Myocarditis

Myocarditis

As you know, a common theme of the Ped EM Morsels is Vigilance: many potentially severe conditions present similarly to benign illnesses.  Kawasaki Disease, Rhabdomyolysis, Crohn’s Disease, and Compartment Syndrome are conditions that come to mind; however, one that warrants special consideration is Myocarditis.

Myocarditis Basics

  • Inflammatory process of the myocardium.
  • Often caused by a viral infection, but many times no pathogen is identified.
  • Rare, but is associated with significant morbidity and mortality!
    • Most common cause of heart failure in previously healthy kids!
    • Can progress to dilated cardiomyopathy.
    • True incidence is unknown, but known cases still comprise a small group.
  • Diagnosis often initially missed as it presents with non-specific symptoms.
  • The rarity, non-specific presentation, and potential significant M&M necessitates our vigilance!

 

 Myocarditis Presentation

  • Often presents with prodromal symptoms.
    • Mean duration, in one study, prior to diagnosis was ~7 days.
  • Studies have consistently shown that younger children do not typically present with “cardiac” symptoms.
  • Adolescents may present with more chest pain complaints similar to adults.
  • Most common initial complaints:
    • Shortness of breath
    • Vomiting and Abdominal Pain
    • Poor feeding
    • Hypoperfusion (following Syncopal Episodes or Seizures)
  • Common MISDIAGNOSES:
    • Pneumonia
    • Asthma
    • URI
    • Gastroenteritis

 

Exam Findings to Look For

  • Hepatomegaly
  • Respiratory distress (ex, tachypnea)
  • Poor Perfusion (ex, mottled skin, decreased cap refill)
  • Lethargy
  • Tachycardia

 

Myocarditis and Tachycardia

So I was taught that the child who is persistently tachycardic, after appropriate therapies, needs to have myocarditis considered on the DDx.  I do think that this is useful to still consider, but the question is, how useful is the lack of tachycardia in ruling out Myocarditis?

  • Sadly, in the three large retrospective studies mentioned in the references, tachycardia was only present in 46 – 58% of cases of myocarditis.
  • Lack of tachycardia does not rule out the condition.

 

Myocarditis Initial Evaluation

  • ECG has been shown to be abnormal in 100% of the cases of myocarditis!
    • That would seem to be awesome…
    • Unfortunately, Sinus Tachycardia counts as being abnormal.
    • Common findings:
      • Sinus Tachycardia (46 – 58%)
      • Evidence of abnormally large voltage
      • Axis deviation
      • ST wave abnormalities
      • T wave abnormalities
      • AV Blocks
      • Ischemic patterns
  • CXR is not as sensitive, but is often abnormal.
    • Cardiomegaly
    • Pulmonary Edema
    • Pleural Effusions
  • ECG and CXR are good screening tools for cases in which you suspect Myocarditis.
    • If both are NORMAL, then an ECHO is unnecessary unless you have high clinical suspicion.
  • Other lab studies have shown promise (Elevated LFTs and Troponin T have been associated with myocarditis).

 

Moral of the Morsel

Myocarditis is a difficult diagnosis to make, but an important one to consider!  Its rarity will make it much more likely that the patient you are sending home with the “viral illness” or “wheezing” will actually have a mild condition; however, our job is to consider the life-threatening as well as the common.

Get into the habit of always checking for hepatomegaly and skin perfusion in any kid with a respiratory complaint or vomiting.  While you are most likely to not find any abnormalities, you will not ever find the important ones if you don’t look for them.

If you are concerned for Myocarditis, check an ECG and a CXR… you could also do a quick bedside ultrasound.

 

References

Shu-Ling C1, Bautista D, Kit CC, Su-Yin AA. Diagnostic evaluation of pediatric myocarditis in the emergency department: a 10-year case series in the Asian population. Pediatr Emerg Care. 2013 Mar;29(3):346-51. PMID: 23426251. [PubMed] [Read by QxMD]

Eisenberg MA1, Green-Hopkins I, Alexander ME, Chiang VW. Cardiac troponin T as a screening test for myocarditis in children. Pediatr Emerg Care. 2012 Nov;28(11):1173-8. PMID: 23114243. [PubMed] [Read by QxMD]

Durani Y1, Egan M, Baffa J, Selbst SM, Nager AL. Pediatric myocarditis: presenting clinical characteristics. Am J Emerg Med. 2009 Oct;27(8):942-7. PMID: 19857412. [PubMed] [Read by QxMD]

Freedman SB1, Haladyn JK, Floh A, Kirsh JA, Taylor G, Thull-Freedman J. Pediatric myocarditis: emergency department clinical findings and diagnostic evaluation. Pediatrics. 2007 Dec;120(6):1278-85. PMID: 18055677. [PubMed] [Read by QxMD]

Sean Fox

I enjoy taking care of patients and I finding it endlessly rewarding to help train others to do the same. I trained at the Combined Emergency Medicine and Pediatrics residency program at University of Maryland, where I had the tremendous fortune of learning from world renown educators and clinicians. Now I have the unbelievable honor of working with an unbelievably gifted group of practitioners at Carolinas Medical Center. I strive every day to inspire my residents as much as they inspire me.

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6 Responses

  1. May I use your cartoon and this article on our website and in our newsletter?

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