From the Guidelines
Group A Streptococcus, not Group C or G strep, is the primary cause of rheumatic fever. Rheumatic fever is an inflammatory disease that can develop as a complication of untreated or inadequately treated Group A streptococcal pharyngitis (strep throat) 1. The condition occurs when the body's immune response to the Group A strep infection triggers an autoimmune reaction that can affect multiple organ systems, particularly the heart, joints, skin, and brain. This happens because certain proteins in Group A strep bacteria share similarities with human tissues, causing the immune system to mistakenly attack the body's own tissues.
Key Points to Consider
- While Group C and G streptococci can cause pharyngitis and other infections, they have not been definitively linked to rheumatic fever development 1.
- Prevention of rheumatic fever involves prompt diagnosis and treatment of Group A strep throat infections, typically with antibiotics like penicillin or amoxicillin for 10 days, or a single injection of benzathine penicillin G for those who may not complete the oral regimen 1.
- The American Heart Association recommends penicillin as the treatment of choice for Group A strep pharyngitis, due to its cost-effectiveness, narrow spectrum of activity, and long-standing proven efficacy 1.
Clinical Implications
- Penicillin is the agent of choice for secondary prophylaxis to prevent recurrences of rheumatic fever in individuals who have had a previous attack, with sulfadiazine or a macrolide or azalide as acceptable alternatives in penicillin-allergic individuals 1.
- The recommended duration of prophylaxis depends on the number of previous attacks, the time elapsed since the last attack, the risk of exposure to GAS infections, the age of the patient, and the presence or absence of cardiac involvement 1.
From the Research
Group C or G Streptococcus and Rheumatic Fever
- Group C Streptococcus is a rare cause of rheumatic heart disease, as reported in a case study of a 7-year-old female who presented with abnormal movements and was diagnosed with rheumatic heart disease after laboratory tests revealed elevated antistreptolysin-O and anti-DNAse antibody levels 2.
- There is no direct evidence in the provided studies that Group G Streptococcus causes rheumatic fever.
- In contrast, Group A Streptococcus is a well-established cause of acute rheumatic fever (ARF) and rheumatic heart disease, with studies showing that prior GAS exposures contribute to the pathogenesis of rheumatic fever 3.
- The epidemiology and clinical considerations of Group A Streptococcus, acute rheumatic fever, and rheumatic heart disease highlight the importance of early recognition and management of GAS pharyngitis to prevent ARF and RHD 4.
- Poststreptococcal reactive arthritis (PsRA) is another disease associated with Group A beta hemolytic streptococcal infection, and while there is debate about its relationship to ARF, it is considered a distinct entity with substantial clinical, immunological, and genetic differences 5.