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Alternative Names Return to topSpinal tap; Ventricular puncture; Lumbar puncture; Cisternal puncture; Cerebral spinal fluid culture
Definition Return to top
Cerebral spinal fluid (CSF) collection is a test to look at the fluid that surrounds the brain and spinal cord. Cerebral spinal fluid acts like a cushion, protecting the brain and spine from injury. The fluid is normally clear. The test is also used to measure pressure in the spinal fluid.
See also: CSF culture
How the Test is Performed Return to top
There are different ways to get a sample of spinal fluid. Lumbar puncture, commonly called a spinal tap, is the most common method. The test is usually performed in the following manner:
Occasionally, special x-rays are used to help guide the needle into the proper position. This is called fluoroscopy.
Lumbar puncture with fluid collection may also be part of other procedures, particularly a myelogram (x-ray or CT scan after dye has been inserted into the CSF).
Alternative methods of CSF collection are rarely used, but may be necessary in the event of a back deformity or infection.
Cisternal puncture uses a needle placed below the occipital bone (back of the skull). It can be dangerous because it is so close to the brain stem.
Ventricular puncture is even more rare, but may be recommended in persons with possible brain herniation. This test is usually done in the operating room. A hole is drilled in the skull, and a needle is inserted directly into one of brain's ventricles.
How to Prepare for the Test Return to top
The patient (or guardian) must give the health care team permission to do the test.
How the Test Will Feel Return to top
The position may be uncomfortable, but it is extremely important that the patient stays in the bended position to avoid moving the needle and possibly injuring the spinal cord.
The anesthetic will sting or burn when first injected. There will be a hard pressure sensation when the needle is inserted, and there is usually some brief pain when the needle goes through the tissue surrounding the spinal cord. This pain should stop in a few seconds.
Overall, discomfort is minimal to moderate. The entire procedure usually takes about 30 minutes, but it may take longer. The actual pressure measurements and fluid collection only take a few minutes.
Why the Test is Performed Return to top
This test is done to measure pressures within the cerebrospinal fluid and to collect a sample of the fluid for further testing. CSF can be used to diagnose certain neurologic disorders, particularly infections (such as meningitis) and brain or spinal cord damage.
Normal Results Return to top
Normal values vary from lab to lab but typically range as follows:
Note: mg/mL = milligrams per milliliter; mEq/L = milliequivalent per liter
What Abnormal Results Mean Return to top
If the CSF looks cloudy, it could mean there is an infection or a build up of white blood cells or protein.
If the CSF looks bloody or red, it may be a sign of bleeding or spinal cord obstruction. If it is brown, orange, or yellow, it may be a sign of increased CSF protein or previous bleeding (more than 3 days ago).
Increased CSF pressure may be due to increased intracranial pressure (pressure within the skull). Decreased CSF pressure may be due to spinal cord tumor, shock, fainting, or diabetic coma.
Increased protein may be due to blood in the CSF, diabetes, polyneuritis, tumor, injury, or any inflammatory or infectious condition. Decreased protein is a sign of rapid CSF production.
Increased CSF gamma globulin levels may be due to diseases such as multiple sclerosis, neurosyphilis, or Guillain-Barre syndrome.
Increased CSF glucose is a sign of high blood sugar. Decreased CSF glucose may be due to hypoglycemia (low blood sugar), bacterial or fungal infection (such as meningitis), tuberculosis, or certain types of meningitis.
Increased white blood cells in the CSF may be a sign of meningitis, acute infection, beginning of a chronic illness, tumor, abscess,stroke, or demyelinating disease (such as multiple sclerosis).
Red blood cells in the CSF sample may be a sign of bleeding into the spinal fluid or the result of a traumatic lumbar puncture.
Additional conditions under which the test may be performed:
Risks Return to top
Risks of lumbar puncture include:
There is an increased risk of bleeding in persons who take blood thinners.
Brain herniation may occur if this test is done on a person with a mass in the brain (such as a tumor or abscess). This can result in brain damage or death. This test is not done if an exam or test reveals signs of a brain mass.
Damage to the nerves in the spinal cord may occur, particularly if the person moves during the test.
Cisternal puncture or ventricular puncture carry additional risks of brain damage and bleeding within the brain.
Considerations Return to top
This test should not be performed on people who have lesions that cause increased intracranial pressure. Others who should not have this test include patients with:
References Return to top
Nathan, BR. Cerebrospinal Fluid and Intracranial Pressure. In: Goetz, CG, ed. Textbook of Clinical Neurology, 2nd ed. Philadelphia, Pa:WB Saunders Company; 2003:511-524.Update Date: 12/12/2008 Updated by: A.D.A.M. Editorial Team: David Zieve, MD, MHA, Greg Juhn, MTPW, David R. Eltz. Joseph V. Campellone, M.D., Division of Neurology, Cooper University Hospital, Camden, NJ. Review provided by VeriMed Healthcare Network (4/30/2007).