All physicians and most parents by now know the importance of recognizing and adequately treating a throat infection caused by Group A streptococcal bacteria. These organisms, if not stopped in their tracks by appropriate antibiotics, can result in rheumatic fever and permanently damaged heart valves, among other serious complications.
Thanks to penicillin, which readily kills strep bacteria, rheumatic fever has all but disappeared in countries like the United States. Now physicians are worried about overtreatment, the prescription of antibiotics for children whose sore throats are caused not by bacteria but by viruses that do not cause long-term damage and are not susceptible to antimicrobial therapy.
Some children and adults are healthy carriers of strep bacteria; the organisms reside in their throats but do not make them sick. They rarely, if ever, spread the infection to others. But when such carriers develop a sore throat for any reason, a positive test result for strep typically leads to treatment with antibiotics, which is often needless and possibly hazardous.
Complicated Decision
Symptoms of a strep throat and a sore throat caused by a virus can overlap (children may experience stuffy noses, coughs and sneezing with a strep infection as well as with a cold), further complicating a doctor’s decision on whether to treat the illness or to let nature take its course. Nationally, 70 percent of children with sore throats who are seen by a physician are treated with antibiotics, though at most 30 percent have strep infections. And as many as half who are treated with antibiotics because a throat culture was positive for strep are healthy carriers and actually have a cold or some other viral infection, says Dr. Edward L. Kaplan, a pediatrician at the University of Minnesota in Minneapolis and an expert on streptococcal illness.
Antibiotic treatment is best reserved for illnesses in which it is likely to be effective. Overuse of antibiotics can give rise to dangerous antibiotic-resistant bacteria. Antibiotics can wipe out friendly bacteria in the gut, and they sometimes cause life-threatening allergic reactions.
Both Dr. Kaplan and Dr. Alan L. Bisno, an internist at the University of Miami School of Medicine and the Veterans Affairs Medical Center in Miami, say there are usually good ways for physicians and parents to distinguish between sore throats caused by a strep infection and those caused by a virus or some other bacterium.
Group A strep causes 15 percent to 30 percent of sore throats in children, Dr. Kaplan and Dr. Bisno reported in the September issue of Mayo Clinic Proceedings. The illness is most common in school-age children as old as 15.
Strep infections are less common in adults, who are also far less likely than children to develop a serious complication like rheumatic fever if a strep infection goes untreated.
Strep bacteria are shed from the nose and throat of infected people and easily spread to others. This is why strep often makes the rounds in classrooms and day care centers. Occasionally, strep infections “ping-pong” among family members, but “there’s no strong evidence that the family pet is a source,” Dr. Bisno said.
In a small proportion of children, strep infections occur repeatedly over the course of several years. Jennifer L. St. Sauver and colleagues at the Mayo Clinic in Rochester, Minn., analyzed cases of strep throat occurring at least one month apart among children ages 4 to 15 in Rochester between Jan. 1, 1996, and Dec. 31, 1998. They found that 1 percent of the children (2 percent of those from 4 to 6 years old) had repeated episodes.
Dr. Kaplan and Dr. Bisno point out, however, that as thorough as the Rochester study was, in all likelihood the incidence of repeated strep throat infections is lower than what the researchers found. In only about a third of the cases counted as strep were data available that showed the cases met the accepted clinical profile of a strep infection.
Classic Symptoms
Here are the classic symptoms of strep throat:
¶Sudden onset of a very sore throat.
¶A beefy red throat and tonsils, sometimes with white patches and pus.
¶Difficulty swallowing.
¶Fever over 101 degrees.
¶Tender and often swollen lymph nodes in the neck.
¶Headache.
¶Shivers and shaking alternating with cold sweats.
¶In children, often nausea, vomiting and abdominal pain.
When someone with a painfully sore throat and fever is taken to the doctor, the appropriate exam includes a rapid strep test — a throat swab that checks for the presence of the strep antigen. The test, which can be done in the doctor’s office, takes 5 or 10 minutes to process and is 70 to 80 percent accurate. If the test is positive and the patient has at least some of the classic symptoms of strep, a prescription for an antibiotic — usually penicillin or a derivative — is considered an appropriate course of action.
If the rapid test is negative, a throat culture should also be done in which the throat swab is plated on a laboratory dish and incubated for 24 to 48 hours. This test, when the throat swab is properly done, is considered the gold standard for detecting the presence of strep bacteria. A positive result, when combined with symptoms of a strep infection, warrants antibiotic treatment.
Two Options for Treatment
Dr. Bisno explained that the examining physician has two options. The preferred course of treatment, as described in the 2002 practice guidelines of the Infectious Diseases Society of America, is to wait for the results of the throat culture before starting antibiotic therapy. The physician can write a prescription for antibiotics but suggest that it not be filled unless the throat culture is positive.
The second option, considered less than ideal, is to start antibiotic therapy right away and then stop it if the throat culture is negative, which almost always means the throat infection is caused by a virus, Dr. Bisno said. But, he added, this course of action is reasonable if, in spite of a negative result on the rapid test, “the child is really sick” with symptoms that suggest a strep infection.
An advantage of this option is that if the infection is indeed strep, 24 hours on an antibiotic renders the patient noncontagious, allowing a return to school or work after just a day’s absence.
With or without treatment, Dr. Bisno said, strep infections are limited, and most people are better within three or four days. Furthermore, he said, it is safe to wait several days — and perhaps as many as nine days — before starting antibiotic therapy without compromising the chances of preventing rheumatic fever.
In addition, the decision to treat or not to treat can be simplified, Dr. Bisno said, if children with sore throats have symptoms of a cold — “no fever, no red throat, a runny nose and a cough.” Such children, he said, “shouldn’t be tested at all for strep” and should not be given antibiotics.
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