ARF and Rheumatic Heart Disease

Question 1

Acute rheumatic fever

Answer 1

Autoimmune consequence of infection with group A strep (beta hemolytic streptococcal pharyngitis)
Generalised inflammatory response
Vague clinical picture
Hard to Dx

Question 2

ARF epidemiology

Answer 2

Affects children and adolescent 5-15 years
Affects poverty stricken and overcrowded areas
Only strep pharyngitis can reactivate another ARF attack

Question 3

Clinical manifestations of ARF

Answer 3

Affects heart/joints/subQT tissue/bones
Pancarditis/SubQT nodules/skin erythema
Pain from frictions rub of parietal and visceral pericardium
Migratory polyarthritis of large joints
Sydenham chorea (neurological alteration at basal ganglia and results in purposeless motor activity)

Question 4

Rheumatic heart disease

Answer 4

Permanent HV damage(fibrosis/stenosis) due to repeated ARF attacks
40-60% of people who experience ARF develop RHD

Question 5

Pathophysiology RHD

Answer 5

Type 2 HS reaction
Group A strep Ag is M protein (same as cardiac self Ag > molecular mimicry)
AB and CD4 TL directed against Ag
AB interact with cardiac tissue and strep primed CD4 TL infiltrate
Autoimmune reaction and complement activation
Release of IFN and TNF/Mac and N recruitment
AB and TL mediated cardiac damage
Increased damage at HV due to scarce IL-4 producing cells

Question 6

RHD genetics

Answer 6

Progression from ARF to RHD is ass. To HLA-DR2 allele and alterations in TNF and MBL-2 genes

Question 7

Morphology acute ARF/RHD

Answer 7

Diffuse inflammation all 3 layers - Pancarditis (endo/myo/periC)
Pancarditis doesn’t usually alter heart function but can lead to restrictive pericarditis
Aschoff bodies present in all 3 layers
Aschoff bodies have a TL foci and Anitschow cells (activated Mac)
Anitschow cells have a wavy pattern of chromatin condensation/abundant cytoplasm/PC/round or ovoid central nuclei)

Question 8

Morphology of valves ARF/RHD

Answer 8

Usually mitral valve affected (25% aortic valve)
Fibrinoid necrosis within cusps/leaflets/tendinous cords
Small vegetations overlying necrotic foci
Subendocardial lesions lead to LA McCallum plaques

Question 9

Morphology chronic ARF/RHD

Answer 9

Leaflet/tendinous cord thickening and fusion
Commissural fissure and thickening
Results of residual and progressive valve damage (>1 ARF attack)

Question 10

Late morphology (post 2-10 years)

Answer 10

Fusion of valve apparatus (commissures/cusps/cordinal attachment)
Leads to stenosis/insufficiency of valve

Question 11

Mitral stenosis as a result of multiple ARF attacks/chronic RHD

Answer 11

Leads to LA dilation/mural thrombi embolisation/congestion/alterations in pulm vasculature and parenchyma therefore RV hypertrophy