Rheumatic Fever

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Basics

Description

  • Acute rheumatic fever (ARF) is an autoimmune, inflammatory response to pharyngeal infection with group A Streptococcus (GAS) that affects multiple organ systems.
  • Can lead to rheumatic heart disease (RHD) if not treated in the acute phase
  • Largely, a disease of poverty and has disappeared from many affluent parts of the world
  • Recurrence in adults and children is common without adequate antibiotic treatment.
  • Organ systems affected include cardiovascular, nervous, hematologic, immunologic, lymphatic, skin/exocrine, and musculoskeletal.

Pediatric Considerations
Most cases occur in children ages 5 to 15 years; rare in children <5 years (1)

Epidemiology

  • ARF and RHD are largely restricted to low-income countries and marginalized sections of society in wealthy countries.
  • Male = female, but females more likely to develop chorea and RHD.
  • Endemic regions include South Pacific, indigenous populations of Australia and New Zealand, Africa, Asia.

Incidence
  • Worldwide, incidence has been declining for 25 years, attributed to increasing antibiotic use and improved living conditions. The large majority of new cases are in developing countries.
  • Mean worldwide incidence ranges from 8 to 51/100,000 school-aged children (1); 500,000 new cases of ARF occur annually (2).
  • Incidence of ARF in the United States is currently <2/100,000 school-aged children.
  • It is estimated that up to 3% episodes of untreated acute GAS pharyngitis go on to develop ARF (1).
Prevalence
  • In developing areas of the world, RHD is estimated to affect >33 million people and is the leading cause of cardiovascular death during the first 5 decades of life.
  • Prevalence has been rising due to improved medical care and longer survival (despite decreasing incidence of ARF).

Etiology and Pathophysiology

  • ARF is preceded 2 to 3 weeks by GAS (Streptococcus pyogenes) tonsillopharyngitis, a gram-positive bacterial infection.
  • Pathogenic mechanism is not completely understood.
  • Molecular mimicry plays an important role: The GAS M protein and the carbohydrate antigen (N-acetyl-β-D-glucosamine) share antigenic epitopes with human cardiac tissue and neuronal cells in the basal ganglia (1). These antigens cross-react with cardiac and vessel endothelial proteins, leading to an inflammatory cascade.
  • Joint involvement is a likely result of immune complex accumulation.

Genetics
  • Susceptibility is associated with certain genetic polymorphisms of genes involved in the innate and adaptive immune pathways; not fully understood
  • ARF appears to be a heritable and susceptibility is most likely polygenic with variable and incomplete penetrance.
  • Increased susceptibility in certain populations, including indigenous Australians, New Zealand Maori, and Pacific Islanders

Risk Factors

  • Poverty, household crowding, and social disadvantage are the strongest risk factors.
  • Genetic susceptibility and ethnic predisposition possibly increase risk.

General Prevention

  • Primary prevention: Antibiotics are effective at reducing incidence of ARF after known or suspected GAS pharyngitis. Appropriate treatment of streptococcal pharyngitis prevents ARF in most cases (3).
  • Secondary prevention: long-term antibiotic prophylaxis (up to 5 to 10 years) to prevent recurrence, which can lead to RHD

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Basics

Description

  • Acute rheumatic fever (ARF) is an autoimmune, inflammatory response to pharyngeal infection with group A Streptococcus (GAS) that affects multiple organ systems.
  • Can lead to rheumatic heart disease (RHD) if not treated in the acute phase
  • Largely, a disease of poverty and has disappeared from many affluent parts of the world
  • Recurrence in adults and children is common without adequate antibiotic treatment.
  • Organ systems affected include cardiovascular, nervous, hematologic, immunologic, lymphatic, skin/exocrine, and musculoskeletal.

Pediatric Considerations
Most cases occur in children ages 5 to 15 years; rare in children <5 years (1)

Epidemiology

  • ARF and RHD are largely restricted to low-income countries and marginalized sections of society in wealthy countries.
  • Male = female, but females more likely to develop chorea and RHD.
  • Endemic regions include South Pacific, indigenous populations of Australia and New Zealand, Africa, Asia.

Incidence
  • Worldwide, incidence has been declining for 25 years, attributed to increasing antibiotic use and improved living conditions. The large majority of new cases are in developing countries.
  • Mean worldwide incidence ranges from 8 to 51/100,000 school-aged children (1); 500,000 new cases of ARF occur annually (2).
  • Incidence of ARF in the United States is currently <2/100,000 school-aged children.
  • It is estimated that up to 3% episodes of untreated acute GAS pharyngitis go on to develop ARF (1).
Prevalence
  • In developing areas of the world, RHD is estimated to affect >33 million people and is the leading cause of cardiovascular death during the first 5 decades of life.
  • Prevalence has been rising due to improved medical care and longer survival (despite decreasing incidence of ARF).

Etiology and Pathophysiology

  • ARF is preceded 2 to 3 weeks by GAS (Streptococcus pyogenes) tonsillopharyngitis, a gram-positive bacterial infection.
  • Pathogenic mechanism is not completely understood.
  • Molecular mimicry plays an important role: The GAS M protein and the carbohydrate antigen (N-acetyl-β-D-glucosamine) share antigenic epitopes with human cardiac tissue and neuronal cells in the basal ganglia (1). These antigens cross-react with cardiac and vessel endothelial proteins, leading to an inflammatory cascade.
  • Joint involvement is a likely result of immune complex accumulation.

Genetics
  • Susceptibility is associated with certain genetic polymorphisms of genes involved in the innate and adaptive immune pathways; not fully understood
  • ARF appears to be a heritable and susceptibility is most likely polygenic with variable and incomplete penetrance.
  • Increased susceptibility in certain populations, including indigenous Australians, New Zealand Maori, and Pacific Islanders

Risk Factors

  • Poverty, household crowding, and social disadvantage are the strongest risk factors.
  • Genetic susceptibility and ethnic predisposition possibly increase risk.

General Prevention

  • Primary prevention: Antibiotics are effective at reducing incidence of ARF after known or suspected GAS pharyngitis. Appropriate treatment of streptococcal pharyngitis prevents ARF in most cases (3).
  • Secondary prevention: long-term antibiotic prophylaxis (up to 5 to 10 years) to prevent recurrence, which can lead to RHD

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