Rheumatic fever


Definition

Rheumatic fever is an inflammatory disease which occur due to delayed sequel to pharyngeal infection with group A streptococci.
It primarily involves the heart ,joints , central nervous system,skin and subcutaneous tissues.


Aetiology

Rheumatic fever follows an antecedent pharyngeal infection with group A beta -hemolytic streptococcus.
The various serotypes of group A streptococci vary in their rheumatogenic potential.the type 5 commonly causes rheumatic fever.

Pathogenesis

Streptococcus - induced autoimmunity is the cause for rheumatic fever.Several streptococcal antigens cause cross-reactivity with cardiac and other tissues.

Epidemiology

Rheumatic fever is a worldwide disease.It is a major cause of death and disability in children and adolescents in socioeconomically areas.
It is most prevalent in areas of poor economic conditions,overcrowding and substandard housing.All of these factors in general reflect the frequency and severity of streptococcal pharnyngitis.
Rheumatic fever is common to see multiple cases among the siblings and the others in the same family.

Clinical features
  • Sorethroat
  • Polyarthritis
    • Arhthritis is the most common manifestation of rheumatic fever and is present in nearly 75% of case.
    • Classical presentation is acute migratory polyarthritis with features of febrile illness
    • Most commonly involve joints are large joint of the extremities
  • Carditis
    • Features of carditis develop early within 3 weeks of onset and occur in 40-50% cases
    • It is more common in younger children and maybe asymptomatic and picked up on ECG only.
  • Subcutaneous nodules
    • Are usually associated with severe carditis and tend to occur after several weeks of onset
    • It is a small, pea-sized, painless nodules over bony prominents
    • Common sites: extensor tendons of hands and feets, elbows, margins of patella, scalp, occiput, over scapulae and over spinous processus of vertebrae
    • Usually persist for 1-2 weeks
  • Erythema marginatum
    • Occurs nearly 10% cases of acute rheumatic fever
    • Erythematous pink rashes with a clear center and round or serpiginous margins.
    • These rashes are transient, migrating from place to place, non-pruritic, non indurated and blanch on pressure
    • Most commonly seen on trunk and proximal parts of extremities, but never ofn face.
  • Sydenham’s Chorea
    • Appears after a long latent period (upto 6 months) after the initial streptococcal infection
    • Occurs in nearly 15% of 1st attacks of ARF and is most common between the ages of 7-14 years. Rare after puberty.
    • Characterized by: sudden, aimless, irregular movements associated with muscle weakness, emotional instability, obsessions and compulsions, tics and psychotic features.
    • Pure chorea is the term used when there is no previous rheumatic manisfestations are noted.
  • Fever
  • Arthralgia
  • Abdominal pain
  • Epistaxis
Diagnosis of ARF

Major manifestations


Minor manifestations

  • Carditis
  • Fever
  • Polyarthritis
  • Arthralgia
  • Chorea
  • Previous RF or RHD
  • Erythema marginatum
  • Raised ESR
  • Subcutaneous nodules
  • Positive CRP
  • Prolonged PR interval;
two major manifestation or one major and two minor manifestations indicate a high probability, with one supporting evidence of preceeding streptococcal infection, eg:
  1. recent scarlet fever
  2. positive throat culture for group A strepcoccus
  3. increased streptococcal antibodies
investigations
    • Isolation of group A streptococci
    • Streptococcal antibody tests (serology test)
      • ASO
      • Anti DNase B
      • Antihyaluronidase
      • Antistreptozyme test
    • Acute phase reactants
      • ESR raised
      • CRP in blood
    • Other tests
      • Polymorphonuclear leucocytosis
      • Increased serum complements
      • Increase in serum mucoproteins, alpha and gamma globulin levels
      • Anaemia due to suppression of erythropoiesis
    • Electrocardiogram
      • Prolonged PR interval
    • chest xray
      • cardiomegaly
      • pulmonary congestion
    • echocardiography can detect:
      • myocardial dysfunction
      • valvular dysfunction
      • pericardial effusion
Management
  1. bed rest
  2. anti streptococcal therapy
  3. salicylates
  4. corticosteroids
  5. supportive therapy like treatmment of CCF, valvular lesions, heart blocks, and chorea