Lumbar punctures are generally very low-risk procedures. However, they sometimes cause short-lived side effects.

Back pain

Some people experience some lower back pain after a lumbar puncture. This is usually felt in and around the area where the needle was inserted, but it can also be felt in the backs of your legs. 

In most cases, the pain will ease after a few days and it can be treated with painkillers, such as paracetamol.

Headache

A headache is a common side effect of a lumbar puncture, usually developing within 24 to 48 hours of the procedure.

Most people describe a dull or throbbing pain at the front of their head, sometimes spreading to the neck and shoulders. The pain is usually worse while standing or sitting up and is usually relieved by lying down.

The headache can usually be treated with simple painkillers such as paracetamol. Some people have also reported that drinks containing caffeine, such as coffee, tea or cola, have helped to reduce the discomfort. 

If post-lumbar puncture headaches persist, are particularly severe, or are accompanied by sickness and vomiting, contact the hospital that carried out the procedure.

Swelling and bruising

You may notice some bruising and minor swelling in your lower back. The swelling is caused by a small amount of fluid leaking and collecting under your skin. This is normally nothing to worry about and the swelling should go down naturally. However, seek medical advice if the swelling continues or gets worse.

Other risks

There is a small risk of a lumbar puncture leading to bleeding inside the head, although this is very rare. In most cases, the benefits of the lumbar puncture far outweigh this risks. The likelihood of a lumbar puncture causing an infection in the spine is also very small. 

However, you should seek medical advice if you develop a temperature or sensitivity to bright lights, if the lumbar puncture site becomes painful and swollen, or if you notice blood or clear fluid around the site.

Rarer side effects include tingling and numbness in your legs, hearing loss and double vision.