A 31-year-old man with a history of high blood pressure presented with a cough, cold, and congestion for two weeks and recent dizziness. He said he hadn't been feeling well off and on with body aches and fatigue. Then he became really dizzy and short of breath, and felt like he was going to faint, so he came to the ED. He had injected conjunctival, looked unwell, and couldn't lie down for long without shortness of breath.
He was afebrile, tachycardic to 110 bpm, and had a blood pressure of 118/89 mm Hg. He received an ECG and then had a troponin of 2.57. He was quickly admitted. What was his diagnosis?
Find the diagnosis and case discussion on next page.
Diagnosis: Acute Myocarditis
Myocarditis, the inflammation of the myocardium, causes dysfunction in the heart. A definitive diagnosis is obtained only by doing a biopsy of the myocaridium, so the diagnosis often comes down to a clinical diagnosis using the Dallas criteria.
Multiple things can cause myocarditis, the most frequent being viral, bacterial, spirochetal, mycotic, rickettsial, protozoal, and helminthic infections. Noninfectious causes include cardiotoxins, hypersensitivity reactions, systemic disorders, and radiation. (Circulation 2006;114:1581; http://bit.ly/2Q6VkqQ.)
Unfortunately, patients with myocarditis present in a variety of ways, with fatigue, chest pain, heart failure, shock, arrhythmias, or even sudden death. Many cases, in fact, go undetected because the amount of inflammation varies by case and patients can present with the whole spectrum of concerns. Its frequency, therefore, is not really known. Researchers looking at causes of unexplained cardiomyopathy found nine percent were ultimately caused by myocarditis. (N Engl J Med 1985;312:885.)
The physical exam usually shows some signs of the heart dysfunction, and could show unexplained fluid overload, tachycardia, shortness of breath while lying down, dyspnea on exertion, and tachypnea.
The initial workup should include an ECG, troponin, chest x-ray, and BNP (if heart failure is suspected). The ECG can be normal, nonspecific, or have patterns similar to pericarditis or acute myocardial infarction. (Heart 2000;84:245; http://bit.ly/2PtEQvT.) The troponin may be elevated, which would reflect some myocardial necrosis; this is seen only in some patients with myocarditis. A chest x-ray, unfortunately, also has limited sensitivity for identifying cardiomegaly. It is also important to perform echocardiography to evaluate for decreased ventricular function. The sensitivity of the echocardiogram is still not perfect, however. Investigators found that the echocardiogram will show left ventricular dysfunction 69 percent of the time. (Am J Cardiol 1988;62:285.)
If your facility has the capability, cardiac magnetic resonance imaging has been found to have a sensitivity of 100% and a specificity of 90%. (Circulation 1999;99:458.) Cardiac catheterization is not usually required, but select patients require coronary angiography when their clinical presentation is too difficult to distinguish from myocardial infarction or they have high risk factors for MI. It is important to have a higher level of suspicion for a patient presenting with otherwise unexplained heart failure, shock, or arrhythmia, especially if infection is present.
Our patient had a cardiac angiography without any disease noted, and was treated for presumed myocarditis.