Neurology - Lumbar Puncture

Introduction

What is a Lumbar Puncture (LP)?

A lumbar puncture (LP), also known as a spinal tap, is a medical procedure where a small amount of fluid called cerebrospinal fluid (CSF) is taken from your lower back. This fluid is made in the brain, which bathes and protects both the brain and spinal cord. The collected fluid is then sent for analysis, which helps the medical team learn more about your health.

Why is a LP performed?

The results from the LP, combined with the clinical history, examination, and scan results, provide the medical team with valuable information about the functioning of your brain and spinal cord.

The fluid obtained during the LP is used for:

1.    CSF analysis to detect infections, bleeding, or other abnormalities for diagnostic purposes

2.    Pressure measurements are taken for both opening and closing pressures, and excess CSF is drained, if necessary.

On other occasions LP can have a therapeutic purpose by directly administering medication into the CSF.

How is a LP performed?

LP will be performed with the following steps:

1. You will be asked to lower your bottom garment to hip level and raise your top garment towards your chest, exposing the lower back for the procedure.
2. You will then be asked to either lie on your left side with your knees curled up toward your chest or assume a sitting position. The choice of position is usually determined based on examination of the back and clinical need.

Fig 1. Two positions in which LP can be performed: the 'lying position' and the 'sitting position'.
 
3.    The medical personnel will then examine the area, which may cause discomfort but should not be painful.

4.    The area is then cleaned with an antiseptic, which may feel wet and cold.

5.    A local anesthetic is then used to numb the area. You may feel a sharp scratch, similar to when getting blood drawn or during  cannulation.

6.    You may also experience a temporary stinging sensation when the numbing agent is introduced into the area, which will subside as the agent begins to take effect.

7.    The medical personnel will wait approximately two minutes for the agent to take effect, after which a needle will be slowly inserted into the numbed area. This may cause a pushing or pressure sensation.

8.    The collection of CSF may take approximately 20 minutes or longer, depending on the rate of drainage. Please remain still in your position until advised by medical personnel that it is safe to move.

9.    After the desired amount of CSF is collected, the needle will be safely withdrawn, and a plaster will be placed over the insertion site. Please keep the plaster on for the next 24 hours and avoid getting it wet.

10.    You will then be asked to lie on your back for a minimum of an hour.

11.    A set of blood samples will then be taken before you are discharged.

The side effects, risks and advice for a LP

The most common side effects are:

Headache, which can last up to 10 days and is typically worsened when standing up but eases when lying down. It presents in approximately 20-40% of the cases.

The second most common is Backache.

• Please keep yourself hydrated with plenty of water and limit caffeinated drinks, such as a bottle of Lucozade, a can of coke, tea, or coffee
• Please be advised that up to 24 hours of bed rest is strongly recommended, along with avoiding swimming, gym activities, exercise, running and heavy lifting
• If necessary, you may use over-the-counter pain relief options like paracetamol and ibuprofen. However, please ensure you do not exceed the maximum dose stated on the packaging
• Please avoid drinking alcohol and taking co-codamol for the next 24 hours

Nausea and vomiting

Please consult your local pharmacy or GP for anti-sickness medication and keep yourself hydrated.

Nerve irritation during procedure

Please inform the medical personnel if you experience any sharp or shooting pain radiating down either one or both legs. They will then safely withdraw the needle to alleviate nerve irritation.

Some rare side effects and potential risks include:

Infection and bleeding

If you experience increasing pain, swelling, redness, pus and bleeding at the puncture site, and/or a temperature above 38°C, please go to your nearest accident and emergency service.

Failed procedure

If the procedure is unsuccessful, you will be referred for an X-ray- guided LP and will be advised on the next steps, as necessary.

Incontinence, restricted mobility and vision problems such as, blurriness or black vision

Seek medical attention immediately.

If you continue to experience the above side effects after following the advice, then please seek immediate medical attention by attending to your nearest Accident and Emergency service.

Preparation for your LP appointment

Before the appointment, you must inform the booking team of the following information:

1. Arrange transport, such as an ambulance, if needed.
2. Arrange interpreter, if needed.
3.  If you are taking any blood-thinning medication such as Aspirin, Clopidogrel, Warfarin, Heparin, Apixaban, Rivaroxaban, Edoxaban, Dabigatran, Enoxaparin, or if you are unsure about your medication. The booking team will advise you on the timeframe for stopping blood-thinning medication before your appointment date. The medical team will inform you when to resume your blood-thinning medication at the time of your procedure.
4. If you have any imaging done or are waiting to have any done, such as MRI or CT scans.
5. If you need to cancel or rearrange your appointment.

What to expect on the day of your appointment?

1. You must sign in at the reception.
2. You will be triaged and either taken to your allocated room or asked to wait in the waiting room.
3. You will then be approached by the medical team, who will be conducting the procedure.
4. You will then be consented, during which you will be informed about how the procedure will be performed and its potential side effects.
5. You will have the opportunity to ask any questions.
6. The procedure will commence once you have given consent.
7. You are permitted to bring one family member or a friend into the room.
8. Please bring a list of your medication.
9. Please bring plenty of fluids with you to ensure that you are hydrated for the procedure.
10. The procedure may take up to 2 hours or longer, depending on clinical need. You will be provided with a clearer timeframe at the time of your appointment.
11. Please refrain from driving for the next 24 hours after your procedure.

Useful contacts

If you need further assistance, please contact us on 0161 206 6744.

If you are unable to contact the above number, then please contact 0161 206 4890 (if no answer, then please leave a voicemail).