Lumbar puncture in babies

What is a lumbar puncture?

A lumbar puncture is a test done by a doctor to get a sample of cerebrospinal fluid, or CSF, from your baby’s back. CSF surrounds the brain and spinal cord. Lumbar puncture is also called a spinal tap or LP.

Why does my baby need an LP?

The LP is usually done to find out if your baby has an infection in the CSF around the brain (meningitis). It is the only way to know for sure if your baby has meningitis or not. Most often when we do the LP, it shows that the baby does not have meningitis. If your baby has meningitis different antibiotics may be needed for a longer period of time than we would normally treat infections. If there is meningitis, other tests may be done to help us and to give you the information you need. Sometimes a ‘therapeutic lumbar puncture’ is done to take away a build up of CSF. This may need to be repeated after a few days.

How is an LP done?

Your baby’s nurse will hold your baby curled up on their side, with the knees tucked into their chest and the head bent forward. The doctor will then put a small needle between the bones of the lower back to get some CSF fluid. The needle does not go near the spinal cord.

Does an LP hurt?

Babies often cry when they are held still for the LP, and having an LP may be uncomfortable and sometimes painful. Your baby will be given sucrose to ease any pain and a dummy to suck for comfort during the test.

What are the risks?

Lumbar puncture is a very safe test. Sometimes it is difficult to get any CSF fluid and the doctor will have to try again. The risk of any serious complications (infection, bleeding or damage to the spinal cord or nerves) is extremely small. We monitor the baby’s heart rate and oxygen levels during the procedure to make sure that the baby is stable throughout.

When will I know the results of the LP?

Some results are known within a couple of hours, and will usually tell us if your baby has meningitis or not. But better information will be available after about two days.