Rheumatic fever

Question 1

What is acute rheumatic fever?

Answer 1

Acute rheumatic fever is an autoimmune condition triggered by streptococcus bacteria. It is caused by antibodies created against the streptococcus bacteria that also target tissues in the body.

It is a multi-system disorder that affects the joints, heart, skin and nervous system. It is rare in the UK due to early treatment of streptococcus with antibiotics.

Question 2

Pathophysiology of rheumatic fever?

Answer 2

Rheumatic fever is caused by group A beta-haemolytic streptococcal, typically streptococcus pyogenes causing tonsillitis. The immune system creates antibodies to fight the infection. These antibodies not only target the bacteria, but also match antigens on the cells of the person’s body, for example the muscle cells in the myocardium in the heart.

This results in a type 2 hypersensitivity reaction, where the immune system begins attacking cells throughout the body. This process is usually delayed 2 – 4 weeks after the initial infection.

Question 3

Presentation of rheumatic fever?

Answer 3

The typical presentation of rheumatic fever occurs 2 – 4 weeks following a streptococcal infection, such as tonsillitis. Symptoms affect multiple systems, causing:

Fever
Joint pain
Rash
Shortness of breath
Chorea
Nodules

Joint involvement:

Rheumatic fever causes a migratory arthritis affecting the large joints, with hot, swollen, painful joints. It is migratory because different joints become inflamed and improve at different times, giving the appearance that the arthritis is moving from one joint to the next.

Heart involvement:

Carditis, or inflammation throughout the heart, with pericarditis, myocarditis and endocarditis, leads to:

Tachycardia or bradycardia
Murmurs from valvular heart disease, typically mitral valve disease
Pericardial rub on auscultation
Heart failure

Skin involvement:

There are two key skin findings with rheumatic fever:

Subcutaneous nodules
Erythema marginatum rash
Firm painless nodules occur over extensor surfaces of joints, such as the elbows. The erythema marginatum rash involves pink rings of varying sizes affecting the torso and proximal limbs.

Nervous system involvement:

Chorea is the key nervous system symptom. This involves irregular, uncontrolled and rapid movements of the limbs. This is also known as Sydenham chorea and historically as St Vitus’ Dance.

Question 4

Assessment rheumatic fever?

Answer 4

Investigations that can help support the diagnosis include:

Throat swab for bacterial culture
ASO antibody titres
Echocardiogram, ECG and chest xray can assess the heart involvement

A diagnosis of rheumatic fever is made using the Jones criteria (see below).

Question 5

ASO titres?

Answer 5

Anti-streptococcal antibodies (ASO) are antibodies against streptococcus. They indicate a recent streptococcus infection and can be helpful in supporting a diagnosis of rheumatic fever. After an acute infection the levels usually:

Rise over 2 – 4 weeks
Peak around 3 – 6 weeks
Gradually falls over 3 – 12 months

ASO levels are usually repeated after 2 weeks to:

Confirm a negative test
Assess whether levels are rising or falling

Question 6

Jones criteria for diagnosis?

Answer 6

A diagnosis of rheumatic fever can be made when there is evidence of recent streptococcal infection, plus:

Two major criteria OR
One major criteria plus two minor criteria
The mnemonic for the Jones criteria is JONES – FEAR.

Major Criteria:

J – Joint arthritis
O – Organ inflammation, such as carditis
N – Nodules
E – Erythema marginatum rash
S – Sydenham chorea

Minor Criteria:

Fever
ECG Changes (prolonged PR interval) without carditis
Arthralgia without arthritis
Raised inflammatory markers (CRP and ESR)

Question 7

Management rheumatic fever?

Answer 7

Treatment of streptococcal infections with antibiotics helps prevent the development of rheumatic fever. Tonsillitis caused by streptococcus should be treated with phenoxymethylpenicillin (penicillin V) for 10 days.

Patients with clinical features of rheumatic fever should be referred immediately for specialist management. Management involves medications and follow up:

NSAIDs (e.g. ibuprofen) are helpful for treating joint pain
Aspirin and steroids are used to treat carditis
Prophylactic antibiotics (oral or intramuscular penicillin) are used to prevent further streptococcal infections and recurrence of the rheumatic fever. These are continued into adulthood.
Monitoring and management of complications

Question 8

Complications of rheumatic fever?

Answer 8

Recurrence of rheumatic fever
Valvular heart disease, most notably mitral stenosis
Chronic heart failure