A healthy food & lifestyle blog specifically catering for & dealing with the symptoms & conditions of : Endometriosis, Polycystic Ovarian Syndrome (PCOS) & Intracranial Hypertension (IH).
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Wednesday, 9 May 2012

Geared up and ready for my procedure...

On Thursday. 10/05/12, this week I am going into Royal North Shore Hospital to get a Venous Sinus Stenting procedure done.
This procedure carries high hopes that it will alleviate some of the pressure in my head and decrease the incidence of headaches and loss of auditory and visual fields.

I have a condition called Idiopathic Intracranial Hypertension (also know as IIH and Pseudotumor Cerebri (PTC)). It affects only 1 in 100,00 people world wide, there is no known cause and there is no cure.

What is Idiopathic Intracranial Hypertension?
In its simplest terms “intra” means within, “cranial” refers to the skull, “hyper” is to raise and “tension” means pressure; therefore Intracranial Hypertension is raised pressure within the skull.
There are two types of Intracranial Hypertension (IH):
     - Primary (Idiopathic) – has no known cause or cure; and
     - Secondary – as a result of a major head trauma and is generally due to an intracranial bleed.

Why is this a problem?The skull is rigid and as such does not allow for swelling or any increases of pressure within it.  So if there is no flexibility outwards then the pressure must be absorbed inwards thereby squeezing the brain and compromising the blood supply to essential nerves such as the optic nerves.
The increased pressure on the brain not only causes a medical problem but is extremely painful.  Patients often complain that it feels like their head is in a vice or that their skull feels too small.  The headache is unrelenting and quite unlike anything else that patients can describe.

What are the symptoms?
Headache, which occurs in almost all (92–94%) cases, generalised in character and throbbing in nature. It may be associated with nausea and vomiting. The headache can be made worse by any activity that further increases the intracranial pressure, such as coughing and sneezing.
The pain may also be experienced in the neck and shoulders.
 Pulsatile tinnitus, a whooshing sensation in one or both ears (64–87%); this sound is synchronous with the pulse. Some patients also experience a high pitched 'electrical hum' noise.
Various other symptoms, such as numbness of the extremities, generalised weakness, loss of smell, and incoordination, are reported more rarely; none are specific for IIH.
The increased pressure leads to compression and traction of the cranial nerves, a group of nerves that arise from the brain stem and supply the face and neck. Most commonly, the abducens nerve (sixth nerve) is involved. This nerve supplies the muscle that pulls the eye outward. Those with sixth nerve palsy therefore experience horizontal double vision which is worse when looking towards the affected side.
More rarely, the oculomotor nerve and trochlear nerve (third and fourth nerve palsy, respectively) are affected; both play a role in eye movements. The facial nerve (seventh cranial nerve) is affected occasionally –- the result is total or partial weakness of the muscles of facial expression on one or both sides of the face.
The increased pressure leads to papilledema, which is swelling of the optic disc, the spot where the optic nerve enters the eyeball. This occurs in practically all cases of IIH, but not everyone experiences symptoms from this. Those who do experience symptoms typically report "transient visual obscuration", episodes of difficulty seeing that occur in both eyes but not necessarily at the same time. Long-term untreated papilledema leads to visual loss, initially in the periphery but progressively towards the centre of vision.
Physical examination of the nervous system is typically normal apart from the presence of papilledema, which is seen on examination of the eye with a small device called an ophthalmoscope or in more detail with a fundus camera. If there are cranial nerve abnormalities, these may be noticed on eye examination in the form of a squint (third, fourth, or sixth nerve palsy) or as facial nerve palsy.
If the papilledema has been longstanding, visual fields may be constricted and visual acuity may be decreased. Visual field testing by automated (Humphrey) perimetry is recommended as other methods of testing may be less accurate. Longstanding papilledema leads to optic atrophy, in which the disc looks pale and visual loss tends to be advanced.

Who is affected?
Secondary IH can happen to anyone at any time although young men playing contact sports are in a higher risk category than most.
Idiopathic IH generally (but is not restricted to) women of child bearing age who are overweight.  That being said, there are currently no statistics in Australia regarding IIH so this information is derived from US studies.
Current research in Australia is being conducted by the Brain Foundation.

How is it diagnosed?
Secondary IH is easily diagnosed as a bleed is evident on either CT or MRI scans and the patient would report or display evidence of significant head injury.  It is generally short term and once the head injury has healed the IH symptoms will also fade without recurrence.
Idiopathic IH is much harder to diagnose and a process of elimination is generally used.  Patients will generally begin complaining to their GP of persistent headaches yet any CT or MRI scans will not display any significant findings.  Most patients do not begin to find answers until they visit their Optometrist who discovers papelodeoma (swelling of the optic nerve).  This is then followed by a visit to an Ophthalmologist who will complete a field of vision test and a more thorough examination of the optic nerve at the back of the eye.  The next step is to visit a Neurologist or Neurosurgeon who will generally require CT and MRI scans to be done.  When these return no significant findings a lumbar puncture is required.  It is this final test that is able to diagnose IIH.
Pressure inside the skull is measured in centimetres of mercury.  “Normal” opening pressure is between 5 and 15 centimetres of mercury; however, one is not usually deemed to have IIH unless they have an opening pressure greater than 20 centimetres of mercury.  Another common factor amongst IIH sufferers is that although CT and MRI results show no “significant” findings, patients do tend to have small or constricted ventricles.  This is in direct opposition to patient suffering with Hydrocephalous.

How is it treated?
The first thing patients are advised to do is lose weight, as little as 5 kg weight losses can reduce the severity of IH symptoms; maintain a healthy lifestyle and reduce stress.
As for medical intervention, Acetazolomide (Diamox) is the most commonly prescribed medication for IH patients.  It works by reducing the overall fluid in the body and can significantly reduce cerebrospinal fluid production.  This is not a successful treatment for all patients due to the side effects of this medication.
Other prescribed medications may include Topiramate (Topamax) or Amitryptiline (Endep). Analgesics (pain killers) may also be prescribed, though some may have little effect, and addiction to these drugs is possible.

Surgical Intervention
A new treatment for IH is venous stenting for patients with venous stenosis (collapsing veins).  When the pressure inside the skull is increased in the brain is squeezed, the blood vessels inside the brain in turn are also squeezed; as such collapsing them; venous stenosis.  If the blood vessels collapse, then the blood cannot flow freely.  This may not seem significant to IH however, CSF is constantly made and replaced.  What happens to the old CSF? It gets absorbed by our blood vessels and taken away.  So clearly if our veins are collapsing then our CSF cannot be drained causing a build-up and IH.  What are stents and how do they help?  Stents are like small, flexible pieces of hose that can be inserted inside a blood vessel and hold it open allowing a constant flow of blood through.
A shunt is a device which drains fluid from one area to another area of the body.  There are many different types of shunts and many different places they can be put although most patients with IH are fitted with an adjustable valve to allow the rate of drainage to be moderated and adjusted by the doctor as required.
There are two main types of shunts used:
  1. Lumbar-Peritoneal  -  draining from the lumbar spine to the peritoneal (abdominal) cavity
  2. Ventricular-Peritoneal – draining from the ventricle (in the head) to the peritoneal cavity.
Although these are the most common shunts used, they are by no means the only options available to IH patients.
Optic Nerve Sheath Fenestration (ONSF)
When an IH patient’s vision is severely affected or at risk to be, an ONSF may be performed. In this procedure, a ‘window’ or slit is cut into the sheath to relieve the pressure optic nerve swelling and allow the CSF to escape. ONSF has little effect on headaches or the overall ICP and is usually only performed to save the patient’s vision. Surgery complications can lead to blindness.

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