Differential Diagnosis for the Patient's Symptoms

The patient presents with a stuffy nose, headache, fever, erythematous nasal mucosa, purulent nasal discharge, and tenderness to maxillary sinuses. Based on these symptoms, the following differential diagnoses are considered:

• Single Most Likely Diagnosis

  • Acute Bacterial Sinusitis (ABS): The patient's symptoms of purulent nasal discharge, facial pain (tenderness with percussion to maxillary sinuses), and fever for over 10 days are highly suggestive of ABS. The most common pathogens responsible for ABS include Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis. While Pseudomonas aeruginosa can cause sinusitis, it is less common in the context of acute community-acquired sinusitis and more typically seen in patients with underlying conditions such as cystic fibrosis or immunocompromised states.

• Other Likely Diagnoses

  • Viral Rhinosinusitis: Although the duration of symptoms is somewhat prolonged for a typical viral upper respiratory infection, some viruses can cause prolonged symptoms. The presence of fever and purulent discharge, however, leans more towards a bacterial etiology.
  • Allergic Rhinitis: Could present with similar nasal symptoms but typically lacks fever and purulent discharge. Seasonal or environmental allergens could exacerbate symptoms.
  • Acute Viral Sinusitis: Similar to viral rhinosinusitis but with specific involvement of the sinuses. The viral etiology is less likely given the duration and nature of the symptoms.

• Do Not Miss Diagnoses

  • Intracranial Complications of Sinusitis: Such as meningitis, brain abscess, or subdural empyema. These are rare but potentially life-threatening complications that require immediate attention.
  • Orbital Complications of Sinusitis: Including orbital cellulitis or abscess, which can lead to serious consequences if not promptly treated.
  • Invasive Fungal Sinusitis: Although rare, this condition is critical to consider, especially in immunocompromised patients, as it requires urgent treatment.

• Rare Diagnoses

  • Wegener's Granulomatosis (Granulomatosis with Polyangiitis): A form of vasculitis that can present with sinusitis among other symptoms.
  • Sarcoidosis: Can involve the sinuses and present with chronic symptoms.
  • Pseudomonas Sinusitis: As mentioned, Pseudomonas aeruginosa is an uncommon cause of community-acquired sinusitis but should be considered in specific contexts such as immunocompromised patients or those with cystic fibrosis.