📄 pharyngitis tonsillitis
ESSENTIALS OF DIAGNOSIS
Sore throat Fever Anterior cervical adenopathy
Tonsillar exudate Focus is to treat group A beta-hemolytic streptococcus infection to prevent rheumatic sequelae General Considerations
Pharyngitis and tonsillitis account for over 10% of all office visits to primary care clinicians and 50% of outpatient antibiotic use
The main concern is determining who is likely to have a group A beta-hemolytic streptococcal (GABHS) infection, as this can lead to subsequent complications, such as rheumatic fever and glomerulonephritis
A second public health policy concern is reducing the extraordinary cost (both in dollars and in the development of antibioticresistant S pneumoniae) in the United States associated with unnecessary antibiotic use
Questions being asked: Have the rapid antigen tests supplanted the need to culture a throat under most circumstances
Are clinical criteria alone a sufficient basis for decisions about which patients should be given antibiotics
Should any patient receive any antibiotic other than penicillin (or erythromycin if penicillin allergic)
For how long should treatment be continued
Numerous well-done studies and experience with rapid laboratory tests for detection of streptococci (eliminating the delay caused by culturing) informed a consensus experience
Clinical Findings
Symptoms and Signs
The clinical features most suggestive of GABHS pharyngitis include fever over 38°C, tender anterior cervical adenopathy, lack of a cough, and pharyngotonsillar exudate
These four features (the Centor criteria). when present, strongly suggest GABHS
When two or three of the four are present, there is an intermediate likelihood of GABHS
When only one criterion is present, GABHS is unlikely
Sore throat may be severe, with odynophagia, tender adenopathy, and a scarlatiniform rash
An elevated white count and left shift are also possible
Hoarseness, cough, and coryza are not suggestive of this disease
Marked lymphadenopathy and a shaggy, white-purple tonsillar exudate, often extending into the nasopharynx, suggest mononucleosis, especially if present in a young adult
With about 90% sensitivity, lymphocyte to white blood-cell ratios of greater than 35% suggest EBV infection and not tonsillitis
Hepatosplenomegaly and a positive heterophile agglutination test or elevated anti-EBV titer are corroborative
However, about one-third of patients with infectious mononucleosis have secondary streptococcal tonsillitis, requiring treatment
Ampicillin should routinely be avoided if mononucleosis is suspected because it induces a rash that might be misinterpreted by the patient as a penicillin allergy
Diphtheria (extremely rare but described in the alcoholic population) presents with low-grade fever and an ill patient with a gray tonsillar pseudomembrane
The most common pathogens other than GABHS in the differential diagnosis of “sore throat” are viruses, Neisseria gonorrhoeae, Mycoplasma, and Chlamydia trachomatis
Rhinorrhea and lack of exudate would suggest a virus, but in practice it is not possible to confidently distinguish viral upper respiratory infection from GABHS on clinical grounds alone
Infections with Corynebacterium diphtheria, anaerobic streptococci, and Corynebacterium haemolyticum (which responds better to erythromycin than penicillin) may also mimic pharyngitis due to GABHS
Laboratory Findings
A single-swab throat culture is 90–95% sensitive and the rapid antigen detection testing (RADT) is 90–99% sensitive for GABHS
Results from the RADT are available in about 15 minutes
Treatment
The Infectious Diseases Society of America recommends laboratory confirmation of the clinical diagnosis by means of either throat culture or RADT of the throat swab
The American College of Physicians–American Society of Internal Medicine (ACP-ASIM), in collaboration with the Centers for Disease Control and Prevention, advocates use of a clinical algorithm alone—in lieu of microbiologic testing—for confirmation of the diagnosis in adults for whom the suspicion of streptococcal infection is high
Others examine the assumptions of the ACP-ASIM guideline for using a clinical algorithm alone and question whether those recommendations will achieve the stated objective of dramatically decreasing excess antibiotic use
A reasonable strategy to follow is that patients with zero or one Centor criteria are at very low risk for GABHS and therefore do not need throat cultures or RADT of the throat swab and should not receive antibiotics
Patients with two or three Centor criteria need throat cultures or RADT of the throat swab, since positive results would warrant antibiotic treatment
Patients who have four Centor criteria are likely to have GABHS and can receive empiric therapy without throat culture or RADT
A single intramuscular injection of benzathine penicillin or procaine penicillin, 1
2 million units is an effective antibiotic treatment, but the injection is painful
It is now used for patients if compliance with an oral regimen is an issue
Currently, oral treatment is effective and preferred
Penicillin V potassium (250 mg orally three times daily or 500 mg twice daily for 10 days) or cefuroxime axetil (250 mg orally twice daily for 5–10 days) are both effective
The efficacy of a 5-day regimen of penicillin V potassium appears to be similar to that of a 10-day course, with a 94% clinical response rate and an 84% streptococcal eradication rate
Erythromycin (also active against Mycoplasma and Chlamydia) is a reasonable alternative to penicillin in allergic patients
Cephalosporins are somewhat more effective than penicillin in producing bacteriologic cures; 5-day courses of cefpodoxime and cefuroxime have been successful
The macrolide antibiotics have also been reported to be successful in shorter-duration regimens
Azithromycin (500 mg once daily), because of its long half-life, need be taken for only 3 days
Adequate antibiotic treatment usually avoids the streptococcal complications of scarlet fever, glomerulonephritis, rheumatic myocarditis, and local abscess formation
Antibiotics for treatment failures are also somewhat controversial
Surprisingly, penicillin-tolerant strains are not isolated more frequently in those who fail treatment than in those treated successfully with penicillin
The reasons for failure appear to be complex, and a second course of treatment with the same drug is reasonable
Alternatives to penicillin include cefuroxime and other cephalosporins, dicloxacillin (which is beta lactamase resistant), and amoxicillin with clavulanate
When there is a history of penicillin allergy, alternatives should be used, such as erythromycin
Erythromycin resistance with failure rates of about 25%—is an increasing problem in many areas
In cases of severe penicillin allergy, cephalosporins should be avoided as the cross-reaction is common (8% or more)
Ancillary treatment of pharyngitis includes analgesics and anti-inflammatory agents, such as aspirin, acetaminophen, and corticosteroids
In meta-analysis, corticosteroids increased the likelihood of complete pain resolution at 24 hours by threefold without an increase in recurrence or adverse events
Some patients find that salt water gargling is soothing
In severe cases, anesthetic gargles and lozenges (eg, benzocaine) may provide additional symptomatic relief
Occasionally, odynophagia is so intense that hospitalization for intravenous hydration and antibiotics is necessary
Patients who have had rheumatic fever should be treated with a continuous course of antimicrobial prophylaxis (erythromycin, 250 mg twice daily orally, or penicillin G, 500 mg once daily orally) for at least 5 years
