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Glossary
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A
Acetazolamide - see Diamox
Amitriptyline - a drug which is used in low dosage in IIH to treat some of the symptoms of the condition.
Analgesic - a drug used to relieve pain, often referred to as painkillers.
Angiogram - a radiological (x-ray) study which shows the blood vessels leading to, and in the brain, by
injecting a dye or contrast substance through a catheter placed in an artery in the leg, arm or neck, see also
venogram.
Anti-seizure drugs - may also be used to treat neuropathic (nerve) pain, for example, Gabapentin
(Neurontin), and Topiramate (Topomax).
Anti-depressants and relaxants - drugs which in low doses can help to relax you, so that you don't get a
tension headache as well as a high pressure headache. Some of the drugs, that are prescribed for IIH are
Amitriptyline (Triptafen), Imipramine (Tofranil), and Diazepam. Because diazepam is highly addictive it is
only used for short spells for acute, very severe, symptoms.
Anti-emetics - drugs that reduce feelings of nausea and vomiting. Some of the drugs that doctors may
prescribe for severe symptoms are Prochlorperazine (Stemetil, Buccastem), Domperidone (Motilium), and
Betahistine (Serc).
Aphasia - loss to, or impairment of the power to use or comprehend words. IIH sufferers may sometimes
experience short, temporary spells of aphasia.
Arachnoid - middle-layer of the membranes which cover the brain and spinal cord.
Ataxia - loss of coordination and balance due to nerve damage may cause trouble walking.
B
Benign - not dangerous to your health.
Benign Intracranial Hypertension (BIH) – This is the old name for Idiopathic Intracranial Hypertension
(IIH).
Betamethasone - a corticosteroid drug which is sometimes used to treat neuropathic (nerve) pain from nerve
compression caused by raised intracranial pressure in IIH.
Blind spot - Everyone has a blind spot in their vision. It is caused by a gap in the retina where the optic nerve
is attached to the back of the eye. It is not normally noticed as the brain compensates for the missing vision
by ‘filling in the gaps’. Sometimes, sufferers of IIH have an increased or enlarged blind spot. This may
become big enough to notice gaps in vision, but is often only picked up during visual field tests.
BMI (Body Mass Index) - Body mass index is a measurement that is used in relation to weight. BMI is the
ratio of body weight to height, estimating the degree by which you are over or underweight, and gives a
general indication of whether your weight falls within a healthy range. A BMI of less than 18.5 indicates that
you are underweight. The normal healthy weight range is considered to be 18.5 to 24.9), while a BMI of 25 –
29.9 is classed as overweight, and a BMI of over 30 is considered obese. BMI=Weight (in kg) / Height (in
m2).
C
CAT scan - a sectional view of the body constructed by computed tomography- called also CT scan. CT
scanning is non-invasive and uses x-rays to create the 'picture'.
Central nervous system - the brain and spinal cord.
Cephalgia - headache.
Cerebrospinal fluid (CSF) - the fluid that surrounds the brain and the spinal cord. The CSF circulates
around the brain and spinal cord (the central nervous system). This "water bath" acts as a support of
buoyancy for the brain and spinal cord. The support of the CSF helps to protect the brain from injury. The
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normal pressure of the fluid which is measured by a manometer during a lumbar puncture is 10-20cm/H20
(although some doctors say that up to 25cm/H20 is normal in patients who are overweight).
Cerebellar tonsils - portion of the cerebellum located at the bottom, so named because of their shape.
Cerebellum - part of the brain located at the bottom of the skull, near the opening to the spinal area;
important for muscle control, movement, and balance.
Chiari malformation - condition where the cerebellar tonsils are displaced out of the skull area into the
spinal area, causing compression of brain tissue and disruption of CSF flow.
Chiari malformation, type II - more severe form of malformation which involves descent of parts of the
brainstem and is usually associated with spina bifida.
Cisterna magna- CSF filled space below the cerebellum.
CNS (central nervous system) - the brain and spinal cord, part of the nervous system.
Codeine - a powerful analgesic drug in the opioid (opiate) class of analgesic drugs.
Corticosteroids - drugs which are sometimes used to treat neuropathic (nerve) pain from nerve compression
from raised intracranial pressure in IIH, such as Dexamethasone and Betamethasone. Because
corticosteroids are very powerful drugs that can have some serious side effects at high dosages especially
when used for extended length of time, they are only used for short periods and at relatively low doses.
Cranial nerve - one of 12 pairs of nerves that originate in the brain as opposed to the spinal cord.
D
Decompression surgery - common term for any of several variations of a surgical procedure to alleviate a
Chiari malformation.
Dexamethasone - a corticosteroid drug which is sometimes used to treat neuropathic (nerve) pain from
nerve compression from raised intracranial pressure in IIH.
Diamox - the trade name of a drug often prescribed to try to control IIH. Diamox (Acetazolamide) is a
diuretic which is often prescribed to glaucoma patients. It is thought that the drug acts in IIH by reducing the
amount of cerebrospinal fluid that is produced by the body.
Diplopia - commonly called double vision, where one object is perceived as two. This can be due to unequal
action of the eye muscles. This is normally reported with binocular vision (using both eyes), but very
occasionally it can still be present when one eye is closed. Some sufferers have permanent double vision,
caused by high pressure causing damage to the nerves that move the eyes, but it is also common to have
temporary episodes. The symptom can sometimes improve with drug treatment – usually Diamox.
Double vision - see Diplopia.
Diuretic - a type of drug which reduces fluid in the body, through increasing the excretion of water and mineral
salts, via the kidneys and so increasing urine production. They are also sometimes called 'water tablets'.
Acetazolomide (Diamox) and Frusemide (Frusol, Lasix) are drugs which are commonly used in IIH because
of their specific effect on cerebral oedema. Sometimes more than one diuretic may be used in combination
to achieve the desired effect and minimise side effects.
Dura - thick outer covering of the brain and spinal cord; beneath the Dura are the arachnoid and the pia.
Dysphasia - loss of or deficiency in the power to use or understand language. IIH sufferers may sometimes
experience short, temporary spells of dysphasia.
E
Enlarged blind spot - see blind spot.
Etiology - the cause of a disease.
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F
Field test - a test performed by ophthalmologists to assesses how much peripheral vision you have, monitor
vision and assess how well patients are responding to treatment.
Foramen magnum - large opening at the base of the skull, through which the spinal cord passes and joins
with the brain.
Frusemide (Frusol, Lasix) - diuretic drug sometimes given in place of or in addition to Acetazolomide.
G
Gabapetin (Neurontin) - an anti-seizure drug which is sometimes used to treat neuropathic (nerve) pain in
IIH.
H
Hydrocephalus - an excess of cerebrospinal fluid inside the skull due to a disruption in normal CSF flow, or
loss of brain tissue. Hydrocephalus is often a congenital condition (i.e. present at birth) which occurs in
conjunction with spina bifida. Hydrocephalus shares many symptoms with IIH, and is usually treated
surgically in the same way as IIH, by use of ventriculo peritoneal shunts.
Hypertension - persistently elevated pressure (e.g. of blood, cerebrospinal fluid etc.)
I
Ibuprofen - common, over-the-counter, anti-inflammatory pain reliever.
ICP - abbreviation for intracranial pressure.
ICP bolt - a device used for ICP monitoring. A subarachnoid screw or bolt is a hollow screw that is inserted
through a hole drilled in the skull and through a hole cut in the Dura mater (the lining that surrounds the brain)
where a sensor measures the ICP and sends it to a recording device.
ICP monitoring - monitoring of intracranial pressure over time, this is often done through the fitting of an ICP
bolt.
Idiopathic intracranial hypertension (IIH) - the term used for intracranial hypertension (IH) for which no
cause can be found.
Idiopathic - unknown cause.
Intracranial - inside the head.
Intracranial hypertension (IH) - a serious neurological condition in which there is high cerebrospinal fluid
(CSF) pressure within the skull. .
Intracranial pressure - the pressure inside the cranial cavity. It is maintained at a normal level by brain
tissue, intracellular and extracellular fluid, cerebrospinal fluid and blood. Normal intracranial pressure is 820cm/H20 (although some doctors say that up to 25cm/H20 is normal in patients who are overweight).
Iris - the coloured part of the eye. It is contraction of the muscle fibres in the iris which regulate the amount
of light entering the eye through the pupil.
J
K
L
LP shunt - see lumbar-peritoneal shunt.
Lumbar puncture (spinal tap) - a procedure where a needle is placed in the spinal canal (the sheath that
surrounds the spinal cord) in the lumbar region of the spinal cord to withdraw cerebrospinal fluid to measure
the pressure of cerebrospinal fluid to diagnose intracranial hypertension. Lumbar punctures may also be used
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therapeutically to ease the symptoms of intracranial hypertension and to protect permanent damage to
vision.
Lumbar-peritoneal shunt - a shunt where tubing is inserted into the area of lumbar spine and into the
abdominal cavity (peritoneum) to allow excess CSF to drain away and be reabsorbed into the body. There
may or may not be a valve attached to an LP shunt.
M
Manometer - a device for measuring pressure by means of a column of liquid. The height of the liquid is
directly proportional to the pressure being measured. In a lumbar puncture, a manometer is attached to the
special needle that is used to withdraw CSF to measure its pressure.
Meninges - the three membranes that cover the brain and spinal cord (singular- meninx).
MRI - a scanning technique. A non-invasive diagnostic technique that produces computerized images of
internal body tissues, based on nuclear magnetic resonance of atoms within the body induced by the
application of radio waves (magnetic resonance imaging).
MRV - an MRI scan where a contrast medium is injected into the veins to enable doctors to clearly see the
veins and sinuses around the brain to check for thrombosis (blood clot) or to rule out compression by tumour
of the cerebral venous sinus.
N
Narcotic - class of drugs derived from the opium plant or created synthetically for the same effect; used as
pain-killers.
Nervous system - the structures controlling the actions and functions of the body; it comprises the brain and
spinal cord (central nervous system) and the peripheral nerve fibres and ganglia.
Neurologist - doctor who specialises in neurological diseases and disorders, those involving the brain and
nervous system.
Neurology/Neurological - relating to the nervous system, the brain and the nerves.
Neuropathic - having to do with damage to a nerve.
Neuropathic pain - pain due to nerve damage, often severe and often described as burning.
Neurosurgeon - surgeon who specialises in surgery of the nervous system.
Neurosurgery - surgery of the nervous system, including procedures such as shunts and optic nerve
sheath fenestration.
Non-opioid (opiate) analgesics - analgesic drugs which are not in the opioid (opiate) class. They have no
tendency to produce dependence, but they also can have side effects. They are sometimes referred to as
weak analgesics. This class also includes NSAIDs - non-steroidal anti-inflammatory drugs. Non-opioids are
often used in combination with other analgesics, e.g. paracetamol with codeine.
NSAIDS - non-steroidal anti-inflammatory drugs. These are in the non-opioid (opiate) class of analgesics,
which includes ibuprofen, naproxen, and others.
O
Oedema - abnormal retention of fluid.
ONSF - see optic nerve sheath fenestration.
Ophthalmological surgeon - surgeon specialising in surgery of the eye.
Ophthalmologist - a medically qualified specialist in ophthalmology.
Ophthalmology/Ophthalmological - relating to the eye.
Ophthalmoscope - an instrument uses to look into the structures of the eye. The ophthalmoscope has a
mirror with a hole in the centre with a light attached that enables the doctor to see into the back of your eye.
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The ophthalmoscope has lenses in the mirror which can be rotated into the opening in the mirror so that the
doctor can clearly focus the various structures within the eye.
Opioids (opiates) - powerful analgesic drugs that act on the central nervous system and alter perception of
pain. Opioids drugs have many possible side effects, including addiction. Opiate drugs also have a tendency
to make you feel drowsy, though there are other potentially serious side effects which make doctors wary of
prescribing opiates unnecessarily.
Optic disc - the point where the optic nerve enters the eyeball.
Optic nerve sheath fenestration (ONSF) - a surgical procedure sometimes performed for IIH to relieve
pressure on the optic nerve. An incision is made in the optic nerve’s protective covering and slits or 'windows'
are cut into the optic nerve sheath, allowing the excess fluid to escape and harmlessly absorb into
surrounding tissues. ONSF can reduce the visual symptoms of IIH but usually has no effect on the
neurological symptoms of IIH.
Orlistat - see Xenical
Orthoptics - the study and treatment of eye movement disorders.
Orthoptis - medical professional who specialises in assessment and treatment of eye movement disorders.
Additionally orthoptists may carry out some visual tests such as visual field.
P
Painkillers - the common name used for drugs that are used to relieve pain, sometimes called analgesics.
Papilloedema - swelling of the optic nerve caused by raised intracranial pressure which can lead to a number
of visual problems. Papilloedema causes protrusion and enlargement of the 'blind spot' on the retina where
the optic nerve enters the back of the eye and can cause a number of visual problems.
Par aesthesia - the tingling of the extremities, particularly hands and feet that is caused by the drug
Acetazolomide (Diamox). Par aesthesia, while irritating, is not harmful, and is a known side effect of the
drug. Par aesthesia is an abnormal sensation, such as burning or tingling.
Photophobia - this is literally ‘fear of light’, a sensitivity to, and sometimes pain caused by, bright light. Many
IIH sufferers have this symptom. Bright light is painful to the eyes, and also increases headache pain. Some
people feel ‘blinded’ by strong light or even normal daylight, and need to be in a dark environment. In rare
cases, the nerves signalling to the muscles moving the iris can become damaged, and the iris will not react
as quickly as normal to light, intensifying the difficulty.
Pseudotumor cerebri (PCT) - a term used for intracranial hypertension from the Latin, which literally
means "false brain tumor" as benign intracranial hypertension (BIH) and idiopathic intracranial
hypertension (IIH) mimics the symptoms of a brain tumour.
Pulsatile tinnitus - "whooshing noise" that is heard in the ears in time with the pulse.
Pupil - the opening in the iris of the eye which allows the passage of light.
Q
R
Retina - the lining of the back of the eyeball where cells convert light into electrical signals, the surface onto
which we see images is projected.
Radicular - relating to the roots; in the case of radicular pain, damage to a nerve root can actually cause
pain at the end of the nerve.
Radiograph - another name for an x-ray, the diagnostic machine which uses radiation to create an internal
image of the body.
Radiological - relating to radiation. An x-ray is a type of imaging study used to look at the bones of the body
which uses radioactive substances.
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S
Shunt - a surgically implanted tube used to divert, or drain, CSF. In IIH this term refers to a device which
moves cerebrospinal fluid from one place, to another (usually the abdominal cavity), where it can be reabsorbed. See also ventriculo-peritoneal shunt and lumbar-peritoneal shunt.
Slit lamp - a microscope with a light attached that allows the doctor to examine your eyes under high
magnification. This instrument is usually used to view the front structures of the eye such as the cornea, iris,
and lens, however, with special lenses, it's possible to examine the back of the eye as well. The instrument’s
name comes from its adjustable light beam. By changing the width of the beam, the doctor can gather
important detail about each eye structure.
Spina bifida - a birth defect where part of the spinal cord develops abnormally, sometimes outside of the
body. As well as abnormalities of the spinal cord itself, often there is abnormality of the spinal column also.
Spina bifida commonly occurs with hydrocephalus.
Spinal tap - see Lumbar puncture.
Spontaneous venous pulsations (SVP) - periodic changes in size of veins in the retina (in the back of the
eye); absence of spontaneous venous pulsations indicates elevated intracranial pressure.
Stenosis - narrowing or blockage of a passage; narrowing of the venous channels.
Stent - a device used to provide a shunt or keep a tube or vessel open. Where high CSF pressure causes
stenosis, narrowing of the venous channels (large veins) around the brain, reducing the blood flow, a stent,
a wire mesh is inserted into the vein and acts as a support, allowing the blood to flow freely. This is still a
relatively new procedure in people with IIH, and further research is needed to determine the actual cause of
the stenosis.
Subarachnoid space (SAS) - space underneath the arachnoid, but above the actual brain and spinal tissue,
which contains the cerebrospinal fluid.
Suboccipital craniectomy - surgical removal of part of the skull, or cranium, in the back of the head, near
the base.
Sub-temporal decompression - This involves removing a portion of the skull and opening the Dura (brain
lining) to relieve pressure. This procedure is not normally recommended nowadays.
T
Tonsillar herniation - displacement of the cerebellar tonsils out of the skull; usually measured in mm below
the bottom of the skull.
Tinnitus - a sensation of noise (may be heard as ringing, buzzing, whistling, roaring, or a variety of other
sounds) that is thought to be caused by a bodily condition and can usually be heard only by the person
affected (see also pulsatile tinnitus).
Topiramate (Topomax) - an anti-seizure drug which is sometimes used to treat neuropathic (nerve) pain
in IIH.
Transient visual obscurations - episodes of temporary blurred vision that usually last less than 30 seconds
and are followed by full recovery of vision. They occur in about 3/4 of IIH patients and may be involve one or
both eyes. They are not correlated with ICP or with the extent of papilloedema.
U
Ultrasound - imaging technique which uses sound waves to create pictures of internal organs and body part.
V
Venous Sinus - Large veins found within the skull.
Venogram - radiological (x-ray) examination of the venous system (blood vessels) in the brain involving
the injection of a contrast medium to clearly show the blood vessels, see also angiogram.
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Ventricles - the fluid filled cavities in the brain where CSF fluid is produced and part of the CSF circulatory
system. The fourth ventricle is a space in the brain where CSF collects.
Ventriculo-peritoneal shunt - in the ventriculo-peritoneal shunt, the shunt is inserted directly in the ventricles
of the brain, the fluid filled cavities in the centre of the brain and the tubing is fed down through the neck into
the peritoneal cavity (abdomen) to allow excess CSF to drain away and be reabsorbed into the body.
Ventriculo-peritoneal shunts are controlled by a valve which prevents back-flow of the fluid and regulates the
rate of drainage.
Vestibular - relating to the balance system; more specifically to the vestibule of the inner ear.
Visual acuity - sharpness of vision.
Visual field test - a test that is performed by ophthalmologists to assess how much each eye is contributing
to the field of vision overall.
Visual field - the entire expanse of space visible at a given instant without moving the eyes - also called field
of vision.
VP shunt - see ventriculo-peritoneal shunt.
W
Water tablets - another name for diuretic drugs
WHO - abbreviation for World Health Organisation
X
Xenical - Xencial (the trade name of Orlistat, also known as tetrahydrolipstatin) is a drug which can be used
as an aid to weight loss. Xenical acts by preventing the absorption of fats from the human diet, thereby
reducing calorific intake. It is intended for use in conjunction with a medically-supervised reduced-calorie diet.
X-ray - a form of ionising radiation used to image some internal structures of the body. X-rays are used in
medicine to examine teeth, lungs, bones, and other parts of the human body; they also occur naturally.
Y
Z
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