• Roos KL (2002). What I have learned about infectious diseases with my sleeves rolled up. Semin Neurol 22:9-15. Summary: The questions most often asked of my residents and myself are the following: (1) How do you interpret the cerebrospinal fluid white blood cell count and polymerase chain reaction results when the lumbar puncture has been traumatic? (2) Does the older adult with a serum sample that tests positive by the Venereal Disease Research Laboratory test need spinal fluid analysis for neurosyphilis, and which of those syphilis tests can become nonreactive even though the patient is never treated? (3) Do you give steroids to patients with bacterial meningitis? (4) What do you do for the patient with cryptococcal meningitis who develops a spastic gait? (5) Are all cases of transverse myelitis "idiopathic"? and (6) When does the patient who has had a stroke need spinal fluid analysis to rule out an infectious etiology? This is how we answer these questions. Department of Neurology, Indiana University, Indianapolis, Indiana 46202-5124, USA.