Spinal fluid surrounds and protects the nervous system, including the spinal cord, and generally maintains a specific level of pressure. If the pressure is too high, or too low, it can cause headaches. Infections in the brain often require a spinal tap in order to diagnose and identify the organism causing the infection.
In some patients, a spinal tap (lumbar puncture) is done to help diagnose the causes of a headache. Other diagnostic tests, such as a myelogram or cisternogram, require a lumbar puncture. Periodically, a new headache occurs following a spinal tap, which is brought on by standing and improving while lying in bed. This is referred to as a “low pressure headache” and is generally self-limited but sometimes requires a blood patch.