Review Question - QID 217170

This patient presents with signs of heart failure, including exertional dyspnea, poor exercise tolerance, bibasilar crackles, S3 heart sound, jugular venous distention, and lower extremity edema, in the setting of a recent viral syndrome (low-grade fever, runny nose, mild cough). This is suggestive of dilated cardiomyopathy secondary to viral myocarditis, which can be diagnosed with an echocardiogram.

Viral myocarditis is a common cause of dilated cardiomyopathy in younger patients. A common etiologic agent is coxsackievirus B. Patients present with signs of heart failure, including acute dyspnea, orthopnea, and signs of volume overload. Diagnosis of dilated cardiomyopathy is secured with an echocardiogram, which shows dilated ventricles, hypokinesis, and a reduced ejection fraction. Patients presenting with decompensated heart failure should receive standard treatment for that condition; treatment for hemodynamically-stable patients may include angiotensin-converting enzyme inhibitors and diuretics (if hypervolemic). Beta-blockers may be used in euvolemic patients to decrease symptoms. Patients who are hemodynamically unstable or in cardiogenic shock may require vasopressor and/or inotropic support; when patients are refractory to this therapy, mechanical circulatory support, such as a ventricular assist device as a bridge to transplant or extracorporeal membrane oxygenation, may be required.

Schultz et al. review the diagnosis and management of viral myocarditis and its complications including dilated cardiomyopathy. They highlight new diagnostic modalities, which include cardiac magnetic resonance imaging. They recommend the use of endomyocardial biopsy in patients who do not respond to conventional supportive therapy.

Incorrect Answers:
Answer 2: Iron supplementation is the treatment for iron deficiency anemia. Patients can present with dyspnea, although severe dyspnea is typically not present except in cases of severe anemia. Prolonged anemia can result in heart failure; however, myocarditis is more likely in this patient with a recent viral prodrome.

Answer 3: Methacholine challenge is used occasionally to diagnose asthma. Asthma can present with dyspnea, especially after viral infections, but would not account for this patient’s volume overload or S3 heart sound.

Answer 4: Supportive measures only is used to treat mild cases of viral myocarditis without signs of heart failure. This patient has clear signs of heart failure, which needs to be diagnosed and managed.

Answer 5: Vancomycin, gentamicin, and cefepime is a broad-spectrum antibiotic regimen, which could be used for the treatment of bacterial endocarditis, which presents with fever, heart murmur, Janeway lesions (non-tender macules on palms or soles), Osler nodes (painful nodules on finger or toe pads), and/or Roth spots (hemorrhagic retinal lesions). Diagnosis adheres to the Duke criteria.

Bullet Summary:
Viral myocarditis is one of the most common causes of dilated cardiomyopathy in younger patients and is diagnosed using an echocardiogram, which shows dilated ventricles and hypokinesis.