A lumbar puncture and opening pressure measurement may be done to diagnose a number of different, potentially serious, clinical conditions. These include meningitis and bleeding or swelling of the brain. The connection between a lumbar puncture and opening pressure is purely in the fact that the opening pressure is measured when a lumbar puncture is performed.
Often referred to as a spinal tap, a lumbar puncture and opening pressure measurement is a process whereby a needle is stuck between two of the bones of the spine to extract a minimal amount of cerebrospinal fluid (CSF). The CSF is a clear, colorless fluid which is found surrounding the brain and spinal cord. By examining it after lumbar puncture and opening pressure measurement, a number of conditions can be diagnosed.
The procedure of lumbar puncture and opening pressure measurement will be done in the doctor’s rooms or hospital, as sterile conditions are necessary to prevent infection. It may be a little bit uncomfortable but is a relatively quick process, taking less than an hour normally. Local anesthetic will usually be given to minimize any pain as the needle is inserted.
Opening pressure refers to pressure of the CSF as the needle is inserted and is measured using a manometer. Both the opening and closing pressure may be measured. High pressure in the CSF may indicate a number of conditions including swelling of the brain, hemorrhage, stroke and infections such as meningitis. If the pressure is too low, it may indicate a blockage in the spine.
Once the CSF has been removed, a number of properties are examined, each which allows diagnosis of various conditions. The general appearance including cloudiness, color and presence of blood; amounts of glucose, protein and blood or tumor cells; and culture of the fluid may all be used to allow the doctor to confirm a specific diagnosis. While lumbar puncture and opening pressure can be used to diagnose many conditions, they are often used in combination with other tests such as magnetic resonance imaging (MRI). Lumbar punctures may be contraindicated in patients with some clinical conditions and taking some medicines, so it is important to discuss these all with the treating doctor. Pregnancy and lactation should also be disclosed to the doctor.
After a lumbar puncture is performed, the patient is usually asked to stay lying down for some hours to minimize the risk of adverse effects. Many people experience a headache after the lumbar puncture, which should clear up a couple of days after the procedure. Should it be severe or prolonged or should any bleeding at the site, stiffness, numbness or fever be experienced, urgent medical attention should be sought.