Pathophysiology of Rheumatic Fever

Rheumatic fever is an inflammatory disease that arises as a post-infectious immune response to Streptococcus pyogenes (Group A Streptococcus) infection. It primarily affects the heart, joints, central nervous system, and skin.

Etiology

The disease develops following an untreated or inadequately treated streptococcal throat infection. The body produces antibodies against the bacterial M protein, which mistakenly cross-react with host tissues.

Pathophysiology

The molecular mimicry between bacterial antigens and human tissues leads to an autoimmune reaction. This results in inflammatory damage across multiple organ systems:

• Heart: Causes pancarditis, primarily affecting heart valves with resultant chronic rheumatic heart disease.
• Joints: Leads to polyarthritis, particularly affecting large joints.
• CNS: Triggers Sydenham's chorea, characterized by involuntary movements.
• Skin: Produces erythema marginatum and subcutaneous nodules.

Clinical Features

Symptoms typically appear within weeks after streptococcal infection, including fever, joint pain, carditis, and neurological abnormalities.

Diagnostic Criteria

The Jones criteria help establish a diagnosis, requiring evidence of previous streptococcal infection along with major and minor clinical manifestations.

Complications

Long-term complications include chronic valvular heart disease, heart failure, and persistent neurological dysfunction.

Prevention & Management

Timely treatment of streptococcal infections with antibiotics reduces the risk of rheumatic fever. Patients diagnosed with rheumatic heart disease may require lifelong prophylaxis and surgical interventions for valve repair.