viral myocarditis

ウイルス性心筋炎

WordNet

1. relating to or caused by a virus; "viral infection"

PrepTutorEJDIC

1. ウィルスの;ウィルスが原因の

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2013/02/15 11:28:24」(JST)

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Myocarditis
Classification and external resources
Histopathological image of myocarditis at autopsy in a patient with acute onset of congestive heart failure
ICD-10	I09.0, I51.4
ICD-9	391.2, 422, 429.0
DiseasesDB	8716
MedlinePlus	000149
eMedicine	med/1569 emerg/326
MeSH	D009205

Myocarditis or inflammatory cardiomyopathy is inflammation of heart muscle (myocardium).

Myocarditis is most often due to infection by common viruses, such as parvovirus B19, less commonly nonviral pathogens such as Borrelia burgdorferi (Lyme disease) or Trypanosoma cruzi, or as a hypersensitivity response to drugs.

The definition of myocarditis varies, but the central feature is an infection of the heart, with an inflammatory infiltrate, and damage to the heart muscle, without the blockage of coronary arteries that define a heart attack (myocardial infarction) or other common noninfectious causes. Myocarditis may or may not include death (necrosis) of heart tissue. It may include dilated cardiomyopathy.

Myocarditis is often an autoimmune reaction. Streptococcal M protein and coxsackievirus B have regions (epitopes) that are immunologically similar to cardiac myosin. During and after the viral infection, the immune system may attack cardiac myosin.

Because a definitive diagnosis requires a heart biopsy, which doctors are reluctant to do because they are invasive, statistics on the incidence of myocarditis vary widely.

The consequences of myocarditis thus also vary widely. It can cause a mild disease without any symptoms that resolves itself, or it may cause chest pain, heart failure, or sudden death. An acute myocardial infarction-like syndrome with normal coronary arteries has a good prognosis. Heart failure, even with dilated left ventricle, may have a good prognosis. Ventricular arrhythmias and high-degree heart block have a poor prognosis. Loss of right ventricular function is a strong predictor of death.

Signs and symptoms

The signs and symptoms associated with myocarditis are varied, and relate either to the actual inflammation of the myocardium, or the weakness of the heart muscle that is secondary to the inflammation. Signs and symptoms of myocarditis include:

• Chest pain (often described as "stabbing" in character)
• Congestive heart failure (leading to edema, breathlessness and hepatic congestion)
• Palpitations (due to arrhythmias)
• Sudden death (in young adults, myocarditis causes up to 20% of all cases of sudden death)
• Fever (especially when infectious, e.g. in rheumatic fever)
• Symptoms in infants and toddlers tend to be more nonspecific, with generalized malaise, poor appetite, abdominal pain, and/or chronic cough. Later stages of the illness will present with respiratory symptoms with increased work of breathing, and is often mistaken for asthma.

Since myocarditis is often due to a viral illness, many patients give a history of symptoms consistent with a recent viral infection, including fever, rash, diarrhea, joint pains, and easy fatigueability.

Myocarditis is often associated with pericarditis, and many patients present with signs and symptoms that suggest concurrent myocarditis and pericarditis.

Causes

A large number of causes of myocarditis have been identified, but often a cause cannot be found. In Europe and North America, viruses are common culprits. Worldwide, however, the most common cause is Chagas' disease, an illness endemic to Central and South America that is due to infection by the protozoan Trypanosoma cruzi.

Infections

• Viral (parvovirus B19, coxsackie virus, HIV, enterovirus, rubella virus, polio virus, cytomegalovirus, human herpesvirus 6 and possibly hepatitis C)
• Protozoan (Trypanosoma cruzi causing Chagas disease and Toxoplasma gondii)
• Bacterial (Brucella, Corynebacterium diphtheriae, gonococcus, Haemophilus influenzae, Actinomyces, Tropheryma whipplei, Vibrio cholerae, Borrelia burgdorferi, leptospirosis, and Rickettsia)
• Fungal (Aspergillus)
• Parasitic (ascaris, Echinococcus granulosus, Paragonimus westermani, schistosoma, Taenia solium, Trichinella spiralis, visceral larva migrans, and Wuchereria bancrofti)

Bacterial myocarditis is rare in patients without immunodeficiency.

Toxins

• Drugs (ethanol, anthracyclines and some other forms of chemotherapy, and antipsychotics, e.g. clozapine, also some designer drugs such as mephedrone)

Immunologic

• Allergic (acetazolamide, amitriptyline)
• Rejection after a heart transplant
• Autoantigens (scleroderma, systemic lupus erythematosis, sarcoidosis, systemic vasculitis such as Churg-Strauss syndrome, and Wegener's granulomatosis)
• Toxins (arsenic, toxic shock syndrome toxin, carbon monoxide, or snake venom)
• Heavy metals (copper or iron)

Physical agents

• Electric shock, hyperpyrexia, and radiation

Diagnosis

Endomyocardial biopsy specimen with extensive eosinophilic infiltrate involving the endocardium and myocardium (hematoxylin and eosin stain)

Myocarditis refers to an underlying process that causes inflammation and injury of the heart. It does not refer to inflammation of the heart as a consequence of some other insult. Many secondary causes, such as a heart attack, can lead to inflammation of the myocardium and therefore the diagnosis of myocarditis cannot be made by evidence of inflammation of the myocardium alone.

Myocardial inflammation can be suspected on the basis of electrocardiographic (ECG) results, elevated C-reactive protein (CRP) and/or Erythrocyte sedimentation rate (ESR) and increased IgM (serology) against viruses known to affect the myocardium. Markers of myocardial damage (troponin or creatine kinase cardiac isoenzymes) are elevated.

The ECG findings most commonly seen in myocarditis are diffuse T wave inversions; saddle-shaped ST-segment elevations may be present (these are also seen in pericarditis).

The gold standard is still biopsy of the myocardium, generally done in the setting of angiography. A small tissue sample of the endocardium and myocardium is taken, and investigated by a pathologist by light microscopy and—if necessary—immunochemistry and special staining methods. Histopathological features are myocardial interstitium with abundant edema and inflammatory infiltrate, rich in lymphocytes and macrophages. Focal destruction of myocytes explains the myocardial pump failure.

Cardiac magnetic resonance imaging (cMRI or CMR) has been shown to be very useful in diagnosing myocarditis by visualizing markers for inflammation of the myocardium. Recently, consensus criteria for the diagnosis of myocarditis by CMR have been published

Treatment

As most viral infections cannot be treated with directed therapy, symptomatic treatment is the only form of therapy for those forms of myocarditis. In the acute phase, supportive therapy, including bed rest, is indicated. For symptomatic patients, digoxin and diuretics provide clinical improvement. For patients with moderate to severe dysfunction, cardiac function can be supported by use of inotropes such as Milrinone in the acute phase, followed by oral therapy with ACE inhibitors (Captopril, Lisinopril) when tolerated. People who do not respond to conventional therapy are candidates for bridge therapy with left ventricular assist devices. Heart transplantation is reserved for patients who fail to improve with conventional therapy.

In several small case series and randomized control trials, systemic corticosteroids have shown to have beneficial effects in patients with proven myocarditis. However, data on the usefulness of corticosteroids should be interpreted with caution, since 58% of adults recover spontaneously, while most studies on children and infants lack control groups.

Epidemiology

The exact incidence of myocarditis is unknown. However, in series of routine autopsies, 1–9% of all patients had evidence of myocardial inflammation. In young adults, up to 20% of all cases of sudden death are due to myocarditis.

Among patients with HIV, myocarditis is the most common cardiac pathological finding at autopsy, with a prevalence of 50% or more.

References

External links

• Myocarditis on emedicine

UpToDate Contents

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• 1. 心筋炎の病因および発症機序 etiology and pathogenesis of myocarditis
• 2. 成人における心筋炎の治療および予後 treatment and prognosis of myocarditis in adults
• 3. 成人における心筋炎の臨床症状および診断 clinical manifestations and diagnosis of myocarditis in adults
• 4. 小児における心筋炎の臨床症状と診断 clinical manifestations and diagnosis of myocarditis in children
• 5. 小児における心筋炎の治療および予後 treatment and prognosis of myocarditis in children

English Journal

• Intricacies of cardiac damage in coxsackievirus B3 infection: Implications for therapy.

• Massilamany C1, Gangaplara A2, Reddy J3.
• International journal of cardiology.Int J Cardiol.2014 Dec 15;177(2):330-339. doi: 10.1016/j.ijcard.2014.09.136. Epub 2014 Oct 18.
• Heart disease is the leading cause of death in humans, and myocarditis is one predominant cause of heart failure in young adults. Patients affected with myocarditis can develop dilated cardiomyopathy (DCM), a common reason for heart transplantation, which to date is the only viable option for combat
• PMID 25449464

• Protective and pathological roles of tissue factor in the heart.

• Bode MF, Mackman N1.
• Hamostaseologie.Hamostaseologie.2014 Dec 1;35(1). [Epub ahead of print]
• Tissue factor (TF) is expressed in the heart where it is required for haemostasis. High levels of TF are also expressed in atherosclerotic plaques and likely contribute to atherothrombosis after plaque rupture. Indeed, risk factors for atherothrombosis, such as diabetes, hypercholesterolaemia, smoki
• PMID 25434707

• Coxsackievirus B detection in cases of myocarditis, myopericarditis, pericarditis and dilated cardiomyopathy in hospitalized patients.

• Gaaloul I1, Riabi S1, Harrath R1, Hunter T2, Hamda KB3, Ghzala AB4, Huber S5, Aouni M1.
• Molecular medicine reports.Mol Med Rep.2014 Dec;10(6):2811-8. doi: 10.3892/mmr.2014.2578. Epub 2014 Sep 18.
• Coxsackieviruses B (CV‑B) are known as the most common viral cause of human heart infections. The aim of the present study was to assess the potential role of CV‑B in the etiology of infectious heart disease in hospitalized patients. The present study is based on blood, pericardial fluid and hea
• PMID 25241846

Japanese Journal

• Anti-β-Adrenoceptors Autoimmunity Causing 'Idiopathic' Arrhythmias and Cardiomyopathy

• BRISINDA Donatella,SORBO Anna Rita,VENUTI Angela,RUGGIERI Maria Pia,MANNA Raffaele,FENICI Peter,WALLUKAT Gerd,HOEBEKE Johan,FRUSTACI Andrea,FENICI Riccardo
• Circulation journal : official journal of the Japanese Circulation Society 76(6), 1345-1353, 2012-05-25
• … PCR analysis from paraffin blocks of the 11 group 1 biopsied patients was negative for EV, EBV, HCV, AV, PVB19, INF A/B,HSV1/2, HHV6 and HHV8 viral genomes. …
• NAID 10030315965

• Contribution of Acquired Factors to the Pathogenesis of Dilated Cardiomyopathy : The Cause of Dilated Cardiomyopathy : Genetic or Acquired? (Acquired-Side)

• YOSHIKAWA Tsutomu
• Circulation journal : official journal of the Japanese Circulation Society 75(7), 1766-1773, 2011-06-25
• … Of these, viral infection causes target organ damage via perforin produced by suppressor T cells. … On the other hand, genetic factors are also involved in susceptibility to viral infection and aberrations of acquired immunity, including antigen presentation and autoantibody production. …
• NAID 10029127144

• ウイルス性心筋炎から拡張型心筋症への進展機序 (特集 炎症・免疫からみた心血管病)

• 中村 浩士,松崎 益徳
• 循環器内科 69(6), 584-587, 2011-06-00
• NAID 40018927317

Related Links

• Myocarditis - Wikipedia, the free encyclopedia

Since myocarditis is often due to a viral illness, many patients give a history of symptoms consistent with a recent viral ... Erythrocyte sedimentation rate (ESR) and increased IgM (serology) against viruses known to affect the myocardium.

• Viral Myocarditis - Circulation

Viral myocarditis has been recognized as a cause of congestive heart failure for > 50 years, but it is still a challenging disease to diagnose and treat.1,2 The history and clinical features are often nonspecific, and practical serological markers ...

Related Pictures

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★リンクテーブル★

リンク元	「ウイルス性心筋炎」
関連記事	「viral」

「ウイルス性心筋炎」

　　[★]

英

viral myocarditis

関

心筋炎

• ウイルス性心筋炎患者のうち、20%でウイルス抗体陽性。

病原体

• コクサッキーウイルスA群、B群　←　B群はウイルス抗体陽性者のうち、53%の症例で陽性
• エコーウイルス　　←　ウイルス抗体陽性者のうち、11%の症例で陽性
• インフルエンザウイルス
• ヘルペスウイルス

治療

• 対症療法

• 急性期

「viral」

　　[★]

• adj.

• ウイルス性の、ウイルスの

関

virally、virogenic、virus