The presented symptoms and investigation findings strongly suggest sarcoidosis as the most likely diagnosis. Here's a detailed breakdown:
1. Ptosis and bilateral facial nerve palsy: The neurological manifestations, such as facial nerve involvement, are consistent with neurosarcoidosis, although rare, it's a known complication of sarcoidosis.
2. Fever and night sweats: These are common systemic symptoms of sarcoidosis due to its inflammatory nature.
3. Leukocytosis: An elevated white blood cell count can occur in sarcoidosis as part of the body's response to inflammation.
4. Bilateral hilar lymphadenopathy: This is a hallmark radiographic finding of sarcoidosis, seen in chest X-rays or CT scans.
Given the clinical and radiographic findings, sarcoidosis is the most fitting diagnosis among the provided options.
Other options are less likely due to the following reasons:
1. Tuberculosis: While it presents with fever, night sweats, and lymphadenopathy, bilateral facial nerve palsy and ptosis are not typical.
2. Lymphoma: Can present with similar systemic symptoms and lymphadenopathy, but facial nerve involvement is less typical.
3. Hypersensitive pneumonitis: More commonly causes respiratory symptoms rather than the neurological and systemic symptoms noted.