Spotlight – Acute Myocarditis

STEP 1: Read this short case report online for free! It describes acute myocarditis, a common differential diagnosis for cardiac sounding chest pain(1)

Lee H, Paj R, Nazzal S et al (2019). STEMI mimicker in a 26-year-old man. BMJ Case Reports. Published online First: [February 2019]. doi: 10.1136/bcr-2018224894

STEP 2: Imagine you are a junior doctor working in the Emergency Medicine department. A 26-year-old male is presenting with cardiac sounding chest pain. How do you proceed?

History and Examination

Cardiac sounding chest pain is typically located in the centre of the chest and can radiate to the jaw or down the arms. It is generally a ‘crushing’ or ‘stabbing’ pain, associated with feeling short of breath, sweating or nausea/ vomiting. The pain may be worse on exertion, and relieved by sitting still. Ask about a personal history of cardiac disease, and risk factors such as smoking or hyperlipidaemia.  There may be a family history of early cardiac death (< 50 years old). 

Chest pain in a young adult, that has been preceded by a viral illness, or that is associated with fever/fatigue/ palpitations/ pleurisy, may be due to myocarditis. In such cases, examination may reveal a tachycardia or a soft S1, S4 gallop in an otherwise healthy young adult. Enquire about drug history- a common cause.  

You suspect myocarditis in this young adult. What investigations would you request(2)? 

Investigations

  • ECG: non specific ST elevation or depression, T wave inversion, atrial arrhythmias, transient AV block.
  • Bloods: Full blood count, C Reactive Protein, Urea and Electrolytes, Troponin, D dimer, Clotting studies, relevant serology (see ‘Causes’ section). 
  • Chest XR: cardiac enlargement 
  • Echocardiogram: to look for evidence of regional wall motion abnormalities. Findings should be correlated with cardiac MRI, which typically reveals delayed enhancement(3).
  • Negative anti myosin scintigraphy also excludes active myocarditis. 

In this case report, trans thoracic echocardiogram and cardiac MRI were relatively diagnostic for myocarditis. However, the team were initially suspicious of myocardial infarction due to specific ECG changes (hence why MI treatment was started). What other differential diagnoses should you consider?

Coronary or aortic dissection, embolism or cardiac sarcoid can produce a STEMI like syndrome. 

STEP 3: The family want to speak to you about the patient. They ask:

What is myocarditis and what is it caused by(4)?

Myocarditis is an inflammation of the myocardium- the heart muscle. It is not related to lifestyle and cannot be prevented. Typical causes include a viral/ fungal/ bacterial infection, a chest infection, an auto immune disease or idiopathic (unknown). 

How will you be treating their relative(5)?

Management in myocarditis is supportive, with bed rest, close monitoring and anti inflammatories. The prognosis is usually good. 

However, in prolonged cases, the patient may go on to develop heart failure. If damage is very severe, the patient may require a heart transplant. In such situations, the patient may require psychological support, which can be accessed via GPs or even the British Heart Foundation.

References

  1. Lee H, Paj R, Nazzal S et al (2019). STEMI mimicker in a 26-year-old man. British Medical Journal Case Reports. Published online First: [February 2019]. doi: 10.1136/bcr-2018224894
  2. Murray Longmore and others. Oxford Handbook of Clinical Medicine, 9th edn, (Oxford: Oxford University Press, 2014), p. 146.
  3. Anne Ballinger. Essentials of Kumar and Clark’s Clinical Medicine, 5th edn, (London: Elsevier, 2012), p. 476.
  4. Oh Ici D, Luvard Y, Unterseeh  T et al (2011). Cardiac MRI findings in patients with myocaridits. J Cardiovasc Magn Reson. 13(Suppl 1): 323. Available online at doi: 10.1186/1532-429X-13-S1-P323
  5. Myocarditis Information and Support, British Heart Foundation website [Online]. Available at: https://www.bhf.org.uk/informationsupport/conditions/myocarditis. (Accessed February 2019).