U01.07.051 Rheumatic fever

Rheumatic fever is a consequence of pharyngeal infection caused by group A β-hemolytic streptococci. This condition primarily affects children and can lead to long-term complications such as rheumatic heart disease, which commonly impacts heart valves.

Pathophysiology of Rheumatic Fever

Late Sequelae: Rheumatic fever can lead to chronic heart valve damage, with the mitral valve most frequently affected, followed by the aortic and tricuspid valves. High-pressure valves, such as the mitral and aortic valves, are more vulnerable.
Early Lesion: The early lesion often presents as mitral valve regurgitation.
Late Lesion: Over time, mitral stenosis may develop.

Key Pathological Features

Aschoff bodies: These are granulomas with giant cells, observed in the affected tissues (highlighted by blue arrows in the image).
Anitschkow cells: Enlarged macrophages with ovoid, wavy, rod-like nuclei (highlighted by red arrows in the image).

Immunological Mechanism

Rheumatic fever is an immune-mediated disorder (type II hypersensitivity) rather than a direct bacterial effect. The condition is believed to occur due to molecular mimicry, where antibodies against the M protein of Streptococcus pyogenes cross-react with self-antigens, particularly myosin.

Diagnostic Markers

Anti-streptolysin O (ASO) titers
Anti-DNase B titers

Clinical Presentation: The J♥NES Criteria

The diagnosis of rheumatic fever is based on the J♥NES criteria, which include both major and minor manifestations:

Major Criteria	Description
J – Joint (Migratory polyarthritis)	Migratory arthritis affecting large joints.
♥ – Carditis	Inflammation of the heart, often leading to valve damage.
Nodules – Subcutaneous nodules	Painless, firm lumps typically located over bony prominences.
Erythema marginatum	An evanescent, ring-like rash with raised margins, seen in the trunk and limbs.
Sydenham chorea	Involuntary, jerky movements, particularly of the face and extremities.

Treatment and Prophylaxis

The treatment and prevention of rheumatic fever involves penicillin to eradicate any residual Streptococcus pyogenes infection and prevent recurrence. Long-term prophylaxis may be necessary to prevent reinfection and further cardiac complications.

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