Sydenham's chorea

Definition

Rheumatic fever (RF) is an illness which arises as a complication of untreated or inadequately treated strep throat infection. Rheumatic fever can seriously damage the valves of the heart.

Description

Throat infection with a member of the Group A streptococcus (strep) bacteria is a common problem among school-aged children. It is easily treated with a ten-day course of antibiotics by mouth. However, when such a throat infection occurs without symptoms, or when a course of medication is not taken for the full ten days, there is a 3% chance of that person developing rheumatic fever. Other types of strep infections (such as of the skin) do not put the patient at risk for RF.

Children between the ages of five and fifteen are most susceptible to strep throat, and therefore most susceptible to rheumatic fever. Other risk factors include poverty, overcrowding (as in military camps), and lack of access to good medical care. Just as strep throat occurs most frequently in fall, winter, and early spring, so does rheumatic fever.

Causes & symptoms

Two different theories exist as to how a bacterial throat infection can develop into the disease called rheumatic fever. One theory, less supported by research evidence, suggests that the bacteria produce some kind of poisonous chemical (toxin). This toxin is sent into circulation throughout the bloodstream, thus affecting other systems of the body.

Research seems to point to a different theory, however. This theory suggests that the disease is caused by the body's immune system acting inappropriately. The body produces immune cells (called antibodies), which are specifically designed to recognize and destroy invading agents; in this case, streptococcal bacteria. The antibodies are able to recognize the bacteria because the bacteria contain special markers called antigens. Due to a resemblance between Group A streptococcus bacteria's antigens and antigens present on the body's own cells, the antibodies mistakenly attack the body itself.

It is interesting to note that members of certain families seem to have a greater tendency to develop rheumatic fever than do others. This could be related to the above theory, in that these families may have cell antigens which more closely resemble streptococcal antigens than do members of other families.

In addition to fever, in about 75% of all cases of RF one of the first symptoms is arthritis. The joints (especially those of the ankles, knees, elbows, and wrists) become red, hot, swollen, shiny, and extraordinarily painful. Unlike many other forms of arthritis, the arthritis may not occur symmetrically (affecting a particular joint on both the right and left sides, simultaneously). The arthritis of RF rarely strikes the fingers, toes, or spine. The joints become so tender that even the touch of bedsheets or clothing is terribly painful.

A peculiar type of involuntary movement, coupled with emotional instability, occurs in about 10% of all RF patients (the figure used to be about 50%). The patient begins experiencing a change in coordination, often first noted by changes in handwriting. The arms or legs may flail or jerk uncontrollably. The patient seems to develop a low threshold for anger and sadness. This feature of RF is called Sydenham's chorea or St. Vitus' Dance.

A number of skin changes are common to RF. A rash called erythema marginatum develops (especially in those patients who will develop heart problems from their illness), composed of pink splotches, which may eventually spread into each other. It does not itch. Bumps the size of peas may occur under the skin. These are called subcutaneous nodules; they are hard to the touch, but not painful. These nodules most commonly occur over the knee and elbow joint, as well as over the spine.

The most serious problem occurring in RF is called pancarditis ("pan" means total; "carditis" refers to inflammation of the heart). Pancarditis is an inflammation that affects all aspects of the heart, including the lining of the heart (endocardium), the sac containing the heart (pericardium), and the heart muscle itself (myocardium). About 40-80% of all RF patients develop pancarditis. This RF complication has the most serious, long-term effects. The valves within the heart (structures which allow the blood to flow only in the correct direction, and only at the correct time in the heart's pumping cycle) are frequently damaged during the course of this pancarditis. This may result in blood which either leaks back in the wrong direction, or has a difficult time passing a stiff, poorly moving valve. Either way, damage to a valve can result in the heart having to work very hard in order to move the blood properly. The heart may not be able to "work around" the damaged valve, which may result in a consistently inadequate amount of blood entering the circulation.

Diagnosis

Diagnosis of RF is done by carefully examining the patient. A list of diagnostic criteria has been created. These "Jones Criteria" are divided into major and minor criteria. A patient can be diagnosed with RF if he, or she, has either two major criteria (conditions), or one major and two minor criteria. In either case, it must also be proved that the individual has had a previous infection with streptococcus.

The major criteria include:

• Carditis
• Arthritis
• Chorea
• Subcutaneous nodules
• Erythema marginatum.

The minor criteria include:

• Fever
• Joint pain (without actual arthritis)
• Evidence of electrical changes in the heart (determined by measuring electrical characteristics of the heart's functioning during a test called an electrocardiogram, or EKG)
• Evidence (through a blood test) of the presence in the blood of certain proteins, which are produced early in an inflammatory/infectious disease.

Tests are also performed to provide evidence of recent infection with group A streptococcal bacteria. A swab of the throat can be taken, and smeared on a substance in a petri dish, to see if bacteria will multiply and grow over 24-72 hours. These bacteria can then be specially processed, and examined under a microscope, to identify streptococcal bacteria. Other tests can be performed to see if the patient is producing specific antibodies; antibodies which are only made in response to a recent strep infection.

Treatment

A 10 day course of penicillin by mouth, or a single injection of penicillin G is the first line of treatment for RF. Patients will need to remain on some regular dose of penicillin to prevent recurrence of RF. This can mean a small daily dose of penicillin by mouth, or an injection every three weeks. Some practitioners keep patients on this regimen for five years, or until they reach 18 years of age (whichever comes first). Other practitioners prefer to continue treating those patients who will be regularly exposed to streptococcal bacteria (teachers, medical workers), as well as those patients with known RF heart disease.

Arthritis quickly improves when the patient is given a preparation containing aspirin, or some other anti-inflammatory agent (ibuprofen). Mild carditis will also improve with such anti-inflammatory agents; although more severe cases of carditis will require steroid medications. A number of medications are available to treat the involuntary movements of chorea, including diazepam for mild cases, and haloperidol for more severe cases.

Prognosis

The long-term prognosis of an RF patient depends primarily on whether he, or she, develops carditis. This is the only manifestation of RF which can have permanent effects. Those patients with no or mild carditis have an excellent prognosis. Those with more severe carditis have a risk of heart failure, as well as a risk of future heart problems, which may lead to the need for valve replacement surgery.

Prevention

Prevention of the development of RF involves proper diagnosis of initial strep throat infections, and adequate treatment with 10 days with an appropriate antibiotic. Prevention of RF recurrence requires continued antibiotic treatment, perhaps for life. Prevention of complications of already-existing RF heart disease requires that the patient always take a special course of antibiotics when he or she undergoes any kind of procedure (even dental cleanings) that might allow bacteria to gain access to the bloodstream.

Key Terms

Antibodies

Specialized cells of the immune system which can recognize organisms that invade the body (such as bacteria, viruses, and fungi). The antibodies are then able to set off a complex chain of events designed to kill these foreign invaders.

Antigen

A special, identifying marker on the outside of cells.

Arthritis

Inflammation of the joints.

Autoimmune disorder

A disorder in which the body's antibodies mistake the body's own tissues for foreign invaders. The immune system therefore attacks and causes damage to these tissues.

Chorea

Involuntary movements in which the arms or legs may jerk or flail uncontrollably.

Immune system

The system of specialized organs, lymph nodes, and blood cells throughout the body, which work together to prevent foreign invaders (bacteria, viruses, fungi, etc.) from taking hold and growing.

Inflammation

The body's response to tissue damage. Includes hotness, swelling, redness, and pain in the affected part.

Pancarditis

Inflammation the lining of the heart, the sac around the heart, and the muscle of the heart.

Further Reading

For Your Information

Books

• Kaplan, Edward L. "Rheumatic Fever." In Harrison's Principles of Internal Medicine, edited by Anthony S. Fauci, et al. New York: McGraw-Hill, 1998.
• Ryan, Kenneth. "Streptococci." In Sherris Medical Microbiology: An Introduction to Infectious Diseases. Norwalk, CT: Appleton and Lange, 1994.
• Stoffman, Phyllis. The Family Guide to Preventing and Treating 100 Infectious Diseases. New York: John Wiley and Sons, Inc., 1995.
• Todd, James. "Rheumatic Fever." In Nelson Textbook of Pediatrics, edited by Richard Behrman. Philadelphia: W.B. Saunders Co., 1996.

  Periodicals

• Albert, Daniel A., et al. "The Treatment of Rheumatic Carditis: A Review and Meta-Analysis." Medicine, 74, no. 1 (January 1995): 1+.
• Capizzi, Stephen A., et al. "Rheumatic Fever Revisited: Keep This Diagnosis on Your List of Suspects." Postgraduate Medicine, 102, no. 6 (December 1997): 65+.
• Eichbaum, Q.G., et al. "Rheumatic Fever: Autoantibodies Against a Variety of Cardiac, Nuclear, and Streptococcal Antigens." Annals of the Rheumatic Diseases, 54, no. 9 (September 1995): 740+.
• Stollerman, Gene H. "Rheumatic Carditis." Lancet, 346, no. 8972 (August 12, 1995): 390+.
• Stollerman, Gene H. "Rheumatic Fever." Lancet 349, no. 9056 (March 29, 1997): 935+.

  Organizations

• Centers for Disease Control and Prevention. (404) 332-4559. http://www.cdc.gov.

Gale Encyclopedia of Medicine. Gale Research, 1999.