acute myocarditis

急性心筋炎

WordNet

1. of critical importance and consequence; "an acute (or critical) lack of research funds"
2. having or demonstrating ability to recognize or draw fine distinctions; "an acute observer of politics and politicians"; "incisive comments"; "icy knifelike reasoning"; "as sharp and incisive as the stroke of a fang"; "penetrating insight"; "frequent penetrative observations" (同)discriminating, incisive, keen, knifelike, penetrating, penetrative, piercing, sharp
3. extremely sharp or intense; "acute pain"; "felt acute annoyance"; "intense itching and burning" (同)intense
4. having or experiencing a rapid onset and short but severe course; "acute appendicitis"; "the acute phase of the illness"; "acute patients"
5. of an angle; less than 90 degrees

PrepTutorEJDIC

1. (先の)『鋭い』,とがった / (痛み・感情などが)『激しい』,強い / (知力・感覚などが)『鋭い』,鋭敏な / (事態が)重大な / (病気が)急性の / (音が)高い,鋭い / 鋭角の

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2013/09/17 11:49:06」(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 (Adenovirus(Most common cause), 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. 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
• 2. 成人における心筋炎の自然経過および治療 natural history and therapy of myocarditis in adults
• 3. 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
• 4. 心筋炎の病因および発症機序 etiology and pathogenesis of myocarditis
• 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

• Diagnosis of acute myocarditis with dual source cardiac tomography.

• Baudry G1, Bouleti C2, Iung B2, Nejjari M2, Laissy JP3, Vahanian A2, Ou P3.
• International journal of cardiology.Int J Cardiol.2015 Jan 20;179:256-7. doi: 10.1016/j.ijcard.2014.11.037. Epub 2014 Nov 6.
• PMID 25464460

• Stress-Induced Cardiomyopathy.

• Boland TA1, Lee VH, Bleck TP.
• Critical care medicine.Crit Care Med.2015 Jan 6. [Epub ahead of print]
• OBJECTIVES:: Reversible stress-induced cardiac dysfunction is frequently seen as a complication of a multitude of acute stress states, in particular neurological injuries. This dysfunction may be difficult to distinguish between that caused by myocardial ischemia and may impact both the treatment st
• PMID 25565459

• Transient left ventricular wall thickening in a 14-year-old girl with influenza A myocarditis.

• Wittlieb-Weber CA1, Harris MA1, Rossano JW1.
• Cardiology in the young.Cardiol Young.2015 Jan;25(1):187-90. doi: 10.1017/S1047951114000018. Epub 2014 Jan 30.
• We describe a case of influenza A myocarditis and transient left ventricular wall thickening in a 14-year-old girl presenting with acute heart failure. Admission echocardiogram revealed significant left ventricular hypertrophy with depressed left ventricular systolic function. The aetiology of the v
• PMID 24480544

Japanese Journal

• 重症左心不全に対し，バルーン心房中隔裂開術を施行し救命し得た新生児心筋炎の1 例

• 平岩 明子,齋藤 和由,伊吹 圭二郎,渡辺 一洋,小澤 綾佳,市田 蕗子,宮脇 利男,芳村 直樹,小浦 詩,藤田 修平,二谷 武,畑崎 喜芳
• Pediatric Cardiology and Cardiac Surgery 29(3), 149-155, 2013
• 　新生児期の心筋炎は極めて予後不良であり，救命のため体外補助循環の装着を必要とすることがある．コクサッキーB4 ウイルス性心筋炎による重症左心不全に対し，体外補助循環の代わりに，バルーン心房中隔裂開術（Balloon atrial septostomy 以下BAS）を施行し，救命しえた新生児例を経験した．この新生児では，肺うっ血と重症僧帽弁逆流を伴った重症左心不全に対して，内科的治療のみでは血行動 …
• NAID 130003380031

• Acute Myocarditis Presenting with Ventricular Arrhythmias: The Role of CMR in the Differential Diagnosis of ARVD

• Huttin Olivier,Frikha Zied,Brembilla-Perrot Béatrice,Sellal Jean-Marc,Mandry Damien,Aliot Etienne,Juilliere Yves,Sadoul Nicolas,Selton-Suty Christine
• Internal Medicine 52(17), 1915-1918, 2013
• … Based on the clinical features as well as the echographic and MRI results, the patient was diagnosed with both acute viral myocarditis and arythmogenic right ventricular dysplasia (ARVD). … This case demonstrates the link between ARVD and myocarditis, and highlights the importance of conducting an RV assessment through a cardiac magnetic resonance (CMR) study in the context of arrhythmia and myocarditis. …
• NAID 130003365780

• Isolated Primary Cardiac Sarcoidosis Presenting as Acute Heart Failure

• Sugizaki Yoichiro,Tanaka Hidekazu,Imanishi Junichi,Konishi Akihide,Yamashita Tomoya,Shinke Toshiro,Ishida Tatsuro,Kawai Hiroya,Hirata Ken-ichi
• Internal Medicine 52(1), 71-74, 2013
• … A 65-year-old man was referred to our hospital due to an acute onset of dyspnea and persistent fever. … The final diagnosis was thus cardiac sarcoidosis with acute inflammation. … This is a rare case in which acute inflammation led to acute heart failure mimicking acute myocarditis. …
• NAID 130003365561

Related Links

• Acute myocarditis - Medical Dictionary - The Free Dictionary

Myocarditis is an inflammatory disease of the heart muscle (myocardium) that can result from a variety of causes. While most cases are produced by a viral infection , an inflammation of the heart muscle may also be instigated by toxins, drugs, ...

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★リンクテーブル★

リンク元	「急性心筋炎」
関連記事	「acute」

「急性心筋炎」

　　[★]

英

acute myocarditis

関

心筋炎

心内膜心筋生検による急性心筋炎の診断基準

• 1．多数の大小単核細胞の浸潤(ときに少数の多核白血球、多核巨細胞の出現)
• 2．心筋細胞の断裂、融解、消失
• 3．間質の浮腫(ときに線維化)

参考

• 1. 急性および慢性心筋炎の診断・治療に関する ガイドライン - 日本循環器学会

http://www.j-circ.or.jp/guideline/pdf/JCS2009_izumi_h.pdf

「acute」

　　[★]

• adj.

• (疾患)急性の、急性型の、急性的な。(形状が)鋭い、鋭角の。(感覚、才知などが)鋭い。明敏な、鋭い眼識のある。

関

acutely、quick、sharp