Lumbar Puncture (cont.)
Kenneth Kaye, MD
Dr. Kaye received a Bachelor of Arts degree with honors from the University of California, San Diego in Applied Mechanics and Engineering Sciences. After graduating from New York Medical College, he completed his internship and residency training in pathology at Harbor - UCLA Medical Center.
William C. Shiel Jr., MD, FACP, FACR
Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.
In this Article
- What is a lumbar puncture (LP)?
- Why is a lumbar puncture done?
- How is the LP performed?
- What is done next?
- What is the cerebrospinal fluid (CSF)?
- What is normal CSF?
- What diseases are diagnosed by examination of the CSF?
- What are the risks of an LP?
- What are the benefits of an LP?
What is normal CSF?
Normal values for spinal fluid examination are as follows:
- Protein (15-45 mg/dl)
- Glucose (50-75 mg/dl)
- Cell count (0-5 mononuclear cells)
- Initial pressure (70-180 mm)
These normal values can be altered by injury or disease of the brain, spinal cord or adjacent tissues. The values are routinely evaluated during examination of the spinal fluid obtained from the lumbar puncture. Additionally, spinal fluid is tested for infection in the microbiology laboratory.
What diseases are diagnosed by examination of the CSF?
Spinal fluid obtained from the lumbar puncture can be used to diagnose many important diseases such as bleeding around the brain; increased pressure from hydrocephalus; inflammation of the brain, spinal cord, or adjacent tissues (encephalitis, meningitis); tumors of brain or spinal cord, etc. Sometimes spinal fluid can indicate diseases of the immune system, such as multiple sclerosis.
What are the risks of an LP?
When spinal fluid is removed during an LP, the risks include headache, brain herniation, bleeding, and infection. Each of these complications are uncommon with the exception of headache, which can appear from hours to up to a day after LP. Headaches occur less frequently when the patient remains lying flat 1-3 hours after the procedure.
What are the benefits of an LP?
The benefits of the LP depend upon the exact situation for which it is performed, but an LP can provide lifesaving information.
Medically reviewed by Jon Glass, MD; American Board of Psychiatry and Neurology
"Harrison's Principles of Internal Medicine 18th Edition, e46"
McGraw-Hill, edited by Eugene Braunwald, et. al., 2012.
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