Introduction

Rheumatic fever was a common infectious disease until around the middle of the 20th century, and was a major cause of childhood mortality and rheumatic (structural) heart disease.

In developed countries, the incidence rapidly declined during the second half of the 20th century, however it remains a common and important disease in developing countries and amongst indigenous populations, particularly in Australia, New Zealand, the Pacific Island nations, and to a lesser extent in South America.

  • The decline in incidence is believed to be multifactorial, due to the advent of penicillin, a decline in virulence in the strains of streptococci that cause the infection, and improved living conditions

It is the result of infection with Group-A beta-haemolytic streptococcus (GpA BHS). These infections are typically pharyngitis or tonsillitis, and less commonly scarlet fever or skin infections.

Rheumatic fever typically begins several weeks after the initial infection – which has often resolved by this point. It is thought that antibodies produced to streptococcal proteins begin to react against cardiac and other tissues.

As well as acute rheumatic fever, there is also a recurrent from of the illness – with episodes of fever months or years after the initial infection (thought to be due to re-infection). About 50% of patients will go on to develop rheumatic heart disease in the long term – the risk is higher in those who have recurrent episodes of fever.

It it not only the heart that is affected, but also skin, joints and nervous system.

You should suspect a diagnosis of rheumatic fever in any patient who presents with chorea (neurological signs) or carditis, without another identifiable cause.

Diagnosis is based on the Jones Criteria.

Management aims to control the symptoms of the arthritis, skin manifestations and chorea, but it is the carditis that is the most serious manifestation of rheumatic fever. It can lead to heart failure, and in some cases, can be fatal in the acute phase.

  • Acute rheumatic fever has a mortality of about 1.5% in the developed world.
  • It is usually recommended that patient start on prophylactic antibiotics to prevent a recurrent infection
  • No treatment has been proven to reduce the risk of progression from rheumatic fever to rheumatic heart disease

In the long-term, any patient who has had previous rheumatic fever, is at almost 50% risk of rheumatic heart disease. This typically manifests as mitral value disease, although other valves can be affected.

Epidemiology

  • High incidence in areas of overcrowding and poor access to healthcare
  • Higher incidence in winter
  • Typically affects school age children
    • Median age 10.4
    • Rare before age 3 and after age 21
  • In developed countries, incidence is <1 in 100 000
  • In indigenous populations in Australia, the incidence is about 375 per 100 000
    • 60% of patients will go on to develop heart disease

Aetiology

  • Poverty
  • Overcrowding
  • Family history / genetic factors

Pathology

The exact pathology is not well understood. It is caused by Group A beta-haemolytic streptococci, of which there are many types. Those with the M antigen are most likely to cause Rheumatic Fever.

  • It is thought that the organ damage caused in the disease is actually a result of a type hypersensitivity reaction – the damage is caused by cross-reacting antibodies – and not by the bacteria itself
    • The antibodies for streptoccoal M protein also act against cardiac myosin
  • Heart valves are infiltrated by T cells – which are reacting against cardiac myosin, having been activated against the M antigen
  • It is believed there is also a genetic susceptibility, as there is great variation in disease in those infected with similar strains
  • In acute rheumatic heart disease, the mitral valve is most commonly affected, although often all 4 valves can be affected.

Presentation

  • Symptoms typically occur 1-5 weeks after an infection (e.g. after a sore throat)
    • In recurrent cases, this period is often shorter due to a quicker immune response
  • Symptoms include:
    • Fever
      • Typically for about 1 week
    • Arthritis
      • The pain is often very severe, and if the lower limbs are affected, patients may be unable to walk
      • Usually asymmetrical, polyarthritis
    • Neurological signs of symptoms (30% of patients)
      • Syndenham’s chorea –¬†rapid purposeless movements, especially of the face and upper limbs
      • Tourrette’s syndromes
      • Often cease during sleep
    • Skin signs and symptoms
      • Subcutaenous nodules (10% of patients)
      • Erythema marginatum / erythema annulare
        • Different names for the same rash
        • Rash with macule or paupules of 1-3cm on the trunk and arms
        • Face is spared
    • Cardiac signs and symptoms (40% of patients)
      • Aortic regurgitation –Austin Flint’s murmur
      • Carey Coombs’ sign¬†refers to a characteristic soft diastolic murmur due to mitral valve invovlement
      • Pericardial rub
      • Tachycardia
      • Endocarditis and Myocarditis
      • Signs on echo include:
        • Mitral valve changes in 70% of patients
        • Aortic vale – 25%
        • Tricuspid – 10%
        • Pulmonary – rare

The Jones Criteria

Diagnosis is based on the Jones Criteria. For diagnoses, the following are required:

  • Evidence of recent streptococcal infection
    • e.g. scarlet fever, or a positive throat or wound swab, or serologically confirmed streptococcal infection – e.g. with a raised anti-streptolysin O titre (ASOT) of >200U/ml
  • PLUS two major criteria, OR one major and two minor criteria

Major Criteria

  • Arthritis
  • Sings of carditis (murmur, echo signs)
  • Chorea
  • Subcutaneous nodules
  • Erythema marginatum / annulare

Minor Criteria

  • Fever
  • Raised CRP or ESR
  • Arthralgia
    • Can’t be used in conjunction with arthritis as a major sign
  • Prolonged PR interval
    • Cant be used in conjunction with carditis as a major sign

Even when the diagnostic criteria are not met consider rheumatic fever is any patient with chorea or carditis without an obvious cause. 

Differential Diagnosis

Investigations

Throat swab

  • Frequently performed – but often the acute infection is long gone by the time the diagnosis has become apparent

Blood tests

  • Anti-streptolysin antibody titre (ASOT)
    • Levels >200 suggest a diagnosis of rheumatic fever
  • anti-DNase B
  • Antibody levels usually rise for the first month of the illness and remain stable for the following 3-6 months

ECG

  • Prolonged PR interval

CXR

Echocardiography

  • To detect signs of carditis
  • Can result in earlier diagnosis – signs of carditis may be apparent on echo before the other symptoms develop

Management

Aims

  • Treat any streptococcal infection that is still present
  • Reduced inflammation related to the immune response
  • Treat complications – especially carditis
    • Neurological, arthritic, and skin symptoms are often self-limiting. The cardiac complications can be life-threatening

Treating infection

  • Penicillin is the treatment of choice against streptococcus
    • Guidelines vary. Both oral and intramuscular preparations are recommended. Intramuscular injections are slow-releasing and long-acting and prevent issues related to compliance with an oral regimen
    • Cephalosporins or erythromycin are suitable alternatives in penicillin allergy

Treating complications

  • Aspirin¬†or other NSAIDs are effective for arthritis
    • High doses are often required
    • Not proven to reduce carditis (but theoretically could)
  • Cardiac complications
    • Treat heart failure as you would for any other patient – e.g. with ACE inhibitors, digoxin, and diuretics if required
    • Mitral valve replace may be required
  • Neruological complications
    • Chorea is typically self-limiting. Diazepam can reduce symptoms in the short term

Prognosis

  • 80% of patients will recover from an acute episode of rheumatic fever within 12 weeks
  • Recurrent episode of rheumatic fever can occur – usually, but not always associated with re-infection with streptococcus
    • If these episodes do occur, it is usually within 5 years of the original diagnosis
  • Rheumatic heart disease occurs in up to 45% of patients in the long-term
    • Patients need life-long cardiology follow-up
  • Recurrent episodes can be triggered by repeat streptococcal infection, pregnancy, or use of the COC pill

Prophylaxis

  • Secondary prophylaxis (long-term antibiotic use) is recommended for all patients
  • Should be continued for a minimum of 5 years, or until the age of 21 – whichever is longest
  • Recommended 10 years for patients with carditis
  • In patients with severe valvular disease, life-long prophylaxis may be recommended

Flashcard

References

  • Rheumatic fever - patient.info
  • Rheumatic fever - BMJ Best Practice
  • Murtagh‚Äôs General Practice. 6th Ed. (2015) John Murtagh, Jill Rosenblatt
  • Oxford Handbook of General Practice. 3rd Ed. (2010) Simon, C., Everitt, H., van Drop, F.

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