Guillain-Barré syndrome - Diagnosing Guillain-Barré syndrome

Your GP may be able to diagnose Guillain-Barré syndrome from your symptoms and by carrying out an examination.

If you've been ill recently and have progressive muscle weakness or paralysis, you may have the condition.

Guillain-Barré syndrome can sometimes be difficult to diagnose as symptoms vary from person to person and can be similar to other brain and nervous system disorders.

In hospital, two specialist tests are usually done to rule out other conditions and confirm a problem in the nerves. These are:

electromyography
lumbar puncture

You may also have blood tests to rule out other possible causes.

Electromyography (EMG)

Electromyography (EMG) measures the health of your muscles and the nerves that control them.

To test the muscles, a needle electrode is inserted into the muscle to give an electrical recording of your muscle activity. This helps determine whether your muscles respond when certain nerves are stimulated. In Guillain-Barré syndrome, the muscles may not respond due to nerve damage.

To test the nerves, a surface electrode (a small, metal disc) is stuck to your skin to stimulate the nerves with a small electric shock. The response from your nerves (how quickly your nerves conduct electric signals) is measured. If you have Guillain-Barré syndrome, your nerve responses may be slower than normal, although the changes may be minor in the early stages.

Lumbar puncture

A lumbar puncture is a procedure carried out under local anaesthetic that involves inserting a needle into the lumbar spinal canal. This is the space in the lower spine (below the end of the spinal cord).

It's used to measure the protein levels (a measure of inflammation) and cell count in the cerebrospinal fluid, and to exclude other causes of nerve inflammation.