PHARYNGITIS










  • Reference [2]
ETIOLOGY OF PHARYNGITIS
Viruses (70 - 95% of infections)
Adenovirus
  • Causes syndrome of fever, sore throat, cough, and conjunctivitis
Herpes simplex 1 virus
  • Gingivostomatitis
  • Causes painful oral ulcers
Coxsaskievirus
  • Hand, foot, and mouth disease
  • Painful sores develop in the mouth (herpangina)
  • Red spots develop on hands and soles of feet
Rhinovirus
Coronavirus
  • Common cold viruses
  • Sore throat is a common feature
Influenza
Parainfluenza
  • Sore throat is a common feature of a flu syndrome
Epstein-Barr Virus
Cytomegalovirus
  • Cause a syndrome of fever, sore throat, lymphadenopathy, and fatigue
  • Also called infectious mononucleosis
Bacteria (5 - 30% of infections)
Group A Streptococcus
  • Most common bacterial cause of pharyngitis
  • Accounts for 20 - 30% of pharyngitis in children and 5 - 15% in adults
Group C Streptococcus
  • More common in adults and college students
  • May occur in outbreaks from contaminated food (e.g. unpasteurized milk)
  • No clear link to rheumatic fever or glomerulonephritis
  • No clear evidence that antibiotic treatment is beneficial
Group G Streptococcus
  • No clear link to rheumatic fever or glomerulonephritis
  • No clear evidence that antibiotic treatment is beneficial
Neisseria gonorrhoeae
  • May occur in sexually active people
Corynebacterium diphtheriae
  • May form thick coat in back of throat
  • Vaccine is part of the standard childhood vaccination schedule
  • Also part of TdaP vaccine (tetanus, diphtheria, pertussis)






  • Reference [1, 2, Manufacturer's PI]
Diagnostic tests for strep throat
Test Accuracy Other
Rapid antigen testing
  • Sensitivity: > 90%
  • Specificity: > 90%
  • Performed in office. Takes about 5 minutes to get results.
  • Antibodies to strep antigen are coated on the test strip. If strep antigen is present in the throat swab, it binds antibody causing the strip to change color.
  • Older versions of rapid antigen testing had lower sensitivities (70 - 90%). Most manufacturers of kits used today report sensitivities > 90%.
  • Some versions of rapid antigen testing use different markers (e.g. immunofluorescence) that are read by a machine
Direct DNA probe tests
  • Sensitivity: > 90%
  • Specificity: > 90%
  • Sample collected in office and sent to lab for processing
  • If Strep RNA is present in the sample, complementary DNA in the test kit will form a complex with it. DNA:RNA complexes are then detected by a machine.
  • More expensive than rapid antigen testing
PCR testing
  • Sensitivity: > 90%
  • Specificity: > 90%
  • Sample collected in office. May be sent to lab. Some office-based machines are available.
  • Strep DNA in the sample is amplified and then detected through polymerase chain reaction (PCR) techniques
  • More expensive than rapid antigen testing
Culture
  • Considered reference standard
  • Sample collected in office and then sent to lab where it is cultured on a plate
  • Prior antibiotics may cause false-negative result
  • Takes 1 - 3 days to get results




  • Reference [2,4,5,6]
Complications of group A strep (GAS) pharyngitis
Rheumatic fever
  • Inflammatory autoimmune reaction that occurs 2 - 4 weeks after GAS infection
  • Symptoms included arthritis (35 - 88%), carditis (50 - 78%), erythema marginatum (< 6%), subcutaneous nodules (1 – 13%), and fever
  • Treatment involves prolonged antibiotic prophylaxis and NSAIDs
Rheumatic heart disease
  • Sequelae of rheumatic fever carditis
  • Thought to occur from antibodies that cross-react with streptococcal proteins and heart tissue
  • Mitral valve is most commonly affected. Mitral regurgitation is the most common disorder while mitral stenosis is pathognomonic.
Otitis media
Peritonsillar abscess
  • Symptoms include dysphagia, ipsilateral ear pain, rancid breath, and drooling
  • Physical findings include swollen tonsil that is displaced medially and inferiorly, uvula deviation, difficulty opening mouth, and muffled voice
  • Treatment includes abscess drainage, antibiotics, and airway support
Post-streptococcal glomerulonephritis
  • May occur 1 - 6 weeks after GAS infection
  • Symptoms include hematuria, proteinuria, edema, hypertension, and reduced kidney function
  • Antibiotic therapy for GAS infections does not appear to prevent post-streptococcal glomerulonephritis
  • Treatment is mostly supportive (e.g. diuretics, blood pressure management, fluid restriction)
  • Most children have complete resolution within weeks while adults are more likely to have residual kidney disease
Guttate psoriasis
  • Psoriatic rash that occurs in some patients after a strep throat infection
  • Most cases resolve spontaneously after weeks to months, but it can become a chronic condition that requires treatment












  • Reference [7]
AAOHNS 2019 recommendations for tonsillectomy
Throat infection criteria
  • Medically documented sore throat and ≥ 1 of the following:
    • Temperature > 38.3°C (101°F)
    • Cervical adenopathy
    • Tonsillar exudate
    • Positive test for GAS

Tonsillectomy may be considered in the following patients:
  • ≥ 7 throat infections in the past year
  • ≥ 5 throat infections per year over the last 2 years
  • ≥ 3 throat infections per year over the last 3 years

Factors that may favor tonsillectomy in patients who do not meet the above criteria:
  • Multiple antibiotic allergies or intolerance
  • PFAPA (periodic fever, aphthous stomatitis, pharyngitis, and adenitis)
  • History of > 1 peritonsillar abscess
  • Obstructive sleep apnea