Good Hope, Heartlands, and Solihull Eye Clinics

IIH: idiopathic intracranial hypertension

David Kinshuck, from lectures

  • IIH Queen Elizabeth Hospital

Terms used

  • ICP = intracranial pressure (pressure in the brain).
  • IIH = idiopathic intracranial hypertension (the name of the condition)
  • CSF = cerebrospinal fluid (the fluid aound the brain)
  • papilloedema = swelling of the brain due its the high pressure

IIH: idiopathic intracranial hypertension

IIH occurs 90% in women, and 95% are <50y age, and is linked to obesity. Patients present with headaches and papilloedema (a type of swollen optic nerve). There may be blurred vision, or double vision. There may be visual obscurations (the sight reduces for a few seconds and returns by itself) and pulsatile tinnitis (noises in the ear linked to heart beating). Brain scans are needed and the intracranial pressure (measured by a lumbar puncture) is raised. The scan will need to exclude other conditions. IIH was formally termed benign intracranial hypertension. Eye news 17:

Diagnostic criteria

  1. Symptoms and signs of raised intracranial pressure including papilloedema.
  2. Elevated CSF pressure >25 (left lateral decubitus position). This is raised intracranial pressure (ICP). Maximum healthy ICP are 25 adult, 28 children. 
  3. Normal csf protein etc.
  4. No venous sinus thrombosis on CT/MRI angiography.
  5. No secondary causes such as hydrocephalus, space occupying lesion, etc.
  6. No cns signs except cranial nerve palsy.

Weight loss

  • there are many studies indicating that losing weight helps in the condition. 2017
  • Other treatments merely help headaches or lower the pressure temporally (acetazolamide) or more long term such as CSF shunting operations
  • bariatric surgery may turn out to be the best treatment for the condition
  • Exenatide (an anti-diabetic drug) may be very helpful treating idiopathic intracranial hypertension. This is a glucagon-like peptide-1 (GLP-1) receptor agonist 2017.

Headaches

  • The headaches after the papilloedema may still be unpleasant, and are due to a combination of raised intracranial pressure, medication overuse, stress or migraine.
  • An exacerbation of headache may respond to ibuprofen (but need to check for papilloedema).
  • Topiramate 2007

New research: a sequence of events

  • New studies identify that there may be anatomical abnormalities causing stenosis of the dural sinus (congenital). But in addtion some of this stenosis may be from brain swelling linked to a certain type of biochemistry, and it is the combination that causes the condition. The biochemical problem is linked to a congenital difference in the patients from normal and the combination with obesity.
  • Thus IIH is due to a combination of obesity, which due to genetic biochemical differences, causes extra brain swelling around the dural sinuses in the brain, and the narrow dural sinuses, which then obstructs the flow of CSF, and this ncreases the intracranial pressure.

Symptoms

  • 92% headache
  • 72% obscuration
  • 60% noises/tinnitus
  • diagnosis of exclusion
  • Headache commonest sign, but 10% no headache

Examination

  • if IIH is suspected, a lumbar puncture is needed
  • a lumbar puncture is needed to exclude other diseases : pressure/protein/cytology/glucose ned examining
  • MRVenography to exclude sinus thrombosis
  • fields
    • full at onset, later field loss
    • large blind spot, generalised constriction, reversible
    • arcuate/altitudinal, (infarcts, not reversible)

Children

  • IIH affects children, more girls, but is commoner after puberty
  • if may follow recent weight gain in older children
  • Younger children half overweight, older most overweight,
  • Downs, turners, sickle cell, anaemia, transretinoic acid, growth hormone, thyroxine etc all may contribute
  • may need sedation for lp, deep sedation, have slightly higher opening pressure.
  • VIn palsy and papilloedema children.

Treat papilloedema itself

  • azetazolamide (diamox) helps JAMA 14   JNO 16    JNO 16
    • older patient 4 g day maximum
  • Frusemide acute to buy time, steroids, surgery
  • Shunt, for fulminant, progressing, or severe headache
  • if the IIH is severe with a really swollen disc a shunt is often needed

Treat underlying problem, obesity

  • treating obesity is the main treatment
  • Bariatric Surgery JNO 16...  Bariatric surgery helps..20. Minutes for gastric band
  • Weight loss helps, androgen pathway improves 5 alpha reductse...this is linked to papilloedema.
  • Psychological treatment is the main treatment to help patients lose weight, as they put weight on tinnitus and headaches and papilloedema returned.
  • 11beta hsd1 elevated in obesity in Choroidal plexus...this level reduces with weight loss and is related to improvements in papilloedema
  • Glp1 glucagon like peptide 1, which reduces appetite, liraglutide, may be helpful 2017

Monitoring

  • retest fields if stable JNO 16 

Problems

  • How do you persuade patients to lose weight, weight loss is the treatment, and can discharge, work out which patients can lose weight and which can't.
  • Patients don't like term obesity, overweight not the first visit, discuss later in outpatients
  • Headache is the main determinant of quality of life
  • increasing in incidence due to increasing obesity
  • empty sella (effect of high ICP)
  • disc haemorrhages increase risk BJO 17
  • stop minocycline (can cause IIH)

 

Support

 

Case1

  • 16y girl, 6 week headache,good vision, lp 25
  • Spontaneous venous pulsation present os not papilloedema
  • drusen b scan optic nerve and needed to treat tension headache

Case2

  • Elevated nerves and field defect..hyperaemic disc swollen= iih
  • 24 h lp monitoring, pressure