Rheumatic fever is caused by group A beta-hemolytic streptococcal (GAS) infection and is an immune-mediated disease that affects multiple body systems. Key points: - It develops 2-4 weeks after a GAS infection, usually pharyngitis. - GAS produces antigens like M protein and toxins like streptolysin O that allow it to evade the immune system initially but can also cause cross-reactivity with human tissues via molecular mimicry. - This cross-reactivity results in an inflammatory response that can affect the heart, joints, brain, and skin.

1. Etiopathogenesis of Rheumatic fever
By Spandana Rallapalli
Pediatrics 1st year PG

2. “Disease of the poverty”
• Agent – Group A Beta hemolyticus Streptococci
Rheumatogenic strains 1,3,5,6,18,29.
• Host – 5-15 years, F=M, Sequelae F>M, Susceptible to
HLA class II.
• Environment- Overcrowded,Developing,Inadequate
hygiene.

3. Conceptual relationship between Streptococci and Rheumatic fever

4. Almost all the cases of rheumatic fever are preceded by
pharyngitis; but not all the cases of pharyngitis succeded by
rheumatic fever(<3%)
Pharyngitis – sublinical or symptomatic.
Average time duration : 3 weeks

6. • M protein – virulent factor - inhibit complement – prevents phagocytosis.
• Antibodies + M protein ( weakest structures ) = destruction of M protein by
macrophages.
• Streptolysin O – Oxygen labile/Antigenic
• Streptolysin S – Oxygen stable/ Non antigenic.
• Streptokinase – Fibrin degradation.
• Pyrogenic exotoxin – Superantigen – B cells – release autoreactive antibodies
– superstimulation of T cells – rekease inflammatory cyokines.
• Anti C5a peptidase,Hyaluronidase,DNAase.
• Cytokines – thalamus - precipitate fever - many patients joints were inflamed
– so this name.

8. Cytotoxic theory
• GAS toxin is involved cytotoxic for
mammalian cardiac cells e.g
streptolysin O, inability to explain the
substantial latent period between
pharyngitis & onset of acute
rheumatic fever.
Immunologic theory
The antigenicity of GAS cellular &
extracellular epitopes & their
immunologic crossreactivity with cardiac
antigenic epitopes- molecular
mimicry.Common epitopes & specific
mammalian tissues
“Licks the joint, bites the heart”

9. Summary
• Rheumatic fever is multisystem , immune mediated , acute inflammation
which is non suppurative, which develops 2-4 weeks after pharygitis by beta-
hemolyticus streptococci lancefied A with rheumatogenic strains.