Perimyocarditis I31.9

According to the ESC (European Society of Cardiology), perimyocarditis is a myocarditis in the foreground with additional left ventricular dysfunction.

Myopericarditis, on the other hand, is a foreground pericarditis with little or no dysfunction of the left ventricle (Pinger 2019).

Myocardial or pericardial involvement may be diffuse or focal (Imazio 2008).

Precise figures are not accessible. The incidence of myocarditis is estimated to be about 1 - 10 cases per 100,000 inhabitants.

In smallpox vaccine-associated myocarditis, the number of cases in the USA was 0.01% of the recruits.

(Yugandhar 2018)

The vast majority of myopericarditis is idiopathic. Even after intensive diagnostics the triggering cause cannot be found.

Otherwise, the causes are divided into infectious and non-infectious pathogens.

(Yugandhar 2018)

Infectious agents include:

• viruses (e.g. adeno-, coxsackie-, cytomegalovirus, influenza, herpes, echo virus, Epstein-Barr virus, paravirus B 19, hepatitis C virus)
• bacteria (e.g. Mycobacterium tuberculosis, Campylobacter, Haemophilus, Legionella, Mycoplasma, Staphylococcus, Streptococcus, Yersinia enterocolitica)
• Fungi (e.g. aspergillus, blastomyces, coccidioidomycosis, histoplasm)
• Parasites (e.g. amoebic disease, Chagas disease, toxoplasms)

Non-infectious triggers include:

• Medicines (e.g. anthracycline, isoniazid, hydralazine, procainamide)
• Alcohol
• systemic inflammatory diseases (e.g. granulomatosis, systemic lupus erythematosus, rheumatoid arthritis, sarcoidosis, scleroderma, Sjögren's syndrome)
• Metastases (especially of bronchial and breast carcinoma, melanoma)
• Thoracic radiology
• primary cardiac tumours (e.g. rhabdomyosarcoma)
• metabolic diseases (e.g. hypothyroidism, uremia)
• chronic intestinal diseases (e.g. ulcerative colitis, Crohn's disease)
• Heavy metals
• Vaccine associated (e.g. after smallpox vaccination)

(Yugandhar 2018)

The course of myopericarditis varies widely. It ranges from a clinically inconspicuous course with self-limitation to severe cardiogenic shock with a lethal outcome (Imazio 2008).

Often, viral prodromes precede the actual disease by 1 - 2 weeks with symptoms such as arthralgias, low-grade fever, rhinitis, etc. (Yugandhar 2018).

Otherwise, the following symptoms may exist:

• circumscribed left thoracic pain
• Occasionally, the pain radiates to the left shoulder, left arm and neck.
• sometimes there is also an isolated pain along the upper edge of the trapezius (pathognomonic for irritations of the pericardium)
• the pain decreases when the patient is bent forward
• the pain increases when the patient is lying down, during deep inspiration, occasionally also when coughing or swallowing.

(Kühl 2004)

• Dyspnoea
• tachycardia
• Fever

Signs of heart failure (e.g., orthopnea, peripheral edema, fatigue, etc.) may sometimes occur with significant myocardial involvement.

Very rarely, arrhythmias, syncope, or sudden cardiac arrest occur.

(Yugandhar 2018)

The differentiation between perimyocarditis and myopericarditis plays a role in diagnosis, since myocarditis requires endomyocardial biopsy with histologic evidence to establish the diagnosis. In contrast, pericarditis that is uncomplicated is not an indication for EMB. (Pinger 2019).

Auscultation

• Pulse-synchronous systolic-diastolic, creaking, near-auricular sound, most evident over the lingula near the sternum (so-called pericardial rubbing).
• Pericardial rubbing may sometimes be present only passively
• intensifies during inspiration (not obligatory; occurs in about 1/3 of patients [Franke 1984])
• no change of sound during respiratory pause (in contrast to pleural rubbing)
• absence of pericardial rubbing, however, does not exclude pericarditis.

(Kühl 2004)

Laboratory

• Slight increase in CK (Herold 2018); occurs in approximately 7.6% of patients
• Troponin rises in 32% of patients (Pinger 2019).

When inflammatory processes spread to the myocardium - in addition to typical inflammatory markers such as ESR acceleration, leukocytosis, elevation of C-reactive protein, etc.) may be elevated:

• Isoenzymes

( (Erdmann 2009)

ECG

The ECG need not be fundamentally altered by pericarditis per se. Rather, the outer layer damage that usually exists in all or several leads results from inflammation of the adjacent myocardial layers (Herold 2018).

In myopericarditis, therefore, monophasic elevations of the ST segment are sometimes found. These may be diffusely distributed or localized, depending on the extent of the affected myocardial components.

The arrhythmias that sometimes occur include both supraventricular and ventricular ectopic beats or timed ventricular arrhythmias (Yugandhar 2018).

Arrhythmias are always indicative of myocardial involvement (Kühl 2004).

Echocardiography

Echocardiography should be performed routinely in cases of v. a. myopericarditis or perimyocarditis. Depending on the severity of the disease, a more or less large pericardial effusion is seen, the hemodynamics of which can be well assessed by echocardiography. Some authors describe a brightness of the pericardium in the presence of pericarditis. However, this represents only a nonspecific finding with limited specificity (Yugandhar 2018).

Occasionally, echocardiography demonstrates left ventricular dysfunction. These patients predominantly present with a more severe course and should be monitored more closely (Yugandhar 2018)

Chest X-ray

In milder forms of the disease, chest x-ray is usually unremarkable. In more severe courses, an enlarged cardiac silhouette is seen due to fluid accumulation in the pericardium (Yugandhar 2018).

Cardiac MRI.

MRI represents an important noninvasive type of examination (Imazio 2008).

With this, it is possible to determine the degree of pericardial and myocardial involvement. A midmyocardial to subepicardial diffuse patchy "late enhancement" is found as a sign of inflammation of the myocardium and a signal enhancement in the T2-weighted sequences as an expression of edema (Ludwig 2008).

Cardio- MRI can also be used - without invasive measures - to delineate the differential diagnosis of CAD (Yugandhar 2018). This is possible, for example, by dobutamine stress MRI and stress perfusion MRI (Laufs 2016) .

Coronary angiography

Coronary angiography is not generally indicated in patients with typical features of myopericarditis.

In patients with risk factors for atherosclerotic cardiovascular disease and in patients with known coronary artery disease, myocardial ischemia sometimes cannot be excluded by noninvasive examinations. In these patients, coronary angiography is recommended (Yugandhar 2018).

Endomyocardial biopsy

Endomyocardial biopsy, both in the case of untargeted puncture and MRI-guided puncture from the area of late enhancement, is of limited value because it is subject to the so-called "sampling error" (i.e., biopsies are taken from areas that are not affected by inflammation and thus yield a false-negative result[Ludwig 2008]).

However, biopsy should still be performed in patients who experience persistent deterioration under standard treatment, thereby allowing the diagnosis and therapy to be revised if necessary (e.g., sarcoidosis, giant cell myocarditis [Yugandhar 2018]).

However, the so-called Dallas criteria, the 1987 criteria for histopathological diagnosis of myocarditis due to lymphocyte infiltrate with necrosis of myocytes, are not present in 80%- 90% of cases with classic symptoms (Kasper 2015).

• Myocardial infarction (in perimyocarditis, the Q-spikes remain unchanged and there is no loss of R [Herold 2018]).

Patients with myopericarditis, in whom signs of pericarditis are predominant and who have preserved left ventricular function, can be treated with NSAIDs (Yugandhar 2018).

Recommended dosage:

• e.g. Ibuprofen 600mg every 8 h
• plus proton pump inhibitors as stomach protection e.g. cimetidine 200mg - 400 mg/d

However, if myocardial involvement is predominant, treatment with NSAIDs should be used with caution and only in small doses for symptomatic relief, as NSAIDs can damage the myocardium (Yugandhar 2018).

In animal experiments, it has even been shown that NSAIDs are not effective in myocarditis and increase the mortality of the disease (Imazio 2008).

In cases of pericarditis alone, treatment with colchicine is recommended. In myopericarditis, however, success with colchicine is not well documented (Yugandhar 2018).

Dosage recommendation:

• z. e.g. colchicine 0.5 mg/d

In patients with significant pericardial effusion, percutaneous or surgical drainage is recommended for hemodynamic stabilization (Yugandhar 2018).

If signs or symptoms of heart failure occur, standard heart failure therapy (with beta blockers and angiotensin-converting enzyme inhibitors and/or diuretics) should be administered (Yugandhar 2018).

Recommended dosage:

• Metoprolol 1 x 12.5 mg to 25 mg/d
• Lisinopril 1 x 2,5 mg to 5 mg/d
• Furosemide 20 mg to 240 mg/d under electrolyte control

(Kasper 2015)

Treatment with corticosteroids is usually only given in certain cases - in addition to other therapeutic drugs / measures (e.g. in giant cell myocarditis, recurrent pericarditis [Yugandhar 2018] or myocarditis caused by sarcoidosis [Kasper 2015]).

Recommended dosage for recurrent pericarditis:

• z. e.g. prednisone 100 mg for 3 days or a maximum of 3 weeks, followed by dose reduction under echocardiographic and also clinical observation (Paumgartner 2015).

In addition, due to myocardial involvement, a minimum 3-month activity restriction is recommended, in individual cases even longer (Yugandhar 2018). Pinger (2019) recommends a general physical rest for 6 months.

The course of myopericarditis or perimyocarditis is generally good. A possible increased troponin level during the course of the disease has no influence on the prognosis (Pinger 2019).

However, the prognosis is less favourable in patients with echocardiographically proven reduced left ventricular function. In this case, lethal progressions can also occur (Yugandhar 2018).

An exception is giant cell myocarditis, which is also mentioned here. This disease has a high mortality rate. Despite early and intensive therapy, about 70 % of patients require a heart transplant within one year (Magerkurth 2008).

Echocardiography is essential for follow-up and also for patients with subclinical course and normal left ventricular function (Imazio 2008).

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