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Fifteen-minute consultation: the child with idiopathic intracranial hypertension
  1. Mohamed O E Babiker1,
  2. Manish Prasad2,
  3. Stewart MacLeod1,
  4. Gabriel Chow3,
  5. William P Whitehouse3,4
  1. 1Fraser of Allander Neurosciences Unit, Royal Hospital of Sick Children, Glasgow, UK
  2. 2Department of Paediatrics, Pinderfield General Hospital, Wakefield, UK
  3. 3Department of Paediatric Neurology, Nottingham Children's Hospital, Nottingham University Hospitals NHS Trust, Nottingham, UK
  4. 4School of Medicine, University of Nottingham, Nottingham, UK
  1. Correspondence to Dr Mohamed Babiker, Department of Paediatric Neurology, Royal Hospital for Sick Children, Glasgow G3 8SJ, UK; mohamedbabiker{at}


Idiopathic intracranial hypertension (IIH) is a rare condition where intracranial hypertension is found in the context of normal brain parenchyma and no mass lesion, ventriculomegaly, underlying infection, or malignancy. Our understanding of this condition has greatly improved in the recent years with neuroimaging features and normal values for lumbar puncture opening pressure now well defined. This article provides a review of IIH in children and revised diagnostic criteria based on recent evidence and published opinion. We have also presented an algorithmic approach to the child with possible IIH.

  • Pseudotumour Cerebri
  • Benign Intracranial Hypertension
  • Cerebrospinal fluid
  • papilloedema

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Idiopathic intracranial hypertension (IIH) has been defined as a condition in which there is increased intracranial pressure (ICP) without a space-occupying lesion or hydrocephalus and with a normal cerebrospinal fluid (CSF) composition.1

The term, IIH, has now replaced the name ‘benign intracranial hypertension’ (BIH). The word, ‘idiopathic’, emphasises that it is a diagnosis of exclusion. One of the earlier names given more than a century ago to this condition was Pseudotumour Cerebri, because its presentation can mimic a ‘brain tumour’. At present, some authors argue that this term should still be used to describe a syndrome that encompasses primary and secondary forms of the condition.2 The term, BIH, should be discouraged in view of the known risk of permanent visual acuity loss in up to 10% in children.3 Moreover, the condition can be associated with chronic debilitating headaches, and the procedures sometimes used for its treatment can be distressing.

This review of IIH also includes secondary cases, and IIH associated with predisposing medical conditions and pharmacotherapy.

What causes IIH?

The exact pathophysiology of CSF dynamics disturbance in IIH is unknown. Obesity is a risk factor for IIH in adults and older children. In one case series, 91% of IIH patients aged 15–17 years were obese, although the association was much weaker in prepubertal children.4 A plausible theory will have to explain the difference between hydrocephalus and IIH, and the similarity between IIH and secondary intracranial hypertension due to venous obstruction, for example, thrombosis. Models involving reduced venous drainage and reduced compartment pressure-volume compliance are promising.5

How common is IIH?

IIH is rare in children, and especially so in infancy.3 A British Paediatric Surveillance Unit (BPSU)-supported study has recently estimated the UK annual incidence of IIH to be 0.8 (1.0 for girls, 0.5 for boys) per 100 000 child population.6 In their survey, the median age of presentation was 12 years, and obese girls were more at risk. The overall incidence of IIH in the USA is on the rise, which has been linked to the increasing prevalence of obesity in the population.7

The new proposed diagnostic criteria

Although the key features of IIH are headache and papilloedema, the diagnostic definition of IIH has evolved over the years with the advances in technology, and reports of atypical IIH without headache2 or papilloedema8 have emerged in the literature.

Recently, a large paediatric prospective study has defined new values for elevated lumbar puncture (LP) opening pressures9 (see later). This can cause diagnostic uncertainty in a patient who has headache and papilloedema, but the measured LP opening pressure is not abnormally elevated. Based on the current evidence and the advances in neuroimaging, new diagnostic criteria have been recently proposed for the paediatric population2 as shown in box 1.

Box 1 Revised diagnostic criteria for idiopathic intracranial hypertension in children and young people (adapted from: Friedman et al2)

  • 1. Required for diagnosis of IIH

    1. Papilloedema

    2. Normal neurologic examination except for cranial nerve abnormalities

    3. Neuroimaging: Normal brain parenchyma without evidence of hydrocephalus, mass, or structural lesion and no abnormal meningeal enhancement on MRI, with and without gadolinium, for typical patients (female and obese), and MRI, with and without gadolinium, and MR venography for others; if MRI is unavailable or contraindicated, contrast-enhanced CT may be used

    4. Normal cerebrospinal fluid (CSF) composition

    5. Elevated lumbar puncture opening pressure (≥25 cm of H2O, or >28 cm of H2O if obese or sedated) in a properly performed lumbar puncture

  • 2. Diagnosis of IIH without papilloedema

    In the absence of papilloedema, a diagnosis of idiopathic intracranial hypertension can be made if B–E from above are satisfied and, in addition, the patient has a unilateral or bilateral abducens nerve palsy

    In the absence of papilloedema or sixth nerve palsy, a diagnosis of idiopathic intracranial hypertension can be suggested but not made if B–E from above are satisfied, and additionally, at least 3 of the following neuroimaging criteria are satisfied:

    1. Empty sella

    2. Flattening of the posterior aspect of the globe

    3. Distention of the perioptic subarachnoid space with or without a tortuous optic nerve

    4. Transverse venous sinus stenosis

  • A diagnosis of IIH is definite if the patient fulfils criteria A–E.

  • The diagnosis is considered probable if criteria A–D are met but the measured CSF pressure is lower than specified for a definite diagnosis.


Important points in the history

Headache is the prominent complaint in up to 91% of children with IIH.10 A standard headache history usually reveals daily occurrence of non-pulsatile moderate to severe headaches. Exacerbation of pain when performing Valsava manoeuvre, lying flat or bending down are useful clues when present. It has to be remembered that IIH without papilloedema can be associated with chronic migraine.11 Hence, migrainous features, such as a throbbing character, photophobia or phonophobia do not rule out the diagnosis. Pulsatile tinnitus that is described as a ‘whooshing sound’ in the ears is commonly reported. Other symptoms may include neck pain, nausea and vomiting.

Visual symptoms include decreased acuity, obscuration and diplopia. Asymptomatic visual field impairment is usually an early sign. The blind spot is commonly affected first followed by the peripheral fields. Visual loss is an alarming symptom and necessitates immediate treatment.

The detailed drug history is important as it serves two purposes. First, it identifies the use of drugs associated with IIH and, secondly it can give clues to other diagnoses, such as medication overuse headache.

Secondary intracranial hypertension

Intracranial hypertension mimicking IIH can complicate the course of a number of endocrinological, chromosomal and haematological conditions as well as certain drugs. Hence every effort should be made in all cases to identify these associations, as treating these conditions or stopping these drugs is essential. Box 2 lists some of these associations.3 ,12–13

Box 2 Medical conditions and drugs associated with intracranial hypertension.

Medical Conditions:

  • Hypothyroidism/hyperthyroidism

  • Cushing's disease/adrenal insufficiency

  • Hypoparathyroidism/hyperparathyroidism

  • Polycystic ovary syndrome

  • Chronic anaemia

  • Vitamin D deficiency

  • Chromosomal abnormalities (Trisomy 21, Tuner syndrome)

  • Cystic fibrosis (mainly secondary to associated nutritional problems)

  • Systemic lupus erythematosus


  • Antibiotics: tetracyclines and related compounds, sulphonamides, nalidixic acid, nitrofurantoin, penicillin

  • Hormones: levothyroxine, growth hormone, oral contraceptive pills

  • Corticosteroids therapy or withdrawal

  • Cyclosporine

  • Amiodarone

  • Phenytoin

  • Lithium

  • Vitamin A analogues and isotretinoin

The clinical examination

By definition, the neurological examination should be normal apart from the following exceptions:

  • papilloedema

  • reduced visual acuity

  • visual fields defects

  • unilateral or bilateral sixth nerve palsy

Formal ophthalmological assessment is recommended. General examination should include blood pressure measurement, weight and height measurements with calculation of the Body Mass Index (BMI) (kg/m2), and BMI centile or BMI standard deviation score (SDS). Ear, nose and throat examination for signs of otitis media, mastoiditis, or sinusitis should be performed. When indicated, pubertal assessment should be considered. A search for clinical signs of medical conditions causing secondary intracranial hypertension is recommended (box 2).

The diagnosis of IIH is not always straightforward

Atypical presentations

IIH can be present without headache, rarely, but especially in young children.14 These patients are more likely to present with severe visual failure, so aggressive therapy may be needed.14

Furthermore, papilloedema can be absent in about 5% of the patients.8 Cases of unilateral or asymmetric papilloedema have also been reported.15 Occasionally patients may present early in the course of the condition, prior to the development of papilloedema. The presenting feature in this scenario is usually a new onset or a worsening headache, which in itself merits further investigation.

It is crucial to correctly diagnose papilloedema as it can be confused with other causes of optic disc swelling. Conditions likely to be confused with papilloedema include optic disc crowding and optic nerve head drusen.16 If uncertainty exists, a paediatric ophthalmology opinion should be sought, and ultrasound (B-scan), optical coherence tomogram (OTC) scan, or fluoroscein angiography can help.

CSF opening pressure

There is conflicting data on the normal CSF opening pressures in children. In adults, the general consensus is that a pressure of 25 cm H2O (∼18 mm Hg) or more is high.1 In a recent study of children <18 years of age, the 90th centile for CSF opening pressure was 28 cm H2O (∼21 mm Hg) in obese or sedated children, and 25 cm H2O for non-obese non-sedated children.9 Interestingly, there was no correlation with age. Although, the study received criticism in its methodology, particularly with respect to the method of determining obesity,17 the evidence in favour of a cut-off value of 25 cm of H2O in non-obese children seems quite robust. As we know that CSF opening pressure tends to be higher in obese children and with sedation we suggest a cut-off value of 28 cm of H2O for these children until more robust evidence is available.

Whenever possible, general anaesthesia (GA) is better avoided as it can elevate CSF pressure, commonly by 5–10 mm  Hg18 (∼6–13 cm H2O). So it is helpful to monitor the end-tidal pCO2, particularly during GA, as a rise of 1 kPa in end-tidal pCO2 is associated with a rise of 3.5–12 cm H2O in the CSF pressure.19

The LP opening pressure measurement indicates the CSF pressure at that given moment, and may, therefore, be misleading for diagnostic purposes.2 If the patient has typical IIH symptoms with papilloedema or sixth nerve palsy, a low or normal opening pressure measurement should not negate the diagnosis as this value may have been taken at the nadir of a pressure wave. In such a case, the options could either be a repeat LP or, if possible, a 24–48 h of continuous ICP monitoring, which can demonstrate B and plateau waves indicative of elevated ICP.2 Similarly, elevated pressure measurements in the absence of other supporting symptoms and signs (eg, papilloedema or sixth nerve palsy) are not diagnostic of IIH.


Blood tests

As mentioned above, contributing and secondary aetiologies should be identified, and investigations tailored according to a thorough history and clinical examination. A reasonable bare minimum of tests is suggested in table 1.

Table 1

Suggested minimal blood tests in a child with suspected IIH


Brain MRI is indicated in all patients suspected of having IIH, and is superior to head CT scanning. Its main role is to exclude space-occupying lesions and ventriculomegaly. MR venography (MRV) or CT venography (CTV) should also be done, to identify cerebral venous system abnormalities.20 ,21

Subtle features of IIH can be seen on the MRI (see box 1).22 Individually, they lack sensitivity and specificity, but if found together, the diagnosis is more likely.2 ,22

A recent prospective blinded study demonstrated that the optic nerve sheath is significantly larger in children with IIH than that in healthy controls regardless of age group and sex. Reference upper limits of normal measurements in different age groups have been proposed.23

Lumbar puncture

This is diagnostic and therapeutic. It must only be performed after satisfactory neuroimaging. It should be performed with the patient in the lateral decubitus position and the manometer should be connected as soon as the stylet is withdrawn. A recent BestBet review found no evidence to support the common practice of extending the child's legs while measuring the pressure.24 The upper end of the CSF column is read when it settles. Record the opening peak pressure, with the child as relaxed as possible. Hyperventilation (eg, with nitrous-oxide analgesia, or crying) and straining will affect the pressure, as explained above. The pressure is then lowered by sequentially emptying the CSF column to the normal level although this only provides temporary relief, as CSF is constantly produced. Samples should always be sent for routine biochemistry and microbiology studies.

Managing IIH

This has two main goals

  • preserve vision

  • alleviate symptoms of raised ICP.

A multidisciplinary approach is recommended with involvement of the local paediatrician, ophthalmologist, orthoptist, paediatric neurologist and neurosurgeon, as indicated.

Generally, the severity of the visual symptoms and signs dictates the suitability of treatment (ie, medical, surgical, or combined). The risks of vision loss should be clearly explained to the patients and parents, as well as the importance of adherence to therapy. The possibility of medication-overuse headache, or other accompanying primary headache, should also be explored in patients with chronic daily headache.

Advice regarding weight reduction in obese patients should be offered as there is evidence of benefit in adults.25 ,26

During the first diagnostic LP, the closing pressure might be brought down to between 15 and 20 cm H2O. Patients and parents should be warned about postprocedure low-pressure headache which can last for a few days, and advised to take extra fluids. Follow-up depends on the visual status of the patient, but some patients will require follow-up on a monthly basis initially.12

Medical treatment

Main indicators of a successful treatment are improvement in headaches and resolution of papilloedema and visual symptoms and signs. The length of treatment varies and may last, in some cases, 9–14 months.3 ,27 Weaning should be considered as soon as improvement is evident. There are no adequately powered trials to date. Table 2 summarises the commonly used agents.

Table 2

Commonly used pharmacological agents in the treatment of IIH

Other treatments

Serial lumbar punctures

Although still practiced by some, there is no evidence that it leads to long-term remission. This is supported by the findings in a few studies, that CSF tends to reaccumulate within several minutes to few hours.15 However, symptoms in some patients seem to settle after the first diagnostic and therapeutic LP.

Surgical treatments

Surgery has been used in up to 20% of patients in some centres.31 The indications are shown in box 3.

Box 3 Indications for surgical treatment in IIH

  • Fulminant IIH presenting with acute visual deterioration or loss.

  • Failure of medical treatment which is reflected by recent deterioration or loss of visual acuity or fields.

  • Severe debilitating headaches not responding to medical treatment.

Table 3 summarises the available neurosurgical and ophthalmological treatments. Thus far, there is no consensus on superiority of one option over the other.15 ,32 The decision is usually made after taking into consideration the risks of the individual procedure as well as the local expertise.

Table 3

Surgical procedures used for the treatment of IIH

Interventional radiology

There is increasing experience in children as well as in adults, of endovascular stenting of a stenosed or narrowed transverse sinus.34 Indications are much the same as for surgical interventions, see box 3.

An algorithmic approach for management of IIH is highlighted in figure 1.

Figure 1

Algorithmic approach to the management of children with suspected IIH. *True presence of papilloedema may require confirmation by an ophthalmologist. **Mimics include: space-occupying lesions, structural brain anomalies (eg, Arnold Chiari malformation), primary headache disorders, drusens optic nerve head, optic disc crowding and optic nerve pathology (eg, optic neuritis). ***See box 2.


Our understanding of paediatric IIH has improved over the last few years, and based on the current evidence, separate diagnostic criteria for children seems reasonable. The previously accepted threshold for identifying abnormally elevated opening CSF pressure of 20 cm of H2O should be reconsidered. For most children, we suggest that a pressure of 25 cm H2O and above should be considered elevated, and for sedated or obese children, 28 cm H2O.

Multiple choice questions

  1. Of the following statements, which is true/false regarding idiopathic intracranial hypertension (IIH) in children:

    1. is commoner in boys

    2. obesity is a prerequisite for diagnosis

    3. has been reported in infants

    4. commonly runs a benign course

    5. can be diagnosed in the absence of headache

  2. Amy is a 14-year-old girl, urgently referred by an optician because of ‘papilloedema’. She has been complaining of headaches, and the possibility of IIH is raised. Which of the following points in the history is relevant:

    1. menstrual irregularities

    2. a history of recent acne treatment

    3. a personal history of migraine headaches

    4. regular use of paracetamol

    5. a recent history of ear infection

  3. Amy's neurological examination is unremarkable apart from ‘swollen optic discs’. From the list below, choose the two most appropriate initial steps in her management:

    1. lumbar puncture (LP) with opening pressure measurement

    2. head CT scan with contrast

    3. brain MRI with MR venography (MRV)

    4. formal ophthalmology assessment

    5. baseline bloods including urea and electrolytes, full blood count, bone profile and thyroid function tests

  4. A diagnosis of IIH has been confirmed in Amy's case. Which of the following would be recommended:

    1. advice regarding weight reduction

    2. acetazolamide as first-line treatment

    3. serial LPs planned as early as possible

    4. escalation of medical therapy mainly guided by persistence of headache

    5. monitoring of visual fields

  5. In which of the following clinical scenarios a diagnosis of IIH is likely:

    1. Papilloedema, Body Mass Index 22 kg/m2, normal brain MRI & MRV, non-sedated LP opening pressure 27 cmH2O

    2. Papilloedema, left sixth cranial nerve palsy, normal head CT with contrast, LP opening pressure 18 cmH2O

    3. Papilloedema, normal brain MRI, MRV shows sagittal sinus thrombosis, sedated LP opening pressure 39 cmH2O

    4. No papilloedema, history of occasional headaches, brain MRI shows dilated optic nerve sheath and MRV normal, non-sedated LP opening pressure 31 cmH2O

    5. No papilloedema, normal brain MRI and MRV, LP (under general anaesthesia) opening pressure 33 cmH2O, end-tidal pCO2 8.5 kPa.

    Answers are on page 172

Answers to the quiz on page 171

  1. (a) F; (b) F; (c) T; (d) F; (e) T

  2. a, b, c, d, e

  3. c, d

  4. a, b, e

  5. a, b, d


View Abstract


  • Contributors MOEB and MP jointly wrote the first draft. GC revised it and contributed to the management section. WPW and SML overlooked the whole draft and made final changes.

  • Competing interests None.

  • Provenance and peer review Commissioned; externally peer reviewed.