Lumbar Puncture and Stroke

What is lumbar puncture?

This is a procedure to help doctors diagnose neurological conditions. (Neurological conditions are those that affect the nervous system.) Lumbar puncture has been an important diagnostic tool since it was introduced in 1891, but it’s now done only rarely in patients with stroke symptoms. It's also called spinal puncture or spinal tap.

The process involves taking samples of the cerebrospinal fluid (or CSF) from around the spinal cord. The tests are done on the fluid samples. This helps doctors gain important information:

• The presence of blood or blood products in the CSF suggests bleeding. Hemorrhagic strokes occur when an artery ruptures and bleeds into or onto the brain.
• CSF analysis can also indicate changes due to tumor, infection and inflammation. Infection and inflammation may lead to symptoms that mimic a stroke.
• Spinal puncture allows the doctor to quantify pressure within the central nervous system.

What other tests can be used to diagnose stroke?

Imaging techniques such as computed tomography (CT) and magnetic resonance imaging (MRI) can be done during acute stroke. In most cases they permit effective, safe diagnosis of ischemic stroke (caused by blood clots) and of bleeding into the brain. These tests largely eliminate the need for lumbar puncture in stroke. These imaging systems also help identify tumors and other conditions that mimic stroke. New monitoring devices can measure CSF pressure and detect changes in intracranial pressure. Pressure-induced shifts in regions of the brain can be imaged by CT and MRI.