Myocarditis (CV)

Question 1

Define myocarditis.

Answer 1

Inflammation of the myocardium in the absence of the predominant acute or chronic ischaemia characteristic of coronary artery disease

(Non-ischaemic myocardial inflammation resulting from a heterogeneous group of infectious, immune and non-immune diseases)

Question 2

What is myocarditis characterised by histopathologically?

Answer 2

Inflammatory cellular infiltrate with or without evidence of myocyte injury

Question 3

What % of sudden deaths in young adults does myocarditis make up?

Answer 3

10%

Question 4

What is the average age of patients who get myocarditis?

Answer 4

40

Question 5

What are the causes of myocarditis? (6 + 4)

Answer 5

• idiopathic - most common
• viral - Coxsackie B, parvovirus, influenza A&B, adenovirus, EBV, CMV
• bacterial - mycobacterial, streptococcal
• fungal
• parasitic
• non-infectious:
  
  • connective tissue diseases e.g. SLE, sarcoidosis
  • toxic myocarditis - cocaine, toxins, medication, alcohol
  • autoimmune
  • drugs - chemo agents, penicillin, chloramphenicol

Question 6

Who is myocarditis more common in?

Answer 6

Can affect all age groups (mainly around 40y), with an apparent slightly higher incidence in males than females, and equal incidence in black people and white people

Question 7

What might myocarditis lead to?

Answer 7

Death

Question 8

What does the prognosis of myocarditis relate to?

Answer 8

Variable prognosis, related to presentation and underlying aetiology:

• viral myocarditis - asymptomatic, spontaneously resolve
• mild-mod HF - tends to improve but may progress to chronic severe HF
• fulminant, acutely decompensated HF - usually recover back to baseline function (if death is prevented through management in acute phase)

Question 9

What are the clinical features of myocarditis? (6)

Answer 9

• prodromal flu-like/viral syndrome - fever, malaise, myalgia, lethargy, URTI symptoms 2-3 weeks before initial presentation
• usually young (<50) with acute Hx (recent flu-like illness)
• dyspnoea/SOB (due to pericardial effusion, myocardial dysfunction)
• chest pain (indicates perimyocarditis)
• palpitations (cardiac arrhythmias)
• dyspnoea, orthopnoea, fatigue

Question 10

What might you see on examination in myocarditis? (5)

Answer 10

• rales
• tachycardia
• elevated neck veins
• soft S1, S3 gallop, S4 gallop
• signs of complications - HF, arrhythmia

Question 11

What can help differentiate pericarditis from myocarditis?

Answer 11

Acute pulmonary oedema in myocarditis

Question 12

What are the risk factors for myocarditis? (5)

Answer 12

• infection (non-HIV)
• HIV infection
• autoimmune/immune-mediated diseases
• peripartum and postnatal periods
• drugs and toxins

Question 13

What are the 1st-line investigations for myocarditis? (5)

Answer 13

• 12-lead ECG
• CXR
• cardiac enzymes - serum CK, serum CK-MB, serum troponin
• bloods
• endomyocardial biopsy

Question 14

What might you see on ECG in myocarditis? (3 + pericarditis)

Answer 14

• non-specific ST-segment and T-wave abnormalities:
  
  • ST elevation
  • T wave inversion
• tachycardia
• arrhythmias (atrial)
• PERICARDITIS: widespread saddle-shaped ST elevation

Question 15

What might you see on CXR in myocarditis? (3)

Answer 15

• cardiomegaly
• pleural effusions
• bilateral pulmonary infiltrates due to CHF - pulmonary oedema

Question 16

What would you see on bloods in myocarditis? (3)

Answer 16

• increased cardiac enzymes (troponin, CK)
• increased ESR
• increased BNP

Question 17

What are some differential diagnoses for myocarditis? (4)

Answer 17

• ACS - atherosclerosis
• dilated cardiomyopathy - Fx, overlap
• pericarditis
• stress-induced cardiomyopathy - acute emotional/physical stressor, rapid recovery within 4-8wk

Question 18

How do we differentiate pericarditis from myocarditis? (5)

Answer 18

• present similarly and can co-exist
• also presents with viral symptoms
• isolated pericarditis would not cause signs and symptoms of LV dysfunction
• troponin less likely to be raised
• global concave (saddle) ST elevation on ECG rather than focal changes seen in myocarditis

Question 19

Which people should myocarditis be a differential in?

Answer 19

Young people with new onset chest pain with a recent history of viral illness

Question 19

What does management of myocarditis involve? (2)

Answer 19

• supportive treatment (e.g. of HF or arrhythmias):
  
  • cardiac monitoring
  • O2 administration
  • analgesics
• treatment of underlying cause:
  
  • Abx for bacterial myocarditis
  • antimycotics for fungal myocarditis

Question 20

What is the first-line treatment for haemodynamically stable myocarditis?

Answer 20

Supportive care + treatment of underlying cause

Question 21

What is the first-line treatment for haemodynamically stable myocarditis with LV systolic dysfunction?

Answer 21

• ACEi/ARB + SGLT2 inhibitor
• treat underlying cause
• consider IV immunoglobulin
• consider beta-blocker
• consider vasodilator/inotrope
• consider diuretics
• consider aldosterone antagonist
• consider long-term anticoagulation therapy

Question 22

What is the first-line treatment for haemodynamically unstable myocarditis? (4)

Answer 22

• 1st line: arterial vasodilator (nitroprusside) + invasive haemodynamic monitoring
• IV GTN (glyceryl trinitrate)
• IV inotrope/vasopressor
• IV immunoglobulin

Question 23

What is the first-line treatment for refractory cardiogenic shock - myocarditis? (4)

Answer 23

• intra-aortic balloon pump
• LVAD
• ECMO
• CPR (paediatric)

Question 24

What is the 1st&2nd-line treatment for end-stage heart failure/refractory life-threatening arrhythmias from myocarditis?

Answer 24

• 1st line: heart transplantation
• 2nd line: LVAD + anticoagulation

Question 25

What are some complications of myocarditis? (5)

Answer 25

• congestive heart failure (treated with diuretics + beta-blockers)
• arrhythmias (possibly leading to sudden death)
• dilated cardiomyopathy (late complication)
• pericarditis –> cardiac tamponade
• multisystem organ failure + death