Rheumatic fever

Rheumatic fever is an inflammatory diseasewhich may develop after a Group A streptococcal infection(such as strep throator scarlet fever) and can involve the heart, joints, skin, and brain.

General Information

Rheumatic fever is common worldwide and is responsible for many cases of damaged heart valves. In the Western countries, it became fairly rare since the 1950's, possibly due to higher hygienic standards. While it is far less common in the United Statessince the beginning of the 20th century, there have been a few outbreaks since the 1980s. Although the disease seldom occurs, it is serious and has a mortality of 2 - 5%.

Rheumatic fever primarily affects children between ages six and 15 and occurs approximately 20 days after strep throat or scarlet fever. In up to a third of cases, the underlying strep infection may not have caused any symptoms.

The rate of development of rheumatic fever in individuals with untreated strep infection is estimated to be 3 percent. The rate of development is far lower in individuals who have received antibiotic treatment. Persons who have suffered a case of rheumatic fever have a tendency to develop flare-ups with repeated strep infections.

The recurrence of rheumatic fever is relatively common in the absence of maintenance of low dose antibiotics, especially during the first three to five years after the first episode of rheumatic fever. Heart complications may be long-term and severe, particularly if the heart valves are involved.

Diagnosis: Modified Jones Criteria

T. Duckett Jones, MD first published these criteria in 1944. They have been periodically revised by the American Heart Associationin collaboration with other groups. Two major criteria, or one major and two minor criteria, when there is also evidence of a previous strep infection support the diagnosis of rheumatic fever. [1][2]

Major Criteria

• Carditis: inflammation of the heartmuscle which can manifest as congestive heart failurewith shortness of breath, pericarditiswith a rub, or a new heart murmur.
• Migratory polyarthritis: a temporary migrating inflammation of the large joints, usually starting in the legs and migrating upwards.
• Sydenham's chorea(St. Vitus' dance): a characteristic series of rapid movements without purpose of the face and arms. This can occur very late in the disease.
• Erythema marginatum: a long lasting rash that begins on the trunk or arms as maculesand spread outward to form a snakelike ring while clearing in the middle. This rash never starts on the face and is made worse with heat.
• Subcutaneous nodules (a form of Aschoff bodies): painless, firm collections of collagen fibers on the back of the wrist, the outside elbow, and the front of the knees. These now occur infrequently.

Minor Criteria

• Fever: temperature elevation
• Arthralgia: Joint pain without swelling
• Laboratory abnormalities: increased Erythrocyte sedimentation rate, increased C reactive protein, leukocytosis
• Electrocardiogram abnormalities: a prolonged PR interval
• Evidence of Group A Strep infection: positive culture for Group A Strep, elevated or rising Antistreptolysin O titre

Other Signs and Symptoms

• Abdominal pain
• Epistaxis

Pathophysiology

Rheumatic fever is an autoimmune diseasewhich occurs after an untreated Group A streptococcal infection, typically a throat infection. The antibodiesformed against the bacteriaattack parts of the body, typically the joints and the heart. [3]

Group A Streptococcus pyogeneshas a cell wallthat is composed of branched polymerswhich sometimes contain "M proteins" which are highly antigenic. The antibodies formed against these proteins sometimes cross-react with normal tissue causing damage. Depending on the site of damage, this can lead to the clinical symptoms described above. [4]

Treatment

The management of acute rheumatic fever is geared toward the reduction of inflammation with anti-inflammatory medicationssuch as aspirinor corticosteroids. Individuals with positive cultures for strep throat should also be treated with antibiotics. Another important cornerstone in treating rheumatic fever includes the continuous use of low dose antibiotics (such as penicillin, sulfadiazine, or erythromycin) to prevent recurrence.

Infection

Patients with positive cultures for Streptococcus pyogenesshould be treated with Penicillinas long as allergyis not present. This treatment will not alter the course of the acute disease.

Inflammation

Patients with significant symptoms may require corticosteroids. Salicylatesare useful for pain.

Heart failure

Some patients develop significant carditiswhich manifests as congestive heart failure. This requires the usual treatment for heart failure: diuretics, digoxin, etcetera. Unlike normal heart failure, rheumatic heart failure responds well to corticosteroids.

Prevention

Prevention of recurrence is achieved by eradicating the acute infection and prophylaxiswith antibiotics. The American Heart Associationrecommends prophylaxiscontinue at least 10 years.

References

• Jones TD. The diagnosis of rheumatic fever. JAMA. 1944; 126: 481?484
• Ferrieri P. Proceedings of the Jones criteria workshop. Circulation.2002; 106 :2521 ?2523
• Acute Rheumatic Fever eMedicine
• Rheumatic Fever Emergency Medicine eMedicine
• Rheumatic Fever Pediatrics eMedicine

External links

• NIH Rheumatic fever guide
• Rheumatic Fever informationfrom Seattle Children's Hospital Heart Center

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It uses material from the http://en.wikipedia.org/wiki/Rheumatic+fever Wikipedia article Rheumatic fever.