What Is a Blood Patch?

A blood patch is a medical procedure that is used to close cerebral spinal fluid (CSF) leaks. A CSF leak can occur when there is a tear or puncture in the dura (the membrane that surrounds the brain and spinal cord) that causes the watery protective fluid (CSF) that circulates around these neurological structures to leak out.

They may be referred to as cranial CSF leaks if they occur in the head (around the brain) or spinal CSF leaks if they occur in the back around the spine. Sometimes they may be further differentiated by the part of the spine they affect such as lumbar area of the spine.

Before going into the specific blood patch procedure it is important to have some basic understanding of CSF leaks.

Causes of CSF Leaks

There are several different causes of CSF leaks but one of the most common for which blood patching is performed is when the dura is accidentally pierced by a needle during spinal anesthesia (such as an epidural) or during lumbar puncture (a test used to diagnose meningitis). Other causes include:

• Injury to the brain or spinal cord during a traumatic accident
• A complication of sinus, brain or spinal surgery
• High pressure hydrocephalus (a condition where there is too much CSF around the brain)
• Spontaneous CSF leaks have no known cause

It should be noted that some studies show spontaneous CSF leaks to be associated with certain inherited connective tissue disorders including Marfan syndrome and Ehlers Dalos syndrome.

Symptoms of CSF Leaks

If you have a CSF leak it may cause one or more of the following symptoms:

• Headaches which may get worse when you are standing and feel better when you lay down (sometimes called spinal headaches)
• Clear fluid coming from the nose or ear
• Blurred vision
• Tinnitus (ear ringing)
• Meningitis (inflammation or infection of the membranes surrounding the brain and spinal cord)
• Nausea and vomiting
• Sound sensitivity
• Poor balance
• Alteration in your sense of smell

Diagnosing CSF Leaks

If you have fluid leaking from your nose or ear it can be tested for a substance called beta-2 transferrin which is found specifically in cerebral spinal fluid. This usually only happens if the leak is around the brain (not in the spine). Imaging tests such as MRI or a special kind of CT scan can also aid in the diagnosis of CSF leaks.

Treatment of CSF Leaks and Indications for Blood Patch

Sometimes small CSF leaks such as those resulting from a lumbar puncture or epidural will heal on their own after a period of bed rest. Increased hydration and caffeine are often recommended to increase blood pressure.

How Is a Blood Patch Done?

Autologous blood is necessary for a blood patch. Autologous is just a fancy medical term that means your own blood is used. It is drawn (usually from a vein in your arm) and then injected into the epidural space, which is the space around the dura.

Usually, a pretty small amount of blood is used—around 15-30 milliliters (mL)—although more may be required depending on your individual circumstance and up to 100 mL has been reported. Even 100 mL is not a large amount of blood for most people and it is unlikely you will experience any side effects from the removal of this blood.

The injection site is typically your back near your spine. The exact location depends on where the CSF leak is. Cervical blood patching (where the injection site is higher up near your neck) is less common. After it is injected into the epidural space the blood then forms a clot over the CSF leak and seals it closed.

You may be given a sedative before this procedure to make you more comfortable. If so you might be given instructions not to eat or drink for a period of time before your scheduled blood patch. The sedative is intended to help you relax and increase your comfort, but it won't put you to sleep. You should be able to eat as soon as your procedure is finished and you feel like it.

The doctor may use medical imaging such as fluoroscopy or ultrasound to help him to get the needle in the correct location but this is not always the case.

You may be instructed to lay flat for a little while after your procedure. Many people feel better almost immediately after getting the blood patch.

You may need to limit certain activities for up to a month. These activities may include things like heavy lifting, bending, twisting or straining. You may also be instructed to avoid soaking in a hot tub or pool for a while to avoid infection at the injection site. Showering is usually fine.

If you were given a sedating medication to help you relax for your procedure you should refrain from driving or participating in activities where it is necessary to be alert, have good judgment, or that require coordination or balance for at least the rest of the day.

Complications of a Blood Patch

Complications after receiving a blood patch may include back pain and bruising or redness at the site of injection for a few days after your procedure. This is fairly common and should go away.

More concerning and less common potential complications include infections or the risk of puncturing the dura and actually creating new CSF leaks.

If you are given medication during your procedure there is always the potential for an allergic reaction or side effects associated with that particular medication.

How Effective Are Blood Patches?

Blood patches are successful about 90% of the time. When they are unsuccessful they may be repeated. A second blood patch has about a 95% success rate.

If a blood patch is unsuccessful a blood patch with a fibrin glue may be tried or surgical repair may be necessary.