Tuberculous Meningitis: This diagnosis is highly considered due to the combination of diffuse leptomeningeal enhancement, low glucose in CSF, high protein in CSF, and the presence of avid hilar nodes, which are suggestive of tuberculosis. The patient's demographic background also supports this diagnosis, as tuberculosis is more prevalent in certain populations.

Cryptococcal Meningitis: This fungal infection is a common cause of meningitis in immunocompromised patients, particularly those with HIV/AIDS, which could be a consideration given the patient's symptoms and demographic. The low glucose and high protein in CSF, along with leptomeningeal enhancement, are consistent with this diagnosis.
Lymphomatous Meningitis: This condition involves the spread of lymphoma to the meninges and can present with similar CSF findings and neuroimaging results. The patient's confusion could be indicative of central nervous system involvement.
Sarcoidosis: Although less common, sarcoidosis can cause leptomeningeal enhancement and hilar lymphadenopathy. It's a systemic disease that can affect multiple organs, including the central nervous system.

HIV-Related Opportunistic Infections: Given the patient's symptoms, it's crucial not to miss the possibility of HIV infection, which could predispose him to a variety of opportunistic infections, including those mentioned above (cryptococcal meningitis, tuberculous meningitis).
Carcinomatous Meningitis: Metastatic disease to the meninges from a primary cancer (e.g., lung, breast) could present similarly and is a critical diagnosis not to overlook due to its implications for treatment and prognosis.
Viral Encephalitis: Certain viral infections (e.g., herpes simplex encephalitis) can cause severe neurological symptoms, including confusion, and require prompt treatment to prevent serious outcomes.

Whipple's Disease: A rare, systemic bacterial infection that can affect the central nervous system, causing symptoms like confusion, and can lead to meningeal enhancement on imaging.
Neurosyphilis: A condition caused by the spread of syphilis to the central nervous system, which can present with a variety of neurological symptoms and CSF abnormalities.
Leptomeningeal Carcinomatosis from a Rare Primary Tumor: Metastasis to the meninges from less common primary tumors (e.g., melanoma, gastrointestinal cancers) is rare but should be considered in the differential diagnosis due to its significant impact on patient management and outcome.