Neurology - Headache

Question 1

Classification of headaches

Answer 1

Headaches can either be primary or secondary (to other pathology). The most common causes of primary headache syndrome are migraine, tension type headache and cluster headache.

Question 2

Common types of migraine

Answer 2

The two commonest types are migraine without aura and migraine with aura. A further category often leading to referral is chronic migraine.

NB - more than one category of migraine may occur in the same patient

Question 3

What is the epidemiology of migraines?

Answer 3

Very common - affect 10% of people worldwide.

It is more common in females than males, and can occur at any age although first attack is most likely during puberty. A first episode of migraine is rare after the age of 40.

Migraine beginning for the first time in older people requires investigation for alternative explanations.

Migraine tends to occur at variable frequency throughout life and attacks often become less severe and less frequent with age.

Question 4

What causes migraine?

Answer 4

Aetiology is unclear.
Approximately 90% have a family history.
Prodromal sensory phenomena (“aura”) have been attributed to vasoconstriction within intracerebral vessels, although a wave of depolarisation spreading across the cortex may account for these symptoms.

After, vasodilation of extra cerebral vessels correlates with the onset of headache.

Question 5

What is the clinical presentation of classical migraine with aura?

Answer 5

Migraine starts with a sense of ill health (lasting up to several hours) followed by visual aura (e.g. shimmering lights, fortification spectra, scotoma) usually in the field opposite to the side of the succeeding headache and lasting up to 1h.

In severe cases patients may develop homonymous hemianopia or even complete blindness.

Sensory symptoms are (e.g. numbness, paraesthesia) are less common. Speech disturbance and or motor weakness are even rarer.

After a throbbing unilateral headache is associated with anorexia, nausea, vomiting, photophobia and withdrawal.
The headache can last several hours or even days in some patients. Neuro exam is usually normal.

Question 6

How is migraine without aura diagnosed?

Answer 6

Diagnosis requires at least 5 lifetime attacks lasting 4-72 hours with two of the four pain features and at least one of the two sets of associated symptoms.

Pain features:

• Unilateral new location
• Pulsating quality
• Moderate or severe pain intensity
• Aggravated by or causing avoidance of, routine physical activity

Associated features:

• Photophobia
• Nausea and vomiting

Question 7

When can migraine be considered chronic migraine?

Answer 7

When attacks occur for 15 or more days per month

Question 8

Does migraine require investigation?

Answer 8

When the diagnosis is clear investigation is not needed, otherwise brain imaging should be performed.

Question 9

How is the acute migraine attack managed?

Answer 9

• Sleeping in a dark room
• Simple analgesics (e.g. aspirin, paracetamol) and an antiemetic agent
• 5-HT1D/B agonists (“triptans”) are effective when taken early and may stop an established attack
• Ergotamine
• Trials involving CGRP (calcitonin gene related peptides) antagonists are underway and may be effective for the third of patients who do not respond to triptans

NB - triptans are contraindicated in patients with known/ suspected coronary or cerebrovascular disease or uncontrolled hypertension

Question 10

When should migraine prophylaxis be considered?

Answer 10

Patients who suffer:

• > 1 acute attack per month
• increasing frequency of headaches
• significant disability despite appropriate treatment for acute attacks

Question 11

Migraine prophylaxis

Answer 11

• Beta blockers, usually propranolol
• amitriptyline
• pizotifen (5-HT antagonist)
• topiramate
• others - e.g. sodium valproate, verapamil or methysergide (this has potentially serious fibrotic side effects and must be used under expert supervision)

Question 12

Why should treatment of acute headache be limited?

Answer 12

Ideally limit to 2-3 times per week. This is to minimise the risk of developing a medication overuse headache, which occurs secondary to frequent use of headache medications.

Question 13

What are the features of tension type headache?

Answer 13

Continuous severe pressure is felt bilaterally over the vertex, occiput or eyes. It may be “band like” or non specific and of variable intensity.
Common in both sexes especially with stress or depression.

It often occurs on a daily basis and may persist for months or even years. Standard analgesics are reported to be ineffective and continuous use may exacerbate the headache, especially when the effects of the medication ware off (rebound headache).

Question 14

How are tension type headaches treated?

Answer 14

Treatment is difficult!
Reassurance that there is no sinister underlying cause may be helpful in some cases.
Avoid excessive analgesic use, but a small dose of amitriptyline at night may be useful.

Question 15

What are cluster headaches?

Answer 15

These are relatively short lived (30-120 min) episodes of severe pain, typically centred on one eye and affecting more men than women (3:1) with an age of onset between 20-60 years.

Question 16

What is the clinical presentation of cluster headaches? What is a known precipitant?

Answer 16

Attacks start without warning and are associated with red eye, eye and nose watering and vomiting.
They may occur several times a day often waking the patient.
Usually cluster headaches are recurrent for several days, weeks or months before the disorder remits and the patient is pain free for months or years.

Alcohol is a known precipitant.

Question 17

How are cluster headaches treated?

Answer 17

Sumatriptan (self administered by sub cut injection) is the treatment of choice for cluster headaches - simple analgesics are often ineffective.

Prophylaxis with verapamil or lithium may be tried (methysergide is reserved for refractory cases and must be used under supervision)

Question 18

Differential diagnosis to cluster headache?

Answer 18

Secondary causes (due to a structural cause) exist and most patients require MRI.
An alternative diagnosis is paroxysmal hemicranias, which is very sensitive to a specific treatment (indomethacin) and should therefore be considered.

Question 19

Characteristics of headache caused by raised intracranial pressure

Answer 19

Usually associated with a tumour, haematoma or abscess, the pain is usually worse in the morning (on waking) and associated with nausea and vomiting.

It improves 1-2 hours after rising and is exacerbated by coughing, sneezing, straining and bending down.

Visual function may be preserved despite papilloedema, but other symptoms and signs related to the primary lesion are usually present.

Question 20

In which group of patients is IIH most common?

Answer 20

Common in young obese women.

Presents with symptoms and signs of raised intracranial pressure but no mass lesion on brain imaging.

Altered CSF dynamics (with impaired absorption) may cause the disorder.

Question 21

Clinical presentation of IIH

Answer 21

Visual disturbance, including diplopia and obscuration (abrupt onset transient visual loss secondary to a change in posture) and examination reveals bilateral papilloedema.

Occasionally bilateral 6th nerve palsies are present and reflect raised intracranial pressure (“false localising sign”) and pulsatile tinnitus is also recognised.

Question 22

How is IIH diagnosed?

Answer 22

CT/MRI is normal with no evidence of hydrocephalus. Lumbar puncture confirms raised CSF pressure.

Secondary causes must be excluded and include:

• Venous sinus thrombosis
• Disorders of calcium metabolism
• Drugs (tetracyclines, isotretinoin, steroids)
• SLE
• Hypervitaminosis A

Question 23

How is IIH treated?

Answer 23

Weight loss may facilitate remission.
Serial “therapeutic” LPs can be used to lower CSF pressure but are unpopular with patients.

Chronic cases are treated with acetazolomide other diuretics or corticosteroids. Surgical intervention (lumboperitoneal shunt or optic nerve decompression) is often required to relieve symptoms and save vision - prolonged raised ICP predisposes to optic atrophy.

Question 24

How does acetazolomide work?

Answer 24

Acetazolomide is a carbonic anhydrase inhibitor. This reduces bicarbonate reabsorption in the proximal tubule by inhibiting the catalysis of CO2 hydration and dehydration reactions. Thus the excretion of Na, bicarb and water increases.

The loss of bicarb causes a metabolic acidosis and the effect of the drug becomes self limiting as the serum bicarb concentration falls.

Increased sodium delivery to the distal nephron increases K+ secretion.

Question 25

Headache caused by meningeal irritation

Answer 25

Meningism occurs in meningitis and SAH. It characteristically produces a triad of symptoms:

1) severe headache - global or occipital associated with nausea and vomiting
2) photophobia
3) neck stiffness

In meningitis the headache evolves over minutes to hours whereas in SAH it is abrupt in onset and may lead to loss of consciousness (“thunderclap”)

Question 26

What is giant cell arteritis?

Answer 26

A condition characterised by chronic vasculitis (granulomatous arteritis) of large and medium sized vessels (in particular affecting the external carotid artery). The aetiology is unknown.

Temporal artery biopsy is highly specific.

Question 27

Clinical presentation of giant cell or temporal arteritis

Answer 27

Headache (most common), jaw claudication (pain on chewing) and visual disturbance, including amaurosis fugax and blindness which may be irreversible.

Patients may also experience systemic symptoms including fever, malaise and MSK problems such as proximal muscle weakness of the shoulders and hips (there is overlap between polymyalgia rheumatic and GCA)

Question 28

How is giant cell arteritis treated?

Answer 28

The rule of 60s!

• most common over 60
• ESR

Question 29

What are neuralgias?

Answer 29

These are intermittent, brief, severe, laminating pains occurring along the distribution of a nerve.

E.g.

• trigeminal neuralgia
• glossopharyngeal neuralgia
• post-herpetic neuralgia

Question 30

What causes trigeminal neuralgia?

Answer 30

Trigeminal neuralgia predominantly affects those over the age of 50 years.

It reflects compression of the sensory root of the trigeminal nerve (e.g. by a tumour or aberrant vessel) or may complicate MS.

Question 31

Clinical features of trigeminal neuralgia

Answer 31

Agonising sharp pain is confined in the distribution of the trigeminal nerve on one side, commonly the maxillary or mandibular divisions.

It lasts only seconds and is usually triggered from a place on the lips, side of the face or nose, by chewing, eating, speaking or by cold breeze.

It tends to get worse with age and eventually a continuous background pain may develop if left untreated.

Question 32

How is trigeminal neuralgia treated?

Answer 32

Simple analgesics are usually ineffective.
Usually carbamazepine provides good symptom control, but sodium valproate, gabapentin, clonazepam, or the tricyclic antidepressants may be tried (adjunct analgesics).

Question 33

Glossopharyngeal neuralgia

Answer 33

A rare disorder precipitated by swallowing, which produces pain in the pharynx or deep inside the ear.

Question 34

What is postherpetic neuralgia?

Answer 34

Patients have a history of herpes zoster infection (shingles) usually in the distribution of the ophthalmic division of the trigeminal nerve.

Pain, itching and altered sensation develop along the course of the affected nerve and persist after the rash has healed. The pain may be difficult to treat, but sometimes responds to TCAs, carbamazepine or topical capsaicin.