giant cell myocarditis
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Epidemiology
- rare
- annual incidence 0.13/100,000 persons
- tends to occur in younger adults & middle-aged persons
- affects men & women equally
Pathology
- T-cell mediated autoimmune process
- myocarditis
- widespread inflammatory infiltrates
- multinucleated giant cells, eosinophils, & lymphocytes causing myocardial necrosis
- myocardial fibrosis, scarring
- with or without noncaseating granulomas[2]
Clinical manifestations
- presentation with palpitations, dizziness, & chest pain
- often quickly progressive
- hypoxia, hypotension
- congestive heart failure
- heart block (5%)[2]
- ventricular arrhythmias
- less commonly, it can mimic an acute myocardial infarction
- syncope
- no lymphadenopathy or rash
Laboratory
- complete blood count
- eosinophils in blood may show eosinophilia
- cardiac troponin T in serum is elevated
Diagnostic procedures
- electrocardiogram
- endomyocardial biopsy is needed to establish a diagnosis
- myocardial involvement typically patchy
- a negative biopsy does not rule out giant cell myocarditis
- sensitivity of endomyocardial biopsy is 69%
- repeat biopsy can increase yield to 80-93%
Radiology
- myocardial perfusion imaging
- no coronary artery obstruction
- cardiac magnetic resonance imaging (MRI)
- subendocardial involvement in giant-cell myocarditis
- right ventricular side of basal interventricular septum is involved in cardiac sarcoidosis[2]
Complications
- sometimes fatal; death or heart transplantation 89%[2]
- sudden cardiac death uncommon
- other autoimmune diseases, including myasthenia gravis, inflammatory bowel disease & thyroiditis are common
Differential diagnosis
- cardiac sarcoidosis
- usually occurs in the setting of systemic sarcoidosis
- HFrEF
Management
- combination immunosuppression:
- 2-3 drugs including cyclosporine, prednisone, azathioprine, mycophenolate mofetil, or muromonab
- presence of eosinophils in diseased myocardium may be associated with greater responsiveness to immunosuppressive therapy
- may increase long-term survival[2]
- implantable cardioverter-defibrillator (ICD)
- even when left ventricular systolic dysfunction is mild
- cardiac transplantation
- inotropic agents & mechanical support as a bridge to cardiac transplantation
- acute rejection is higher with giant-cell myocarditis than with dilated cardiomyopathy (16% vs 5%)[2]
- 5-year survival rate of 71%[1]
- 1, 5, & 10 years after transplantation are 94%, 82%, & 68%, respectively[2]
- recurrence of giant-cell myocarditis in cardiac-transplant recipients occurs in 20-25%, but may respond to an increase in immunosuppression
More general terms
References
- ↑ 1.0 1.1 Jani SM, Nallamothu BK, Cooper LT, Smith A, Fazel R. Beating, Fast and Slow. N Engl J Med 2017; 377:72-78. July 6, 2017 <PubMed> PMID: https://pubmed.ncbi.nlm.nih.gov/28679100 <Internet> http://www.nejm.org/doi/full/10.1056/NEJMcps1608688
- ↑ 2.00 2.01 2.02 2.03 2.04 2.05 2.06 2.07 2.08 2.09 2.10 Rothaus C A Man with Cardiomyopathy and Ventricular Tachycardia. NEJM REsident 360. April 25, 2018 https://resident360.nejm.org/content_items/a-man-with-cardiomyopathy
- ↑ 3.0 3.1 Medical Knowledge Self Assessment Program (MKSAP) 20 American College of Physicians, Philadelphia 2025
- ↑ Bang V, Ganatra S, Shah SP, et al. Management of patients with giant cell myocarditis: JACC Review Topic of the Week. J Am Coll Cardiol. 2021;77:1122-1134. PMID: https://pubmed.ncbi.nlm.nih.gov/33632487