Differential Diagnosis for a 31-year-old Woman with Fever, Altered Mental Status, and Bilateral Periorbital Edema

• Single most likely diagnosis:
  • Cavernous sinus thrombosis: This condition is suggested by the combination of recent sinus infection, fever, altered mental status, and bilateral periorbital edema. The cavernous sinuses are located near the sphenoid sinus, and an infection there can spread to cause thrombosis, leading to these symptoms.
• Other Likely diagnoses:
  • Meningitis: Given the fever, altered mental status, and recent history of sinus infection, meningitis is a plausible diagnosis. However, the presence of bilateral periorbital edema is more suggestive of cavernous sinus thrombosis.
  • Orbital cellulitis: This condition could explain the periorbital edema and fever, especially with a recent sinus infection. However, altered mental status is less commonly associated with orbital cellulitis alone.
• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.):
  • Brain abscess: Although less likely, a brain abscess could present with altered mental status and fever. The recent sinus infection increases the risk, and missing this diagnosis could be fatal.
  • Sepsis: The patient's vital signs (hypotension, tachycardia, fever) suggest sepsis, which is a life-threatening condition requiring immediate attention.
• Rare diagnoses:
  • Wegener's granulomatosis (Granulomatosis with Polyangiitis): This is a rare autoimmune disorder that could potentially cause the combination of sinus infection, fever, and altered mental status, but it would be an unusual presentation.
  • Fulminant invasive fungal sinusitis: Although rare, this condition can occur, especially in immunocompromised patients, and presents with similar symptoms, including fever, periorbital edema, and altered mental status.