Differential Diagnosis for Tonsillitis vs Strep

When considering a differential diagnosis for a patient presenting with symptoms of tonsillitis or a suspected strep infection, it's crucial to approach the diagnosis systematically. The following categories help in organizing the thought process:

• Single Most Likely Diagnosis
  • Viral Pharyngitis: This is the most common cause of tonsillitis, often presenting with symptoms such as sore throat, fever, and swollen lymph nodes. The justification for this being the single most likely diagnosis is the high prevalence of viral infections in the community and the fact that most cases of tonsillitis are viral in nature.
• Other Likely Diagnoses
  • Streptococcal Pharyngitis (Strep Throat): Caused by Group A beta-hemolytic streptococcus, this condition presents similarly to viral pharyngitis but requires antibiotic treatment to prevent complications. The presence of a severe sore throat, fever, and absence of cough are typical indicators.
  • Mononucleosis (Infectious Mononucleosis): Caused by Epstein-Barr virus, this condition can mimic strep throat and viral pharyngitis but is distinguished by the presence of fatigue, lymphadenopathy, and sometimes hepatosplenomegaly.
• Do Not Miss Diagnoses
  • Lemierre's Syndrome: A rare but potentially life-threatening condition that occurs as a complication of bacterial pharyngitis, characterized by septic thrombophlebitis of the internal jugular vein. It's crucial to consider this diagnosis due to its high morbidity and mortality if not promptly treated.
  • Peritonsillar Abscess: A collection of pus behind the tonsils that can cause severe throat pain, difficulty swallowing, and fever. This condition requires urgent drainage and antibiotic treatment.
  • Epiglottitis: Inflammation of the epiglottis that can lead to airway obstruction, presenting with severe sore throat, difficulty swallowing, and shortness of breath. This is a medical emergency.
• Rare Diagnoses
  • Diphtheria: A bacterial infection affecting the mucous membranes of the throat and nose, though rare in areas with high vaccination coverage, it can cause severe respiratory illness.
  • Tularemia: A rare infectious disease caused by Francisella tularensis, which can present with pharyngitis among other symptoms, and is typically associated with contact with infected animals or contaminated water.

Each of these diagnoses has distinct clinical features and requires a tailored approach to diagnosis and treatment. A thorough history, physical examination, and when necessary, laboratory tests, are essential for making an accurate diagnosis.