30: Sore Throat

CHIEF COMPLAINT

CONSTRUCTING A DIFFERENTIAL DIAGNOSIS

Sore throat is a common condition seen in outpatient clinical practice. This chapter focuses on patients that present with the acute onset of sore throat. Infectious diseases are the cause of acute sore throat in the overwhelming majority of patients. Patients with chronic sore throat, those who do not have signs of infection, or those who do not respond to treatment should be evaluated for noninfectious causes of sore throat.

A useful framework for the differential diagnosis of acute sore throat is shown below. This framework divides the diagnoses into those caused by infection (bacterial and viral) and those caused by noninfectious processes. Viral respiratory infections are the most common cause of infectious pharyngitis with the common cold caused by rhinoviruses and coronaviruses accounting for at least 25% of cases. Group A beta-hemolytic streptococcus (GABHS) is the most common cause of acute bacterial pharyngitis, accounting for 5–15% of sore throats in adults. Approximately 30% of cases of pharyngitis have no identifiable cause. Table 30-1 shows the differential diagnosis with the estimated percentage of cases of sore throat and the associated clinical syndrome.

1. Infectious causes of sore throat

   1. Viruses

      1. Rhinovirus

      2. Coronavirus

      3. Adenovirus

      4. Herpes simplex virus (HSV)1 and 2

      5. Influenza A and B

      6. Parainfluenza virus

      7. Epstein-Barr virus (EBV)

      8. Cytomegalovirus (CMV)

      9. Human herpesvirus (HHV) 6

      10. HIV

   2. Bacteria

      1. GABHS

      2. Group C beta-hemolytic streptococci

      3. Neisseria gonorrhoeae

      4. Corynebacterium diphtheriae

      5. Mycoplasma pneumoniae

      6. Chlamydophila pneumoniae

      7. Fusobacterium necrophorum

2. Noninfectious causes of sore throat

   1. Persistent cough

   2. Postnasal drip

   3. Gastroesophageal reflux disease (GERD)

   4. Acute thyroiditis

   5. Neoplasm

   6. Allergies

   7. Smoking

Clinically, the primary goal when seeing a patient with acute, probably infectious sore throat is to identify and treat patients with GABHS pharyngitis in order to prevent complications of acute rheumatic fever, acute glomerulonephritis, and suppurative sequelae. The secondary goal is to diagnose the less common infections (peritonsillar abscess) as well as ...