Rheumatic Fever

Overview

Rheumatic fever is an autoimmune disease that may happen following a throat infection with group A Streptococcus i.e. Streptococcus pyogenes. It is thought to be the result of molecular mimicry. This is where the antigens presented on the bacterium are mistaken to be the same as antigens on the human host tissue.

The disease can affect joints, skin, the heart, and the nervous system. It can lead to mitral stenosis and congestive heart failure.

Epidemiology

• Incidence is lower in developed countries, but higher in developing countries
• Incidence is highest in school-aged children aged 5-14 years 

Risk Factors

• Younger age
• Poverty
• Overcrowding in living conditions
• Family history

Diagnosis

Jones Criteria

Symptoms usually appear between 1-5 weeks after a sore throat with an average of 3 weeks. The Jones Criteria are used to diagnose rheumatic fever. Diagnosis can be made if there is:

• Evidence of recent streptococcal infection and two major criteria or
• Evidence of recent streptococcal infection and one major and two minor criteria

Major criteria

• Arthritis:
  • Often extreme and if it affects the lower limb, patients often cannot walk
  • Most commonly affected joints: knees, ankles, hips, wrists, elbows
  • Usually asymmetrical and can be migratory
  • Usually one joint is hot and painful while another is improving
• Carditis – inflammation of the pericardium, myocardium, and endocardium
  • This manifests as chest pain
  • Tachycardia out of proportion with the fever is seen
  • A pericardial rub may be heard
  • There may be palpitations
  • A murmur may be heard, this is often mitral regurgitation and is pan-systolic loudest at the apex radiating to the axilla
• Chorea – also known as Sydenham’s chorea
  • More common in females and can happen up to 6 months after the preceding throat infection
  • Rapid and purposeless movements, usually in the face and upper extremities
  • Always disappears in sleep and is more pronounced with movement
• Erythema marginatum
  • Pale-red macules or papules on the trunk and proximal limbs
  • Never seen on the face
• Subcutaneous nodules
  • Usually seen on extensor surfaces of the elbows, knees, ankles, scalp, and spinous processes of the lumbar and thoracic vertebrae
  • Firm and painless

Minor criteria

• Fever ≥38.0°C
• Monoarthralgia
• Elevated inflammatory markers i.e. elevated ESR/CRP
• Prolonged PR interval on an ECG

Some patients may only have chorea alone.

Differential Diagnoses

Infective endocarditis

• Patients usually have signs of sepsis
• They may have Janeway lesions, Osler nodes, and splinter haemorrhages, and these are less common in children
• Blood cultures are positive
• Echocardiography may show vegetations

Juvenile idiopathic arthritis

• Joint involvement persists for many weeks
• They may not have joint pain
• Eye inflammation may be present
• Autoantibodies may be present e.g. positive rheumatoid factor (RF), anti-nuclear antibody (ANA), anti-dsDNA, and anti-cyclic citrullinated peptide (anti-CCP)
• If systemic juvenile idiopathic arthritis, there may be a light pink rash 

Septic arthritis

• Usually one joint involved
• Arthritis is not migratory
• Patient looks septic

Lyme disease

• Erythema migrans present at the tick bite site
• Later in the disease, patients have flu-like symptoms
• Acute neurological symptoms present such as cranial nerve palsies
• Arthritis usually affects the knees
• Patients may have heart block

Systemic lupus erythematosus

• Patients may have a malar “butterfly” rash on their face
• Renal dysfunction may be present
• Autoantibodies may be present e.g. ANA, anti-dsDNA, anti-Smith

Investigations

All patients

• Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP):
  • Usually raised
• Full blood count (FBC):
  • May have elevated white cells
• Blood cultures:
  • To rule out sepsis or infective endocarditis
• ECG:
  • May show PR prolongation which is an acute criterion
• Chest x-ray:
  • May show cardiomegaly and congestive cardiac failure
• Echocardiogram:
  • May show valvular dysfunction e.g. mitral regurgitation
• Throat swab and culture:
  • May show group A Streptococci e.g. Streptococcus pyogenes
  • Provides evidence of a streptococcal infection
• Throat swab and rapid antigen test for group A Streptococci
  • Provides evidence of a streptococcal infection
• Anti-streptococcal serology – anti-streptolysin:
  • May be positive
  • Provides evidence of a streptococcal infection
• Throat swab and polymerase chain reaction (PCR):
  • May be positive
  • Provides evidence of a streptococcal infection

Diagnosis

Jones Criteria

Diagnosis is based on the Jones criteria (mentioned in presentation). Diagnosis can be made if there is:

• Evidence of recent streptococcal infection and two major criteria or
• Evidence of recent streptococcal infection and one major and two minor criteria

Management

Possible or suspected rheumatic fever

• 1^st line: IM benzathine benzylpenicillin secondary prophylaxis
  • Use erythromycin if penicillin-allergic
• Arthralgia:
  • NSAIDs are avoided for joint pain as they can mask the symptoms. Options for analgesia are:
    • Paracetamol
    • Codeine phosphate

Confirmed rheumatic fever

• 1^st line: IM benzathine benzylpenicillin or oral phenoxymethylpenicillin (penicillin V)
  • If allergic then give erythromycin
• If arthritis present:
  • NSAIDs: ibuprofen or naproxen
• If heart failure develops:
  • Treat with standard heart failure treatment

Monitoring

• Most patients respond well to treatment and can be discharged within 2 weeks
• Patients with significant carditis need longer admissions and are often monitored with echocardiography, ECGs, and chest X-rays
• CRP and ESR should be measured weekly then 1-2 weekly until they stabilise
• All patients who have had carditis should be reviewed by their GP every 6 months and with a cardiologist with echocardiography for 1-2 years

Patient Advice

• Patients should be educated regarding the risk of rheumatic fever affecting their heart. If the first episode doesn’t affect their heart, this doesn’t guarantee future episodes won’t affect the heart.
• Patients should be reminded of the importance of good dental hygiene to avoid infective endocarditis.
• Patients should be safety-netted on seeking help when they have sore throats and be treated promptly to avoid rheumatic fever.

Complications

• Carditis
• Mitral stenosis
• Congestive heart failure

Prognosis

• Rheumatic heart disease occurs in 30-45% of patients with acute rheumatic fever
• Chorea can sometimes continue in a remitting fashion for years