Acute Pharyngitis
PATIENT HISTORY
The patient was a 6 year-old male who had been in good health with no significant medical problems. In late September he presented to his pediatrician’s office with a complaint of sore throat, fever, headache, and swollen glands in his neck for the past 36 h. On physical examination
(PE), he had a fever of 38◦C (100.4◦F), a red posterior pharynx, yellowish exudate on his tonsils, and multiple, enlarged, tender cervical lymph nodes.
There were no other pertinent symptoms.
LABORATORY TESTS
pain on swallowing, as well as erythema with or without exudate on the
tonsils and tender cervical lymph nodes. There are no clinical indicators
that would make it possible to accurately predict the cause of this child’s
pharyngitis. Laboratory tests are required to make a diagnosis.
When deciding whether to perform a laboratory test, clinical and epidemiological
features as well as the availability and usefulness of treatment
must be considered. While viruses are the most common cause
of acute pharyngitis in both adults and children, lab testing for viruses
is not warranted because antiviral agents are not used to treat acute
pharyngitis. Given the age of this patient, the absence of travel, and the
lack of suspicion of child abuse, GAS is the most likely etiologic agent.
Since GAS pharyngitis is the most commonly occurring form of pharyngitis
for which antibiotic therapy is indicated, lab testing should be directed
at ruling out GAS. Appropriate laboratory tests for this would
include:
Rapid strep test. This is not a culture; the test detects a unique carbohydrate
on the cell wall of GAS.
Throat culture. This test will grow the GAS organism from a throat
specimen taken from the patient and will require overnight incubation
at the minimum. Most labs offer a specific “rule out GAS”
throat culture.
The specimen required for each of these tests is a throat swab. Use of a
double-swab format allows one to obtain sufficient specimen to perform
both tests if necessary. As with any microbiology test, the quality of the
results is contigent on whether the laboratory receives a well-taken specimen.
The double swab should be firmly rubbed over much of the surface
of both tonsils and the posterior pharyngeal area and rolled to ensure
that there is ample specimen is on each swab tip. If exudate is present, it
should also be sampled on the same swabs. Care should be taken to avoid
touching other areas of the oropharynx, mouth, and tongue.
DirectGramstains fromthroat swabs are not at all useful becausemany
bacteria normally reside in the throat, including nonpathogenic streptococci
that have Gram stain appearance identical to that of GAS.
TREATMENT AND PREVENTION
Treatment of group A streptococcal pharyngitis is important in order to
relieve the patient’s symptoms and to prevent the transmission to others.
Prompt treatment will also prevent complications such as peritonsillar abscess
and acute rheumatic fever. Symptoms will often disappear within
3–4 days even without antibiotics, but early antibiotics can shorten the
duration of symptoms. Pharyngitis caused by S. pyogenes can be effectively
treated with a penicillin. In children, like this patient, amoxicillin
is routinely prescribed. Patients must complete the course of antibiotic to
eradicate the organisms from the pharynx. For patients who are allergic
to penicillin, erythromycin would be an acceptable alternative. If left untreated,
patients with GAS infection may develop the sequellae of heart
valve damage (RF) or kidney damage (GN).
Susceptibility tests on GAS would not be performed since resistance
to penicillin has not been documented in these organisms to date. Carriers
maintain S. pyogenes in their throats despite appropriate antibiotic therapy;
it is not because the organisms are resistant to penicillin. Carriers are not
symptomatic but can spread the organism to others who may develop an
infection.