Myocarditis
To the Editor
A large variety of infectious agents are associated with acute and chronic myocarditis, as discussed by Feldman and McNamara (Nov. 9 issue).1 In areas infested with vector ticks of Lyme borreliosis, infection with Borrelia burgdorferi may also be involved in myocarditis, pericarditis, and cardiac-rhythm disorders.2
The seminal description of a patient with dilated cardiomyopathy and culture of an endomyocardial-biopsy specimen that was positive for B. burgdorferi was published in the Journal. 3 Specific histologic staining may also confirm the diagnosis of Lyme borreliosis in acute myocarditis; however, as with other causes of myocarditis, even negative results cannot rule out the infection. To support the diagnosis in patients with positive serologic findings, use of antimyosin scintigraphy, echocardiography, and magnetic resonance imaging can be helpful.4
Treatment with appropriate antibiotics may lead to improvement of ventricular function in myocarditis and even cardiomyopathy due to Lyme borreliosis.3,5 Thus, in areas where the disease is endemic, Lyme borreliosis should be considered in the differential diagnosis of perimyocarditis.
Jutta Bergler-Klein, M.D.
Gerold Stanek, M.D.
University of Vienna, A-1095 Vienna, Austria
1. Feldman AM, McNamara D. Myocarditis. N Engl J Med 2000;343:1388-1398
2. Steere AC. Lyme disease. N Engl J Med 1989;321:586-596
3. Stanek G, Klein J, Bittner R, Glogar D. Isolation of Borrelia burgdorferi from the myocardium of a patient with longstanding cardiomyopathy. N Engl J Med 1990;322:249-252
4. Bergler-Klein J, Sochor H, Stanek G, Globits S, Ullrich R, Glogar D. Indium 111-monoclonal antimyosin antibody and magnetic resonance imaging in the diagnosis of acute Lyme myopericarditis. Arch Intern Med 1993;153:2696-2700
5. Gasser R, Fruhwald F, Schumacher M, et al. Reversal of Borrelia burgdorferi associated dilated cardiomyopathy by antibiotic treatment? Cardiovasc Drugs Ther 1996;10:351-360
To the Editor
Feldman and McNamara mention thyrotoxicosis as an immune-mediated cause of myocarditis. I wonder how they come to this view.
As far as I know, there are only rare case reports of cardiomyopathy associated with Graves' disease.1 Despite the fact that thyrotropin-receptor messenger RNA has been found by several investigators to be expressed in the myocardium,1-3 the authors of a recent report on a series from the Mayo Clinic4 concluded on the basis of endomyocardial-biopsy findings that “among patients with Graves' disease, most cases of low-output cardiac dysfunction appear to be due to causes other than an active autoimmune inflammatory process.”
Are there other data of which I am unaware? The clinical ramification of this issue seems important: should a patient with Graves' disease and concomitant low-output cardiac dysfunction be evaluated for myocarditis, or is this unnecessary because of a “well-known” relation?
Michael Weissel, M.D.
Medical University Clinic III, A-1090 Vienna, Austria
1. Koshiyama H, Sellitti DF, Akamizu T, et al. Cardiomyopathy associated with Graves' disease. Clin Endocrinol (Oxf) 1996;45:111-116
2. Drvota V, Janson A, Norman C, et al. Evidence for the presence of functional thyrotropin receptor in cardiac muscle. Biochem Biophys Res Commun 1995;211:426-431
3. Sellitti DF, Hill R, Doi SQ, et al. Differential expression of thyrotropin receptor mRNA in the porcine heart. Thyroid 1997;7:641-646
4. Fatourechi V, Edwards WD. Graves' disease and low-output cardiac dysfunction: implications for autoimmune disease in endomyocardial biopsy tissue from eleven patients. Thyroid 2000;10:601-605
To the Editor
The important review article on myocarditis by Feldman and McNamara is very carefully written and clearly documented. However, Table 1, entitled Causes of Myocarditis, mislabels actinomyces as a fungus. Actinomyces are anaerobic, non–spore-forming, gram-positive bacilli.1 In addition, since the authors separate bacterial from spirochetal causes of myocarditis, why does Treponema pallidum remain in the first group?
Jaime Luís Lopes Rocha, M.D.
Hospital Nossa Senhora das Graças, 80810-040 Curitiba, PR, Brazil
1. Murray PR, Rosenthal KS, Kobayashi GS, Pfaller MA. Medical microbiology. 3rd ed. St. Louis: Mosby, 1998.
Response
The authors reply:
To the Editor: Drs. Bergler-Klein and Stanek raise important points regarding the importance of considering Lyme borreliosis as a possible cause of myocarditis in areas infected with vector ticks. However, we would argue that antimyosin scintigraphy does not have sufficient sensitivity and specificity to be useful in the diagnosis and that serologic analysis is far more useful.
Our inclusion of thyrotoxicosis as an immune-mediated cause of myocarditis is based on rare case reports in which thyroiditis was associated with myocarditis in a patient with severe lupus,1 a patient with both giant-cell thyroiditis and myocarditis,2 and a woman during the postpartum period.3 Although the recent report from the Mayo Clinic4 suggests that autoimmune myocardial disease in patients with thyroiditis is a rare finding, the possibility of its presence should not be overlooked in patients who have relevant symptoms.
It is correct that actinomyces are gram-positive bacteria, not fungi.
Arthur M. Feldman, M.D., Ph.D.
Dennis M. McNamara, M.D.
University of Pittsburgh Medical Center, Pittsburgh, PA 15213
1. Macro M, Le Gangneux E, Gallet E, Maragnes P, Galateau F, Loyau G. Severe lupus with infectious thyroiditis and lethal cardiomyopathy. Clin Exp Rheumatol 1995;13:99-102
2. Benisch BM, Josephson M. Subacute (giant cell) thyroiditis and giant cell myocarditis in patient with carcinoma of lung. Chest 1973;64:764-765
3. Yagoro A, Tada H, Hidaka Y, et al. Postpartum onset of acute heart failure possibly due to postpartum autoimmune myocarditis: a report of three cases. J Intern Med 1999;245:199-203
4. Fatourechi V, Edwards WD. Graves' disease and low-output cardiac dysfunction: implications for autoimmune disease in endomyocardial biopsy tissue from eleven patients. Thyroid 2000;10:601-605
