PHARYNGITIS










  • Reference [2]
ETIOLOGY OF PHARYNGITIS
Viruses - viruses account for the majority of throat infections
Adenovirus
  • Causes syndrome of fever, sore throat, cough, and conjunctivitis
Herpes simplex 1 virus
  • Gingivostomatitis
  • Causes painful oral ulcers
Coxsaskievirus
  • Hand, foot, 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
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 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 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 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



  • * Do not use in patients with immediate type hypersensitivity to penicillin
  • Pricing based on a standard course of therapy in a child or adult. $ = 0-$50, $$ = $51-$100, $$$ = $101-$150, $$$$ = > $150
  • Reference [2]
First-line (non-penicillin allergic) - IDSA recommendations
Medication Pediatric dosing Adult dosing Duration / Price
Penicillin
(Pen VK®)
250 mg twice daily or 3 times daily 250 mg 4 times daily or 500 mg twice daily 10 days ($)
Amoxicillin 50 mg/kg once daily (max 1000 mg) OR 25 mg/kg (max 500 mg) twice daily 1000 mg once a day or 500 mg twice a day 10 days ($)
Penicillin G benzathine
(Bicillin L-A®)
  • < 27 kg - 600,000 units IM
  • ≥ 27 kg - 1,200,000 units IM
1,200,000 units IM 1 dose ($$-$$$)
Penicillin allergic
Cephalexin*
(Keflex®)
20 mg/kg/dose twice daily (max 500 mg/dose) 500 mg twice a day 10 days ($)
Cefadroxil*
(Duricef®)
30 mg/kg once daily (max 1000 mg) 1000 mg once a day 10 days ($)
Clindamycin
(Cleocin®)
7 mg/kg/dose 3 times daily (max 300 mg/dose) 300 mg three times a day 10 days ($-$$$)
Azithromycin
(Zithromax®)
12 mg/kg once daily (max 500 mg) 500 mg once a day 5 days ($)
Clarithromycin
(Biaxin®)
7.5 mg/kg/dose twice daily (max 250 mg/dose) 250 mg twice daily 10 days ($-$$)







  • 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


Steroids for pharyngitis

Effect of Oral Dexamethasone Without Immediate Antibiotics vs Placebo on Acute Sore Throat in Adults, JAMA (2017) [PMID 28418482]
  • Design: Randomized, placebo-controlled trial (N=565 | length=1 month)
  • Treatment: Dexamethasone 10 mg one time vs Placebo
  • Primary outcome: Proportion of participants experiencing complete resolution of symptoms at 24 hours
  • Results:
    • Primary outcome (24 hours): Dexamethasone - 22.6%, Placebo - 17.7% (p=0.14)
    • Primary outcome (48 hours): Dexamethasone - 35.4%, Placebo - 27.1% (p=0.03)
  • Findings: Among adults presenting to primary care with acute sore throat, a single dose of oral dexamethasone compared with placebo did not increase the proportion of patients with resolution of symptoms at 24 hours. However, there was a significant difference at 48 hours.

Corticosteroids for pain relief in sore throat: systematic review and meta-analysis - BMJ (2009) [PMID 19661138]
  • Design: Systematic review and meta-analysis (8 RCTs encompassing 743 patients)
  • Treatment: Corticosteroids vs Placebo
  • Outcome measures: Percentage of patients with complete resolution at 24 and 48 hours, mean time to onset of pain relief, mean time to complete resolution of symptoms, days missed from work or school, recurrence, and adverse events
  • Findings: Corticosteroids provide symptomatic relief of pain in sore throat, in addition to antibiotic therapy, mainly in participants with severe or exudative sore throat.