Rheumatic Fever

What causes rheumatic fever

Group A Streptococcus bacteria cause strep throat and scarlet fever. In a small proportion of people, especially when the infection is not treated with antibiotics, the immune system makes antibodies that cross-react with proteins in the heart, joints, brain and skin (molecular mimicry). This causes inflammation 2 to 4 weeks after the sore throat, when the throat itself may have recovered.

Risk factors

• Age 5 to 15
• Untreated or incompletely treated strep throat
• Crowded housing and poverty
• Limited access to healthcare
• Genetic susceptibility
• Previous rheumatic fever, which greatly increases the risk of recurrence

Rheumatic fever is rare in the US but remains a major problem worldwide, with rheumatic heart disease affecting tens of millions of people.

Symptoms

Major features

• Arthritis: painful, hot, swollen joints, usually large joints like knees, ankles, elbows and wrists. Pain often moves from joint to joint (migratory) and responds dramatically to anti-inflammatory medicine. It does not cause lasting joint damage
• Carditis: inflammation of the heart, especially the valves. May cause a new murmur, fast heartbeat, chest pain, breathlessness or heart failure, or may be silent and found only on echocardiogram
• Sydenham chorea: sudden, jerky, purposeless movements of the face, hands and feet, clumsiness, slurred speech and emotional changes. It can appear months after the infection. See Sydenham's chorea
• Erythema marginatum: a pink, ring-shaped, non-itchy rash on the trunk that comes and goes
• Subcutaneous nodules: small, painless lumps over bony areas such as elbows, knees and spine

Minor features

• Fever
• Joint pain without swelling
• Raised inflammatory markers (ESR, CRP)
• Prolonged PR interval on ECG

Diagnosis: the Jones criteria

Diagnosis requires evidence of a recent group A strep infection (positive throat culture or rapid test, or raised antistreptolysin O or anti-DNase B antibodies) plus:

• 2 major criteria, or
• 1 major and 2 minor criteria

The 2015 AHA revision includes slightly different thresholds for high-risk populations and recognizes subclinical carditis found by echocardiogram.

Tests include:

• throat swab
• strep antibody blood tests
• ESR, CRP and blood count
• ECG
• echocardiogram, recommended for all suspected cases

Treatment

• Antibiotics (usually penicillin) to eradicate remaining strep bacteria
• Anti-inflammatory medicines such as aspirin or naproxen for arthritis and mild carditis, under medical supervision. This is one of the few situations where aspirin is used in children, because the benefit outweighs the risk of Reye syndrome; it is only given on a doctor's advice
• Corticosteroids sometimes for severe carditis
• Heart failure treatment if needed
• Treatment of chorea with rest, a calm environment and sometimes medicines
• Bed rest during acute illness, with gradual return to activity

Rheumatic heart disease

Repeated or severe episodes of carditis can scar heart valves, most often the mitral valve, causing narrowing (mitral stenosis) or leaking (regurgitation), and sometimes the aortic valve. Rheumatic heart disease can lead to:

• heart failure
• atrial fibrillation and stroke
• infective endocarditis
• pregnancy complications

Treatment includes medicines, balloon valvotomy and valve repair or replacement surgery.

Prevention

Primary prevention

Prompt testing and full antibiotic treatment of strep throat prevent most cases of rheumatic fever. Complete the full course, usually 10 days of oral penicillin or amoxicillin, or a single penicillin injection.

Secondary prevention

After rheumatic fever, regular antibiotics prevent recurrences, which cause further heart damage:

• Benzathine penicillin G injection every 3 to 4 weeks, or daily oral antibiotics
• Duration depends on whether carditis occurred: at least 5 years or until age 21 without carditis, and 10 years or until age 40 or longer with persistent valve disease

Good dental care is important for people with valve damage.

Outlook

Arthritis and chorea resolve completely. The long-term outlook depends on heart involvement. Mild carditis can resolve, especially with consistent preventive antibiotics, while severe or repeated carditis can lead to chronic valve disease needing lifelong care.

Frequently asked questions

What causes rheumatic fever?

It is caused by an abnormal immune reaction to a group A strep throat infection. Antibodies made against the bacteria attack the body's own tissues, especially the heart, joints, brain and skin, usually 2 to 4 weeks after the sore throat.

What are the symptoms of rheumatic fever?

Common symptoms include fever, painful swollen joints that move from one joint to another, and sometimes heart inflammation causing breathlessness or chest pain. Others are jerky movements (chorea), small lumps under the skin and a ring-shaped rash.

Can rheumatic fever be prevented?

Yes. Treating strep throat promptly with a full course of antibiotics prevents most cases. People who have had rheumatic fever take long-term preventive antibiotics to stop recurrences that could further damage the heart.

What is rheumatic heart disease?

Rheumatic heart disease is lasting damage to heart valves, especially the mitral valve, caused by rheumatic fever. It can lead to heart failure, irregular heartbeat, stroke and endocarditis, and may need valve surgery.

Is rheumatic fever contagious?

Rheumatic fever itself is not contagious. The strep throat infection that triggers it is contagious and spreads through respiratory droplets, which is why outbreaks can occur in crowded settings.