosuppressive treatment to a cyclophosphamide-based regimen and led to the rapid improvement in ejection fraction in this young patient. She received 6 fortnightly doses of iv cyclophosphamide and is now maintained on hydroxychloroquine, mycophenolate mofetil and rituximab. Disclosures H. Wilson-Morkeh: None. T. Youngstein: None. S. Shabbir: None. J. Bakshi: None. T. Pihlajavaara: None. M. Bellamy: None. T. Cairns: None.