Acute myocarditis (AM) is defined as an inflammatory disease involving the myocardium and its exact pathogenesis model remains to be completely elucidated [1] [2] [3] [4]. AM can arise on the grounds of various infections and autoimmune disorders [1] [2] [3] [4]. By far, viruses are responsible for the majority of cases, primarily enteroviruses (coxsackie A or B and echoviruses), but also Epstein-Barr virus (EBV), hepatitis C virus (HCV), and increasingly important human herpesvirus 6 (HHV6) and parvovirus B19, which were recently identified as the main causes of myocarditis in Germany [1] [5] [6]. In addition, bacteria (Brucella spp., Clostridium spp., Francisella spp., Legionella, etc.), fungal microorganisms (Aspergillus, Candida, Cryptococcus, Histoplasma), and a number of parasites have been reported as a cause of myocarditis as well [1] [4]. On the other hand, sarcoidosis, Wegener's granulomatosis, celiac disease, connective tissue disorders, rheumatic fever, but also various drugs (antimicrobials, diuretics, antipsychotics, etc.) are notable non-infectious etiologies of myocarditis [1] [4]. The clinical presentation starts with a flu-like symptomatology (fatigue, malaise, and constitutional symptoms), followed by dyspnea, palpitations, arrhythmias, and chest pain with discomfort as the main symptoms [1] [7]. However, patients may be completely asymptomatic or develop severe cardiac insufficiency that results in heart failure and sudden death, and up to 9% of all sudden cardiac deaths have been attributed to myocarditis in certain reports [4] [7] [8]. Tachycardia, cardiogenic shock, and a syndrome mimicking myocardial infarction (MI) or coronary heart disease (CAD) can be seen in severe cases [1] [2]. Although the short-term prognosis of acute myocarditis is generally good [7], long-term sequelae in the form of cardiomyopathy and progressive decline in cardiac functions are observed [3] [4], thus illustrating the importance of an early diagnosis and proper treatment.

The life-threatening nature of AM necessitates a thorough diagnostic workup, starting with a detailed patient history that will identify the course and progression of symptoms, recent travel (to exclude certain viral, fungal or parasitic infections), and the presence of comorbidities that may contribute to clinical deterioration. The physical examination is perhaps even more important, which can reveal tachycardia, cardiac murmurs (soft S1 sound, S3 or S4 gallop, as well as sounds pointing toward insufficiency of the mitral or tricuspid valve), a pericardial friction rub, and a displaced punctum maximum [1] [4]. A full body inspection must not be overlooked, as it may lead to findings such as lymphadenopathy, subcutaneous nodules, joint sensitivity (typical for sarcoidosis and rheumatic fever, respectively) or other signs of that might point to the underlying cause [4]. As soon as the heart is identified as the source of symptoms, cardiac enzymes: troponin I, troponin T, and creatine kinase-MB (CK-MB) must be evaluated to exclude myocardial infarction, after which electrocardiography (EKG) and imaging studies, primarily cardiac ultrasonography, should be employed [1]. Although clear diagnostic criteria do not exist for acute myocarditis, an overall reduced activity of the myocardium (hypokinesia) is the main finding, but more importantly, other etiologies (valvular or congenital heart disease, as well as myocardial infarction) can be ruled out [1] [4]. Extensive microbiological testing is available, mainly through serology and blood cultures, but the introduction of molecular testing (eg. polymerase chain reaction, or PCR) has markedly improved the overall success of identifying microorganisms in patient samples [1]. Endomyocardial biopsy is a definite method for confirmation of AM, but it is indicated only if the procedure is assumed to have a vitally important effect on the therapeutic course [1] [4] [9] [10].

Treatment for acute myocarditis focuses on managing symptoms and addressing the underlying cause. Patients may be advised to rest and avoid strenuous activities. Medications such as anti-inflammatory drugs, beta-blockers, or ACE inhibitors may be prescribed to reduce inflammation and support heart function. In severe cases, hospitalization may be required, and treatments like intravenous medications or mechanical support devices may be used. If an infection is the cause, appropriate antimicrobial therapy will be administered.

The prognosis for acute myocarditis varies depending on the severity of the condition and the underlying cause. Many patients recover fully with appropriate treatment, but some may experience long-term complications such as chronic heart failure or arrhythmias. In rare cases, acute myocarditis can lead to sudden cardiac death. Regular follow-up with a healthcare provider is essential to monitor heart function and manage any ongoing symptoms.

Acute myocarditis can be caused by a variety of factors. Viral infections are the most common cause, with viruses such as the Coxsackievirus, adenovirus, and parvovirus B19 frequently implicated. Bacterial, fungal, and parasitic infections can also lead to myocarditis. Non-infectious causes include autoimmune diseases, such as lupus, and exposure to certain drugs or toxins, including alcohol and cocaine.

The exact incidence of acute myocarditis is difficult to determine, as many cases are mild and go undiagnosed. It is estimated to affect people of all ages, but young adults and males are more commonly affected. The condition can occur worldwide, with variations in incidence depending on the prevalence of specific infectious agents and environmental factors.

The pathophysiology of acute myocarditis involves an inflammatory response in the heart muscle. This inflammation can be triggered by direct infection of the heart tissue or by an immune response to an infection elsewhere in the body. The inflammation damages the heart muscle cells, leading to impaired heart function and, in some cases, the development of scar tissue. This can disrupt the heart's electrical system and lead to arrhythmias.

Preventing acute myocarditis involves reducing the risk of infections and avoiding exposure to known triggers. Good hygiene practices, such as regular handwashing, can help prevent viral infections. Vaccinations, such as the flu vaccine, may also reduce the risk of myocarditis. Avoiding excessive alcohol consumption and illicit drug use can prevent toxin-induced myocarditis. For those with autoimmune conditions, managing the underlying disease can help reduce the risk of myocarditis.

Acute myocarditis is an inflammation of the heart muscle that can affect its ability to pump blood effectively. It can be caused by infections, autoimmune diseases, or exposure to toxins. Symptoms range from mild to severe and may include chest pain, fatigue, and shortness of breath. Diagnosis involves clinical evaluation and various tests, while treatment focuses on managing symptoms and addressing the underlying cause. The prognosis varies, with many patients recovering fully, though some may experience long-term complications.

If you suspect you have symptoms of acute myocarditis, it is important to seek medical evaluation. Symptoms like chest pain, shortness of breath, and palpitations should not be ignored. Early diagnosis and treatment can improve outcomes and reduce the risk of complications. Maintaining a healthy lifestyle, practicing good hygiene, and managing any underlying health conditions can help prevent myocarditis. Regular follow-up with your healthcare provider is crucial for monitoring heart health and managing any ongoing symptoms.

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