Pharyngitis & Tonsillitis

For further information, see CMDT Part 8-20: Pharyngitis & Tonsillitis

Essentials of Diagnosis

• Sore throat

• Fever

• Anterior cervical adenopathy

• Tonsillar exudate

• Goal is to treat group A β-hemolytic streptococcus infection to prevent rheumatic sequelae

General Considerations

• Group A β-hemolytic streptococci (Streptococcus pyogenes) are the most common bacterial cause of exudative pharyngitis

• The main concern is to determine whether the cause is group A β-hemolytic streptococcal infection (GABHS), because of the complications of rheumatic fever and glomerulonephritis

• A second public health policy concern is to reduce the extraordinary cost (in both dollars and development of antibiotic-resistant Streptococcus pneumoniae in the United States associated with unnecessary antibiotic use)

• 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

Demographics

• Pharyngitis and tonsillitis account for > 10% of all office visits to primary care clinicians and 50% of outpatient antibiotic use

Symptoms and Signs

• Centor diagnostic criteria

  • Fever > 38°C

  • Tender anterior cervical adenopathy

  • Lack of cough

  • Pharyngotonsillar exudate

• Sore throat may be severe, with odynophagia, tender adenopathy, and a scarlatiniform rash

• 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

Differential Diagnosis

• Viral pharyngitis

• Epstein-Barr virus (EBV)/infectious mononucleosis

• Primary HIV infection

• Candidiasis

• Necrotizing ulcerative gingivostomatitis (Vincent fusospirochetal disease)

• Retropharyngeal abscess

• Diphtheria

• Neisseria gonorrhoeae

• Mycoplasma

• Anaerobic streptococci

• Corynebacterium haemolyticum

• Epiglottitis

Laboratory Tests

• The presence of the four Centor diagnostic criteria strongly suggests GABHS

• When two or three of the four are present, there is an intermediate likelihood of GABHS

• When zero or one Centor criterion is present, GABHS is unlikely; throat culture or rapid antigen detection testing of throat swab is not necessary

• With about 90% sensitivity, lymphocyte to white blood cell ratios of > 35% suggest EBV infection and not tonsillitis

• Patients with zero or one Centor criteria should not receive antibiotics

• Patients with two or three Centor criteria whose throat cultures or rapid antigen detection testing show positive results should receive antibiotic treatment

• Patients who have four Centor criteria can receive empiric therapy without throat culture or rapid antigen detection testing

Medications

• Benzathine penicillin intramuscular injection

  • 1.2 million units once is optimal but painful

  • Used for noncompliant patients

• Analgesic, anti-inflammatory drugs (aspirin, acetaminophen, corticosteroids)

• Oral antibiotics

  • Penicillin V potassium (250 mg three times daily or 500 mg twice daily orally for 10 days) or cefuroxime axetil (250 mg twice daily orally, 5–10 days)

  • Efficacy of 5-day penicillin V similar to 10-day course: 94% clinical response, 84% eradication

  • Erythromycin (500 mg four times daily orally) for penicillin-allergic patients

  • Macrolide antibiotics have been reported to be successful in shorter-duration regimens, eg, azithromycin (500 mg once daily for 3 days)

  • Cephalosporins more effective than penicillin for bacterial cure (eg, cefpodoxime and cefuroxime for 5 days)

• Treatment failure

  • Second course with same drug

  • Penicillin alternatives: cephalosporins (eg, cefuroxime), dicloxacillin, amoxicillin-clavulanate

  • Erythromycin resistance (failure rates of ∼25%) increasing

  • With severe penicillin allergy, avoid cephalosporins; cross-reaction common (≥ 8%)

Surgery

• Remove tonsils in cases of recurrent abscess

Therapeutic Procedures

• Salt-water gargling may be soothing

• Anesthetic gargles and lozenges (eg, benzocaine) for additional symptomatic relief

Follow-Up

• 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

Complications

• Low (10–20%) incidence of treatment failures (positive culture after treatment despite symptomatic resolution) and recurrences

• Rheumatic myocarditis

• Glomerulonephritis

• Scarlet fever

• Local abscess formation

Prognosis

• Streptococcal pharyngitis usually resolves after 1 week

• Spontaneous resolution of symptoms without treatment still leaves the risk of rheumatic complications

When to Refer

• Peritonsillar abscess

When to Admit

• Occasionally, odynophagia is so intense that hospitalization is necessary for intravenous hydration and antibiotics

• Suspected or known epiglottitis