Differential Diagnosis for Sore Throat

Given the patient's symptoms of a sore throat that does not alleviate after 3 days of azithromycin, with a red and swollen throat and uvula, mild swelling, neck pain, and no lymphadenopathy, the following differential diagnoses are considered:

• Single Most Likely Diagnosis

  • Streptococcal Pharyngitis: This is a common cause of sore throat and can present with symptoms similar to those described. The lack of response to azithromycin, which is more effective against bacterial infections other than streptococcal infections (for which penicillin or amoxicillin are preferred), suggests that the initial treatment might not have been targeted at the correct pathogen. Streptococcal infections are typically treated with penicillin or amoxicillin.

• Other Likely Diagnoses

  • Viral Pharyngitis: Many viruses can cause pharyngitis, and the symptoms can be similar to bacterial causes. The absence of lymphadenopathy does not rule out viral pharyngitis, as this symptom can be variable. Viral infections would not respond to azithromycin, explaining the persistence of symptoms.
  • Mononucleosis (Infectious Mononucleosis): Caused by Epstein-Barr virus (EBV), this condition can present with sore throat, fever, and fatigue. Although lymphadenopathy is common, it's not universal, and the absence of it doesn't rule out the diagnosis.
  • Acute Laryngitis: Inflammation of the larynx can cause throat pain and is often viral in nature. The symptoms can overlap with pharyngitis, and the lack of response to antibiotics would be expected.

• Do Not Miss Diagnoses

  • Lemierre's Syndrome: A rare but serious condition that starts with pharyngitis and can progress to septicemia and thrombophlebitis of the internal jugular vein. It's caused by Fusobacterium necrophorum and can present with neck pain and swelling, making it a critical diagnosis not to miss.
  • Epiglottitis: Although more commonly seen in children, adults can also be affected. It presents with severe sore throat, difficulty swallowing, and shortness of breath. The absence of lymphadenopathy and the presence of neck pain could be consistent with this diagnosis, which requires immediate medical attention.
  • Retropharyngeal Abscess: This condition involves a collection of pus in the tissues in the back of the throat. It can cause severe throat pain, neck stiffness, and difficulty swallowing. Although it's more common in children, it can occur in adults and is a medical emergency.

• Rare Diagnoses

  • Diphtheria: A bacterial infection affecting the membranes of the throat and nose. Although rare in areas with widespread vaccination, it can cause severe respiratory illness and should be considered in patients with a sore throat that does not respond to typical treatments, especially if they have not been vaccinated.
  • Tuberculous Pharyngitis: A rare form of tuberculosis that affects the pharynx. It can present with chronic sore throat, among other symptoms, and is more likely in immunocompromised individuals or those from areas with high TB prevalence.
  • Syphilitic Pharyngitis: Caused by Treponema pallidum, the bacterium that causes syphilis. It's a rare cause of sore throat but should be considered in patients with risk factors for sexually transmitted infections.