Editor
Myocarditis is an uncommon condition encompassing a spectrum from asymptomatic cases to fulminant heart failure. Acute fulminant myocarditis is characterised by severe haemodynamic compromise often necessitating circulatory support. The diagnosis and management of myocarditis remains challenging with uncertainty surrounding the role of immunosuppression therapy. We describe a case of biopsy-proven acute necrotising lymphocytic myocarditis which responded rapidly to steroids, mycophenolate and immunoglobulins.
A 53 year old male was admitted to a District General Hospital with a 4-day history of chest pain and ‘flu-like symptoms. He had a history of mixed connective tissue disease (MCTD). Physical examination revealed sinus tachycardia (126bpm) and mild pulmonary oedema.
The ECG on admission showed sinus rhythm with Q waves in the anterior chest leads and T wave inversion in leads I, aVL and V3-V6. High-sensitivity troponin T (hsTNT) was 5220ng/L and the C-reactive protein (CRP) was 328mg/L. Within 24 hours he developed cardiogenic shock with severe pulmonary oedema, left bundle branch block and severe left ventricular systolic dysfunction (LVSD). Transfer was arranged due to clinical instability. At cardiac catheterisation, the aortic pressure was 83/55mmHg with a left ventricular end-diastolic pressure of 35mmHg. Coronary angiography showed no obstructive disease and an intra-aortic balloon pump (IABP) was sited.
With the progressing ECG abnormalities, echocardiographic findings and rising biomarkers, a diagnosis of acute myocarditis was made. Urgent right ventricular endomyocardial biopsies were undertaken with frozen section analysis confirmed acute necrotising myocarditis. There was no evidence of vasculitis and giant cells were absent on histopathology (Figures 1 & 2). Immunohistochemistry was negative for Epstein Barr virus (EBV) and parvovirus. Viral polymerase chain reaction (PCR) was weakly positive for both. Screening for hepatitis B, C, cytomegalovirus (CMV), erythrovirus B19, streptococcus pneumoniae and picornavirus was negative.
Fig 1.
Histology specimen from the endomyocardial biopsy demonstrating myocardium with a dense infiltrate of inflammatory cells (L)-(dark blue nuclei) separating the myocytes (M)
Fig 2.
Histology specimen from the endomyocardial biopsy demonstrating extensive myocyte necrosis and phagocytosis (P). Immunohistochemistry has been performed highlighting the T lymphocytes (L)
Oral prednisolone (40mg OD) and mycophenolate mofetil (500mg BID) were commenced on rheumatological advice. A total dose of 300g of Human Immunoglobulin [Privigen® (CSL Behring, PA, US)] was administered over 5 days.
A rapid clinical improvement ensued, facilitating IABP removal and discontinuation of inotropes after 72 hours. Standard heart failure therapy was commenced. Repeat echocardiography by day 9 showed only mild global left ventricular systolic impairment. Temporary interruption in mycophenolate therapy occurred due to shingles (treated with Ganciclovir). He was discharged on day 15.
DISCUSSION
The diagnosis of myocarditis should be considered in any patient presenting with acute heart failure. Non-invasive imaging modalities (ECHO and Cardiac MR) are helpful in establishing the diagnosis. Ultimately, myocarditis is a histopathological diagnosis. Multiple endomyocardial biopsy samples are required as sampling error can occur in the setting of patchy disease. The most common histopathological form of acute myocarditis is a lymphocytic pattern. The mainstay of treatment in acute myocarditis is inotropic agents and circulatory support. The efficacy of intravenous immunoglobulin (Ig) and immunosuppression remains unproven. Studies have demonstrated mortality benefits with early IG and steroid administration.
Acknowledgments
The authors have no conflicts of interest