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What is Intracranial Hypotension?

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Are you experiencing a headache every time you sit up or stand? Does this headache improve or go away when you lie down? Are you experiencing “brain fog” and memory issues that seem to have come on suddenly or after an acute SARS-CoV-19 infection? Intracranial hypotension, or a reduction in cerebrospinal fluid (CSF), could be to blame.

In this article, we examine what intracranial hypotension is, what can cause it, common symptoms associated with the drop in CSF volume, and how it is diagnosed and treated.

What is Intracranial Hypotension?

Intracranial hypotension refers to abnormally low pressure within the skull and cerebrospinal fluid (CSF). It occurs when there is a decrease in the volume or pressure of CSF, which is the fluid that surrounds and cushions the brain and spinal cord. CSF also works to remove impurities from the brain, as well as transfer nutrients that the brain needs. Intracranial hypotension is usually caused by a cerebrospinal fluid leak, where the CSF leaks out of the spinal canal.

To better understand this, a healthy adult has an intracranial pressure of 7-15 mmHg in the supine position. Less than 6 mmHg signals a significant drop in intracranial pressure.

Common Causes

The most common cause of intracranial hypotension is a spontaneous cerebrospinal fluid leak, which can occur without a known cause or be related to certain factors such as trauma, previous spinal surgeries, spinal procedures (e.g., lumbar puncture), or connective tissue disorders. Other less common causes include tumors or cysts in the brain or spinal cord, spinal cord malformations, or certain medications that affect CSF production or absorption.

Common Symptoms

Symptoms of intracranial hypotension can include:

·        Positional headaches that worsen when sitting up and improve when you lie down

·        Nausea and/or vomiting

·        Sensitivity to light and/or sound

·        Neck pain or stiffness

·        Changes in hearing, such as muffled

·        Tinnitus

·        Cognitive dysfunction, such as trouble concentrating or memory issues

·        Dizziness

·        Double vision

Diagnosing Intracranial Hypotension

The diagnosis of intracranial hypotension involves a combination of clinical evaluation, medical history, and imaging studies. Imaging techniques such as magnetic resonance imaging (MRI) or computed tomography (CT) scans can help identify the presence of CSF leaks or other underlying causes. In some cases, additional tests like a myelogram (a specialized imaging test using contrast dye) or a radionuclide cisternogram (a nuclear medicine test) may be performed to pinpoint the location of the leak.

Treatment Options

Treatment options aim to relieve symptoms and seal the CSF leak. Conservative management options may include bed rest, increased fluid, and caffeine intake to help increase CSF volume, and medications to alleviate pain or reduce CSF production. However, if conservative measures are ineffective or if the leak persists, more invasive treatments may be necessary. These can include epidural blood patches (injecting a person’s own blood into the spinal canal to seal the leak), targeted image-guided injections of fibrin glue or other sealants, or surgical repair of the leak.

Intracranial Hypotension, Long COVID, and Other Conditions

Intracranial hypotension is a condition that is often underdiagnosed or misdiagnosed. In terms of Long COVID, many patients meet the criteria for postural orthostatic tachycardia syndrome (POTS). POTS has many symptoms, including headaches, that worsen with an upright posture, similar to the headaches seen with intracranial hypotension. To make things even more difficult, it is possible for a person to have both POTS and intracranial hypotension. Those with EDS or Chiari malformations are also more prone to both POTS and intracranial hypotension. Because these conditions have similar presentations and can occur at the same time, it is important that both are investigated.

At RTHM, our providers understand these more complex conditions and comorbidities and how they can mimic one another. Our clinicians work with you to evaluate any potential cause of symptoms you are experiencing, such as headaches, and work to rule out all possibilities in order to find the right treatment and improve your quality of life. 

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