Lumbar Puncture

Blausen_0617_LumbarPuncture

It’s a Saturday and because she has no class, Giselle decided that it would be the best time to take a break from all her nursing school requirements and just have a chill day. After cooking something to eat, she sits on her comfy couch and surfs the television for something to watch. After changing from one channel to another, she finally settles down to a drama movie.

The movie has got her so engrossed. She wipes a single tear escaping from her right eye as she watches the doctor tell the main character about the probability of her having brain cancer and that she needs to undergo a spinal tap procedure.

As the character later gets placed on a side lying position, Giselle tries to recall everything they have discussed in the classroom about the procedure.

“How is it done again? What are the things that need to be considered when performing the procedure?” she asks herself as she continues to watch as a needle gets inserted at the lower back of the main character.

Overview of the Lumbar Puncture Procedure

Lumbar puncture is often performed in the emergency department to obtain information about the cerebrospinal fluid (CSF). Also known as spinal tap, this procedure can help diagnose serious and sometimes life-threatening infections, including meningitis; disorders of the central nervous system, such as Guillain-Barre syndrome and multiple sclerosis; or cancers of the brain or spinal cord. At other times, doctors use lumbar puncture to inject anesthetic medications or chemotherapy drugs into the cerebrospinal fluid.

Lumbar puncture is performed in the patient’s lower back, specifically in the lumbar region. During this procedure, a needle is inserted between two vertebrae to remove a sample of cerebrospinal fluid, which surrounds the brain and spinal cord to protect them from injury.

This procedure should be performed only after a neurologic examination but should never delay potentially life-saving interventions, which includes the administration of antibiotics and steroids to patients with suspected bacterial meningitis.

Indications for this procedure

Lumbar puncture may be done to:

  • Collect cerebrospinal fluid for laboratory analysis
  • Measure the pressure of your cerebrospinal fluid
  • Inject spinal anesthetics, chemotherapy drugs or other medications
  • Inject dye (myelography) or radioactive substances (cisternography) into cerebrospinal fluid to make diagnostic images of the fluid’s flow

Information gathered from a lumbar puncture can help diagnose:

  • Serious bacterial, fungal and viral infections, including meningitis, encephalitis and syphilis
  • Bleeding around the brain (subarachnoid hemorrhage)
  • Certain cancers involving the brain or spinal cord
  • Certain inflammatory conditions of the nervous system, such as multiple sclerosis and Guillain-Barre syndrome

Risks

However, just like any other procedure, lumbar puncture comes with risks and precautions. Risks include:

  • Post-lumbar puncture headache, which may be due to a leak of fluid into nearby tissues
  • Back discomfort or pain, which might radiate down the back of your legs.
  • Bleeding, which may occur near the puncture site or, rarely, into the epidural space.
  • Brainstem herniation, since increased intracranial pressure, due to a brain tumor or other space-occupying lesion, can lead to compression of the brainstem after a sample of cerebrospinal fluid is removed.

Preparation

Before the lumbar puncture is done, certain preparatory procedures may be performed:

  • A physical examination may be done as well as a complete health history may be obtained including a review of the medications that the patient is receiving
  • Blood tests may be ordered if the patient has bleeding/clotting disorders
  • A CT scan may be performed to determine if the patients has any abnormal swelling in or around your brain

The procedure itself

These are what happens when a spinal tap is done:

  1. A local anesthetic is injected into your lower back to numb the puncture site before the needle is inserted. The local anesthetic will sting briefly as it’s injected.
  2. A thin, hollow needle is inserted between the two lower vertebrae (lumbar region), through the spinal membrane (dura) and into the spinal canal. You may feel pressure in your back during this part of the procedure.
  3. Once the needle is in place, you may be asked to change your position slightly.
  4. The cerebrospinal fluid pressure is measured, a small amount of fluid is withdrawn, and the pressure is measured again. If needed, a drug or substance is injected.
  5. The needle is removed and the puncture site is covered with a bandage.

 

Results

The procedure may last up to about 45 minutes. After the fluid is obtained, it will be sent to the laboratory where it will be thoroughly examined including its general appearance, Protein (total protein and the presence of certain proteins), White blood cells, Sugar (glucose), Microorganisms, and Cancer cells.Laboratory results are ten combined with information obtained during the test, such as spinal fluid pressure, to help establish a possible diagnosis.

 

Sources:

Liane Clores, RN MAN

Currently an Intensive Care Unit nurse, pursuing a degree in Master of Arts in Nursing Major in Nursing Service Administration. Has been a contributor of Student Nurses Quarterly, Vox Populi, The Hillside Echo and the Voice of Nightingale publications. Other experience include: Medical-Surgical, Pediatric, Obstetric, Emergency and Recovery Room Nursing.

What Do You Think?