Acute Rheumatic Fever

Acute Rheumatic Fever

multisystem immunologic disorder that usually follows a strept infection Characterized by inflammatory reactions involving: heart, joints, basal ganglia

Chronic Rheumatic Heart Disease

occurs is first attack of ARF is severe or with recurrent attacks Chronically damaged valves show fishmouth or buttonhole deformity--> mitral and aortic stenosis- CHF

Aschoff Body

the pathognomonic lesion of RF Are reactive histiocytes- Fuse and form Aschoff multinucleated giant cells.

Jones Major Criteria for ARF

1. Migratory asymmetric Polyarthritis 2. Carditis 3. Sydenham's chorea due to involvement of Basal G 4. Subcutaneous nodules 5. Erythema marginatum

Complications of Chronic Rheumatic Heart Disease

Bacterial endocarditis- damaged valves are easily seeded by bacteria Mural thrombi: stasis of blood leads the the formation of thromboemboli- infarcts Congestive hear failure: due to aortic stenosis

Endocarditis

Characterized by inflammation of valve surfaces Leading to development of Sterile verrucoid appearing vegetations (platelet and fibrin clots) along the line of closure of the valve

Erythema marginatum

Circular ring of erythema with central clearing.

Diagnosis of ARF

Clinical history and Two of five major criteria or One Major and two minor criteria

Jones Minor Criteria for ARF

Fever , Arthralgia Leukocytosis, elevated ESR ,C-reactive protein (CRP) and antistreptolysin O (ASO titers). Previous rheumatic fever or rheumatic heart disease

Fibrinous pericarditis

Fibrin deposits on pericardium on visceral and parietal layers "bread and butter appearance" Precordial chest pain with friction rub for clinical diagnosis

Pathogenesis

Immune mediated- follows GAS infection Abs against the M protein cross react with human tissue(heart and joints) --> molecular mimcry

Migratory asymmetric Polyarthritis

MC (~ 75%) initial presentation of ARF Occurs in large joints (Knees) and small joints (wrists, ankles) Joints are tender and swollen- there is no permanent joint damage

What valve is most commonly involved?

Mitral Valve Can cause Mitral valve regurgitation or Aortic valve regurgitation May result in CHF.

What is the most common cause of death in Acute Rheumatic Fever

Myocarditis Myocardium becomes flabby with hypocontraction leading to heart failure

Do the vegetations embolize?

No

Epidemiology

Occurs at 5-15 years of ages Develops 1 - 5 wks after group A beta hemolytic streptococcal pharyngitis or tonsillits relapse may lead to rheumatic heart disease

What layers of the heart are affected?

Pancarditis: involves all 3 layers endocardium (especially valves), myocardium, and epicardium.

Sydenham's chorea

Reversible rapid, involuntary movements affecting all muscles Mainly due to the involvement of Basal Ganglia

What are the primary symptoms of acute rheumatic fever?

The major clinical manifestations of ARF are migratory polyarthritis, carditis, subcutaneous nodules, erythema marginatum, and Sydenham chorea. The attack rate for ARF is approximately 3% following infection with group A beta-hemolytic streptococci.

Subcutaneous nodules

They are painless, firm, movable nodules and are usually located on the extensor surface of joints Fibrinoid necrosis surrounded by histiocytes