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 to the antibodies 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 (see rheumatic fever prevention) and NSAIDs
Rheumatic heart disease
  • Sequelae of rheumatic fever carditis
  • Thought to occur from antibodies that cross-react with streptococcal proteins and heart tissue
  • Rheumatic heart disease typically affects the mitral valve. Mitral valve stenosis is almost exclusively caused by rheumatic heart disease, and its presence is considered pathognomonic for the condition. However, mitral valve regurgitation is the most common defect observed.
  • See rheumatic fever prevention below for recommendations on preventing recurrence
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 [8,9]
ANTIBIOTIC CHOICE
Antibiotic Regimen
Penicillin G benzathine
  • Weight ≤ 60 lbs (27 kg): 600,000 units IM every 4 weeks
  • Weight > 60 lbs (27 kg): 1,200,000 units IM every 4 weeks
  • If patient develops rheumatic fever while receiving every 4 week regimen, switching to every 3 weeks may be appropriate
Penicillin (Pen VK®)
  • 250 mg twice daily
Sulfadiazine
  • Weight ≤ 60 lbs (27 kg): 500 mg once daily
  • Weight > 60 lbs (27 kg): 1000 mg once daily
Macrolide antibiotics
  • May be used in penicillin allergic patients. There are no good studies to guide dosing.

  • Reference [8]
DURATION OF PROPHYLAXIS
Type of disease Duration after last attack
Rheumatic fever with carditis and residual heart disease (clinical or echocardiographic)
  • 10 years or until patient is 40 years of age (whichever is longer)
Rheumatic fever with carditis but no residual heart disease
  • 10 years or until patient is 21 years of age (whichever is longer)
Rheumatic fever without carditis
  • 5 years or until patient is 21 years of age (whichever is longer)
Lifelong prophylaxis may be recommended if the patient is at high risk of group A streptococcus exposure. Secondary rheumatic heart disease prophylaxis is required even after valve replacement.



  • 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