Historically, the process of diagnosis involved attempting to identify any infectious causes as these may be treatable with antibiotics or other medications. Lumbar puncture would be performed to collect cerebral spinal fluid (CSF) to culture for bacterial growth. Growth indicated a bacterial meningitis, while no growth indicated another cause denoted<unk> " meningitis. The most common form of this is viral meningitis. Recent medical advances allows rapid polymerase chain reaction (PCR) testing that analyzes the CSF for DNA or RNA. This can quickly determine if there are bacterial or viral species present in the CSF. If these are ruled out, as well as other causes such as parasitic or fungal causes, then the cause of the meningitis is likely noninfectious in nature. DIAM is among these noninfectious causes of<unk>  meningitis. Once infectious causes ruled out, noninfectious causes should be investigated. These include a history of chemical irritation from recent surgery or chemicals injected into the subarachnoid space such as spinal anesthesia, other inflammatory or vascular conditions such as sarcoidosis or vasculitis, as well as Neoplastic conditions such as lymphoma. CSF analysis tends to show inflammatory changes in DIAM such as elevated white blood cells and elevated protein levels. Glucose was either normal or low. MRI and CT imaging of the brain has shown changes consistent with blood-brain barrier disruption or cerebral edema including T2-weighted changes that were normalized after resolution of the condition. In patients with SLE, DIAM should be distinguished from lupus<unk>  meningitis (LAM). This can be done by CSF analysis (DIAM has a neutrophilic predominance while LAM has a lymphocytic predominance), as well as assessment of relevant labs such as complement levels and signs of Lupus flareup.
Drug-induced aseptic meningitis
Fungal meningitis
Aseptic meningitis
Viral meningitis
Herpesviral meningitis
Viral encephalitis
Tuberculous meningitis
Granulomatous meningoencephalitis