Pharyngitis (acute sore throat) - approach to the patient

onsider throat lozenges or nonsteroidal anti-inflammatory drugs (NSAIDs) for symptomatic relief. Corticosteroids, such as dexamethasone 10 mg....
Abdelwahab Ward, BS Pharm, PharmD

Introduction ã…¡ Pharyngitis is an inflammation of the pharynx (or sore throat) diagnosed clinically, and which may be due to either infectious or noninfectious causes. Clinical factors, particularly age, greatly influence the likelihood of specific infectious pathogens as the cause of pharyngitis.

Infectious causes include

  1. Viral causes, such as adenovirus and rhiniovirus are common causes.
  2. Streptococcal pharyngitis is the most common cause of acute bacterial pharyngitis in children. Its peak incidence occurs between ages 5-11 years old.
  3. Adolescents and young adults are particularly vulnerable to symptomatic Epstein-Barr virus-associated infectious mononucleosis, pharyngitis due to Fusobacterium necrophorum, or non-group A (group C or G) Streptococcus, and if sexually active, these patients may be at risk for Neisseria gonorrhoeae.
  4. Adolescents and young adults may also have increased risks for peritonsillar abscesses or acute HIV infection. The elderly aged > 80 years old are susceptible to acute epiglottitis (which also has a high incidence in infants).

Noninfectious causes are generally distinguished by lack of fever and chronicity of symptoms.

Assessment

When to treat

Avoid antibiotics as 82% resolve in 7 days without, and pain only reduced by 16 hours. Average total length of illness is one week. Complications are rare and include acute otitis media, acute sinusitis and quinsy. Consider the person's signs and symptoms, and use the FeverPAIN or Centor clinical prediction score to determine the likelihood of streptococcal infection (and therefore the need for antibiotic treatment). Pharyngitis/tonsillitis is common in children and adolescents aged 5 to 15 years and is more common in the winter (or early spring) in temperate climates. Streptococcal infection is suggested by fever > 38.5°C, exudate on the pharynx/tonsils, anterior neck lymphadenopathy, and absence of cough. A scarlatiniform rash may be present, especially in children.

FeverPAIN criteria is score 1 point for each (maximum score of 5) include fever over 38°C, purulence (pharyngeal/tonsillar exudate), attend rapidly (3 days or less), inflamed tonsils plus no cough or coryza.

  • Score of 0 or 1 is associated with a 13% to 18% likelihood of isolating streptococcus.
  • Score of 2 or 3 is associated with a 34% to 40% likelihood of isolating streptococcus.
  • Score of 4 or 5 is associated with a 62% to 65% likelihood of isolating streptococcus.

Centor criteria include tonsillar exudate, tender anterior cervical lymphadenopathy or lymphadenitis, history of fever (over 38°C) and absence of cough. Each of the Centor criteria score 1 point (maximum score of 4).

  • Score of 0, 1 or 2 is thought to be associated with a 3 to 17% likelihood of isolating streptococcus.
  • Score of 3 or 4 is thought to be associated with a 32 to 56% likelihood of isolating streptococcus.

If the diagnosis of GAS needs to be confirmed with certainty (such as in people at high risk of rheumatic fever, vulnerable people such as the very old or young, or people who are at risk of immunosuppression, or people with very severe symptoms), arrange a rapid antigen test for group A streptococcus. A negative antigen test in a person (particularly a child) with suspected GAS should be followed up with a throat culture. Or if systemically very unwell (see cautions below) or has symptoms and signs of a more serious illness or condition or has high risk of complications.

When to investigate

Throat swabs or rapid antigen tests should not be carried out routinely in the investigation of acute sore throat. Suspect glandular fever in a person with a sore throat that fails to improve, or becomes worse, after several days.

Treatment choices

Consider throat lozenges or nonsteroidal anti-inflammatory drugs (NSAIDs) for symptomatic relief. Corticosteroids, such as dexamethasone 10 mg orally as a 1 time dose, may hasten pain relief for acute pharyngitis.

Antibiotic therapy is considered for:

  1. Patients with FeverPAIN score of 0 or 1 or Centor score of 0, 1, 2, do not offer antibiotic.
  2. Patients with FeverPAIN score of 2 or 3, consider a 3 day delayed antibiotic.
  3. Patients with FeverPAIN score of 4 or 5, or Centor score of 3 or 4, consider immediate antibiotic or 48 hours delayed antibiotic.

Antibiotic options for patients without penicillin allergy, options include penicillin V with dose 250 mg orally 2-3 times daily for 10 days in children. In adults and adolescents, prescribe 250 mg orally 4 times daily or 500 mg orally twice daily for 10 days. Amoxicillin 50 mg/kg orally once daily (maximum 1000 mg) or 25 mg/kg (500 mg maximum dose) orally twice daily for 10 days can be used. For patients with penicillin allergy, options include azithromycin 12 mg/kg orally once daily (maximum 500 mg) for 5 days (check for local group A streptococcus resistance). Clarithromycin 7.5 mg/kg orally twice daily (250 mg maximum dose) for 10 days (check for local group A streptococcus resistance).

CAUTIONS ã…¡ Admit immediately anyone who has:

  1. Stridor or respiratory difficulty.
  2. Respiratory distress, drooling, systemically very unwell, painful swallowing, and muffled voice: suspect acute epiglottitis. Do not examine the throat of anyone who has suspected epiglottitis.
  3. Upper airway obstruction.
  4. Dehydration or reluctance to take any fluids.
  5. Severe suppurative complications (e.g., peritonsillar abscess or cellulitis, parapharyngeal abscess, retropharyngeal abscess, or Lemierre syndrome) as there is a risk of airway compromise or rupture of the abscess.
  6. Signs of being markedly systemically unwell and is at risk of immunosuppression.
  7. Suspected Kawasaki disease, diphtheria yersinial pharyngitis, or profoundly unwell with cause unknown or rare cause suspected, (e.g., Stevens-Johnson syndrome).

References

Abdelwahab Ward, BS Pharm, PharmD