When to get help urgently
Call 000, or go to an emergency department now, if
- a headache comes on suddenly and severely and reaches its worst within a minute, even if it then eases
- you have sudden loss, dimming or blurring of vision, even if brief, double vision, a new drooping eyelid or one pupil larger than the other (brief greying-out on standing or bending if you are under 50: see the same-day GP list)
- you are over 50 with a new headache, or a change in your usual headaches, and you notice blurring, double vision, or sight that dims or goes dark in one eye, even if it lasts only a few minutes
- you have numbness or weakness of the face, an arm or a leg, slurred speech or sudden unsteadiness
- the headache comes with fever and a stiff neck, a rash that does not fade when pressed, confusion, unusual drowsiness or a seizure
- you are 20 or more weeks pregnant or had a baby in the last 6 weeks and have a severe headache, a headache that does not get better with simple pain relief, blurred vision or flashing lights, sudden swelling of the face, hands or feet, pain under the ribs or in the upper tummy, or vomiting with a headache: go to your maternity unit or an emergency department now; call 000 for a seizure, trouble breathing or chest pain
A sudden, explosive headache can mean bleeding around the brain. A loss of vision, double vision, a drooping eyelid, unequal pupils, weakness or slurred speech can mean a stroke, pressure on a nerve, or pressure that is threatening your sight. In someone over 50, a new headache with a change in vision can mean giant cell arteritis is cutting off the blood supply to the eye: treated the same day, sight can usually be saved, but sight that is lost rarely comes back. Fever with a stiff neck, or a rash that does not fade, can mean meningitis. In pregnancy or soon after a birth, a severe headache can be a sign of pre-eclampsia, a condition of high blood pressure in pregnancy. All need urgent treatment. If you have migraine, your usual aura (shimmering or zigzag lines that spread slowly over several minutes and clear within an hour) does not need 000 on its own. A first aura after 50, or an aura different from your usual ones, needs an emergency department the same day.
Go to an emergency department the same day if
- your sight is getting worse over days: more blur, a shrinking field of view, or greying-out that comes more often or lasts longer, whether or not you have been diagnosed with IIH. If you have an eye specialist, contact them now; if you cannot reach them that day, go to an emergency department.
In a small number of people, IIH damages sight quickly, over days, sometimes before it has been diagnosed, and the pressure has to be lowered urgently to save it.
See your GP the same day if
- a headache is worse when you lie down, or is worst on waking and comes with vomiting or blurred vision
- a headache comes with a whooshing sound in the ears in time with your heartbeat, or is brought on by coughing, sneezing, laughing or straining
- a headache is getting steadily worse over days or weeks
- your vision greys out or goes dark for a few seconds when you stand up or bend, then clears completely, and you are under 50. If you are 50 or over, or it lasts longer than a few seconds, or comes on without standing or bending, call 000.
- it is a new headache, or a change in your usual headaches, and you are over 50, especially with a new tender scalp that does not go away, pain in the jaw when you chew that eases when you stop, aching shoulders, or feeling generally unwell; with any change in your vision, see the 000 list
- you are pregnant or have had a baby in the last 6 weeks and have a new or worse headache: contact your midwife, maternity unit or GP the same day
A headache that is worse lying down, a whooshing in the ears, a headache brought on by coughing or straining, or one that keeps getting worse can be a sign of raised pressure inside the head or another cause that needs a scan. The doctor will look at the back of your eyes and arrange a scan or blood tests; if you cannot see your GP that day, go to an emergency department. Greying-out for a few seconds when you stand or bend can be a sign of swelling at the back of the eyes. If you already have IIH and your eye specialist knows about these episodes, tell them the same day if they come more often or last longer; if you cannot reach them that day, go to an emergency department. Greying-out or dimming of vision on standing or bending, if you are 50 or over, follows the 000 list, with or without a headache. After 50, a new headache with a tender scalp or jaw pain when chewing can be giant cell arteritis, which needs blood tests that day. Pregnancy and the weeks after a birth make some serious causes more likely, so the bar for checking is lower. If something matches more than one list, follow the most urgent one.
Idiopathic intracranial hypertension (IIH) means the pressure of the fluid around the brain is higher than it should be, with no tumour or other cause found to explain it. It causes headaches and, most importantly, it can swell the nerves at the back of the eyes and damage your sight if it is not treated.
IIH used to be called benign intracranial hypertension, and is sometimes called pseudotumour cerebri. “Benign” was dropped because the condition can harm sight. The encouraging news is that with early diagnosis, treatment and regular eye checks, sight can usually be protected, and for many people the condition settles.
What is idiopathic intracranial hypertension?
The brain and spinal cord sit in a clear fluid, the cerebrospinal fluid. In IIH the pressure of this fluid is raised. “Idiopathic” means that no single cause is found, although IIH is strongly linked to body weight and hormones. The raised pressure presses on the optic nerves, the nerves that carry sight from the eyes to the brain, and makes the ends of them swell where they enter the back of the eye (papilloedema).
IIH is most common in women aged about 15 to 45 who are above a healthy weight, often after recent weight gain. It also occurs in men, in children and in people of any weight. Men with IIH are more likely to lose sight, so they need the same careful eye checks.
Before IIH is diagnosed, other causes of raised pressure are looked for, including a blood clot in the large veins that drain the brain (venous sinus thrombosis), some medicines and supplements, and some other medical conditions. Tell your doctor about everything you take.
Symptoms of IIH
Headache
The most common symptom. Often daily, and can be worse lying down or on waking. It can feel like migraine.
Whooshing in the ears
A sound in time with your heartbeat (pulsatile tinnitus), often worse lying down or in a quiet room.
Brief greying of vision
Vision greys out or goes dark for a few seconds, often on standing up or bending (visual obscurations).
Blurred or narrowed vision
Blurring, or loss of vision at the edges. This is the most serious effect, and any change in sight needs checking: see the warning signs at the top of this page.
Double vision
The pressure can affect a nerve that moves the eyes, so two images appear side by side.
Neck, shoulder and back pain
Common alongside the headache, as are dizziness and a dislike of bright light.
Some people have no symptoms at all, and the swelling at the back of the eyes is first noticed at a routine eye test.
How IIH is diagnosed
IIH is diagnosed by putting together the eye findings, a scan and a measurement of the fluid pressure:
Eye examination
An optometrist or eye specialist looks at the optic nerves at the back of the eyes, usually with photographs or a scan of the nerve, and tests the field of vision, including side vision.
MRI of the brain and its veins
An MRI scan, with a scan of the veins that drain the brain (an MR venogram), looks for a tumour, a blockage or a clot.
Lumbar puncture
A fine needle in the lower back measures the pressure of the fluid, and the fluid is tested to make sure it is otherwise normal. See will I get a headache from my lumbar puncture?
Examination and other tests
A neurological examination, blood pressure, blood tests and a review of your medicines look for other causes.
A normal MRI does not rule IIH out. In IIH the scan often looks normal, or shows only subtle signs of raised pressure. The diagnosis rests on the eye examination and the pressure measured at lumbar puncture.
How IIH is treated
Treatment has three aims: to protect your sight, to lower the pressure, and to ease the headache.
Weight loss
For people above a healthy weight, losing weight is the main long-term treatment, and it lowers the pressure. Support from a dietitian or a structured programme helps. In a UK trial in women with a high body weight, weight-loss surgery lowered the pressure more than a community weight programme.
Medicines
A medicine that reduces how much of the fluid is made is often used, alongside treatment for the headache. Your doctor can advise whether a medicine suits you.
Regular eye checks
Your sight and optic nerves are checked regularly, most often in the early months, to make sure treatment is protecting your vision.
Procedures when sight is at risk
If sight is threatened or getting worse despite treatment, options include a thin tube that drains the fluid (a shunt), a stent to widen a narrowed vein that drains the brain, or an operation on the sheath around the optic nerve.
A plan for the headache
The headache can carry on after the pressure is under control, and often behaves like migraine, so it needs its own plan. Pain relief taken on many days a month can itself cause more headaches: see medication overuse headache.
Pregnancy
IIH can be managed in pregnancy. Tell your doctor early if you are planning a pregnancy or become pregnant, because some treatments are changed and weight loss is not advised while pregnant.
Repeated lumbar punctures are not usually used as a treatment: a lumbar puncture can ease the headache for a short time, but the pressure soon builds again.
In a trial of 165 people with newly diagnosed IIH and mild loss of vision, a low-calorie diet with a medicine that reduces the fluid improved vision a little more than the diet alone. Read more in our report of that trial.
Reassuring: with treatment and regular eye checks, sight can usually be protected, and for many people IIH settles over months to a few years.
Outlook
IIH can come back, especially with weight gain, so eye checks continue even when you feel well. The headache often improves as the pressure comes down, but some people have headaches that continue and need their own treatment.
IIH care at East Neurology
Dr Ron Granot, neurologist with a special interest in headache, sees people with IIH and IIH headaches at East Neurology in Bondi Junction. He works with your GP and your eye specialist, who checks and protects your sight, and arranges the scans and tests needed.
Frequently asked questions
Is IIH serious?
It can be. IIH is not a tumour, but the raised pressure can damage the optic nerves and cause permanent loss of sight if it is not treated. With early treatment and regular eye checks, sight can usually be protected. If your sight is suddenly lost, dims or blurs, even briefly, or you see double, call 000 or go to an emergency department; if your sight is getting worse over days, go to an emergency department the same day.
Why was IIH called benign intracranial hypertension?
Because it is not caused by a tumour. The name “benign” was dropped because IIH can damage sight. If your sight is suddenly lost, dims or blurs, even briefly, or you see double, call 000 or go to an emergency department.
Can IIH make you go blind?
Untreated, IIH can cause permanent loss of sight, usually starting with gradual loss of side vision. In a small number of people, sight is lost quickly, over days. Regular eye checks pick up changes early, so treatment can be stepped up. If your sight is suddenly lost, dims or blurs, even briefly, or you see double, call 000 or go to an emergency department; if your sight is getting worse over days, go to an emergency department the same day.
Does a normal MRI mean I do not have IIH?
No. In IIH the MRI often looks normal, or shows only subtle signs of raised pressure, so a normal scan does not rule it out. The diagnosis rests on the eye examination and the pressure measured at lumbar puncture. A headache that is worse when you lie down, or worst on waking with vomiting or blurred vision, or a headache with a whooshing sound in the ears in time with your heartbeat, needs your GP the same day, even if a scan was normal. If your sight is suddenly lost, dims or blurs, even briefly, or you see double, call 000 or go to an emergency department.
Is IIH curable?
There is no single cure, but IIH often settles, especially with weight loss in people above a healthy weight. It can come back, for example with weight gain, so eye checks continue even when you feel well. If your sight is suddenly lost, dims or blurs, even briefly, or you see double, call 000 or go to an emergency department; if your sight is getting worse over days, go to an emergency department the same day.
How can I ease an IIH headache?
Treating the raised pressure usually helps, but the headache can carry on after the pressure is under control and often behaves like migraine, so it needs its own plan with your doctor. Pain relief taken on many days a month can itself cause more headaches. A headache that comes on suddenly and reaches its worst within a minute, or comes with sudden loss, dimming or blurring of vision or double vision, needs 000.
Can I get pregnant if I have IIH?
Yes. Many women with IIH have healthy pregnancies. Tell your doctor if you are planning a pregnancy or become pregnant, because some treatments are changed and weight loss is not advised while pregnant. If you are pregnant or have had a baby in the last 6 weeks and have a new or worse headache, contact your midwife, maternity unit or GP the same day. If you are 20 or more weeks pregnant or had a baby in the last 6 weeks and have a severe headache, a headache that does not get better with simple pain relief, blurred vision or flashing lights, sudden swelling of the face, hands or feet, pain under the ribs or in the upper tummy, or vomiting with a headache, go to your maternity unit or an emergency department now; call 000 for a seizure, trouble breathing or chest pain. If your sight is suddenly lost, dims or blurs, even briefly, or you see double, call 000 or go to an emergency department.
Related reading
- Headache location: what the place of the pain can and cannot tell you
- IIH: what a 2015 treatment trial found
- Will I get a headache from my lumbar puncture?
- Dr Ron Granot, neurologist with a special interest in headache
This page is general information about idiopathic intracranial hypertension for people in Australia and is not personal medical advice. Please contact the practice to discuss your individual situation.
Book an appointment
To arrange a consultation about IIH with Dr Ron Granot, neurologist with a special interest in headache, ask your GP for a referral, then get in touch. New patients and second opinions are welcome.
Or call 02 9388 0615. East Neurology, Bondi Junction; your Medicare rebate is processed for you on the day.