Cerebrospinal Fluid

Cerebrospinal fluid, also known as CSF, is a clear, colorless fluid that flows through the brain and spinal cord, surrounding and cushioning it from injury. CSF has the same consistency as water and delivers nutrients to your central nervous system (CNS). In addition, the choroid plexus produces cerebral spinal fluid in your brain's ventricles (hollow spaces). CSF is completely replaced every few hours and carries away waste material.

Cerebrospinal Fluid Analysis

Examination of the cerebrospinal fluid helps to diagnose diseases, including infectious diseases of the central nervous system, causes of brain hemorrhages, immunological disorders, and cancer. Fluid is obtained by performing a lumbar puncture, also known as a spinal tap.

Lumbar Puncture

During a lumbar puncture, a long, thin, hollow needle is inserted between spaces in your spinal cord to obtain a fluid sample. You may feel pressure and a bit of soreness as the needle enters your body. After the fluid is removed, you will be asked to lie flat for an hour or more after the test. This is to prevent a headache. If you develop a headache, it may last up to a couple of days after the test.

The CSF is analyzed for its pressure, appearance, protein, glucose, cell count, and identification of cells. It is stained for microscopic examination and cultured to look for bacteria and other infectious organisms. Other chemistry tests include looking for tumor markers, amyloid beta 42 and tau protein in Alzheimer's disease, myelin essential protein in multiple sclerosis, and various other assays.

Purpose of CSF Analysis

Infectious diseases such as viruses, bacteria, fungi, and parasites can infect the central nervous system. The most common infections of the CNS include:

• Meningitis
• Encephalitis
• Tuberculosis
• West Nile Virus
• Fungal infections

Cerebrospinal fluid analysis can identify hemorrhagic diseases such as intracranial bleeding due to stroke, high blood pressure, and aneurysms.

Immunological disorders can disrupt the central nervous system with inflammation, producing antibodies and destroying the myelin sheathing around the nerves. Common immunological diseases include:

• Guillain-Barré
• Sarcoidosis
• Neurosyphilis
• Multiple sclerosis

Primary brain or spine tumors can be detected by analyzing the cerebrospinal fluid. It can also detect cancer that has metastasized to other areas of the central nervous system. For example, a lumbar puncture is significant for people who may have brain lymphoma because the lymphoma cells often spread into the cerebrospinal fluid. In addition, CSF analysis can be used to determine the type and grade of cancer.

Injections Into the CSF for Treatment of Brain or Spinal Cord Cancer

A lumbar puncture may be used to deliver chemotherapy medication to treat brain or spinal cord cancer. This process is known as intrathecal chemotherapy. It is used in the treatment of some types of leukemia or lymphoma.

The procedure, which typically takes 20 minutes, includes numbing an area of skin over your spine. Then, a needle will be gently inserted, and the chemotherapy will be injected through the needle into the CSF. A benefit of this process is that there are very few post-chemotherapy side effects. However, some side effects may include a headache.

Summary

Cerebrospinal fluid supports the nervous system, including the brain and spinal cord. A lumbar puncture is a procedure that can access the CSF for a fluid sample for disease diagnosis.

A Word From Verywell

A lumbar puncture can identify infections in the CSF or serious diseases that affect the nervous system. Your healthcare provider will explain the procedure's details if necessary. A severe headache is a possible side effect of a lumbar puncture, and you should immediately notify your healthcare provider if this occurs.