Myocarditis

There are lots of things that cause myocarditis, but we think it's an immunological thing. It affects children and adults. More likely in immuno-compromised patients - who are more likely to get CMV.

- active viral

   * coxsackie virus B - enterovirus

   * parasitic - Chagas' disease is the most common cause. Endemic in Central and South America

- post viral (lymphocytic - or rheumatic fever)

- hypersensitivity

- autoimmune (SLE, polymyositis, scleroderma, sarcoidosis, DM, thyrotoxicosis, IBD)

- infectious

- giant cell myocarditis

- (HIV is normally another infection rather than being causative)

Symptoms- Chest pain, fatigue, dyspnoea & palpitations

- Often with a prodrome of fever, malaise and arthralgia (89%)

- 60% have a fever, 15% have palpitations

- May be with myopericarditis. 

May be quite hard to differentiate from ACS, especially with troponin rises.

Signs

Fever, tachycardia, pericardial rub + signs of failure. 

Investigations

Cardiac biomarkers may be elevated - but only 1/2 of patients had an elevated troponin 

ECG: non-specific ST segment and T wave changes. Sinus tachycardia. ECG changes not normally in single vessel territory. 

CXR: Normal, or features of cardiomegaly 

Echo: Let ventricular dysfunction in 69% of patients

Treatment

Supportive - inotropes if needed

Immunosuppressive therapy has no evidence.

Prognosis

Heart failure, syncope, BBB or reduced ejection fraction on echo all are associated with poor outcome.

References

http://www.rcemlearning.co.uk/references/myocarditis/

http://www.rcemlearning.co.uk/modules/causes-and-management-of-myocarditis/pre-test/

http://lifeinthefastlane.com/ecg-library/myocarditis/

http://socmob.org/2015/01/pericarditis-myocarditis-calgary-em-journal-club/

http://circ.ahajournals.org/content/113/6/876.full

http://pedemmorsels.com/myocarditis

http://thebluntdissection.com/2012/10/01/more-than-man-flu-part2/

http://calgaryguide.ucalgary.ca/slide.aspx?slide=Myocarditis.jpg