Idiopathic Intracranial Hypertension/IIH

Idiopathic Intracranial Hypertension or IIH is a rare neurological condition, that has no cure,  and affects 1 in a 100,000.

Idiopathic-of unknown cause. Intracranial-occurring inside the skull. Hypertension-increased pressure
Simply put, this condition is raised pressure inside the skull, usually with no known cause.

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This rare condition has few case studies, so I am also drawing on my own and other’s accounts too. Many patients compare their symptoms to those of a brain tumour patient’s; thankfully, in my opinion, without the tumour. IIH occurs when the cerebral spinal fluid (CSF), which surrounds the brain, has nowhere to go; due to increased pressure in the skull. IIH is most common in overweight women of childbearing age. There is usually no known cause but studies show that; some medication, hormones and restricted venous outflow; are probably some causes of raised pressure. Current UK statistics show: 93% of sufferers are obese (bmi >30); 25% of men with IIH have permanent, severe vision loss and about 5000 UK citizens have IIH; with more than 800 of these, being children. Statistics taken from IIH UK

PROGNOSIS:
Sometimes all symptoms unexpectedly disappear, but usually a mix of medical and surgical treatments are used with varying success. For others, everything is tried, but the patient is left with debilitating symptoms. IIH used to be called Pseudotumor Cerebri or Benign Intracranial Hypertension, however, these are now considered outdated, as both terms suggest that the condition isn’t harmful. This is misleading, as although IIH isn’t usually life threatening; unmonitored pressure or repeated surgery can be dangerous. Almost always, those affected have to cope with a life changing condition.

SYMPTOMS:
* Papilledema
* Pulsatile tinnitus
* Chronic migraine/severe headache disorder
* Temporary vision loss
* Pain behind the eye and on movement.
* Blindness
* Diplopia (double vision)
* Vertigo
* Nausea/vomiting
* Fatigue
* Aphasia (difficulty using or understanding words)
* Disorientation
* Depression/Anxiety
* Pain in arm, shoulder and/or neck
* Balance issues (acting as though drunk)
* Decreased depth perception
* Poor spatial awareness
* Visual disturbances; particularly poor peripheral/field vision
* Photophobia
* Photophobia/Hyperacusis (extreme amplified sound, such as a kettle boiling sounding like a jet engine))
* Long and/or short term memory loss
* Confusion/Brain fog
* Mood swings
* Alloydynia (pain sensitivity-pain following activities that wouldn’t normally hurt, such as having a shower)
These are not all present in all patients and many symptoms overlap other conditions; particularly chronic migraine. Each patient is different so this is not an extensive list, or for self-diagnosis. Seek medical attention if you are concerned.

MOST COMMON SYMPTOMS:
Papilledema (swelling of the optic nerve) is the most commonly accepted indicator of IIH. The majority of patients with IIH, suffer from visual disturbances. Often papilledema is found during a routine eye examination. If left untreated, papilledema can cause peripheral, partial or full loss of vision. Any sign of swollen optic nerves need urgent medical attention, as swelling of this important nerve (that carries information from the brain to the eye), can indicate a variety of serious medical conditions. The optic nerve is surrounded by CSF (to protect it from sudden movement). To read more; see this article. (Please remember that Benign Intracranial Hypertension and Pseudotumor Cerebri are outdated terms).

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IIH WITHOUT PAPILLEDEMA
Many neurologists/doctors do not accept that IIH without papilledema (IIHWOP) exists. Through the IIH UK forum, many patients without papilledema, describe being misdiagnosed or told they are in remission. Something needs to change for these patients, so that research such as this-Comparison of IIH with and without papilledema  is heard by the specialists.
Recently published research from a team in the UK, looks at how skull surgery may help a small group of patients who have restricted venous outflow, and CSF readings below the markers for diagnosis of IIH. These patients often respond well to interventions and surgery. The data is limited and it is controversial amongst neurologists. Read the abstract to the published paper here.

PULSATILE TINNITUS:
Pulsatile tinnitus (PT) is usually present with raised intracranial pressure. Pulsatile tinnitus is different to ringing tinnitus because it, almost always, has an underlying cause. PT is a whooshing or rhythmical sound that is in time with your pulse. It may be present continually and usually indicates that there is a change to the blood flow in the vessels or arteries near the ear. Pulsatile tinnitus is either objective or subjective. If the pulsing can only be heard by the patient, it is subjective, however, if someone else hears it, it’s objective. If severe headaches present with PT; this can be a sign that there is IIH. The presence of pulsatile tinnitus may be a sign of a serious condition, so please seek medical advice if you are concerned. To find out more about pulsatile tinnitus, please read this information from The British Tinnitus Association.

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SEVERE HEADACHES:
Debilitating headaches and pain around the eye(s) are present in nearly all (about 90%) cases of IIH. Patients report IIH headaches to be more severe and different to previous headaches. In one study, 78% of patients report this as their first symptom and 72% as the most severe. 73% report it to be a daily symptom. The pain is linked to increased intracranial pressure, so it usually worsens when the patient is lying down, bending over and on standing. As the headaches associated with both IIH and migraine are so similar; there is strict criteria for diagnosis. Migraine is usually unilateral/one sided and pulsating, whereas IIH headaches have to have at least one of these characteristics: daily occurrence, aggravated by coughing or sneezing and non-pulsating pain. IIH headache improves when CSF fluid is removed via a lumbar puncture. Many patients suffer both conditions so symptoms can be difficult to distinguish. Figures taken from this report.
DIAGNOSIS:
As more research into IIH happens, the indicators for diagnosis change. To diagnose IIH, neurologists follow the Modified Dandy criteria. This entails an LP to determine signs of raised pressure from the CSF fluid-now classed at >25cm H2O, normal CSF composition, small/normal ventricles and no mass on imaging. Diagnosis establishes known symptoms of IIH and rules out symptoms of other brain conditions. It entails a thorough eye examination, usually using an ophthalmoscope to detect swelling of the optic nerve. An MRI or CT scan is usually obtained. In some cases, an MRI/CT scan with dye is taken, showing the makeup of the blood vessels. An LP measures CSF fluid and is used to see if it produces prolonged relief of symptoms after 72 hours. An ICP bolt may be used to measure pressure over a longer period of time. Read more about this here . As mentioned previously; a new trial works with UK patients, who have restricted venous outflow; as the cause of increased pressure. In these cases, a ct venogram or venoplasty is usually performed. This is where a camera is inserted through a catheter in a vein in the groin; they measure pressures in the skull and a ballon may expand a vein to monitor after effects.

TREATMENT:
Medication:
* Acetazolamide (Diamox) reduces the amount of CSF fluid, the body produces. It is the most commonly prescribed medication for IIH.
* Topiramate (Topamax) is an anti-seizure medicine which reduces the amount of CSF fluid, that the body produces and can act as a preventative for the headaches associated with this condition.
* Diuretics such as Furosemide or Bendrofluazide may be prescribed
* Analgesics such as Tramadol, Fentanyl, and Morphine may be prescribed to help with severe pain.
Please find more information about these medications here: Common medications for IIH
Surgical:
If medications are not as effective as required, surgical options will be discussed.
* A shunt-a catheter is used to divert CSF from one place to another where it can be re-absorbed, safely, into the body. There are 2 main types of shunt and 2 less common: A Lumbo-peritoneal (LP) shunt-inserted into the back to drain into the abdominal cavity; A Ventricular Peritoneal (VP) Shunt-placed into the ventricles in the brain to divert the spinal fluid into the peritoneal cavity; Ventriculo-atrial (VA) shunt-the lower catheter drains into the heart’s atrium; Ventricular-Plerual (VPL) shunt-fluid drains into the pleural cavity surrounding the lung.
* A venous transverse stent is an option for IIH sufferers who have transverse venous stenosis (abnormal narrowing). This is a very small (usually titanium) coil that is put in place and then allowed to expand so that the blood can flow more freely and therefore reduce intracranial pressure. Stents cannot be moved once they have been dilated.
* In very severe cases of papilledema, an ONSF (optical nerve sheath fenestration) may be used to reduce the pressure on the optic nerve.
* Styloidectomy is a procedure that has been trialed by a team in the UK-the only team in the world to do so, for this purpose. This involves removing a small piece of bone from the skull, the styloid process (see diagram), to allow more room for blood to flow through constricted veins. This then allows for stents to be used, in the best position.

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Much more information about this disease can be found here at www.iih.org.uk

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