Primary Impression and Differential Diagnoses

The patient's presentation of watery nasal discharge, metallic taste, and fever following transsphenoidal resection of a pituitary tumor strongly suggests a cerebrospinal fluid (CSF) leak. The primary impression is that the patient has developed a complication related to the surgical site, potentially leading to infection.

Differential Diagnoses

• Single most likely diagnosis:
  • CSF Leak with Meningitis: The patient's symptoms of watery nasal discharge, metallic taste, and fever, combined with the history of recent pituitary surgery, make a CSF leak with secondary meningitis the most likely diagnosis. The presence of systemic infection and fever supports the suspicion of meningitis.
• Other Likely diagnoses:
  • Pneumonia: Initially considered due to the patient's cough, pneumonia could still be a contributing factor, especially if the patient has aspirated or has a secondary infection.
  • Sinusitis: The patient's symptoms of postnasal drip, cough, and nasal discharge could also suggest sinusitis, potentially as a complication of the CSF leak or as a separate entity.
• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.):
  • Brain Abscess: Although less likely, a brain abscess is a potentially life-threatening complication that could arise from a CSF leak or as a result of the initial surgery. The absence of headache, nausea, or vomiting does not rule out this diagnosis.
  • Subarachnoid Hemorrhage: Though the patient does not exhibit typical symptoms like headache or neck stiffness, a subarachnoid hemorrhage could occur, especially in the context of recent neurosurgery.
• Rare diagnoses:
  • Empty Sella Syndrome: This condition, where the sella turcica appears empty due to a defect in the diaphragma sellae, could potentially lead to CSF leaks. However, it is less directly related to the patient's current symptoms and recent surgical history.

Management Plan

1. Continue Empirical Antibiotics: Maintain the current antibiotic regimen (e.g., Vancomycin) to cover for potential bacterial meningitis until CSF culture results are available.
2. CSF Analysis: Perform a lumbar puncture (if not contraindicated) to analyze CSF for signs of infection, including culture, glucose, protein, and cell count.
3. Imaging Studies: Conduct CT or MRI scans of the head to evaluate the surgical site, assess for any signs of complication (e.g., abscess, hemorrhage), and confirm the presence of a CSF leak.
4. ENT Consultation: Consult with an ENT specialist to consider endoscopic exploration and potential repair of the CSF leak.
5. Monitor for Complications: Closely monitor the patient for signs of worsening infection, increased intracranial pressure, or other neurological complications.
6. Supportive Care: Provide supportive care, including management of fever, pain, and any respiratory symptoms, and ensure the patient is hydrated and nutritionally supported.