Lumbar Puncture The diagnosis of<unk>  is made by clinical history, physical exam, and several diagnostic tests. Kernig and Brudzinski signs may be elucidated with specific physical exam maneuvers, and can help diagnose<unk>  at the bedside. Most importantly however, cerebrospinal fluid (CSF) is collected via lumbar puncture (also known as spinal tap). This fluid, which normally surrounds the brain and spinal cord, is then analyzed for signs of infection. CSF findings that suggest a viral cause of<unk>  include an elevated white blood cell count (usually 10-100 cells/µL) with a lymphocytic predominance in combination with a normal glucose level. Increasingly, cerebrospinal fluid PCR tests have become especially useful for diagnosing<unk> , with an estimated sensitivity of 95-100%. Additionally, samples from the stool, urine, blood and throat can also help to identify<unk> . CSF vs serum c-reactive protein and procalcitonin have not been shown to elucidate whether<unk>  is bacterial or viral. In certain cases, a CT scan of the head should be done before a lumbar puncture such as in those with poor immune function or those with increased intracranial pressure. If the patient has focal neurological deficits, papilledema, a Glasgow Coma Score less than 12, or a recent history of seizures, lumbar puncture should be reconsidered. Differential diagnosis for<unk>  includes<unk>  caused by bacteria, mycoplasma, fungus, and drugs such as NSAIDS, TMP-SMX, IVIG. Further considerations include brain tumors, lupus, vasculitis, and Kawasaki disease in the pediatric population.
Viral meningitis
Aseptic meningitis
Fungal meningitis
Herpesviral meningitis
Viral encephalitis
Drug-induced aseptic meningitis
Tuberculous meningitis
Herpesviral encephalitis