Back
ditki Logo
medical & biological sciences
All Access Pass - 1 FREE Month!
Institutional email required, no credit card necessary.

Pharyngitis for the ABIM

Free One-Month! Institutional (.edu or .org) email required
Log in or start your One-Week Free Trial!
Pharyngitis for the American Board of Internal Medicine Exam
Etiology
  • Viral Causes:
    • Most common: Pharyngitis is primarily caused by viruses (up to 80% of cases). Common viral pathogens include:
    • Rhinovirus: The most frequent viral cause, especially in adults.
    • Adenovirus: Associated with pharyngoconjunctival fever (sore throat, fever, conjunctivitis).
    • Coronavirus: Including common cold coronaviruses and SARS-CoV-2.
    • Epstein-Barr Virus (EBV): Causes infectious mononucleosis, presenting with sore throat, fever, and lymphadenopathy.
    • Influenza and Parainfluenza: These can cause pharyngitis with associated systemic symptoms like fever, myalgia, and fatigue.
    • Herpes Simplex Virus (HSV): May cause vesicles and ulcers on the pharyngeal mucosa.
  • Bacterial Causes:
    • Group A Streptococcus (GAS) (Streptococcus pyogenes): The most common bacterial cause of pharyngitis, responsible for 5-15% of cases in adults and 20-30% in children.
    • Other Streptococci: Group C and G streptococci can also cause pharyngitis but are less common.
    • Other Bacterial Causes: Include Neisseria gonorrhoeae (gonococcal pharyngitis), Corynebacterium diphtheriae (diphtheria), and Mycoplasma pneumoniae.
Clinical Features
pharyngitis
  • Viral Pharyngitis:
    • Sore throat is often mild, with other upper respiratory symptoms such as cough, rhinorrhea, and hoarseness.
    • Low-grade fever and fatigue are common.
    • Conjunctivitis, particularly with adenovirus, or oral ulcers with HSV may also be present.
    • Influenza typically presents with abrupt onset fever, myalgias, and more severe systemic symptoms.
    • EBV (infectious mononucleosis): Sore throat, fever, posterior cervical lymphadenopathy, and fatigue. Patients may also have splenomegaly and exudative pharyngitis.
  • Bacterial Pharyngitis (GAS):
    • Sudden onset of sore throat without cough or rhinorrhea.
    • Fever: Usually higher (>38°C).
    • Tonsillar exudates: Purulent or white patches on the tonsils.
    • Tender anterior cervical lymphadenopathy: Enlarged, tender lymph nodes.
    • Scarlet fever: May occur as a complication, presenting with a fine, sandpaper-like rash and strawberry tongue.
    • Other findings: Headache, abdominal pain (especially in children).
  • Complications of GAS Pharyngitis:
    • Rheumatic fever: A post-infectious autoimmune complication causing arthritis, carditis, and chorea.
    • Post-streptococcal glomerulonephritis: Presents with hematuria, edema, and hypertension after streptococcal infection.
    • Peritonsillar abscess: Localized infection leading to severe sore throat, "hot potato" voice, and trismus.
Diagnosis
  • Clinical Scoring Systems (Centor Criteria):
    • The Centor score helps predict the likelihood of GAS pharyngitis and includes:
    • Tonsillar exudates (+1)
    • Tender anterior cervical lymphadenopathy (+1)
    • Absence of cough (+1)
    • Fever history (+1)
    • Age <15 years (+1) or >44 years (-1)
    • Scores of 3 or more suggest the need for further testing (e.g., rapid strep test or throat culture).
  • Rapid Antigen Detection Test (RADT):
    • Used to detect Group A Streptococcus (GAS) with high specificity. A positive test confirms the diagnosis, and antibiotics can be started.
    • Negative RADT in adults typically does not require further testing, but in children, a throat culture is often performed to rule out false negatives.
  • Throat Culture:
    • Considered the gold standard for diagnosing GAS pharyngitis, with results available in 24-48 hours. Used to confirm negative RADT in children.
  • EBV Serology:
    • For patients with suspected infectious mononucleosis, heterophile antibody testing (Monospot) or specific EBV serologies can confirm the diagnosis.
  • Other Tests:
    • If gonococcal pharyngitis is suspected in sexually active individuals, a throat swab for Neisseria gonorrhoeae culture or nucleic acid amplification testing (NAAT) can be performed.
Management
Viral Pharyngitis
  • Supportive Care:
    • Viral pharyngitis is typically self-limiting. Treatment focuses on symptom relief:
    • Analgesics (e.g., acetaminophen, ibuprofen) for fever and pain.
    • Throat lozenges, saltwater gargles, and hydration.
    • Avoid antibiotics: Antibiotics are not indicated for viral infections.
  • Influenza:
    • Antiviral agents (e.g., oseltamivir) may be used if the patient presents within 48 hours of symptom onset or has risk factors for severe disease.
  • Herpes Simplex Pharyngitis:
    • Acyclovir or valacyclovir can be used to shorten the duration of symptoms, particularly in severe cases or immunocompromised patients.
  • EBV (Infectious Mononucleosis):
    • Supportive care is recommended. Avoid contact sports due to the risk of splenic rupture in patients with splenomegaly. Corticosteroids may be considered in severe cases (e.g., airway obstruction, hemolytic anemia).
Bacterial Pharyngitis (GAS)
  • Antibiotics:
    • Prompt antibiotic therapy is recommended to reduce symptom duration, prevent complications (e.g., rheumatic fever), and reduce transmission. First-line options include:
    • Penicillin V (or amoxicillin): 10-day course is preferred.
    • Penicillin allergy: Cephalexin (if mild allergy) or clindamycin/ azithromycin (if severe allergy).
  • Symptom Relief:
    • Analgesics such as acetaminophen or ibuprofen for pain and fever control.
    • Throat lozenges and saltwater gargles to soothe sore throat.
  • Follow-up:
    • No follow-up cultures are required after successful treatment, except in cases of recurrent infections or family members with rheumatic fever.
Complications
  • Suppurative Complications:
    • Peritonsillar abscess: Results in severe throat pain, uvular deviation, trismus, and muffled voice. Treated with incision and drainage and antibiotics.
    • Retropharyngeal abscess: Can present with neck stiffness, dysphagia, and airway compromise. Requires surgical drainage and IV antibiotics.
  • Nonsuppurative Complications:
    • Acute rheumatic fever: Prevented by timely treatment of GAS. Manifests with arthritis, carditis, and Sydenham’s chorea.
    • Post-streptococcal glomerulonephritis: Occurs after GAS pharyngitis, presenting with hematuria, edema, and hypertension.
Key Points
  • Pharyngitis is most commonly caused by viral infections (e.g., rhinovirus, adenovirus). Group A Streptococcus (GAS) is the most common bacterial cause.
  • Viral pharyngitis often presents with mild sore throat, rhinorrhea, and cough, whereas bacterial pharyngitis (GAS) presents with sudden onset sore throat, fever, tonsillar exudates, and tender anterior cervical lymphadenopathy.
  • GAS pharyngitis should be diagnosed using clinical scoring systems (e.g., Centor criteria), rapid antigen detection tests (RADT), or throat culture.
  • Treatment of viral pharyngitis is supportive, while GAS pharyngitis requires antibiotics (e.g., penicillin, amoxicillin) to prevent complications.
  • Complications of GAS pharyngitis include rheumatic fever, post-streptococcal glomerulonephritis, and suppurative complications such as peritonsillar abscess.

Related Tutorials