Most people will experience headaches at some point in their lives, and with over 200 types, it can be challenging to know what kind you may be dealing with. Headaches are generally categorized as primary (not caused by another condition) or secondary (caused by a separate underlying condition). While most are not dangerous, certain types can signal the need for further investigation or immediate medical care.

A headache caused by idiopathic intracranial hypertension (IIH) results from increased pressure in the skull around the brain. This high pressure causes extra stress on the optic nerve at the back of the eye, affecting its function. Swelling can cause vision problems and is one of the earliest signs of IIH.

Although not life-threatening, early detection and treatment are essential to prevent vision loss and legal blindness. Left untreated, vision loss can be irreversible.

What causes IIH?

While the exact cause of IIH is unknown, it most frequently occurs in women of reproductive age. Strongly associated with obesity, it is 2 to 6 times more common in overweight women with a body mass index (BMI) above 30. Currently, there is no firm evidence of a genetic link or heredity.

Signs and symptoms of IIH

IIH was formerly known as pseudotumor cerebri, or false brain tumor, because the symptoms can mimic those of a brain tumor.

Suspicions of IIH may arise from an MRI finding such as “empty or partially empty sella” or one optic nerve edema, which is often detected during an eye exam with or without symptoms. This type of headache is characterized by a pressure or squeezing sensation that extends across the entire head.

Warning signs may include:

• Persistent, positional headache that is worse when lying down.
• Brief episodes of visual loss or blurry vision that occur with a change in position.
• Ringing in the ears is often described as a “whooshing” sound or hearing your own heartbeat that gets worse when lying down and is often noticed in both ears.
• Side-by-side double vision or loss of peripheral vision (rare).
• Swollen optic nerves, often detected during an eye exam.

“While most patients are referred to me from eye doctors or neurologists, those with ringing in ears come from ENT doctors, others come from family doctors with treatment-resistant headaches says neuro-ophthalmologist Dmitry Balian, MD. “Upon further questioning, we find their symptoms are related to elevated intracranial pressure. Not all patients have symptoms with their vision either, but may be dealing with other manifestations of increased intracranial pressure like positional headaches.”

When to see a doctor

Persistent headaches, especially those accompanied by vision changes or headaches that don’t respond to traditional medications, warrant a thorough eye examination by an optometrist or ophthalmologist. If swelling is observed around the optic nerve, immediate medical attention is recommended to undergo an MRI and MR venogram.

The MR imaging helps a neurologist and neuro-ophthalmologist rule out other conditions that are associated with optic nerve edema and can present with similar symptoms and mimic IIH, including:

• Cerebral venous sinus thrombosis.
• Brain tumor or lesion.
• Meningitis or encephalitis.
• Hydrocephalus.
• Medication-induced intracranial hypertension.
• Obstructive sleep apnea.
• An inflammatory condition.
• Intracranial hypotension.
• Infection or other cause.

Once referred, a neurologist will discuss your symptoms and review your test results to confirm the diagnosis and determine the next steps. If you have a diagnosis of IIH, you may be referred to a neuro-ophthalmologist who specializes in disorders affecting the optic nerve. 

“The most fearful complication of IIH is permanent damage to the optic nerve,” adds Dr. Balian. “So, early intervention is crucial to preventing irreversible vision loss. When detected early, we have time to work on alleviating the symptoms through medical therapy and weight loss. If medication treatment is unsuccessful or cannot be tolerated due to side effects, surgical options may be considered to help relieve the pressure.”

Get your annual checkups and eye exams

Yearly physical and eye exams are always a good first line of defense. During an annual eye exam, dilation and visual field tests can help detect blind spots in your vision and any signs of swelling in the optic nerve.

If you’re experiencing headaches and are unsure how to manage them, consult your doctor about your symptoms. Headaches are complex, and it’s crucial to rule out potential causes, especially if they’re not responding to treatment. 

If you experience a sudden onset of a severe headache, especially if accompanied by weakness, dizziness or significant changes in vision or hearing, go to the emergency room.