“Wherever the art of medicine is loved, there is also a love of humanity.”
— Hippocrates
Lumbar Puncture Or Spinal Tap
In this post, we will explore how lumbar punctures are performed, their clinical uses, and the potential risks. A lumbar punch or puncture is also called a spinal tap. It is a medical procedure used to collect cerebrospinal fluid (CSF) from the spinal cord. This fluid provides important information about the brain and spinal cord, helping diagnose various neurological, infectious or autoimmune conditions.
Therefore, a spinal tap procedure is commonly performed to detect various medical conditions. these include: infections, like meningitis, or autoimmune illnesses like multiple sclerosis (MS) and sarcoidosis. A lumbar puncture may also diagnose subarachnoid haemorrhage. A subarachnoid haemorrhage is any bleed located underneath one of the protective layers of the brain. This layer is known as the arachnoid layer.
What is a Lumbar Puncture?
During a lumbar puncture a needle is inserted between two lumbar vertebrae in the lower spine. A vial is then used to withdraw cerebrospinal fluid (CSF) one drop at a time. CSF is a clear fluid that surrounds the brain and spinal cord, providing cushioning and removing waste products. By analysing this fluid, doctors can diagnose or rule out certain conditions.
Lumbar punctures are typically performed under local anaesthesia. The patient will lie on their side or sit in a curled position to widen the spaces between the vertebrae.
Why is a Lumbar Puncture Done?
Lumbar punctures are ordered to diagnose a wide range of conditions that affect the brain and spinal cord. Some of the most common reasons include:
Meningitis
A lumbar puncture can help detect infections in the CSF, such as bacterial, viral, or fungal meningitis.
Multiple Sclerosis (MS)
CSF analysis can show abnormalities in protein levels or immune cells, which are common in MS patients.
Subarachnoid Haemorrhage
A lumbar puncture can reveal blood in the CSF when a brain bleed is suspected but not detected by CT scan.
Neurological Conditions
Lumbar punctures can be used to diagnose Guillain-Barre syndrome, neurosyphilis, and other neurological disorders.
Measurement of CSF Pressure
This is important in conditions like hydrocephalus, where an abnormal build-up of CSF leads to increased pressure on the brain.
What Is It Like To Have A Lumbar Puncture Procedure
The lumbar puncture is a straightforward procedure but requires careful attention to sterile technique. Here’s how it typically unfolds:
Preparation
The patient is positioned on their side or seated with their spine arched. This posture creates more space between the lumbar vertebrae. Local anaesthesia is applied via a needle injection to numb the area.
Insertion of the Needle
A thin, hollow needle is inserted into the spinal canal between the third and fourth lumbar vertebrae.
CSF Collection
Once the needle reaches the correct location, CSF is drawn into small vials for testing. The required amount is usually 15ml but this may vary.
Post-Procedure
The needle is removed, and a bandage is applied to the puncture site. The patient is usually asked to lie flat for a short period to prevent headaches, a common side effect.
Are you sedated for a lumbar puncture?
As described above you are not sedated. A general anaesthetic is not used. Only local anaesthetic is used to numb the area on the lower spine.
Is a lumbar puncture very painful?
The spinal tap procedure I had was very similar to the one outlined above. I was an inpatient at the time so I was transferred in my bed to the procedure room. I remained in my bed, however, I did sit up on the side of the bed. My feet were supported on a chair. I hugged a pillow as I bent over my knees and arched or rounded my back.
The doctor used a marker pen to mark the space between the vertebrae in my lower spine.
An anaesthetic was then injected into the marked area to numb the spine. This felt like a sharp pin prick and was not too painful.
Shortly after, another fine needle was inserted into the space between the vertebrae. This did not hurt. I just felt some pressure. I could then feel the needle travelling down my spine until the doctor found the spinal area he required. This felt strange, like something was crawling down my spine. It was not unpleasant or painful, just a weird sensation.
How Long Does A Lumbar Puncture Take?
The needle stayed in situ (about 4 minutes) until the required amount of CSF was collected. In this case it was 15 ml. It takes a few minutes as the CSF drips out slowly. CSF is not under pressure so does not flow out quickly like a blood test from a vein. The needle was then removed and a small plaster was put over the needle insertion point.
The whole procedure was over in less than 15 minutes. Once the needle was removed I was asked to lie flat on my back. Only a low pillow was provided to support my head. I was told to lie flat like this for 4 hours to prevent a low CSF pressure headache.
Risks and Side Effects of Lumbar Punctures
While lumbar punctures are generally considered safe, there are some risks and side effects to be aware of which include:
Infection
Though rare, infections can occur if proper sterile techniques are not followed.
Bleeding
Some patients may experience minor bleeding at the puncture site or, in very rare cases, bleeding into the spinal cord.
Nerve Damage
While extremely uncommon, nerve damage may occur if the needle touches a nerve root. It is important that patients report any signs of infection. these include fever or redness at the puncture site without delay.
Lower Back Ache
You may feel pain or tenderness in your lower back after the procedure. The pain might radiate down the back of your legs. This pain can be treated with paracetamol and usually eases within a few days.
What is a low CSF pressure headache?
The most common complication is a post-lumbar puncture headache, which occurs in about 10-20% of patients. A cerebrospinal fluid (CSF) low-pressure headache occurs when there is an internal spinal fluid leak. The leak may occur after a spinal tap procedure or another form of trauma or accident. The severity of this headache can range from mild and constant to severe and disabling.
The brain is suspended in a sac filled with CSF, which extends from the skull down into the spine. This sac is formed by membranes known as the meninges (the same membranes that can become inflamed in meningitis).
The CSF cushions the brain and helps remove waste products. If the pressure of the CSF drops because there is a small leak in the meninges, the brain may shift downward. This shift occurs when the person is sitting or standing upright. This downward sagging stretches the meninges and nerves around the brain, leading to pain in the form of a headache.
It is advised to lie flat for 4 hours after a lumbar puncture. This position avoids downward pressure on the brain, meninges, and nerves. Drinking plenty of fluids is also important as it helps re-hydrate you after the spinal tap.
Believe me the headache hurts so it is worth lying flat as long as possible. When you do get up and about, take it slow and steady. Drinking fluids is also comforting and effective in treating the headache. Taking some paracetamol is also an option if you develop a headache.
Recovery and Aftercare
After the procedure, you are usually monitored for a short period in recovery or in your ward. As discussed above you will need to lie down for 4 hours. After that you are best to rest and take it easy for 24 hours.
I was instructed to avoid walking around excessively. I should also refrain from stretching or exercising for 72 hours. This is to prevent the puncture site from opening or stretching.
You can shower after the lumbar puncture. First, you must have complete bed rest for 4 to 6 hours. Only shower if you are feeling well enough to do so.
To prevent headaches, you should drink plenty of fluids. Avoid strenuous activities for the next 2 to 3 days.
Should You Worry About Having A Spinal Tap?
A lumbar puncture or spinal tap sounds far worse than it is. A neurologist or specialist wants to order one for you for good reason. That’s a good enough reason to put your big pants on and get it done. A lumbar puncture is a critical diagnostic tool for detecting various neurological conditions. In my case I had a history of sarcoidosis and pulmonary mould infection.
The cardiologist and neurologist wanted to screen me for these two infections. This was part of their diagnostic testing. They aimed to identify possible Cardiomyopathy or Pericarditis.
While the procedure carries some risks, it is generally safe. It also provides valuable insights into conditions affecting the brain and spinal cord. Having an accurate diagnosis is more than half the battle in being correctly treated and recovering.
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II hope you found this post helpful. Consider reading: Types of Organ Donation, Infections After An Organ Transplant, Preventing Infections and Infections From Donated Organs. By far my most popular post has been about Hair Loss.
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References
Australian and New Zealand Association of Neurologists. (2022). Lumbar Puncture Guidelines. Retrieved from https://www.anzan.org.au
Mayo Clinic. (2023). Lumbar Puncture (Spinal Tap). Retrieved from https://www.mayoclinic.org
NHS England. (2023). Lumbar Puncture: What to Expect. Retrieved from https://www.nhs.uk
Royal Melbourne Hospital. (2023). Lumbar Puncture Procedure. Retrieved from https://www.thermh.org.auSydney Children’s Hospitals Network. (2023). Lumbar Puncture in Children: What You Need to Know. Retrieved from https://www.schn.health.nsw.gov.au