Differential Diagnosis for an 18-year-old girl with one week of and three days of sore throat and fever

• Single most likely diagnosis
  • Viral Pharyngitis: This is the most common cause of sore throat and fever in young adults, often caused by viruses such as adenovirus, influenza, or respiratory syncytial virus. The symptoms presented, such as sore throat and fever, are typical for viral pharyngitis, and the duration of one week is consistent with the natural course of many viral infections.
• Other Likely diagnoses
  • Streptococcal Pharyngitis (Strep Throat): Caused by Group A beta-hemolytic streptococcus, this condition presents with sore throat, fever, and can be accompanied by other symptoms like swollen lymph nodes and white patches on the tonsils. It's a common bacterial cause of pharyngitis that requires antibiotic treatment.
  • Infectious Mononucleosis: Caused by Epstein-Barr virus, it can present with sore throat, fever, fatigue, and lymphadenopathy. The age of the patient and the combination of symptoms make this a plausible diagnosis.
  • Acute Tonsillitis: Can be caused by either viral or bacterial pathogens, leading to inflammation of the tonsils, sore throat, and fever.
• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
  • Lemierre's Syndrome: A rare but potentially life-threatening condition that starts with pharyngitis and progresses to septicemia and thrombophlebitis of the internal jugular vein, typically caused by Fusobacterium necrophorum. Early recognition is crucial for effective treatment.
  • Retropharyngeal Abscess: A serious infection in the tissues at the back of the throat, which can lead to airway obstruction and other complications if not promptly treated.
  • Epiglottitis: Inflammation of the epiglottis that can cause severe swelling, potentially leading to airway obstruction. It's more common in children but can occur in adults, especially if they have certain underlying health conditions.
• Rare diagnoses
  • Diphtheria: A bacterial infection affecting the membranes of the throat and nose. Though rare in areas with widespread vaccination, it remains a consideration in unvaccinated individuals or those traveling to areas where diphtheria is more common.
  • Gonococcal Pharyngitis: Caused by Neisseria gonorrhoeae, this condition can present with sore throat and fever in sexually active individuals, highlighting the importance of taking a thorough sexual history.
  • Tuberculous Pharyngitis: A rare form of tuberculosis that affects the pharynx, more common in individuals with compromised immune systems or those from areas with high TB prevalence.