Case Presentation: A 22-year-old female with history of anxiety presented to the emergency room with chest pain described as someone “sitting on her chest” since morning. Symptoms began three days ago as sore throat, nonproductive cough, subjective fever, and chills. She was evaluated at an urgent care and had negative strep test but was given amoxicillin. This morning, she woke up with 7/10, non-positional, left-sided chest pain with shortness of breath and nausea. Symptoms lasted four hours and self-resolved. Patient was on oral contraceptives as outpatient. She denied any smoking or drug use.In the ED, vitals were stable. The heart was regular rate and rhythm and chest was minimally tender to palpation. There was no edema. Lungs were clear. Initial labs were notable for troponin 183 and NT-proBNP 236. Additionally, ESR was 62 and CRP 5.5. HIV, monospot, and respiratory panel were negative. EKG was sinus with T-wave inversions in leads III, V1, V3. CTA was negative for PE. Echo showed normal biventricular function without valvular abnormalities. Given the elevated troponin and inflammatory markers in the setting of a recent viral illness and absence of obvious ischemic event, there was increased suspicion for myocarditis. Antistreptolysin O titer was negative, however throat culture returned positive for group A strep. Cardiac MRI was consistent with myocarditis and acute/subacute pericardial inflammation. Our patient did not meet full major or minor Jones criteria and was thus determined to have non-rheumatic myocarditis. The patient was treated with a 10-day course of amoxicillin for group A streptococcal pharyngitis with plans for repeat CMRI in 3-6 months. Additional workup for etiology revealed negative HHV and Parvovirus IgM, and positive Parvovirus IgG and Coxsackie antibody following discharge.
Discussion: The diagnosis of non-rheumatic strep myopericarditis is made in the context of a recent upper airway infection by group A strep without rheumatic disease. The complication of chest pain can mimic a heart attack and usually presents within one week of initial respiratory symptoms. This indicates that the pathophysiology of cardiac injury in this disease process (direct bacterial toxin effect versus autoimmune versus cross-reactivity, etc.) may be different than that of rheumatic myocarditis given its shorter latency. Additionally, rheumatic carditis most consistently features valvulitis. Rheumatic fever requires long-term antibiotic prophylaxis, however data for treatment of non-rheumatic myocarditis is not standardized. Prognosis for those treated with antibiotics appears to be favorable with resolution of both symptoms and imaging findings.
Conclusions: The overall incidence of non-rheumatic myocarditis is not known as diagnosis is often termed idiopathic. Young patients without risk factors who present with chest pain should raise suspicion for myocarditis, and history regarding recent episodes of upper respiratory illness should be obtained. Further research is necessary to guide management of non-rheumatic myocarditis.