Intended for healthcare professionals

Practice Easily Missed?

Raised intracranial pressure in those presenting with headache

BMJ 2018; 363 doi: (Published 04 October 2018) Cite this as: BMJ 2018;363:k3252
  1. Susan P Mollan, consultant neuro-ophthalmologist1 2 3,
  2. David Spitzer, general practitioner4,
  3. David J Nicholl, consultant neurologist5 6
  1. 1Birmingham Neuro-Ophthalmology Unit, University Hospitals Birmingham NHS Trust, Queen Elizabeth Hospital Birmingham, Edgbaston, Birmingham, UK
  2. 2Metabolic Neurology, Institute of Metabolism and Systems Research, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
  3. 3Institute of Translational Medicine, Birmingham Health Partners, University of Birmingham, UK
  4. 4PHGH Doctors, Temple Fortune Medical Centre, London, UK
  5. 5Department of Neurology, City Hospital, Birmingham, UK
  6. 6Department of Neurology, University Hospitals Birmingham NHS Trust, Queen Elizabeth Hospital Birmingham, Edgbaston, Birmingham, UK
  1. Correspondence to SP Mollan susan.mollan{at}

What you need to know

Untreated raised intracranial pressure (ICP) can lead to permanent sight loss, permanent neurological deficits, and ultimately death.

Typical characteristics of new onset constant or near constant severe headache are non-specific, and only one third of patients with raised pressure report that the headache is worse on waking.

  • Request an ophthalmology opinion if there is difficulty examining for papilloedema, and to determine any visual deficit.

A 24 year old woman attended the emergency department after experiencing a blackout. She was diagnosed with a panic attack and discharged. She returned two days later with increasing headaches and visual disturbances, and was admitted to hospital for investigation. Computed tomography scans of the head and a computed tomography venogram taken on day 3 were normal. On day 7, she underwent lumbar puncture and her cerebrospinal fluid opening pressure was 70 cm CSF. On day 8, she was examined with an ophthalmoscope and found to have papilloedema. Her best corrected visual acuity was reduced at 6/24 bilaterally and she had bilateral peripheral visual field loss to confrontation. She received a diagnosis of fulminant idiopathic intracranial hypertension and was transferred to the neuroscience centre, where on day 9 she underwent an emergency lumbar peritoneal shunt. Within two weeks, her vision improved to 6/9 bilaterally.

Speaking to the BBC about her experience, she says, “I can’t imagine what it would have been like to have been blind”(video 1).

Video 1

Patient experience

What is raised intracranial pressure?

Raised intracranial pressure (ICP) is an abnormal elevation of brain pressure and is a medical emergency. Data on the frequency of raised ICP are lacking (box 1). It has many causes, including some serious ones (box 2), and can be sight and life threatening. The headache history is important, as is examination for signs of papilloedema and documentation of visual function.

Box 2

Causes of raised intracranial pressure

  • Congenital (hydrocephalus)

  • Iatrogenic (certain medications and post-neurosurgical procedures)

  • Idiopathic intracranial hypertension

  • Infectious (intracranial abscess, meningitis, encephalitis)

  • Trauma

  • Tumour

  • Vascular (aneurysm, arteriovenous malformation, haemorrhage (subdural, intraventricular), cerebral venous sinus thrombosis)


This article is focused on the diagnosis of raised ICP in people presenting with headache. The constellation of symptoms of raised ICP is similar regardless of the underlying pathology. The diagnosis of raised ICP is likely to be made in secondary care; patients need to be urgently referred from primary care for imaging and further investigation to aid diagnosis and prevent deterioration, including loss of vision. The aim of this article is to help clinicians recognise when raised ICP is a likely differential diagnosis in a person presenting with headache and advise about appropriate investigations and management.

Box 1

How common is it?

No robust epidemiological data exist to compare the relative frequencies of the causes of raised ICP (box 2). In UK general practice 6.4 women and 2.5 men per 100 appointments consult about headaches.1 Primary headaches (such as migraine, tension type, and cluster)2 account for most of these, and only 2% are referred on to neurology.3 One study1 calculated the risk of a general practitioner seeing a primary or undifferentiated headache that subsequently revealed itself as a secondary cause (such as subarachnoid haemorrhage, primary brain tumour, benign space occupying lesion); this risk was low, ranging from 0.004% to 0.28% within 1 year of initial presentation. The risk of headache belying serious underlying pathology is higher in secondary care. New attendances for headache in the emergency department were recorded in one series at 0.36% of all attendances, and of these 16% had serious underlying pathology.4

Why is it missed?

Insidious onset and non-specific symptoms

The insidious nature of onset of raised ICP can lead to diagnostic delay and misdiagnosis. Some of the key characteristic symptoms are non-specific, and signs might not be immediately recognised. One study describing the presentation of intracranial tumours in children and young adults before diagnosis found that non-localising symptoms and signs (such as headache, parental concern, lethargy, fatigue, drowsiness, appetite loss, irritability, faltering growth) were more than twice as common as focal neurological signs (such as sixth nerve palsy and visual disturbances).5

Incomplete history and examinations

In patients presenting to the emergency department with headache there is evidence of inadequate medical examination and history taking, with only 0.3% having a full history recorded. A typical headache history would record the type and location of the pain, onset, duration, severity, associated symptoms, any precipitating factors, history of headaches, and medications.6 Evidence of incompletely recorded examination is replicated on the wards: in the TOS (tendon hammer, ophthalmoscope, stethoscope) study, only 52% of neurology inpatients recalled being examined with an ophthalmoscope, compared with 96% recalling examination with a stethoscope.7


Funduscopy forms part of a complete neurological examination, and raised ICP can easily be missed if funduscopy is not performed or is interpreted incorrectly. Direct ophthalmoscopy can be difficult if not practised regularly. Box 3 offers practical tips on performing funduscopy.

Box 3

Practical tips for performing funduscopy

Explain to the patient what you are going to do.

  • Ask the patient to remove their spectacles (unless they have a very high refractive or astigmatic error)

  • Where possible, dim the room lighting.

  • Use the smallest aperture/spot on the ophthalmoscope if the pupils are small.

  • It is helpful to be at the same level as the patient.

  • Hold the ophthalmoscope in your right hand and use your right eye when viewing their right eye. Reverse this for the left eye examination (left hand and left eye).

  • Ask the patient to fix their gaze at an object in the distance.

  • To look at the optic disc, start at “0.” Use your forefinger to turn the lens dial to focus the image, if necessary.

  • Check for the red reflex shining the light between each of the subject’s eyes at about arm’s length to the patient. At this point you should be at arm’s length

  • The observer then moves to view one eye from the side of the patient at a 45° angle to the nose.

  • Make sure you are close enough (often it is helpful to rest your free hand on the patient’s forehead and your thumb on yours)

  • Once you see vessels, move to find the optic disc. The “V” of the blood vessel branching will point towards the optic disc.

  • Assess the disc for colour, contour, and any associated signs such as cotton wool spots or haemorrhages.

  • Examine for spontaneous venous pulsations (video 2).


Pharmacological dilation with guttae tropicamide 1% is safe and makes funduscopy easier8 (pupils can remain dilated for a few hourstherefore instruct patients not to drive immediately afterwards). Instruments that might be easier to use than the standard direct ophthalmoscope include the PanOptic ophthalmoscope (Welch Allyn),9 and the Arclight, a pocket ophthalmoscope.10 Another option is fundus photography, using (for example) the Peek Retina, a smart phone attachment,11 or a non-mydriatic camera.12 If there is doubt regarding the examination or imaging findings seek review from an experienced ophthalmologist or optometrist, specifically asking for comment on the presence or absence of papilloedema,13 as ophthalmoscopy is a common diagnostic error in patients with headache12 and those with idiopathic intracranial hypertension.14

Why does this matter?

The consequences of failing to detect raised ICP in a timely manner can cause permanent sight loss, permanent neurological deficits, and ultimately death.1516 Missed diagnoses of raised ICP have led to high profile cases, both in criminal court and coroners’ inquests. For example, in the UK, an optometrist was initially convicted for gross negligence manslaughter for missing papilloedema in a child15; this was subsequently overturned at the Court of Appeal as it was deemed to be a “serious breach of duty.” The verdict of gross negligence manslaughter, in this case, would have had serious implications for the medical profession by reason of negligent omissions, for example unreasonable foreseeable failure to carry out examination and tests that would reveal fatal conditions. In Australia, delays in neuro-imaging were highlighted in a symptomatic patient who died from acute hydrocephalus.16

How is it diagnosed?

Clinical features

There is variability in how people present with raised ICP. They can report the following:


Typical characteristics of the new onset constant or near constant severe headache are non-specific, and only one third of patients with raised pressure report that the headache is worse on waking.17 Most patients complain of a progressively worsening headache over weeks, but some can develop a rapid increase in ICP within hours to days. Some report pulsating elements to the headache, which can be aggravated by bending, coughing, straining, and physical activity. Raised ICP headaches can mimic chronic migraine, chronic tension type headaches, or both.18 A new headache or a substantial change in previous headache pattern suggests, therefore, that the headache could be secondary and requires appropriate action.21718

Visual disturbances: blurred vision, transient visual obscurations, double vision, visual loss

Visual disturbances include blurring or double vision, and in one study of people under 24 diagnosed with a primary intracranial tumour, this was the commonest reported symptom.6 Patients can describe transient loss of vision and/or “greying out” of vision, termed transient visual obscurations. These are often related to postural changes and tend to last for less than one minute, but can occur with increasing frequency as the intracranial pressure goes up. In raised ICP, visual acuity is typically normal. It is the visual fields that initially are affected, with a big blind spot. This progresses to constriction of the peripheral visual field until the central field is extinguished. Horizontal diplopia can result from a false localising sixth cranial nerve palsy.

Associated symptoms

Other symptoms include neck pain, back pain, pulsatile tinnitus, lethargy, behavioural changes, weakness, vomiting, problems with moving or talking, decreased consciousness, and seizures.

Ask directly about pulsatile tinnitus, as most people will not offer this symptom readily. Typically, this is a rhythmic “whooshing” sound heard in either or both ears, that is synchronous with the patient’s own heartbeat and is believed to arise from intensified vascular pulsation occurring with high ICP. Pulsatile tinnitus is a non-specific symptom, and is documented more frequently in those with idiopathic ICP, but also in up to a quarter of migraineurs in one series.17


  • Measure blood pressure to exclude malignant hypertension, a rare but treatable cause of raised ICP.131920

  • Perform a full neurological examination, eg testing of cranial nerves, sensory and motor function of arms and legs and reflexes.

  • Visualise the optic disc to note the features and severity of possible swelling (fig 1). Presence of spontaneous venous pulsation at the optic nerve head may be reassuring (video 2). Where there is diagnostic difficulty in detecting papilloedema—eg, mild disc swelling, suspicion of a lumpy optic disc (drusen), or myopic tilted disc, prioritise a second opinion to avoid invasive investigations (such as neuroimaging and lumbar puncture) in the normal patient.131920

Fig 1
Fig 1

Composite of colour fundus photographs showing (A) normal right optic nerve head with a physiological cup and distinct disc margins, (B) severe disc swelling with dome shaped elevation of the optic nerve head with surface hyperaemia and complete obscuration of all the retinal vessels at the disc, (C) severe swelling with cotton wool spots and haemorrhages, (D) moderate to severe swelling of the optic nerve head with tortuosity of the retinal vessels. NB, there are no clinical signs of papilloedema that help distinguish the underlying diagnosis.

Video 2

Spontaneous venous pulsation (SVP): this infrared reflectance movie shows a right optic disc. Venous calibre changes and blood column colour changes are most prominently seen at four o’clock of the optic nerve head in the inferior retinal veins. SVP is a helpful sign in conditions where there is a large variation in ICP, such as in idiopathic ICP. If observed, the ICP is likely normal (although absence of SVP does not confer a diagnosis of raised ICP)

How is it investigated further and managed?

If there is papilloedema and no evidence of malignant hypertension, refer for neuroimaging on the same day (magnetic resonance imaging of the head and orbits with intravenous contrast and venography, or computed tomography of the head with venogram). Venography can exclude cerebral venous sinus thrombosis. After an intracranial structural lesion is excluded on neuroimaging, it is deemed safe to proceed to a lumbar puncture (in the lateral decubitus position) to record the opening pressure and send cerebrospinal fluid for analysis to exclude infective, malignant, and inflammatory causes.1920

Further management depends on the underlying cause and whether there is any visual dysfunction. It is useful to note that visual fields to confrontation is a gross test, so secondary care doctors must seek formal visual fields at the earliest opportunity.1319 High risk patients are those with established or impending visual loss. These patients need close observation and often urgent surgical management, because of the risk of permanent visual loss. Initially specialist services, such as neurology or neurosurgical teams, will guide care but some conditions may require ongoing joint management in primary care. For example, patients with idiopathic intracranial hypertension can have chronic headaches with migrainous phenotype which will require input from their family doctors.1920

Education into practice

  • How do you determine when to perform funduscopy in patients presenting with headache? Does this offer ideas on modifying your approach?

  • How do you refer or request imaging of those people presenting with symptoms suggestive of raised intracranial pressure?

  • What will you do differently as a result of reading this article?


  • This is one of a series of occasional articles highlighting conditions that may be more common than many doctors realise or may be missed at first presentation. The series advisers are Anthony Harnden, professor of primary care, Department of Primary Care Health Sciences, University of Oxford, and Dr Kevin Barraclough, School of Social and Community Medicine, University of Bristol. To suggest a topic for this series, please email us at

  • Contributors’ statement: Susan Mollan: Article drafting, acquisition of SVP video and images, analysis and interpretation of data, and revision of manuscript. David Spitzer: Analysis and interpretation of data, critical revision of manuscript for intellectual content. David Nicholl: Concept of article, acquisition of data, critical revision of manuscript for intellectual content and overall article supervision.

  • Competing interests: All authors have read and understood BMJ policy on declaration of interests and have no relevant interests to declare

  • Provenance and peer review: commissioned; externally peer reviewed.

  • Patient consent obtained.


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