Lumbar Puncture

ExitCare ImageA lumbar puncture (LP) is a procedure in which a small amount of the fluid that surrounds the brain and spinal cord is removed and examined. The fluid is called the cerebrospinal fluid, or CSF. This test is also called a spinal tap. This is a very safe and commonly used test. Your caregiver will explain the need for this in your child. This test can be lifesaving when infections are present.

The most common reason for doing a lumbar puncture in infants and children is to look for an infection of the meninges. The meninges cover and help protect the brain and spinal cord. Meningitis is an infection that inflames the meninges. Lumbar punctures are also done to remove fluid and relieve pressure with certain types of headaches. Sometimes they are performed to look for bleeding in the central nervous system or to place medicine into the spinal fluid.


One of the risks of this test is bleeding. This most often occurs in people with bleeding disorders. These are disorders in which the blood does not clot normally. Your caregiver always makes sure the benefits outweigh the risks. Paralysis following a LP would be an extremely rare complication. The most common problem following an LP is a spinal headache. This is uncomfortable but not dangerous. The spinal headache can easily be treated. This headache comes with sitting up or standing following a spinal tap. It is due to a change in pressure that is seen after fluid is withdrawn.


  • The person is positioned so that the spaces between the bones of the spine (vertebrae) are as wide as possible. This position makes it easier to pass the needle into the spinal canal. Infants and small children lie on their sides, curled up with their knees under their chin. Teens or adults may sit with their heads resting on a pillow that is placed on a table at waist level.

  • The skin covering the lower or lumbar region of the back is cleaned. Sometimes the skin is numbed with medicine.

  • A small needle is then inserted until it enters the space that contains the spinal fluid. The needle does not enter the spinal cord because the test is done below the level of the spinal cord.

  • The needle is withdrawn and a bandage is placed on the site.

  • The spinal fluid is collected into tubes. It is then sent to a laboratory where it is examined.

Cultures may be taken if an infection is suspected. These studies give valuable information to help diagnose various problems including meningitis, encephalitis, bleeding within the brain and spinal cord areas (central nervous system), multiple sclerosis, AIDS, and other problems. Some results are available within 30 minutes. If cultures are done to look for infection, the results are usually not available for a couple days. If your caregiver suspects infection, antibiotic medicine may be started before the results are back. The pressure of the spinal fluid can also be measured as part of the test.


  • Remain lying down (except for bathroom use) for 1 hour or as long as your caregiver suggests.

  • Avoid heavy lifting (over 10 pounds) for at least 12 hours after the procedure.

  • Drink enough fluids to keep your urine clear or pale yellow.

  • Notify your caregiver immediately if you develop any numbness or tingling in your legs or if you are unable to control your bowel or bladder.