RHEUMATIC FEVER: Down But Not Out
Just a few years ago rheumatic feverwas described as a vanishing disease. Children's hospitals devoted solely to the care of rheumatic fever victims closed their doors forever because of lack of patients; registries maintained by some states to track the disease were allowed to languish. But sometimes you can't keep a bad disease down. Rheumatic fever--with its risk of serious heart complications --has reappeared in some parts of the country, and in a particularly virulent form.
Though this reemergence of a diseaseonce thought to be mostly conquered worries physicians, the few hundred cases that have been reported in the current epidemic are still a small blip in the statistics compared to the incidence of rheumatic fever in days gone by. Up until the 1940s, an estimated 250,000 Americans developed rheumatic fever every year.
Much of the credit for eliminating thisscourge goes to a team of medical researchers who conducted a clinical study at the end of World War II. Their efforts saved future generations of children and young adults, both here and throughout the rest of the world, from the effects of a sometimes savage disease.
The study took place at Fort FrancisE. Warren, an Air Force technical training base in southeastern Wyoming. Its purpose was to determine whether acute rheumatic fever could be prevented by treating upper respiratory strep infections ("strep throat') with penicillin.
Rheumatic fever gets its name fromtwo of its most common symptoms-- joint pains and fever. When rheumatic fever develops, it appears a few weeks after a strep throat, usually when the patient seems to be fully recovered. In children, the illness often begins with a fever--sometimes as high as 104 degrees Fahrenheit in the first few days--that may last as long as two weeks. Rheumatism often follows.
In the 1940s, streptococcal diseasewas a major health problem both in the general population, where it was known as an "occupational disease of school children,' and in the military. Over 7,000 servicemen developed rheumatic fever each year after such infections, spread by respiratory droplets and often reaching epidemic proportions in Army camps. In some cases, rheumatic fever led to the most feared complications-- carditis (inflammation of the heart) and heart valve damage. Not only was the disease expensive to treat, but the armed services were compelled to discharge those who were left with serious disabilities.
The Air Force investigators were agroup of enthusiastic physicians in charge of the streptococcal disease laboratory at Fort Warren. The subjects were over 1,600 Air Force trainees, divided into two groups; those whose serial numbers ended in an even digit were the treated group. When they reported to the hospital with strep throat or tonsillitis, they got an injection of penicillin--a drug that had been available for only a few years and whose effectiveness in treating strep throat for the prevention of rheumatic fever was not known.
Trainees with serial numbers ending inan odd number received treatment for their symptoms, but no antibiotic, because they constituted--in research language --the control group.
Of the 798 trainees who were treatedwith penicillin, only two developed rheumatic fever. Of the 804 men in the control group, 17 came down with the disease, a statistically significant difference. Thus, administering an adequate amount of penicillin resulted in over a 90 percent reduction in the occurrence of initial attacks of rheumatic fever. This proved to the researchers that penicillin therapy for strep throat infections would almost completely prevent the subsequent development of rheumatic fever. It also won for them the Lasker Award in medicine, one of the most prestigious awards for medical research.
The results of the study filtered overinto civilian medicine and eventually changed the way doctors dealt with upper respiratory tract infections in children. Before the study, according to Dr. Milton Markowitz (writing in The Journal of Pediatrics, April 1985), doctors rarely took a throat culture to determine what was causing a sore throat unless diphtheria was suspected. Strep throats did not get special attention unless they were accompanied by a scarlet rash (scarlet fever). Drugs, such as sulfa and penicillin, were prescribed for these infections, but only for three or four days, not long enough to knock out the bacteria. But by 1970, says Dr. Markowitz, doctors throughout the country were routinely using throat cultures to diagnose strep infections. What's more, they were administering injections of long-acting penicillin or prescribing oral penicillin for a minimum of 10 days (or erythromycin for those allergic to penicillin), enough to cure the infection.
People, especially children, still get asmany strep throats as they ever did, but because they're usually properly diagnosed and treated, acute rheumatic fever develops so infrequently now that many young U.S. doctors have never seen a case of it. Penicillin and throat cultures are not the only heroes of this public health triumph, however. Other factors undoubtedly contributed to this decline, because the incidence of rheumatic fever was decreasing even before the discovery of antibiotics. In the United States, Western Europe and Japan, a better standard of living--with less crowding in the home, better diets, better health care for low-income families--and possibly less virulent strains of streptococcal bacteria may have had an effect.
Dr. Helen Taussig, a renowned pediatriccardiologist, said in an interview in Medical Times in November 1978: "I don't think there's any question that penicillin controlled rheumatic fever. But when we learned not to put all of the children in one bed together, and with less poverty and more food--that too helped bring down the incidence of rheumatic fever. Getting the child who was
infected and loaded with strep out of the household also helped.'
As a result, in affluent societies suchas ours, rheumatic fever has just about disappeared. In a New England Journal of Medicine editorial (Feb. 19, 1987), titled "Acute Rheumatic Fever: Forgotten but Not Gone,' Alan Bisno, M.D., University of Tennessee College of Medicine, wrote: "The decline in the incidence of acute rheumatic fever in North America and Western Europe since the end of World War II has been truly phenomenal. Indeed in the past 20 years alone, the annual incidence rate among school-age children in major cities has dropped by more than 90 percent.' New cases occur mostly among the poor or those who do not receive adequate medical attention. (It is difficult to estimate the number of cases that occur annually in the United States because the disease is not now required to be reported to public health officials, and it is often undiagnosed.)
But, obviously, while rheumatic feveris not the threat it used to be, it can't be counted out--not yet, anyway. A recent outbreak in Utah, as well as reports of new cases in Pennsylvania, Ohio, Texas and other parts of the United States, attest to this fact.
The Utah epidemic is particularly serious.While, on average, only six cases a year were referred to physicians at Primary Children's Medical Center in Salt Lake City from 1975 to 1985, in the 18-month period from January 1985 to June 1986, 74 cases were referred. Since that time there have been almost as many more. Surprisingly, the children who developed rheumatic fever came not from poor, minority neighborhoods, but mostly from white families with above average incomes and good access to medical care. But crowding in the home may have been a factor in the epidemic. The children's families averaged twice as large (6.5 members) as other Utah families, and the majority of the children shared bedrooms with other family members.
Over 90 percent of the Utah childrensuffered from heart inflammation, a higher than normal rate for this complication. Thirteen children who had cardiac involvement suffered from congestive heart failure. Two of them needed artificial heart valve replacements. "We don't know why there was such a high incidence of heart damage in this sudden outbreak. It may be that particularly virulent strains of streptococci are being introduced into the population. This is of concern to biomedical scientists and clinicians, and we are looking into this possibility,' says Edward L. Kaplan, M.D., head of the World Health Organization Collaborating Center for Reference and Research on Streptococci, Department of Pediatrics, University of Minnesota Medical School.
"The current outbreak is quite worrisome,'Dr. Kaplan continues. "We have to rethink our current methods of control. Diseases are best controlled when we know exactly how they are caused. We know that rheumatic fever results from the strep infection, but we don't know how. This outbreak points out the need for additional intensive study and research of its epidemiology, microbiology, immunology, diagnosis and therapy.'
While this rise in the number of casesalarms public health authorities, the incidence here is no match for that in developing countries, where about four-fifths of the world's population resides. There, rheumatic fever continues to rage unabated. Each year, rheumatic fever still "bites the heart and licks the joints' of 15 million to 20 million people, and is the leading cause of death from heart disease in those from 5 to 30 years of age. In Brazil, about 10 percent of school children have hearts damaged by rheumatic fever. In India, rheumatic heart disease accounts for 35 percent of all heart disease in a population of 500 million.
As Dr. Kaplan noted, rheumatic feveris still not completely understood by physicians. It is not an infection in itself, but may follow an upper respiratory infection caused by certain strep bacteria-- group A beta-hemolytic streptococci (S. pyogenes). Strep throats are contagious, but rheumatic fever is not. While antibiotics will usually prevent rheumatic fever from developing in the first place (as was conclusively demonstrated by the Air Force studies), they won't cure it.
The disease presents other paradoxes.A mild, untreated strep throat may lead to rheumatic fever, while a severe one may not. More than a third of patients with acute rheumatic fever don't remember having had a previous sore throat at all. (In the Utah epidemic, two-thirds of the children had no clear-cut history of a sore throat in the three months before the appearance of the disease.) Though some attacks of rheumatic fever can result in fatal heart damage--almost 13,000 deaths from rheumatic heart disease were reported in 1975--others produce no adverse effects. Also, unlike many other infectious diseases, in which one attack confers lifelong immunity, rheumatic fever can recur with subsequent strep throats.
Another insidious side of rheumaticfever is that some people can have an acute attack with heart damage and not be aware of it. The damage is discovered much later, sometimes by accident. In fact, many adults found to have rheumatic heart damage have no memory of a rheumatic fever attack. The disease wasn't detected in the first place because they didn't feel sick enough to go to the doctor. Some children have neither fever nor rheumatism, making diagnosis difficult. Also lacking is a specific lab test for the disease.
These problems have led physicians torely on certain criteria set up by Harvard's Dr. T. Duckett Jones in the 1940s (and later revised by the American Heart Association) for differentiating between rheumatic fever and childhood rheumatoid arthritis, gout, acute appendicitis, sickle-cell anemia, and other diseases with similar symptoms.
Patients are likely to have rheumaticfever when two major symptoms, or one major and two minor, are present. The major symptoms are a painful form of arthritis, known as migrating polyarthritis, that travels from joint to joint (knee, ankle, elbow, wrist), and inflammation of the heart, which develops in about half of those who have the arthritis.
An unusual symptom called St. Vitus'dance, or Sydenham's chorea, may develop in about one out of 10 children up to six months after the initial attack and afflicts mostly girls who have not yet reached puberty. Facial grimaces, uncontrolled twitching of the arms and legs, clumsiness, and changes in personality are some of its features. Another uncommon major symptom is a fleeting, nonitchy, "chicken wire' rash, found on the chest and abdomen, that becomes more prominent when heat is applied to it. Painless, firm nodules that form under the skin over large joints can also develop in later stages of the illness, usually in conjunction with heart inflammation.
The minor manifestations are less specificand include fever, joint pains, and a history of previous attack of rheumatic fever. Symptoms such as evidence of prior strep infection--as shown by the strep antibody level in the blood, nosebleeds, and abdominal pain that resembles acute appendicitis--are also helpful in diagnosis. All symptoms disappear within weeks or months with no lasting ill effects, with the exception of heart valve damage.
Although what triggers rheumaticfever is known (the group A streptococcus), how strep damages the heart is still unclear. One explanation is that damage is done by toxins produced by the streptococci. Another is that an abnormal immune response by the body produces antibodies to strep bacteria that cross-react with heart tissue. These are theories that still need proof.
The heart damage takes various forms.During the acute stage of the illness, inflammation may occur in the heart's muscle tissue or in the sac that surrounds the heart, but more commonly in the heart's valves, particularly the mitral and aortic valves. When the valves heal, scar tissue makes the valves stiff, holding back the flow of blood, or preventing proper opening and closing. These irregularities in the heart's blood flow cause "murmurs' that the doctor can hear with a stethoscope.
Rheumatic fever is a double dealer.Even if the disease doesn't recur, the heart damage can get worse in time. If rheumatic fever does recur, the heart damage is likely to be more severe. Replacement of damaged heart valves with artificial valves is sometimes necessary.
Those who have had one attack ofrheumatic fever are particularly susceptible to future ones. To prevent recurrent strep infections, doctors prescribe continuing antibiotics (mostly penicillin) for long periods--sometimes for life. It's especially important for those with rheumatic heart disease to have appropriate antibiotic prophylaxis (as suggested by the American Heart Association) before dental work or surgery, because bacteria entering the bloodstream during these procedures may infect the heart's valves or lining.
While the Air Force study proved oneimportant point--that penicillin for strep throat is extremely effective in preventing the development of rheumatic fever--the disease continues to challenge researchers. Still to be discovered are how reumatic fever develops, why it appears in some and not in others after a strep throat infection, how to recognize the disease when it has no symptoms, and how to identify susceptible individuals. Also waiting to be developed are drugs that will more adequately treat rheumatic fever's signs and symptoms.
Researchers are working on a vaccineto prevent streptococcal infections, but its development is hampered by the large number of different group A streptococci types. Another problem is that a vaccine must evoke protective immunity to group A streptococcal bacteria, but must be free of substances (antigens) that stimulate the production of antibodies that may cross-react with heart tissue.
Other researchers are taking anotherapproach, as there's some preliminary evidence that susceptibility to rheumatic fever may be inherited. The goal of these scientists is to develop a blood test that would screen individuals for this genetic susceptibility, if it exists. High-risk individuals could then be identified and given priority treatment (or a vaccine, if one can be produced) when they develop strep infections.
COPYRIGHT 1987 U.S. Government Printing Office
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