Investigations: Cerebrospinal fluid
In the second part of our series, Suneeta Kochhar and William Marshall guide you through the basics of interpreting CSF results
After taking a history and doing a physical examination it is important to order appropriate investigations and interpret the results in order to formulate a diagnosis and make treatment decisions.
Cerebrospinal fluid (CSF) investigations are usually done when meningitis is suspected. But examining CSF may also be useful when diagnosing suspected subarachnoid haemorrhage, multiple sclerosis, and certain polyneuropathies, such as Guillain-Barré syndrome and chronic inflammatory demyelinating polyneuropathy.
CSF is produced by the choroid plexus and circulates in the subarachnoid space--a sample is usually obtained by lumbar puncture. A lumbar puncture is also done for intrathecal administration of drugs to treat pain and severe spasticity, measurement of CSF pressure when there is clinical evidence of rising intracranial pressure, and for the therapeutic removal of CSF in benign intracranial hypertension to prevent visual disturbances and secondary brain injury.
Collect approximately 2 ml of fluid in numbered bottles in a sequential manner. At