Idiopathic Intracranial Hypertension in Children aged 1-18 years
Idiopathic Intracranial Hypertension Flow Chart
Introduction
Idiopathic intracranial hypertension occurs in around 0.5-0.9 children per 100,000 per year. The incidence in post-pubertal children aged 12-17 years old is much higher (range 0.80 to 8.69 per 100,000 children/year) compared with the pre-pubertal group aged 2-11 years old (range 0.16 to 1.16 per 100,000 children/year).
Scope and Purpose
This guideline applies to all health providers in the regional District General Hospitals (DGH) in the Wessex region and within University Hospital Southampton (UHS) NHS Foundation Trust. 

The purpose is to provide standardised care throughout the region and improve patient safety and clinical outcomes. 

​The purpose of this document is to provide regional guidelines for doctors in the clinical management of children with a suspected diagnosis of Idiopathic Intracranial Hypertension (IIH).​
Definitions
Idiopathic intracranial hypertension (IIH) also known as pseudotumour cerebri or benign intercranial hypertension is defined as a condition of elevated intracranial pressure (ICP) of unknown aetiology, combined with normal neuroimaging and CSF composition. It is important to diagnose IIH early as some of the visual disturbances associated can be progressive and may lead to prolonged ischaemia to the optic nerve head resulting in permanent visual loss in 1-2% of IIH patients per annum.

  • IIH – Idiopathic Intracranial Hypertension
  • CSF – Cerebrospinal Fluid
  • ICP – Intracranial Pressure 
  • LP – Lumbar Puncture​
Clinical Symptoms
Pre-pubertal children 

Symptoms 
  • Headaches 
  • Visual symptoms – blurriness of vision
  • Fatigue
  • Lack of appetite,
  • Nausea and vomiting
  • Other neurological symptoms – ataxia, dizziness, limb paraesthesia

Signs
  • Normal BMI  
  • Decreased visual acuity and colour vision
  • Papilloedema
  • Visual field defect

Post- pubertal children 

Symptoms
  • Headache →
    • Worse on awakening, one that can cause the patient to wake from sleep, aggravated on exertion e.g.by bending down or coughing/ sneezing.
  • Visual disturbance → Transient uni- or bi-lateral darkening of vision, blurring and horizontal diplopia. Later scotoma/ blindness.
  • Other → Pulsatile tinnitus, back pain, dizziness, neck pain, cognitive disturbance, radicular pain and vomiting. 
Signs
  • High Body mass index (BMI)
  • Decreased visual acuity and colour vision.
  • Papilloedema 
  • Visual field defect
Risk Factors
In a patient with symptoms of raised ICP and where an ophthalmic examination has been conducted to show papilloedema, it should be considered whether the patient has risk factors for IIH, which include:
​
  • Female   - post-pubertal
  • Overweight and obesity – pre and post-pubertal
  • Endocrine conditions, including Addison’s disease and hypoparathyroidism
  • Vitamin A intoxication including isotretinoin and retinoic acid
  • Obstructive sleep apnoea
  • Systemic Lupus Erythematosus
  • Malignant hypertension
  • Infections such as Lyme’s, mycoplasma, EBV, Covid-19
  • Drugs
    • Antibiotics such as tetracyclines and nitrofurantoin
    • Indomethacin, Nalidixic acid, Lithium
    • Thyroid replacement therapy
    • Steroid
Height and weight measured, charted and their BMI calculated using the formula below: 
BMI = weight (kg) / [height (metres)]2
Investigations
Ophthalmology
Papilloedema is an important sign of IIH and is usually suggestive of raised ICP. An ophthalmology assessment is needed to confirm papilloedema in IIH, exclude differentials and evaluate the current risk to the patient’s vision. 
The ophthalmologist examination will include visual acuity, colour vision, pupil examination, ocular motility, anterior and posterior segment examination, optic disc assessment with fundal examination and Optical Coherence Tomography (OCT) imaging including volumetric ONH parameters, RNFL thickness parameters and macular GCL readings. Visual field examination should be performed with automated perimetry for children older than 10 years that can cooperate to perform the test. 
After someone is diagnosed with IIH, an ophthalmologist will be involved in monitoring IIH patients due to risk of vision loss associated with the condition.
Blood tests
Depending on how the patient presents, appropriate blood tests should be conducted to exclude other conditions and causes of raised ICP.
Blood tests may include:
Imaging
An MRI and MRV brain scans are needed in all cases of suspected IIH, in order to identify secondary causes of raised ICP, including space occupying lesions and to rule out venous sinus thrombosis or abnormal venous sinus anatomy. MRI is also useful to identify indirect signs of raised ICP. Neuroimaging should be conducted within 24 hours of papilloedema 

being identified. However, if child presents with visually threatening papilloedema and or acute visual loss, imaging should be performed sooner.

If an MRI scan is not available within 24 hours, then an urgent CT and CTV scan should be conducted. 

Should the CT and CTV scans be reported normal, in some children an MRI scan may need to be arranged within a few days depending on presentation. Please discuss with paediatric neurologist if needed. 
Performing a lumbar puncture
A lumbar puncture is necessary for the diagnosis of IIH in all patients following normal imaging. 

If there is acute visual loss, the first LP should be performed in suspected IIH as a matter of urgency after discussion with paediatric neurology.

​Local Safety Standards for Invasive Procedures

Before performing a lumbar puncture 
  • Confirm patient’s identification
  • Confirm no contraindications 
  • Obtain consent from parents and child if applicable 
  • Ensure adequate environment and material for the procedure 
  • Ensure adequate analgesia 
  • Ensure all sharps are disposed and samples sent to the lab. 
  • Documentation in the notes ​
​Preparation
  • An anxious patient will make it more difficult to interpret the results of the opening pressure as it is affected by hyperventilation. Therefore, the procedure and necessity of the lumbar puncture should be explained to the patient (and their parent/guardian) to help alleviate any fear/anxiety and informed consent should be documented in the clinical notes.
  • Two manometers may be needed as the opening pressure may be more than 40cm of H20.
​Positioning
  • It is important for the lumbar puncture to be performed with the patient in the lateral decubitus position. 
  • Patients should be comfortable laying in the left lateral decubitus position with the bed horizontal. 
  • Keep the neck neutral.
  • Patient should have their knees and hips flexed but not excessively. 
  • It has been shown that measuring the opening pressure with the patient sitting can lead to elevated measures captured. On occasion it may be necessary to insert the needle with the patient in the sitting position and then carefully move them to lateral decubitus to allow correct recording of CSF.
​Pressure reading
  • It is important to allow the CSF level to settle before taking the opening pressure. The meniscus will normally appear pulsatile reflecting changes in breathing and HR.  Ideally observe the opening pressure for a period of time for more reliable reading.
  • Patients having an LP under GA should have their GA drugs documented and their end-tidal carbon dioxide level checked, maintained and documented between 4.5-5kPa. A rise of 1kPa in end-tidal pCO2 is associated with a rise of 3.5-12cm H2O in the CSF pressure.
​Reducing Pressure
  • An opening pressure <20cm H2O is normal. 25cm H2O is the upper limit of normal pressure in non-sedated patients. 
  • If CSF opening pressure is >28cm H2O it should be reduced to 20-25cm H2O. CSF pressure should be rechecked very 4-5mls of CSF drainage until pressure is within normal limits (up to 10-15mls of CSF)
  • For opening pressures above 40cm H2O, bring down by half. As an example, if OP is 50cm H2O, bring down to 25cm H2O.
  • Closing pressure should be documented.
  • The opening pressure and result of CSF analysis are part of the criteria of IIH diagnosis.
  • If there is uncertainty or atypical aspects seek opinion from a clinician with experience of IIH.
  • Maximum LPs a patient should have over the course of their illness should be fewer than 5.
  • Repeated LPs should be offered if visual changes progress and there is a threat to vision on medical management and/or when symptoms are not responsive to medical management.
Holland JAA, et al. How to use lumbar puncture manometry in children. Arch Dis Child Educ Pract Ed 2023
​Post Lumbar puncture management
  • Some patients may experience the following symptoms after a lumbar puncture is performed:
    • Low pressure headache –mostly resolved within 48hours, however it can last up to 2 weeks. 
    • Neck stiffness
    • Nausea and vomiting
  • If these symptoms are experienced, the patient should be advised to lie supine without a pillow and to ensure adequate hydration is maintained. IV fluid administration may be necessary.​
IIH Diagnostic Criteria (Friedman's criteria)
Required for diagnosis of IIH
  1. Papilloedema confirmed by ophthalmologist with optical tomography OCT
  2. Normal neurologic examination except for 3rd and/or 6th cranial nerve abnormalities
  3. Neuroimaging: Normal brain parenchyma* and normal MRV
  4. Normal CSF composition
  5. Elevated LP opening pressure (≥25cm CSF in adults and ≥28cm CSF in children [25cm CSF if the child is not sedated and not obese]) in a properly performed lumbar puncture

Diagnosis of IIH without papilloedema:

In the absence of papilloedema, a diagnosis can be made if B-E from above are satisfied, if patient also has a unilateral or bilateral 6th nerve palsy. In the absence of papilloedema or 6th nerve palsy, a diagnosis can be suggested if B-E present with particular neuroimaging criteria. This diagnosis should be discussed and agreed with a paediatric neurologist.
Medical Management
Weight management

Weight loss is the main management of IIH if child is obese or overweight. Children over 2 years of age with BMI >99.6th centile or BMI >98th centile and diagnosed with IIH should be referred to the Paediatric Obesity Service. 
Medications 
 
  • For the treatment of IIH, Acetazolamide is the most commonly used first line drug.
  • Topiramate use may lead to weight loss due to its effect on appetite suppression; worth considering as weight loss has been associated with reducing both the headaches and papilloedema associated with IIH. Furthermore, topiramate may also prevent the development of migraines.
  • Anecdotal reports show that oral Prednisolone can be helpful in treating IIH. The UHS team do not advocate the use of prednisolone in IIH.
Name
Mechanism of action
Dose
Side Effects
Other
Acetazolamide
Carbonic anhydrase inhibitor, lowers ICP by decreasing the production of CSF. Inhibition of CA results in reduction in sodium ion transport across the choroidal epithelium 
Initially 8mg/kg TDS.
Increasing by 8mg/kg/dose each week up to 32mg/kg/dose TDS
Gastrointestinal disturbances including diarrhoea and vomiting, malaise, fatigue, depression, paraesthesia
Distorted sense of taste (dysgeusia).
First line treatment.
 
Needs monitoring of electrolytes
Immediate release tablets can be crushed and dispersed in water. 
Topiramate
Weak carbonic anhydrase inhibitor
and can suppress appetite 
Initial dose:
1-3mg/kg OD (max per dose 25mg).
 
Dose usually increased every 7-14 days to a maximum of 100mg twice daily.
Dose may be increased up to every 3 days if rapid dose escalation is required,
Cognitive impairment
​Paraesthesia
Anxiety
Fatigue
Insomnia
Nephrolithiasis
Second line
 
Side effects are more likely to occur with rapid dose escalation.
Females of child bearing potential should be counselled regarding potential teratogenic effects.
Medications 
 Monitor full blood count and plasma electrolyte concentrations.
  •  week after commencing but sooner if symptomatic with side effects.
  • pH, bicarbonate, U&E
  • Oral sodium bicarbonate replacement might be necessary depending on blood results.
  • Repeat blood tests every 2-4 weeks.
Surgical Management of IIH

This may be necessary for patients with rapidly declining vision despite therapeutic lumbar puncture +/- medication. 

In children, surgical options include lumboperitoneal shunt, ventriculoperitoneal shunt and optic nerve sheath fenestration. 

ICP bolt monitoring should be considered and discussed for patients with contraindication to lumbar puncture (Chiari malformation etc), in equivocal cases and patients with persistently raised LP opening pressure measurements and papilloedema not responding to treatment. 

In post-pubertal children, venous sinus stenting may be considered if there is evidence of stenosis of the venous sinus which is not responding to conventional management. 
Follow up and monitoring
Any child diagnosed with IIH should ideally be followed up by a paediatric ophthalmologist and paediatric neurologist/paediatric team at an appropriate individualised interval.

Paediatric ophthalmology follow up should include assessment of visual acuity, colour vision, pupil reaction, optic disc examination and OCT of the disc including parameters such as optic nerve volume (ONH) and RNFL along with macular GCL. It is imperative that the same imaging modality be used during follow up visits to monitor progression. Visual field assessment with automated perimetry should be offered to children older than 10 years old who can cooperate and should be tested with the same machine and protocol to monitor progression.
 
Pre-pubertal children with diagnosis of IIH should be referred to paediatric neurology team. 
 
If used, medication may be stopped once papilloedema has resolved.
 
Children diagnosed with IIH may develop symptoms of other primary headaches later, migraine being the most common and it should be treated accordingly.
Lumbar Puncture Flow Chart
Process for monitoring compliance
The PIER network will review problems associated with this guideline through governance process.

Guideline to be reviewed after three years or sooner as a result of audit findings or as any changes to practice occurs.
References
  1. Matthews Y-Y, Dean F, Lim MJ et al. Pseudotumor cerebri syndrome in childhood: incidence, clinical profile and risk factors in a national prospective population-based cohort study. Archives of childhood disease. 2017. 102(8), 715-721. 
  2. Best JL, Silvestri G, Burton BJ et al. The incidence of Blindness Due to Idiopathic Intracranial Hypertension in the UK. The Open Ophthalmology Journal. 2013. 7, 26-29.
  3. Hoffmann, J., Mollan, S.P., Paemeleire, K. et al. European Headache Federation guideline on idiopathic intracranial hypertension. J Headache Pain 19, 93 (2018) doi:10.1186/s10194-018-0919-2
  4. Mollan SP, Davies B, Silver NC, et al Idiopathic intracranial hypertension: consensus guidelines on management Journal of Neurology, Neurosurgery & Psychiatry 2018;89:1088-1100.
  5. Patterson DF, Ho ML, Leavitt JA, et al. Comparison of Ocular Ultrasonography and Magnetic Resonance Imaging for Detection of Increased Intracranial Pressure. Front Neurol. 2018;9:278. Published 2018 Apr 24. doi:10.3389/fneur.2018.00278
  6. Chen J, Wall M. Epidemiology and risk factors for idiopathic intracranial hypertension. Int Ophthalmol Clin. 2014;54(1):1–11. doi:10.1097/IIO.0b013e3182aabf11
  7. Position-Related Variability of CSF Opening Pressure Measurements
  8. K.M. Schwartz, P.H. Luetmer, C.H. Hunt, A.L. Kotsenas, F.E. Diehn, L.J. Eckel, D.F. Black, V.T. Lehman, E.P. Lindell. American Journal of Neuroradiology Apr 2013, 34 (4) 904-907; DOI: 10.3174/ajnr.A3313
  9. Scotton, W. J., Botfield, H. F., Westgate, C. S., Mitchell, J. L., Yiangou, A., Uldall, M. S., … Sinclair, A. J. (2019). Topiramate is more effective than acetazolamide at lowering intracranial pressure. Cephalalgia, 39(2), 209–218. 
  10. Delphi consensus for the UK guideline for management and surveillance of Idiopathic Intracranial Hypertension in children and young people. 
  11. Different Characteristics of Pre-Pubertal and Post-Pubertal Idiopathic Intracranial Hypertension: A Narrative review H. S. Lyons at all Neuro-ophthalmology Vol 47 No2 63-74 
  12. How to use lumbar puncture manometry in children. Holland JAA, et al. Arch Dis Child Educ Pract Ed 2023
Appendix A - More information and Patient Information leaflets
  1. IIH UK Patient Information Leaflet
  2. Holland JAA, et al. How to use lumbar puncture manometry in children. Arch Dis Child Educ Pract Ed 2023 
Document Version: 
1.0

Lead Authors: 
Rosie Edgeley, Medical Student
Ellen Bodger, Medical Student
Lucia Santos, Associate Specialist
Eleni Zopounidou, Consultant Paediatric Ophthalmologist
J Singh, Consultant Paediatric Neurologist​
Approving Network:
Wessex Neurosciences Network
​
Date of Approval: 


Review Due: