Beware Pediatric Myocarditis

July 29, 2021

Written by Carmen Wolfe

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The presentation of myocarditis in children is heterogenous, and arriving at the definitive diagnosis is complicated. If you suspect it, respect it – these kids are at high risk for arrhythmia and decompensation.

Why does this matter?
Myocarditis occurs in all ages. We covered myocarditis generally yesterday. Although many clinical manifestations are the same in children, we cover the pediatric specific highlights from this article. While pediatric myocarditis is not common, it can be deadly. A high level of suspicion and a conservative approach to management is prudent.

A heartfelt manifesto from the AHA
This detailed review article from the AHA comes down to this: the scientific community needs to focus on a standardized definition for diagnosis of pediatric myocarditis, and then design rigorous trials to assess for therapeutic benefits of multiple treatment options. Until then, this article offers the best summary of what we do know. Here is what is most relevant for EM docs:

• Etiology: May be infectious (most likely viral, including SARS-CoV-2) or non-infectious (autoimmune, hypersensitivity, medication-induced, toxin-mediated)

• Presentation: Heterogenous and non-specific. By history, patients may report a viral prodrome (41-69%), arrhythmias (11-45%), or syncope (4-10%). Common symptoms include fatigue (25-70%), shortness of breath (35-69%), fever (31-58%); chest pain (24-42%) and palpitations (16%) were less common. On exam, look for tachypnea (52-60%), tachycardia (32-57%), hepatomegaly (21-50%), or respiratory distress (21-47%); murmur (26%) and gallop (20%) are less common. The authors note that a fulminant presentation seems more common in hospitalized children than in adults.

• Diagnosis: Elevated troponin and BNP are associated with worse outcomes, but normal values can’t exclude the diagnosis. Similarly, don’t be fooled by a normal WBC, ESR, or CRP. ECG might show anything from sinus tachycardia to ischemic changes; heart block to tachyarrhythmias of supraventricular or ventricular origin. Echocardiography is widely used and considered a first line imaging modality. Cardiac magnetic resonance imaging and endomyocardial biopsy may also be useful.

• Management: Supportive care is the mainstay, with heart failure managed with inotropes +/- vasopressors as needed. Defer to the inpatient team for consideration of IVIG, steroids, or antivirals, as evidence isn’t conclusive for any of these options.

• Disposition: For any suspicion of myocarditis, admit for arrhythmia monitoring. Transfer to a center with capacity for mechanical circulatory support if your patient is trending toward hemodynamic compromise – up to 23% of patients might need ECMO or VAD.

Editor’s note: If you are considering myocarditis, don’t overdo it with fluid boluses if hypotensive. Learn from my mistakes. ~Clay

Source
Diagnosis and Management of Myocarditis in Children: A Scientific Statement From the American Heart Association. Circulation. 2021 Jul 7;CIR0000000000001001. doi: 10.1161/CIR.0000000000001001. Online ahead of print.