Differential Diagnosis for Worsening Sore Throat
- Single most likely diagnosis
- Viral pharyngitis: The patient's symptoms worsened after a week, and the initial negative rapid strep and throat culture suggest that the cause might not be streptococcal. Many viral infections can cause prolonged sore throat and low-grade fever.
- Other Likely diagnoses
- Sinusitis: Postnasal drip from sinusitis can cause sore throat, and the low-grade fever could be indicative of a bacterial infection. The worsening symptoms could suggest a secondary bacterial infection.
- Mononucleosis (Mono): Although less common, mono can cause severe sore throat and fever. The fact that the symptoms worsened over time could suggest a more complex infection like mono.
- Persistent or recurrent streptococcal pharyngitis: Despite the initial negative tests, it's possible that the patient has a persistent or recurrent streptococcal infection, especially if the initial treatment was not fully effective or if the patient was exposed again.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Lemierre's syndrome: A rare but life-threatening condition that can occur as a complication of bacterial pharyngitis, characterized by sepsis and thrombophlebitis of the internal jugular vein.
- Epiglottitis: Although more common in children, epiglottitis can occur in adults and is a medical emergency. Symptoms can include severe sore throat, difficulty swallowing, and high fever.
- Peritonsillar abscess: A complication of tonsillitis that can cause severe sore throat, fever, and difficulty swallowing. If not treated promptly, it can lead to serious complications.
- Rare diagnoses
- Toxoplasmosis: A parasitic infection that can cause sore throat and fever, although it's more commonly associated with other symptoms like lymphadenopathy.
- HIV pharyngitis: Primary HIV infection can cause sore throat and fever, among other symptoms. This diagnosis would be considered in patients with risk factors for HIV.
- Other rare infections like tularemia or diphtheria, although these would be extremely uncommon and typically associated with specific exposures or risk factors.