Lumbar puncture (liquor puncture)
The brain and spinal cord are surrounded by nerve water, the liquor. Liquor is obtained through a lumbar puncture for the examination in the laboratory, the so-called liquor diagnosisOur content is pharmaceutically and medically tested
Lumbar puncture - briefly explained
The name lumbar puncture means that the doctor takes nerve water from the vertebral canal in the area of the lumbar spine with a hollow needle. This is examined as part of CSF diagnostics: even the mere sight of the nerve water provides the trained eye with initial clues. In healthy people, the nerve water is clear. A reddish discoloration indicates fresh bleeding, a yellowish discoloration indicates older bleeding. In addition, the nerve water can be cloudy when there is inflammation. A laboratory is then responsible for the precise analysis of the ingredients.
When is a CSF examination necessary?
Changes in the composition of the nerve water occur in numerous diseases of the brain and spinal cord. CSF diagnostics help diagnose the following clinical pictures:
- Inflammation of the brain and the meninges (encephalitis and meningitis) - under certain circumstances the responsible germs can be detectable here
- Multiple sclerosis - in this long-lasting, inflammatory disease, which is caused by an overreaction of the own immune system, certain proteins (proteins) and inflammatory cells accumulate in the liquor
- Cancer of the meninges
- Bleeding in the vicinity of the nerve water area, especially subarachnoid haemorrhage
How does the lumbar puncture work?
First, the doctor checks that nothing speaks against the puncture. A contraindication could, for example, be an increased risk of bleeding. In addition, the patient must be informed about the procedure beforehand and give his or her written consent.
In which posture is the lumbar puncture performed?
The patient should make a back that is as round as possible (like a "hunchback"). Either he sits bent over on the examination table or he takes the embryonic position while lying on his side so that the elbows and knees touch. He should be supported with pillows in such a way that the head is at the same height as the later puncture point in the lower back area. It is also important that the patient's shoulders are vertical in this horizontal position so that the spine does not twist. The strong flexion of the spine means that there is enough space between the vertebrae for the needle to be inserted.
The puncture may only be performed or instructed by a very experienced doctor who has mastered this technique. The work is carried out under “sterile conditions”, which means that the skin is thoroughly disinfected and the area of the skin is masked with a sterile cloth. A local anesthetic is then given by injection. When this anesthetic has developed its full effect after about two minutes, the doctor inserts the puncture needle between two lumbar vertebrae. Usually he chooses a space between the vertebrae between the third and fifth lumbar vertebrae. At this level and further down, there is no longer any spinal cord, so there is no risk of injury from the puncture needle. When the spinal canal is reached, nerve water begins to drip from the needle. The nerve water pressure can also be determined with a so-called riser pipe. When the doctor has taken enough nerve fluid for the laboratory test, he withdraws the needle and the small puncture site is covered with a band-aid.
With a cat's hump under sterile conditions - this is how the lumbar puncture is performed
© W & B / Martina Ibelherr
What are the risks?
Serious consequences such as bleeding or even infections are extremely rare after a lumbar puncture. If the puncture is performed according to all the rules of medical art with the use of atraumatic needles and a special procedure during the puncture, there is only a low risk of around one percent for a so-called post-puncture headache. However, a few factors favor this:
- young age
- female gender
- frequent headaches in everyday life
The temporary headache after the puncture occurs only in an upright posture. It subsides when lying down. This pain can last a few days, very rarely weeks. If there are other complaints, it is referred to as negative nerve water pressure syndrome. This includes:
- Neck stiffness
- Ringing in the ears
Painkillers do not help with post-puncture headache; caffeine and theophylline are less effective. The most effective method of ending post-puncture headache within half an hour is the so-called blood patch. With this method, the doctor uses at least 20 milliliters of the patient's own blood to seal the CSF leak caused by the puncture. A blood patch treatment directly after the lumbar puncture, in order to avoid a headache at all, turned out to be ineffective.
In addition, there are sometimes temporary sensations of pain around the point of the puncture that radiate into the hip region.
Contraindications: When should a lumbar puncture not be performed?
- If there is a tendency to bleed: if the bleeding tendency is greatly increased or the patient has taken substances that inhibit blood clotting. Then there is too great a risk of bleeding from the puncture.
- In the event of inflammation: If the skin or the surrounding tissue near the puncture site is inflamed, no puncture is usually performed.
- With increased pressure in the brain: In this case too, a lumbar puncture must be avoided. Otherwise, the tapped nerve water threatens to pinch the elongated spinal cord at the transition from the skull to the spine. Computed tomography or magnetic resonance imaging of the head can clarify whether there is increased intracranial pressure if there are symptoms.
Is the lumbar puncture also used for treatment?
Sometimes the lumbar puncture is used not only for examination, but also for treatment:
- Medication administration: This way the spinal cord is reached much more directly than via the blood. This is due to the so-called blood-brain barrier, which certain drugs can only cross with great difficulty. One example is chemotherapy drugs used to treat tumors.
- Pain relief during surgical interventions: The lumbar puncture is useful in the form of lumbar anesthesia (also: spinal anesthesia) for a caesarean section or hip operation, for example.
- Therapy for agonizing headaches: Even in the case of a so-called spontaneous low pressure CSF syndrome with very severe headaches in an upright position, the doctor can provide relieving relief through a lumbar puncture with an injection of at least 20 milliliters of autologous blood directly in front of the CSF space.
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Consulting expert: Privatdozentin Dr. med. Ilonka Eisensehr, specialist in neurology. She studied at the Ludwig Maximilians University in Munich and the Tufts University in Boston and completed her habilitation at the University of Munich on the dopamine system and sleep-related movement disorders. She works in her own neurological practice in Munich and is a member of the teaching staff at the University of Munich. She has written numerous publications on the subject of the dopamine system, sleep medicine and epilepsy and is a member of many scientific committees. Her focus areas are: neurological diagnostics, diagnostics and treatment of movement disorders, sleep disorders and restless legs syndrome, as well as a stroke check including color duplex sonography.
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This article contains general information only and should not be used for self-diagnosis or self-treatment. He can not substitute a visit at the doctor. Unfortunately, our experts cannot answer individual questions.