35. INFECTIOUS HEART DISEASES: MYOCARDITIS, PERICARDITIS, ENDOCARDITIS

Question 1

Infective endocarditis affects…

Answer 1

Heart valves, parietal endocardium and endothelium of the large vessels

Question 2

Infective endocarditis etiology:

Answer 2

Staphylococcus and streptococcus
mycotic, rickettsae, viral infections

Viridans streptococci are the principal causes in children with congenital heart diseases without previous surgery.

Question 3

Most affected valves in infective endocarditis:

Answer 3

• 80-90% - aortic and mitral valves

Question 4

Endocarditis antibiotic therapy:

Answer 4

Amoxicillin 50mg/kg (up to 2g)
Ampicillin 50mg/kg IV/IM

With penicillin allergy:
Cephalexin 50mg/kg p.o. (up to 2g)
Clindamycin 20mg/kg (up tp 600mg)
Azithromycin/clarithromycin 15mg/kg (up to 500mg)

Question 5

Myocarditis etiology:

Answer 5

Coxsackie type B 1-6
Parvovirus B19
Rickettsiae, fungi, parasites, protozoa
Non-infectious systemic diseases - SLE, RA, scleroderma, Takayasu arteritis, Wegener granulomatosis, RD, Kawasaki

Toxic cardiotropic agents - sulfonamides, cephalosporins, anthracyclines, diuretics
+ cocaine, diphtheria toxin, anoxic agents

Question 6

Myocarditis stages:

Answer 6

ACUTE:
Primary infection and myocardial damage due to viral replication occur
Viral phagocytosis is activated
SUBACUTE:
Cell-mediated autoimmune response through the cytokine system
CHRONIC:
Cardiac remodeling develops
Progresses to dilated cardiomyopathy
Lesions are focal and diffuse
Necrosis of the myocytes and cell infiltrates are seen in the acute phase
Infiltrates only (lymphocytic, eosinophilic and granulomatous) are present in the chronic phase
Inflammation leads to loss of the myocytes and their replacement with fibrous tissue
Causing decrease in myocardial contractility

Answer 7

Recent respiratory infection
Fatigue
Dyspnoea
Chest pain
Myalgia
Syncope
Rhythmic history with palpitations and chest discomfort
Clinical features can often be non-specific

Symptoms of heart failure can develop at an early age:
Tachycardia
Gallop rhythm
Tachypnoea
Sweating
Less often cyanosis
Tachypnoea
Fine crackles
Pulmonary oedema

Soft systolic murmur at the apex due to dilation of the mitral ring and development of mitral insufficiency