What is Intracranial Hypertension?

Chances are you have developed a headache after a stressful day at work or as a symptom associated with other conditions, such as allergies. However, if a sudden, severe headache hits for no reason, often causing vision changes, a condition known as intracranial hypertension could be to blame. Intracranial hypertension is a condition that causes increased pressure in the skull, known as intracranial pressure (ICP), that in turn affects the brain and optic nerve.

Here we take a closer look at intracranial hypertension, what may cause this increased cranial pressure, potential risk factors, symptoms, and treatment options available.

What is Intracranial Hypertension?

Intracranial hypertension refers to the increased pressure within the skull. It is a condition characterized by the elevation of pressure in the cerebrospinal fluid (CSF) that surrounds and cushions the brain and spinal cord.

Normally, the CSF flows within the ventricles (cavities) of the brain and circulates around the brain and spinal cord, providing buoyancy and protection. However, certain conditions can disrupt the balance between CSF production and absorption, leading to an accumulation of fluid and subsequent increased pressure inside the skull. This pressure can affect the brain and the optic nerve of the eye.

To better understand, a healthy adult has an intracranial pressure of 7-15 mmHg in the supine position. Values above 15 mmHg are considered to be increased and meet the criteria for intracranial hypertension.

Common Causes

Intracranial hypertension can occur due to various causes, including:

•       Idiopathic Intracranial Hypertension (IIH) – This condition, also known as pseudotumor cerebri, occurs when the pressure inside the skull increases without an apparent underlying cause.
•       Head Injury – Traumatic brain injury or severe head trauma can lead to increased ICP.
•       Brain Tumors – Tumors within the brain or skull can cause increased pressure by occupying space or obstructing the flow of CSF.
•       Hydrocephalus – This condition involves the accumulation of excess CSF in the ventricles, leading to increased pressure.
•       Brain Infections – Certain infections, such as meningitis or encephalitis, can cause inflammation and increased ICP.
•       Bleeding in the Brain – Intracranial hemorrhage, such as subarachnoid or intracerebral hemorrhage, can elevate ICP.

Risk Factors for Intracranial Hypertension

Intracranial hypertension can affect anyone, though it is most commonly seen in women between the ages of 20 and 50. Other factors that can increase your risk include:

•       Body mass index above 30
•       Chronic kidney disease
•       Iron deficiency anemia
•       Autoimmune conditions, such as lupus
•       Polycythemia vera (increased red blood cells)
•       Sleep apnea
•       Blood-clotting disorders
•       Endocrine disorders, such as Cushing’s disease or hyperthyroidism, Behcet’s syndrome, and more
•       Certain medications, including supplements, like Tetracycline and Vitamin A
•       Pregnancy

Common Symptoms

Symptoms of intracranial hypertension can vary depending on the underlying cause and the rate at which the pressure increases. Common symptoms may include:

•       Severe headache, often originating behind the eyes
•       Nausea
•       Vomiting
•       Visual disturbances (such as blurred or double vision)
•       Tinnitus (ringing in the ears)
•       Dizziness
•       Pain in the neck and shoulder region
•       “Feeling” your pulse in your head
•       Fatigue

In severe cases, it can lead to more serious complications like seizures, loss of consciousness, or herniation of brain structures.

Diagnosing Intracranial Hypertension

The diagnosis of intracranial hypertension typically involves a combination of clinical evaluation, neurological examination, and imaging studies such as MRI or CT scan to assess the structure of the brain and the presence of any underlying abnormalities. Measurement of intracranial pressure through invasive procedures like a lumbar puncture or placement of an intraventricular catheter may be necessary in some cases. Eye exams and visual field tests are also common to check for swelling near the optic nerve and potential blind spots.

Treatment Options

Treatment aims to reduce the pressure within the skull and manage the underlying cause. This may involve medications, such as diuretics to decrease CSF production or corticosteroids to reduce brain inflammation. In some instances, surgical intervention may be necessary to address the underlying cause, relieve pressure, or improve CSF circulation. This can include a neurological shunt or an optic nerve fenestration.

The management of intracranial hypertension requires close monitoring and ongoing care by a medical professional, typically a neurologist or neurosurgeon, to prevent potential complications and optimize outcomes.

Intracranial Hypertension and Long COVID

Headaches are a common symptom seen in both acute COVID-19 and Long COVID. From early in the pandemic to more recently, clinicians and researchers have seen increased cases of IIH in both acute and Long COVID.

Idiopathic Intracranial Hypertension Associated with SARS-CoV-2 B.1.1.7 Variant of Concern

Covid 19 Associated Idiopathic Intracranial Hypertension and Acute Vision loss

Here at RTHM, we are aware of this potential risk and evaluate all of our patients for this potential risk and condition.  If you are experiencing severe headaches or vision disturbances, it is important to discuss it with your clinician as soon as possible.

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