Differential Diagnosis for a 15-year-old with Fever, Sore Throat, and Swollen Posterior Tonsils
- Single Most Likely Diagnosis
- Streptococcal Pharyngitis (Strep Throat): This is the most likely diagnosis given the symptoms of fever, sore throat, and swollen, painful tonsils. Strep throat is a common bacterial infection in adolescents that presents with these exact symptoms.
- Other Likely Diagnoses
- Viral Pharyngitis: Many viruses can cause pharyngitis, which presents similarly to strep throat but is more likely to be accompanied by other symptoms such as cough, runny nose, or conjunctivitis. The absence of these additional symptoms makes viral pharyngitis less likely but still a consideration.
- Mononucleosis (Mono): Caused by the Epstein-Barr virus, mono can present with fever, sore throat, and swollen tonsils, often accompanied by lymphadenopathy and fatigue. The age of the patient and the presence of malaise increase the likelihood of mono.
- Do Not Miss Diagnoses
- Lemierre's Syndrome: A rare but potentially life-threatening condition that starts with pharyngitis and progresses to a severe infection of the jugular vein, characterized by high fever, severe neck pain, and swelling. Although rare, it's critical to consider due to its high morbidity and mortality if not promptly treated.
- Peritonsillar Abscess: A complication of tonsillitis where an abscess forms beside the tonsils, causing severe throat pain, difficulty swallowing, fever, and a muffled voice. It requires urgent medical attention, often involving drainage of the abscess.
- Rare Diagnoses
- Diphtheria: A bacterial infection affecting the membranes of the throat and nose. Although rare in countries with widespread vaccination, it can cause severe respiratory illness and should be considered in unvaccinated individuals or those who have traveled to areas where diphtheria is common.
- Tonsillar Carcinoma: Extremely rare in adolescents, but any persistent or severe tonsillar symptoms without a clear infectious cause should prompt consideration of malignancy, especially if there are risk factors such as smoking or a family history of cancer.