Headache

Question 1

Mr Lennon is a 74-year-old gentleman referred to the hospital by his general practitioner (GP) because of a severe headache.
Headache is a common symptom with many causes. It is essential to rule out the sinister causes first, i.e. those that require urgent investigation and management because if left untreated they cause last- ing damage and/or mortality.
What sinister causes must you rule out?

Answer 1

The sinister causes can be remembered using the mnemonic VIVID:
Vascular: subarachnoid haemorrhage (SAH), haematoma (subdural or extra-
dural), cerebral venous sinus thrombosis, cerebellar infarct
Infection: meningitis,encephalitis
Vision-threatening: temporal arteritis†, acute glaucoma, pituitary apoplexy, posterior leucoencephalopathy, cavernous sinus thrombosis
Intracranial pressure (raised): space-occupying lesion (SOL; e.g. tumour, abscess, cyst), cerebral oedema (e.g. trauma, altitude), hydrocephalus, malig- nant hypertension
Dissection: carotiddissection

Question 2

What is temporal arteritis also known as

Answer 2

† Note that temporal arteritis is another name for giant cell arteritis, a systemic vasculitis. The term
temporal arteritis is more common when headache is the presenting symptom.

Question 3

Taking a good history is key to any diagnosis, but particularly so when tackling headache as the symptom is so subjective and examination findings are often unhelpful.
With a mental list of the sinister causes, what questions will you ask first in the history? What ‘red flags’ will help you exclude the sinister causes?

Answer 3

The approach to headache is the same as that to pain anywhere in the body: you need to start by characterizing the pain. One useful way of doing this is by following another mnemonic, SOCRATES:
Site of pain, and has it moved since it began?
Onset of pain – was it sudden or gradual, and did something trigger it?
C haracter of pain – stabbing, dull, deep, superficial, gripping, tearing, burning? Radiation of pain – has the pain spread?
Attenuating factors – does anything make the pain better (position? medications?)
Timing of pain – how long has it gone on for, has it been constant or coming and going?
Exacerbating factors – does anything make the pain worse (moving? breathing?) Severity – on a scale of 0 to 10, where 10 is the worst pain ever (e.g. childbirth).

Question 4

Describe decreased levels of consciousness as a red flag

Answer 4

• Decreased level of consciousness. This is a worrying feature of any medical presentation. Combined with headache, SAH needs exclusion. If there is a history of head injury, it could suggest a subdural haematoma (fluctuating consciousness) or extradural haematoma (altered consciousness following a lucid interval). Meningitis and encephalitis can also affect consciousness.

Question 5

Describe a sudden onset headache, worst ever as a red flag

Answer 5

Sudden onset, worst headache ever. Suggests SAH, with blood in the cer- ebrospinal fluid (CSF) irritating the meninges. It can be informative to ask the patient whether they remember the exact moment when the headache started – a very severe headache of almost instantaneous onset is characteristic of SAH. Patients describe it like, for example, ‘being hit on the head with a base- ball bat’.

Question 6

Describe a seizure or focal neurological deficit as a red flag

Answer 6

Seizure(s) or focal neurological deficit (e.g. limb weakness, speech difficul- ties). Suggests intracranial pathology.

Question 7

Describe the absence of previous episodes as a red flag

Answer 7

• Absence of previous episodes. Recurrent episodes are usually less sinister. A new onset of headache suggests a new pathology. In someone over 50 years old, a new onset headache should raise your suspicions of temporal arteritis until proven otherwise.

Question 8

Describe reduced visual acuity as a red flag

Answer 8

• Reduced visual acuity. Temporal arteritis is common in older patients. Tran- sient blindness (amaurosis fugax) is usually due to a transient ischaemic attack (TIA), but these rarely produce a headache. In the context of headaches, loss of vision can be due to temporal arteritis, carotid artery dissection causing decreased blood flow to the retina, or acute glaucoma.

Question 9

Describe a persistent headache, which is worse when lying down as a red flag

Answer 9

• Persistent headache, worse when lying down, and coupled with early morn- ing nausea. Suggests raised intracranial pressure. This is worse when lying flat for prolonged times (e.g. overnight) due to the effect of gravity, but can even occur when the patient is bending over. Headaches that are worse when standing up suggested reduced intracranial pressure and are common after a lumbar puncture (LP), but these are not sinister and resolve with hydration and lying down for several hours.

Question 10

Describe a progressive, persistent headache and constitutional symptoms as a red flag

Answer 10

• Progressive, persistent headache. This could be an expanding SOL (e.g. tumour, abscess, cyst, haematoma).
• Constitutional symptoms. Weight loss, night sweats, and/or fever may sug- gest malignancy, chronic infection (e.g. tuberculosis), or chronic inflamma- tion (e.g. temporal arteritis).

Question 11

You start by characterizing Mr Lennon’s headache. He tells you the pain is on the right side of his head and hasn’t ever moved. It started 4 days ago, since when it has been getting worse. He can only charac- terize it as intense. He has tried over-the-counter analgesics with no benefit, and when asked specifi- cally, says there is no change with position or time of day.
He has had no changes in consciousness, nor seizures, that he is aware of. When asked about other symptoms, he tells you he has found it hard to eat and open his mouth properly since yesterday because of jaw pain. He has not noticed any constitutional symptoms, and he hasn’t noticed any change in vision. He has never had anything like this before.
How does this information help focus the differential diagnosis and your approach?

Answer 11

Mr Lennon gives a good description of his headache. The gradual onset over 4 days makes a number of the more sinister causes less likely, specifically SAH. In addition, one of the red flags is present: a new onset headache in someone older than 50. In such presentations, particularly given suggestive symptoms like possible jaw claudication, your priority is to exclude temporal arteritis.

Question 12

Whilst you have begun to narrow your diagnosis, you still want to exclude sinister causes with your examination and investigations.
What signs will you look for on clinical examination?

Answer 12

Basic observations
• Altered consciousness. Assess Mr Lennon’s Glasgow Coma Scale (GCS) score, although it is likely to already be obvious from the history taking. The significance of altered consciousness is discussed above.
• Blood pressure and pulse. Check for malignant hypertension.
• Temperature. Fever and headache suggests meningitis or encephalitis.

Question 13

What focal neurological signs do you want to look out for

Answer 13

Note that the list below is not exhaustive.
• Focal limb deficit. Makes intracranial pathology more likely.
• Third nerve palsy. This consists of ptosis (droopy eyelid), mydriasis (dilated pupil), and an eye that is deviated down and out. One cause is an SAH due to a ruptured aneurysm of the posterior communicating artery (PCOM). PCOM aneurysms are a cause of headache.
• Sixth nerve palsy. Convergent squint and/or failure to abduct the eye later- ally. This nerve can be compressed either directly by a mass or indirectly by raised intracranial pressure. Remember that the sixth nerve has the longest intracranial course and is therefore most likely to get compressed at some point.
• Twelfth nerve palsy. Look for tongue deviation. A twelfth nerve palsy can arise from a carotid artery dissection.

                    • Horner’s syndrome. Triad of partial ptosis, miosis (constricted pupil), and anhydrosis (dry skin around the orbit). Results from interruption of the ipsilateral sympathetic pathway. In the context of our differential diagnosis, Horner’s syndrome should raise suspicions of a carotid artery dissection (ask about neck pain) or cavernous sinus lesion.

Question 14

What should you look for on eye inspection

Answer 14

• Exophthalmos? This may indicate a retro-orbital process such as cavernous sinus thrombosis.
• Cloudy cornea? Fixed, dilated/oval pupil? This may suggest acute glaucoma.
• Optic disc appearance on fundoscopy. Look for papilloedema, indicating raised intracranial pressure.

Question 15

What other signs should you look out for on examination

Answer 15

• Reduced visual acuity. This can suggest acute glaucoma or temporal arteritis for example.
• Scalp tenderness. Classically seen in temporal arteritis.
• Meningism. Check whether the patient has a stiff neck or photophobia, sug-
gesting meningism due to infection or SAH.

Question 16

On examination, Mr Lennon is not obviously photophobic as he is sitting in a well-lit environment. His heart rate is 84 beats/min (bpm), his blood pressure is 134/81 mmHg, and his temperature 36.5°C. Examination of his cranial nerves reveals reduced visual acuity in his right eye but not his left, which he previously hadn’t noticed. Fundoscopy is normal. The rest of his cranial nerves are intact but you do notice that his right scalp is tender to light touch. There are no limb signs and no neck stiffness.
Mr Lennon is an elderly man with a 4-day history of new-onset right-sided temporal headache, possibly jaw claudication, a right-sided decrease in visual acuity, and a tender scalp.
What is the most likely diagnosis? What is the pathology, and why is it an emergency?

Answer 16

Mr Lennon’s history and clinical features are highly suggestive of temporal arteritis (aka giant cell arteritis, GCA). This is a disease of unknown aetiology that typically appears in patients over 50 years of age. It is characterized by the formation of immune, inflammatory granulomas in the tunica media of medium/large-sized arteries. The inflammation (or thrombosis or spasm induced by it) can be sufficient to block the lumen of medium-sized arteries affected by this disease. Inflamma- tion of the mandibular branch of the external carotid artery causes jaw claudica- tion. Inflammation of the superficial temporal branch of the external carotid artery causes headache and scalp tenderness. Inflammation of the posterior ciliary arteries causes visual disturbances, due to ischaemia to either the retina (blurring, visual field loss) or the optic motor muscles (double vision = diplopia).
The reason to worry about this presentation is that with visual loss in one eye the other eye is at risk without prompt treatment. Temporal arteritis with visual distur- bance is therefore an ophthalmological emergency and patients should be referred to the on-call ophthalmologist as soon as possible. Unfortunately, visual loss prior to arrival at hospital is unlikely to be reversed regardless of treatment.

Question 17

How will you proceed in light of your working diagnosis?

Answer 17

Having taken a full history and examined the patient, one should arrange only first-line investigations that are quick to do – such as blood tests to demonstrate an elevated erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) that would be consistent with a systemic inflammation such as temporal arteritis. Management should then aim to reduce the immune-mediated inflammation that is causing the ischaemia in Mr Lennon’s arteries and the best way to do this is using high-dose corticosteroids.
Once initial treatment is under way, one can arrange for more time-consuming investigations to help confirm the diagnosis and rule out alternatives. In this case, a temporal artery biopsy should be arranged to help confirm the diagnosis (it will show granulomas in temporal arteritis). Note that the principal reason for urgent treatment of temporal arteritis is to protect the vision in the fellow, unaffected eye, rather than aiming to restore vision to the affected eye.

Question 18

Mr Lennon’s 40-year-old daughter has come to see her father. You have explained that you think he has temporal arteritis, an inflammation of some of the blood vessels supplying his head. Poor Miss Lennon is worried that she may have the same problem as she also frequently gets headaches.
You ask her to characterize the headache using SOCRATES. She tells you the headaches only affect the right side of her head. They come on over half an hour, and make her feel nauseated and sensitive to bright light and noise. She only finds relief by hiding in a dark room and getting some sleep. They last hours, but less than a day, and are relatively infrequent, occurring three or four times a year since her early twenties. You also ask about the red flags, none of which are present.
The lack of red flags makes a sinister cause of headache unlikely. But there are several non-sinister syndromes that cause headache. These syndromes are not ‘benign’ because they cause significant morbidity (in the form of pain). However, they are unlikely to cause lasting damage or mortality in the short term.
What different types of non-sinister headache are there?

Answer 18

Tension-type headache Migraine
Sinusitis
Medication overuse headache
Temporomandibular joint (TMJ) dysfunction syndrome (TMJ syndrome) Trigeminal neuralgia
Cluster headache

Question 19

Some of these are ‘primary headaches’ because the symptom (headache) is primary, i.e. if the head- aches were removed there would be no harmful pathology. This is in contrast to ‘secondary headaches’, where the headache is only one of many possible symptoms that result from pathology such as head trauma, intracranial lesion (e.g. tumour), vascular lesion (e.g. SAH), or infection. The following are sec- ondary headaches: sinusitis, medication overuse headache, and TMJ syndrome. Sinusitis and TMJ syn- drome cannot be diagnosed in the absence of additional symptoms. A diagnosis of medication overuse headache can only be made in patients using analgesic and/or migraine medication.
In addition to the pain history (e.g. SOCRATES), what questions should you ask to characterize non-sinister headaches?

Answer 19

• Does the patient suffer from different types of headache? If so, separate histories will be needed for each as they may reflect distinct syndromes. Thus patients with migraine are also vulnerable to medication overuse headaches from the treatment for their migraine.
• Are there any predisposing (trigger) factors? Factors such as stress and fatigue are known triggers for tension headaches and migraines. Some migraine sufferers point to certain foods as triggers (e.g. cheese, caffeine), and alcohol can trigger cluster headaches.
How disabling are the headaches? Migraines render many sufferers incapa- ble of performing even the activities of daily living for around a day. Cluster headaches are severely painful and disabling but often occur at night, allow- ing daytime duties to continue. Tension-type headaches usually allow normal activities to be continued.
• Does the patient get an ‘aura’ before the headache? Auras are usually visu- al phenomena, although focal neurological deficits (e.g. limb weakness) are sometimes present. About a third of migraine sufferers report auras as a fea- ture of their migraines.

Question 20

Describe the key features of tension headaches

Answer 20

• Tension-type headaches. Very common. Often bifrontal pain. They are epi- sodic, occurring with variable frequency. The pain is described as pressure or tightness around the head like a tightening band. Other than the head- ache there are no other features (e.g. no photophobia). The headaches last no more than a few hours and are not severely disabling. However, in rare cases they may occur almost daily, in which case they become disabling. Stress and fatigue are well-known trigger factors.

Question 21

Describe the key features of migraines

Answer 21

• Migraine. Common, although not as common as tension headaches, and twice as common in women than men. Migraines are stereotyped, i.e. attacks exhib- it the same pattern of symptoms and become recognizable to patients. They are typically unilateral (migraine is a corruption of the Latin (he)mi-cranium). Associated with an aura in about a third of sufferers (migraine with aura or classical migraine, as opposed to migraine without aura or common migraine). The pain is described as throbbing or pulsatile. There is sensitivity to light, sound, and even smell, and nausea can also be a feature. Migraines last between 4 and 72 hours, unless successfully treated. Some patients suffer from aura without migraine. Such attacks are in the differential for TIAs (particu- larly in older patients) and epilepsy.

Question 22

Describe the key features of sinusitis

Answer 22

• Sinusitis. Patients usually report facial pain coming on over hours to days in conjunction with coryzal symptoms. The pain is tight, as in tension headaches, and is often exacerbated by movement. The headaches last several days, with a time course consistent with the infection. The headaches are moderately severe but not disabling. However, patients with chronic sinusitis may find the headaches frequent enough to interfere with their daily activities.

Question 23

Describe the key features of medicine overuse

Answer 23

• Medication overuse. Surprisingly common, particularly in women (about five-fold the incidence in men). This is seen particularly with migraine medi- cations and analgesics. The headaches experienced resemble either migraine or tension-type headaches. Most patients will be taking very large quantities of medication (on average 35 doses of six different agents a week). It is often difficult for patients to accept that the over-treatment of headache is actually the cause of their ongoing headaches. Treatment consists of withdrawal from analgesic use, which often results in a period of exacerbation before improve- ment occurs.

Question 24

Describe the key features of TMJ syndrome

Answer 24

• TMJ syndrome. Most common in individuals aged 20–40, and four times more prevalent in women. As well as headache, patients get a dull ache in the muscles of mastication that may radiate to the jaw and/or ear. Patients also often report hearing a ‘click’ or grinding noise when they move their jaw.

Question 25

Describe the key features of trigeminal neuralgia

Answer 25

• Trigeminal neuralgia. A rare condition, occurring more often in women, with a typical age of onset around 60–70 years. Patients complain of unilat- eral facial pain involving one or more of the divisions of the trigeminal nerve. The pain lasts only seconds, and can be triggered by eating, laughing, talking or touching the affected area. Although attacks last seconds, there may be several or even hundreds a day and patients can develop a longer-lasting back- ground pain. Patients often avoid known triggers like shaving. Interestingly, attacks rarely occur during sleep, unlike migraine or cluster headaches.

Question 26

Describe the key features of cluster headaches

Answer 26

• Cluster headache. Predominantly affects men. The headaches occur in ‘clus- ters’ for about 6–12 weeks every 1–2 years, hence the name. Attacks tend to occur at exactly the same time every day or night, like an alarm clock going off. The pain is focused over one eye. The pain is intense and causes the patient to wake up and can be so severe that suicide is contemplated, until the pain diminishes, around 20–30 minutes later. They will probably have a red, watery eye, rhinorrhoea, and Horner’s syndrome, suggested by a history of ptosis. These headaches are very disabling.

Question 27

You ask the additional questions listed above. Miss Lennon tells you she sometimes gets ‘normal’ head- aches, which respond to paracetamol, but it is these other headaches that she worries about. When you ask about any ‘aura’ or visual disturbance, she tells you they are often preceded by seeing a small black spot with bright, zig-zagging lines. When she has a headache, she has to stay in bed all day until it goes, but will be fit and well the day after.
What is the most likely diagnosis, given Miss Lennon’s history?

Answer 27

It may be tempting to dismiss Miss Lennon’s headaches as tension headaches, which almost everyone experiences at some point. However, Miss Lennon describes a unilateral headache that makes her feel sick, photophobic, phonophobic, and is preceded by a visual phenomena (zig-zag lines). It is therefore very likely that Miss Lennon suffers from migraine with aura.
Migraine affects about 15% of the population, but many do not seek help as they
think there is no treatment. This is not true, as acute abortive treatment includ-
ing triptans (5HT -agonists such as sumatriptan), analgesics (aspirin, paracetamol), 1
and anti-emetics (metoclopramide) have been shown to be highly effective if the patient takes them as soon as they feel a migraine coming on – something that most migraine sufferers recognize easily. Preventative treatments are only useful with high frequencies of attacks (e.g. fortnightly) and will usually only reduce migraine frequency by 50%.

Question 28

Should you examine Miss Lennon and, if so, what would you look for? Should you order any investiga- tions and, if so, which?

Answer 28

All of the non-sinister causes of headache are diagnosed on history. However, you should conduct a physical examination, both to provide the patient with reassur- ance and to look for:
• Blood pressure, to exclude malignant hypertension.
• Head and neck examination for muscle tenderness, stiffness, or limited move- ment – which can occasionally mimic tension-type headaches. If present, such findings may need treatment in order to relieve the headache.
• Focal neurological signs. The presence of focal neurological signs in some- body with headache should alert you to intracranial pathology.
• Fundoscopy, to exclude raised intracranial pressure.
Investigations are only ever indicated where warranted by the history and exami- nation and should not be ordered routinely.

Question 29

Mrs Harrison is a 42-year-old who presents to accident and emergency (A&E) complaining of a severe headache and nausea. She has a history of migraine attacks but this time she says it is different – it came on suddenly after dinner, without warning, and felt as if someone had punched her in the back of the head. Her husband, annoyed at having to drive her to the hospital in the middle of the night, cynically thinks she is just having ‘a bad migraine’.
What is the likely diagnosis? What key investigation should be requested?

Answer 29

Patients know their disease better than any doctor, so if a patient tells you that something doesn’t feel like what they normally have (e.g. migraines in this case), take them seriously. You should take a full history and examine the lady for key signs as discussed in the main case (e.g. neck stiffness suggesting meningism). But the history given is classic for an SAH, so you should arrange an urgent computed tom- ography (CT) head scan, looking for blood in the CSF (this appears bright on CT, for example in the Sylvian fissures). An LP looking for xanthochromia (yellow CSF due to bilirubin content) must be performed to exclude SAH if the CT is negative. Note that CT is only useful as an aid to diagnosis of SAH in the first days following a bleed – by approximately day 7 the scan will have ~50% sensitivity (i.e. you might as well flip a coin). LP should be delayed for 12 hours after the onset of the headache as false negative results can occur before that time. It remains reliable for up to 12 days (12 hour to 12 day rule).
If the CT confirms an SAH, Mrs Harrison will need urgent referral to a neurosurgi- cal unit. Patients are initially managed with nimodipine (a calcium-channel blocker that reduces spasm of the ruptured cerebral artery, thus preventing ischaemia, i.e. a stroke) and bed rest.
If she survives and her symptoms improve, she should receive cerebral angiogra- phy to find the source of a bleed – usually a ruptured aneurysm. The neuroradiolo- gist will usually be able to insert a platinum coil to cause the aneurysm to clot, scar, and heal. Coiling has been shown by the ISAT Study1 to have fewer complications than surgically clipping the aneurysm via an open craniotomy. The family should be made aware that SAH carries a high risk of mortality and morbidity: 50% of patients die before arriving at hospital; a further 17% die in hospital; another 17% survive but with lasting neurological deficits; and only 17% survive without any sequelae.

Question 30

Mr McCartney is a 32-year-old salesman who is worried that he might be having repeated ‘mini-strokes’ (TIAs), like his father. He says that every couple of months he suffers from an attack where he sees a shimmering light in the corner of his eyes and gets a ringing in his ears. This usually occurs towards the end of the day, lasting half an hour. He is fully conscious throughout and never feels dazed or confused afterwards.
Could this gentleman be suffering from TIAs like his father?

Answer 30

TIAs and strokes are caused by areas of the brain ceasing to function due to a lack of blood (because of an embolism or haemorrhage) and are therefore characterized by ‘negative’, loss of function, symptoms and signs (loss of vision, numbness, loss of power in muscles). In contrast, epilepsy is caused by over-activation of areas of the brain and thus produces ‘positive’, gain of function, symptoms and signs (flash- ing lights, muscle convulsions, odd sensations in the skin). Migraine can produce both negative and positive symptoms. This gentleman describes clear gain of func- tion symptoms (shimmering light, noises) that are more suggestive of epilepsy or migraine.
It could be epilepsy, but seizures tend to be followed by a post-ictal phase where the patient is exhausted and sometimes confused. It is therefore more likely to be a case of migraine aura without headache. A characteristic feature is a slow march of symptoms (e.g. visual disturbance affecting more and more of the visual field) then resolution in a similar fashion. Migraine without aura is an odd condition where patients experience the aura signs of typical migraine patients (e.g. shimmering lights with ziz-zagging edges, noises) but without the headache. One can reassure the patient that his symptoms are almost certainly not ‘mini-strokes’ but more likely due to a type of migraine without headaches. The patient may wish to have a trial of antimigraine medication as soon as one of these attacks starts (e.g. sumatriptan) or prophylactic medication to prevent it occurring (e.g. propanolol, pizitofen) and see if they help.

Question 31

Ringo is a 16-year-old who presents with a runny nose and headache. He has been blowing out green mucus from his nose for a few days but has come to see you because the headache, which is located above his eyes, is now very bad. His nasal septum is slightly deviated and his forehead is indeed tender to gentle tapping.
Can we send this patient home on analgesia and rest?

Answer 31

It is possible that this young man simply has a viral rhinosinusitis, but the green mucus and the highly localized pain above his eyes suggest he may have developed an infection of his frontal sinuses.
Sinusitis usually affects the maxillary sinus and resolves spontaneously, occasion- ally needing a helping hand from antibiotics (e.g. amoxicillin) if it fails to resolve. However, frontal sinusitis can be particularly dangerous because it is possible for the bacteria to erode backwards into the brain, causing meningitis or a brain abscess. For this reason, a suspected case of frontal sinusitis should be taken seri- ously and referred to ear, nose, and throat (ENT) specialists who can arrange a CT head scan to check if either frontal sinus is affected. If it is, he will need antibiotics and draining of the frontal sinuses (antral lavage). It is possible that his deviated nasal septum is predisposing him to episodes of sinusitis and, if so, he could benefit from a re-arrangement of his nasal septum (septoplasty).

Question 32

A 10-year-old girl is referred to the hospital by her GP for persistent headache in the occipital area that is worse in the morning. The parents have also noticed that she has become clumsy over the last few months. As part of your cranial nerve examination you perform fundoscopy, where you see the result

What is your next step?

Answer 32

The appearance of the optic disc (poorly defined margins) is suggestive of papill- oedema, potentially due to raised intracranial pressure. This would be consistent with headaches which are worse in the morning. One cause of raised intracranial pressure is brain tumour, and in children most brain tumours are found in the pos- terior fossa that would explain the occipital headache. In addition, the most com- mon type of tumour in children is a medulloblastoma in the cerebellum, which may explain her clumsiness. Thus you must rule out a CNS tumour as the problem in this child. An urgent head magnetic resonance imaging (MRI) scan should there- fore be requested.
If a tumour is found, the neurosurgeon will use dexamethasone to reduce the brain inflammation (improving the headache) and discuss the surgical options to remove the tumour with the family.

Question 33

What are the main causes of SAH

Answer 33

The main causes of SAH are:
• Rupture of an arterial aneurysm, usually a ‘berry aneurysm’ at the junction between arteries of the circle of Willis (~45%)
• Trauma (~45%)
• Arteriovenous malformations, rupture of haemangiomas, rupture of cerebral vein around the brain-
stem (~10%)

Question 34

What is your differential diagnosis for intracranial tumours

Answer 34

he list of possible intracranial tumours is very long but the most common are:
• Secondary brain tumours (metastatic). These are the most common type of brain tumours in adults, accounting for ~90% of all intracranial tumours. The five most common sources of primary cancer metastasizing to the brain are lung, kidney, breast, melanoma, and colon.
• Primary brain tumours. These can be divided into axial (within the brain parenchyma) and extra-axial:
− Axial or neuroepithelial tumours (~50%). These are tumours of the brain matter itself. They include
(the latter three are more common in children):
Astrocytomas (glioblastoma multiforme is a grade 4 astrocytoma) Ependymomas
Oligodendrogliomas
Medulloblastomas
− Extra-axial
Meningioma (~15%). A slow-growing tumour of the meninges that compresses the brain. Often
associated with neurofibromatosis type II (inherited predisposition to schwannomas and menin-
giomas), these tumours can usually be surgically removed with good prognosis
Vestibular schwannoma. Previously and incorrectly called an ‘acoustic neuroma’, this type of tumour is relatively common in young adults. It may compress cranial nerve VIII (hearing loss) and VII
(facial palsy)
Pituitary adenomas, prolactinomas, and craniopharyngiomas
Other: choroid plexus papillomas, haemangiomas, pineal gland tumours, etc.

Question 35

At what level of the spine should you insert a needle during an adult LP? What are the surface anatomy
landmarks? What structures do you pass through as you perform an LP?

Answer 35

The spinal cord in adults ends at L1/L2, with peripheral nerves extending beyond that as a loose bundle of nerve fibres floating in CSF (the cauda equina, literally the ‘horse’s tail’). Modern studies have shown that in children the spinal cord ends only slightly lower (L2/L3) but certainly not as low as many older textbooks claim. A safe place to insert the needle is thus at or below L3/L4. This can be found by tracing a line between the posterior superior iliac crests (Tuffier’s line), which marks the L4/L5 space.
The following structures are sequentially traversed as you perform an LP:
• Skin
• Subcutis
• Supraspinous ligament
• Interspinous ligament
• Ligamentum flavum (first ‘give’ as you push the needle)
• Dura mater (second ‘give’ as you push the needle)
• Arachnoid space – the destination

Question 36

What are the indications, contraindications, and risks of an LP?

Answer 36

Indications
• Diagnostic LP: looking for oligoclonal bands (e.g. multiple sclerosis), high protein (Guillain–Barré syn- drome), blood or bilirubin (e.g. SAH), pathogens (e.g. bacterial meningitis, viral encephalitis), malignant cells (e.g. CNS lymphoma), or a rapid improvement in gait and cognitive function after removal of 30 mL of CSF (e.g. normal pressure hydrocephalus).
• Therapeutic LP: intrathecal drug administration (e.g. haematological malignancy in children), tempo- rary reduction in intracranial pressure (e.g. idiopathic intracranial hypertension).
Relative contraindications
• Raised intracranial pressure due to an SOL, as the sudden drop in pressure can cause the brainstem to cone through the foramen magnum. Suspect raised intracranial pressure in a history of early morn- ing headaches, nausea, and vomiting that are made worse by lying down or straining; in anyone with impaired consciousness, papilloedema on fundoscopy, focal neurological signs (e.g. nerve VI palsy). If there is any doubt about an SOL then imaging should be performed prior to LP.
• Increased bleeding tendency (e.g. patient on warfarin, disseminated intravascular coagulation).
• Infection at prospective site of puncture.
• Cardiorespiratory compromise. Deal with this before doing any other procedure

Question 37

Wha are the risks of an LP

Answer 37

Risks
• Headache. About 30% of patients will get a headache due to the intracranial hypotension. This risk can be minimized by keeping the patient lying flat for at least 2 hours. Some needle types are less likely to cause headaches then others (smaller calibre is better).
• Nerve root pain. About 10% of patients will get pain in a lumbosacral nerve root distribution, due to irritation by the needle of one of the nerves that form the cauda equina. This can be minimized by inserting the needle slowly and withdrawing it from the cannula slowly. Provide analgesia and reassure the patient that the pain will gradually subside.
• Infection at the site of the puncture.

Question 38

With regards to raised intracranial pressure, what are (1) its main symptoms and signs and (2) its main causes?

Answer 38

1) The main symptoms and signs of raised intracranial pressure are: Headache, often worse when lying down
Nausea, usually first thing in the morning, after lying down all night Papilloedema, a swollen optic disc when visualized by fundoscopy Visual blurring
Cushing’s reflex, a paradoxical bradycardia and raised blood pressure, often with irregular breathing Cushing’s peptic ulcer, causing epigastric pain
2) There are a variety of mechanisms that can lead to raised intracranial pressure:
SOL, such as a tumour, haematoma, abscess, or cyst
Cerebral oedema, secondary to trauma or some other lesion
Increased blood pressure in the CNS, due to vasodilator drugs (glyceryl trinitrate (GTN) spray, Viagra),
malignant hypertension, hypercapnic vasodilation, venous sinus thrombosis, or superior vena cava
obstruction
Increased volume of CSF (hydrocephalus), which can be due to obstruction of CSF drainage (e.g. by a
tumour), dysfunction of the arachnoid granulations responsible for CSF reabsorption (e.g. SAH or meningitis irritating the granulations, idiopathic intracranial hypertension), or increased CSF produc- tion (by a choroid plexus papilloma)