Myocarditis Flashcards
What is myocarditis?
Acute inflammation of the myocardium.
It is often associated with pericardial inflammation labelling it myopericarditis.
Causes of myocarditis.
Idiopathic (50%)
Viral - Enteroviruses, adenoviruses, EBV, CMV, influenxa, hepatitis, mumps, rubeola, Coxsackie, polio, HIV, HSV
Bacterial - Stap, strep, clostridia, TB, meningococcus, mycoplasma, brucellosis, psittacosis
Spirochaetes - leptospirosis, syphilis, Lyme disease
Protozoa - Chagas’ (Trypanosoma cruzi), Leishmania, Toxoplasmosis
Drugs - Cyclophosphamide, penicillin, trasuzumab etc…
Toxins - Cocaine, lithium, alcohol, lead, arsenic
Immunological - SLE, Sarcoid, Kawasaki, scleroderma, heart transplant rejection.
Clinical features of acute myocarditis.
ACS-like symptoms
Heart failure symptoms
Palpitations
Tachycardia
Soft heart sounds
Chest pain
Dyspnoea
Pericardial friction rub might be heard
Investigations of acute myocarditis.
ECG
Bloods - CRP, ESR and troponin may be raised
Echo
Cardiac MR
Endomyocardial biopsy - gold standard but only reserved for selected patients
ECG findings in acute myocarditis.
Sinus tachycardia with non-specific ST segments and T wave inversion is the most common presentation.
ST changes and T-wave inversion
Atrial arrhythmias
Transient AV block
QT prolongation
Can also have features of pericarditis such as saddle shaped concave ST elevation and PR depression and refractory ST depression and PR elevation in lead aVR and V1
Management of acute myocarditis.
Supportive
Treat the underlying cause.
Treat any associated arrhythmia and heart failure.
Avoid exercise
Prognosis of acute myocarditis.
50% will recover within 4 weeks on supportive treatment.
12-25% will develop dilated cardiomyopathy and severe heart failure.
DCM can occur years after apparent recovery
What is seen on endomyocardial biopsy in acute myocarditis?
Increased interstitial inflammatory cells.
What is giant cell myocarditis?
On biopsy multinucleated giant cells are seen within the myocardium.
The cause is unknown but is associated with sarcoidosis, thymomas and autoimmune disease.
Poor prognosis and immunosuppression is recommended.
What is Chagas’ disease?
Caused by the protozoon Trypanosoma cruzi.
This is an endemic in South America.
It presents with features of myocarditis, fever and congestive heart failure.
There is progression to dilated cardiomyopathy + heart block and ventricular arrhythmias.
