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Acute Rheumatic Fever and rheumatic heart disease. Acute rheumatic fever (ARF). Systemic inflammatory diease Delayed non- suppurative sequalae to URTI with Group A Beta Haemolytic Streptococci Associated with skin infections in Aboriginals Affects heart, skin, joints and CNS
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Acute rheumatic fever (ARF) • Systemic inflammatory diease • Delayed non-suppurativesequalae to URTI with Group A Beta Haemolytic Streptococci • Associated with skin infections in Aboriginals • Affects heart, skin, joints and CNS • First attack most commonly children aged 5-15 years • Notifiable disease in QLD
Epidemiology • Burden of ARF rapidly declined in 20th century – improved living standards and medical care • More common in developing countries • High incidence in Aboriginals • Also higher incidence of ongoing heart disease in Aboriginals • Higher incidence due to: • Overcrowding • Poor sanitation • Poverty • Lack of early treatment
Pathogenesis • 3-5% of population has susceptibility to ARF • Time course: • URTI with Group A Strep • 1-3 week later – Acute rheumatic fever • Autoimmune reaction triggered by molecular mimicry between cell wall M proteins of Strep and cardiac myosin and laminin (CNS) • NOT due to direct infection of the heart or production of a toxin
Pathologic lesions • Fibrinoid degeneration of connective tissue, inflammatory edema, inflammatory cell infiltration & proliferation of specific cells resulting in formation of Ashcoffnodules • These are made up of Anitschkow cells – enlarged macrophages with linear arranged chromatin
Clinical Findings • Pancarditis in the heart • Arthritis in the joints • Ashcoff nodules in the subcutaneous tissue and erythemamarginatum • Basal gangliar lesions resulting in chorea
Carditis • Manifests as pancarditis (any heart tissue affected) • Occurs in 40-50% of cases • Only manifestation of ARF that leaves sequelae and permanent damage to the organ • Acute phase – Valvulitis with vegetation, Aschoff’s nodules and valvular oedema • Chronic phase – Fibrosis, calcification and stenosis of heart valves - RHD • Most common in mitral and aortic valves
Clinical signs of Carditis • Tachycardia • Murmers • Cardiomegaly • Rhythm disturbances (prolonged PR interval) • Pericardial friction rub • Cardiac failure
Arthritis • Occurs in 80% of cases • Painful, fleeting migratory polyarthritis • Affects large joints eg knees, elbows, ankles, wrists • Ceases when acute inflammation disappears
Sydenham’s chorea • Occurs in 10% of cases • Due to hypermetabolic state in basal ganglia • Often occurs months after initial infection • Rapid, irregular movements • Begins in hands and becomes generalised • Clinical findings: • Emotional lability • Fluctuating grip strength • Tongue darting • Facial grimacing • Explosive speech • Tongue clucking • Loss of fine motor skills • General weakness and hypotonia
Subcutatneous nodules • Occurs in 10% of patients (usually not alone) • Painless, pea sized, palpable nodes of inflammatory tissue • Similar to those seen in rheumatoid arthritis • Over extensor surfaces
Erythemamarginatum • Occurs in less than 5% of cases • Pale centre with red irregular margins • Non itchy, on trunk and limbs • Microscopically – neutrophilic and mononuclear infiltration of dermis • Often associated with chronic carditis
Other features • Fever • Athralgia • Malaise • Epistaxis • Pallor • Abdo Pain • Anorexia • Loss of weight
Lab findings • High ESR • High C Reactive Protein (CRP) • Throat swab – Group A Strep Positive • Antistreptolysin O (ASO) titre elevated • AntiDNAse B elevated
Diagnosis – Modified jones criteria Presence of 2 or more major clinical manifestations OROne major manifestation plus two or more minor features
Rheumatic Heart Disease • Results from damage to heart valves caused by an episode or recurrent episodes of ARF • Occurs in about 50% of those affected by ARF with carditis • Secondary prevention of ARF is crucial in the prevention of RHD – Antibiotics • More common in Aboriginals – due to inability to get sufficient medical treatment for ARF and secondary prophylaxis
Valvular lesions in rhd • Mitral valve only in 50-60% of cases • Combined lesions of aortic and mitral valve in 20% of cases • Pure aortic lesions uncommon • Tricuspid involvement in 10% of cases but only in addition to mitral or aortic lesions • Pulmonary valve rarely affected
Mitral Valve lesions in RHD • Mitral Regurgitation • Due to deformity of valve leaflets and thickening, fibrosis and shrinking of chordaetendinae • Causes left atrial dilatation • Mitral Stenosis • Due to valve thickening, cusp fusion, calcium deposition, narrowed valve orifice and progressive imobility of cusps • Causes left atrial hypertrophy and dilatation as well as pulmonary hypertension
Aortic Valve lesions in RHD • Aortic regurgitation • Due to fibrosis of valve leaflets and vegetation in ARF • Causes left ventricular hypertrophy and increased risk of cardiac ischaemia • Aortic Stenosis • Progressive fusion, thickening and calcification of valve • Causes left ventricular hypertrophy and increased risk of cardiac ischaemia