Myocarditis is a potentially fatal inflammatory disorder of the heart. Viral infection is the most common cause but can also result from toxic, autoimmune, or other infectious etiologies. Complications include life-threatening dysrhythmias, heart failure, and fulminant myocarditis. Typically affects young patients (20-50 years old).

• Diagnosis can be challenging. Presentation can range from nonspecific symptoms and normal hemodynamics to cardiogenic shock.
• Dyspnea was found to be the most common presenting symptom in one study
• Other symptoms include fever, malaise, chest pain, palpitations, fatigue, nausea, vomiting
• Consider the diagnosis in young patient with suspected sepsis but worsens with IV fluids with signs of volume overload
• Initial assessment should include ECG, CBC, CMP, inflammatory markers, cardiac biomarkers, CXR. Obtaining an echo is important. Perform POCUS to assess for global hypokinesis, reduced EF, wall motion abnormalities, pericardial effusion, B-lines.

ED management pearls

• Initiate vasopressors and inotropic support if hemodynamically unstable: norepinephrine + inotropic agent (e.g. milrinone, dobutamine) is recommended. In a few studies, epinephrine was associated with increased mortality when used in cardiogenic shock.
• Diurese if evidence of volume overload
• NIPPV or intubation if respiratory failure
• Avoid NSAIDs which may worsen mortality
• Consider mechanical circulatory support (e.g. ECMO, IABP, VAD) in refractory hypotension despite appropriate medical therapy

References

Gottlieb, Michael et al. "Diagnosis And Management Of Myocarditis: An Evidence-Based Review For The Emergency Medicine Clinician". The Journal Of Emergency Medicine, vol 61, no. 3, 2021, pp. 222-233.