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Recommendations for Viral Myocarditis - a Serious Complication of the Flu

February 20, 2007

These are the joint recommendations of Pediatric Cardiology, ICU and Infectious Diseases.

Viral myocarditis is a rare but serious complication of influenza and other viral infections. Myocarditis can lead to acute heart failure culminating in cardiogenic shock, ventricular arrhythmias, or pericardial effusion.

This complication is generally treated with supportive care at a cardiac specialty care center.

Early warning signs may include, but are not limited to:

  1. Poor perfusion — often accompanied by decreased urine output
  2. Extra heart sounds such as an S3 and/or S4 “, e.g. gallop” rhythm on physical examination.
  3. Tachycardia, dyspnea, tachypnea — sometimes confounded by fever, but nearly always present
  4. Hepatomegaly, jugular venous distension, abdominal pain though not always present early on
  5. Hypotension is a late, not an early sign. Normal BP is not necessarily reassuring in the face of poor perfusion!

In addition to a very thorough history and examination, the following tests are suggested:

  1. Chest radiograph
  2. EKG
  3. Blood pressure and pulse oximetry
  4. Blood tests for: troponin and/or BNP (B-type naturietic peptide)

If a pediatric patent’s cardiac status is compromised by influenza or there is suspicion of myocarditis or heart failure (regardless of the result of any specific test result), the child should be transferred to a tertiary pediatric cardiac care center.