Lumbar Puncture


What is it?

The brain and the spine are bathed in a layer of fluid. A lumbar puncture involves taking a sample of this fluid from the lower back. This is then analysed in the laboratory.


Why is it performed?

There are a number of reasons that a Lumbar Puncture is performed. Most commonly it is performed if there is a suspicion of an infection of the brain or spine. A lumbar puncture is sometime required is some forms of leukaemia or lymphoma. This is to assess whether the brain or spine are affected by the disease and to determine if they need treating.


How is it performed?

A lumbar puncture is performed by a Doctor who will talk you through the procedure before it is performed. The skin is cleaned and then a local anaesthetic is applied to the lower back. The anaesthetic does sting a little before the area goes numb. A sample of fluid surrounding the lower spine is then removed using a fine needle. The whole process is very similar to an epidural which women sometimes have during pregnancy. The only difference is that with epidurals drugs are injected into the fluid around the spine rather then removing some of the fluid.


What do I need to know about it?

The whole process takes around 15 minutes. You will be required to lie on your side in a curled up position whilst the fluid is being removed. The main side effect from the procedure is a headache. To minimise this happening you will be asked to lie down for an hour after the procedure is finished. The site where the fluid is taken from may feel bruised afterwards for a few days but this should not prevent you from doing anything.


When will I get the results?

The results are obtained quickly when looking for infections. Other tests can take longer to process, this will be completed after around a week.


Further information

Lumbar puncture at Macmillian cancer support



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Written by: Dr T Rider

Editor: Dr J Newman

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