Headache

Headache is the most frequently reported neurological symptom, accounting for considerable morbidity in the general population. The clinician’s challenge is to exclude a treatable underlying intra- or extracranial secondary cause (Table 15.1) and to make a definitive diagnosis. The history provides important clues and should ascertain:

• date of onset, frequency and duration of episodes
  
• precipitating and relieving factors
  
• type and location of pain
  
• severity
  
• associated features.

Table 15.1 Causes of Headache and Facial Pain

Primary Headache Syndromes

Secondary Causes of Headache

See Table 15.1.

Raised Intracranial Pressure

Usually secondary to an intracranial tumour, haematoma or abscess, the pain is worse on waking and associated with nausea and vomiting. It improves 1–2 h after rising and is exacerbated by coughing, sneezing, straining and bending down. Visual function may be preserved despite papilloedema, but other neurological symptoms and signs related to the primary lesion are usually evident. The pain often responds to simple analgesics.

Idiopathic (‘Benign’) Intracranial Hypertension (IIH; Pseudotumour Cerebri)

IIH is commonest in young obese women with symptoms and signs of raised intracranial pressure but no mass lesion on brain imaging. Altered cerebrospinal fluid (CSF) dynamics (with impaired absorption) have been suggested to underlie the disorder. The patient may report visual disturbance, including diplopia and obscurations (abrupt onset transient visual loss secondary to changes in posture), and examination reveals bilateral papilloedema. Occasionally, bilateral sixth cranial nerve palsies are present and reflect raised intracranial pressure (‘false-localising’ sign). Pulsatile tinnitus is another recognised feature.

CT/MRI scanning of the brain is normal without hydrocephalus but lumbar puncture confirms raised CSF pressure. Intracranial venous sinus thrombosis, disorders of calcium metabolism, drugs (tetracyclines, isotretinoin, hormonal contraceptives, growth hormone and corticosteroids), systemic lupus erythematosus and hypervitaminosis A may all present with a syndrome similar to IIH, thus secondary causes must always be excluded.

Weight loss may facilitate spontaneous remission. Serial ‘therapeutic’ lumbar punctures can be used to lower CSF pressure but are unpopular with patients. In more chronic cases, medical therapy with acetazolamide, other diuretics or corticosteroids may be tried but surgical intervention (lumboperitoneal shunt or optic nerve sheath decompression) is often required to relieve symptoms and/or protect vision – prolonged raised intracranial pressure predisposes to optic atrophy.

Meningeal Irritation

Irritation of the meninges (meningism) occurring in meningitis or following subarachnoid haemorrhage characteristically produces a triad of symptoms:

• severe headache – global or occipital associated with nausea/vomiting
  
• photophobia
  
• neck stiffness.

In meningitis the headache evolves over minutes to hours whereas in subarachnoid haemorrhage it is abrupt in onset and may be followed by loss of consciousness.

Post-Concussion

Similar to tension headache but usually associated with dizziness (not vertigo) and impaired concentration, post-concussion headache persists for months and there may be a history of inadequate recovery following the head injury.

Giant-cell Arteritis

This is an important cause of headache in patients over 50 years of age (see rheumatology, p. 284).

Neuralgias

Epilepsy

Most epilepsy is idiopathic. There may be a family history suggesting genetic susceptibility, particularly with petit mal seizures. Seizures may be secondary to cerebral disorders, metabolic dysfunction and drug ingestion (Table 15.2).

Table 15.2 Causes of Epilepsy

Provocation of Seizures

A variety of factors can provoke seizures in patients not usually prone to epilepsy (e.g. drug overdose, hypoglycaemia). In those with known epilepsy, seizures may be provoked by sleep deprivation, stress, alcohol and, occasionally, stimuli such as television or strobe lighting. In some women seizures may increase in frequency around the time of menstruation.

Differential Diagnosis

• syncope: e.g. vasovagal faints, postmicturition and cough syncope
  
• cerebrovascular disease: e.g. transient ischaemic attacks, critical carotid artery stenosis, vertebrobasilar ischaemia
  
• vestibular disorders
  
• low cardiac output states
  
• metabolic: e.g. hypoglycaemia
  
• postural hypotension
  
• narcolepsy
  
• psychiatric disorders: e.g. conversion hysteria

Clinical Features

Epilepsy in Childhood

Absence Seizures (‘Petit Mal’)

This usually presents between 4 and 10 years and is more common in girls. It is characterised by brief (10–15 s) moments of absence without warning (e.g. the child stops talking and stares blankly) followed by immediate recovery. It rarely continues beyond puberty, although 5–10% of children will develop adult seizures.

Febrile Convulsions

These are seizures occurring in the context of fever, usually in young children under 5. The majority are ‘one-off’ events although up to 5% go on to develop epilepsy. They are usually generalised and brief but occasionally longer lasting or focal in nature.

Infantile Spasms

These are brief spasms (typically ‘shock-like’ with flexion of the arms, head and neck and drawing up of the knees) associated with progressive learning difficulties. Aetiology includes perinatal asphyxia, metabolic disorders, encephalitis and cerebral malformations.

Juvenile Myoclonic Epilepsy

This form of primary generalised epilepsy with typical onset in teenagers is characterised by relatively infrequent generalised seizures, daytime absences and myoclonus.

Epilepsy in Adulthood

Primary Generalised Epilepsy (Tonic–Clonic Seizures/Grand Mal)

Seizures may be preceded by a prodrome/aura in which the patient reports dizziness, irritability or other non-specific symptoms. This is followed by loss of consciousness and the tonic phase (characterised by generalised muscle spasms), which usually lasts up to 30 s. Cyanosis may occur. The clonic phase, characterised by sharp repetitive muscular jerks in all limbs, follows. Tongue biting, salivation and involuntary micturition may occur. Consciousness remains impaired typically for around 30 min, with drowsiness and confusion lasting several hours.

Temporal Lobe Epilepsy

Patients typically experience an aura which may include a sense of fear or déjà-vu, hallucinations (visual, olfactory or gustatory) or a rising sensation in the epigastrium. Confusion and anxiety may develop and some patients exhibit automatism (organised stereotyped movements, e.g. chewing, lip-smacking).

Jacksonian (Focal) Epilepsy

Epileptic activity originates in one part of the motor cortex. Each seizure begins in one body part and may proceed to involve that side of the body and then the whole body. Temporary paresis of the originally affected limb may persist after the attack (Todd’s paralysis). Sensory epilepsy is a parallel condition originating in the sensory cortex.

Investigation

The object is to detect treatable underlying brain disease and identify provoking factors.

A full history and clinical examination should identify other causes of loss of consciousness. Biochemical evidence of excess alcohol, hypoglycaemia, hyponatraemia or hypocalcaemia should be sought.

An EEG should help to confirm the diagnosis, but both false positive (in 1% of the normal population) and false negative results occur. EEG diagnosis can be enhanced by prolonged recording especially after sleep deprivation.

CT or MRI scanning is performed in most adult patients presenting with a seizure to identify structural lesions. Imaging is of particular value in late-onset epilepsy, partial seizures and in patients with generalised epilepsy where the EEG discloses a focal abnormality.

Management

A single fit rarely requires treatment but an underlying cause should be sought. Most neurologists would begin treatment with prophylactic anticonvulsants after a second episode. However, it may be prudent to treat after a first seizure when neuroimaging reveals a structural lesion or when there is no reversible precipitant.

The choice of pharmacological therapy is determined by the type of epilepsy, for example:

• Partial seizures (with or without secondary generalisation): carbamazepine, lamotrigine, oxcarbazepine and sodium valproate are the drugs of choice; second-line agents include clobazam, gabapentin, levetiracetam, pregabalin and topiramate.
  
• Generalised tonic–clonic: carbamazepine, lamotrigine and sodium valproate are first-line agents; clobazam, levetiracetam, phenytoin and topiramate are useful second-line options.
  
• Absence: ethosuximide or sodium valproate are the drugs of choice for classical absence seizures; clonazepam and lamotrigine are alternatives.
  
• Myoclonic: sodium valproate is the drug of choice for most cases; clonazepam, levetiracetam and topiramate may be tried as second-line agents.

In addition, age, sex, child-bearing potential, comorbidity and concomitant medication should be taken into account. Seizure control with minimal adverse effects can be achieved using a single anticonvulsant in 75% of patients. The addition of a second drug produces satisfactory control in a further subgroup.

Refractory epilepsy (inadequate control on multiple agents) may reflect:

• poor compliance
  
• pseudoseizures or non-epileptic attacks (either alone or in combination with genuine seizures)
  
• an underlying structural brain lesion
  
• excess alcohol or illicit drug usage.

Status Epilepticus

This is defined as recurring or continuous seizures, in which the patient does not regain consciousness between attacks. It is a medical emergency as hypoxia/anoxia can lead to permanent brain damage or even death. Key principles of management include:

• basic life support/resuscitation
  
• seizure control
  
• identification and correction of predisposing cause.

The choice of agent used to terminate seizure activity depends on the stage/duration, but may include:

• Intravenous lorazepam (4 mg) (clonazepam and diazepam are alternatives) – dose may be repeated after 10 min if seizures recur/continue.
  
• Intravenous phenytoin (15 mg/kg, maximum rate of 50 mg/min), fosphenytoin (prodrug of phenytoin), both of which require ECG monitoring, or phenobarbitone (10 mg/kg, maximum rate of 100 mg/min) should be used when there is established status.
  
• Intravenous thiopentone (bolus followed by infusion), combined with ventilation/neuromuscular blockade, is required when seizures continue beyond 30–60 min. Midazolam and propofol have also been used in this setting. EEG monitoring is required to confirm termination of seizure activity.

Patients should be nursed in a high dependency/intensive care setting. Regular anticonvulsant therapy should be reinstituted as soon as possible in those with known epilepsy.

Surgical Treatment of Epilepsy

This should be considered in patients with intractable epilepsy if a focus for seizure onset can be identified using MRI and electrophysiology mapping.

Epilepsy and Pregnancy

Uncontrolled seizures in pregnancy present a serious risk to both mother and fetus. Anticonvulsant drugs must be continued especially if there is a history of recent seizure activity. In women with no recent (2– 3 years) history of seizures, a trial off therapy before pregnancy should be considered.

Women with epilepsy who wish to become pregnant should receive pre-pregnancy counselling about the risk of congenital abnormality and the individual pros and cons of continuing treatment. Wherever possible, the lowest dosage of a single agent should be used. Screening for neural tube defects is especially indicated in women taking sodium valproate or carbamazepine, and folic acid supplementation is essential both preconception and throughout the pregnancy.

For mothers taking carbamazepine, phenobarbitone or phenytoin (enzyme inducing agents), vitamin K should be prescribed before delivery and for the newborn.

NB Carbamazepine, phenytoin and phenobarbitone all induce hepatic microsomal enzymes and increase metabolism of oestrogens and progestagens, making oral contraception unreliable.

Epilepsy and Driving

In the UK all patients with a history of seizures must report their condition to the Driver and Vehicle Licensing Agency (DVLA). Currently, for an isolated seizure, a 6-month ‘off driving period’ is stipulated providing the individual has undergone assessment by an appropriate specialist and no relevant abnormality has been identified on investigation. A 12-month ‘off driving period’ applies if there is deemed to be the potential for further seizures. Patients with a history of epilepsy must be seizure free for 1 year before being allowed to drive. More stringent regulations apply to licences for heavy goods or passenger-carrying vehicles (www.dft.gov.uk/dvla/drivers.aspx). Patients with sleep-related epilepsy may drive if they have an established pattern of seizures that have occurred only in relation to sleep during the previous 3 years.

Epilepsy and Employment

There are certain statutory employment restrictions for individuals with epilepsy, including in relation to the emergency and armed services, pilots and train drivers.

Epilepsy and Lifestyle

There are no ‘absolute rules’, but it is sensible to avoid heights/ladders, operating heavy machinery, working underground and activities such as unsupervised swimming until seizure control is established. Fires should be guarded and children should not be left in the bath unattended.

Prognosis in Epilepsy

The long-term prognosis of epilepsy is good, with most patients attaining a 5-year remission and many stopping treatment in due course. The decision to discontinue anticonvulsant therapy is determined by: type of epilepsy; duration of remission; potential deleterious effects of seizure recurrence (driving and employment) and side effects of treatment.

Stroke

The introduction and promotion of ‘diagnostic aids’ such as ‘FAST’ (Box 15.1) and ‘ROSIER’ (Fig. 15.1) have facilitated earlier assessment and treatment, including thrombolysis in selected cases.

Box 15.1 The Face, Arm and Speech Test (‘FAST’)

Facial weakness	Ask the person to smile or show their teeth.
	Look for an unequal smile or grimace – has their mouth or eye drooped or is there obvious facial asymmetry?
Arm weakness	Lift the patient’s arms together and ask them to hold the position for 5 s after you have let go.
	Does one arm drift down or fall rapidly?
Speech problems	Check for difficulties with speech.
	Can the person speak clearly and understand what you say? Is there any slurring of speech or difficulty finding words/naming common objects?
Time to call emergency services
Adapted from Harbison et al., Stroke 2003; 34: 71–76. Reproduced with permission from Wolters Kluwer Health.

---

Figure 15.1 The Recognition of Stroke In the Emergency Room scale (‘ROSIER’). BM = blood glucose; BP = blood pressure (mmHg); GCS = Glasgow Coma Scale; E = eye; M = motor; V = verbal component. Reproduced with permission from Elsevier. Nor et al., Lancet Neurology 2005; 4: 727–734.

Although the diagnosis of stroke is primarily clinical, CT scanning is required to reliably distinguish cerebral infarction from haemorrhage, and early scanning is therefore recommended in the majority of patients (on CT a low-density area appears within a few hours of a cerebral infarct, whereas a high-density area appears immediately after a bleed; brainstem, cerebellar and small cortical infarcts may not be visible). MRI is more sensitive for detecting ischaemic stroke, but takes longer to perform and requires greater cooperation from the patient. Immediate CT/MRI scanning is especially important if any of the following are present:

• indication for thrombolysis or early anticoagulation treatment
  
• on anticoagulant therapy or known bleeding diathesis
  
• reduced level of consciousness or unexplained progressive/fluctuating symptoms
  
• papilloedema, neck stiffness or fever
  
• headache at onset of symptoms.

Investigations to Establish the Aetiology

• full blood count (± ESR), coagulation (± thrombophilia) screen, urea and electrolytes, glucose/HbA1c, fasting lipids
  
• ECG
  
• chest X-ray
  
• echocardiography
  
• duplex imaging of the extracranial carotid and vertebral arteries

Less common causes of stroke should be considered, particularly in young patients and those without risk factors (serum protein electrophoresis, autoantibody screen, protein C, S and antithrombin III levels, sickle test, blood cultures, urine for homocystinuria). Angiography may be helpful in detecting cerebral vasculitis.

Early Management

Wherever possible, patients should be admitted as soon as possible to a specialist stroke unit, as research demonstrates significant improvements in outcome when patients are managed by a multidisciplinary specialist team. Thrombolysis with recombinant tissue plasminogen activator (alteplase) should be considered and commenced within 3 h of symptom onset for patients whose CT or MRI scan excludes cerebral haemorrhage. The efficacy of thrombolysis is highly time dependent and the decision to thrombolyse should be taken by a specialist stroke physician/neurologist.

For patients with haemorrhagic stroke, any predisposing coagulopathy (including warfarin therapy) should be immediately corrected. Neurosurgical intervention is only rarely indicated in acute stroke, e.g. for symptomatic hydrocephalus.

Once admitted to the stroke unit, further assessment/management includes:

• administration of aspirin 300 mg unless contraindicated; this is typically continued for 2 weeks after symptom onset, following which long-term antithrombotic therapy is instituted (see below)
  
• swallowing screen and institution of alternative feeding strategies if required
  
• malnutrition screen and nutritional support as required
  
• early mobilisation wherever possible
  
• specialist physiotherapy, occupational therapy and speech therapy input.

Prevention and Treatment of Complications

• Antithrombotic therapy: long-term aspirin (or clopidogrel) is indicated in most patients for secondary prevention. Anticoagulants should be considered for those with atrial fibrillation or other cardiac sources of emboli.
  
• Hypertension: in the longer term, good blood pressure control is crucial to reducing the risk of further cerebrovascular events. Unless there is evidence of hypertensive encephalopathy, hypertensive cardiac or renal failure, aortic dissection or pre-eclampsia/eclampsia, most physicians do not treat high blood pressure in the early stages following stroke for fear of lowering cerebral blood flow and exacerbating ischaemia.
  
• Chest infection: aspiration is common and treatment with antibiotics and physiotherapy should be started early.
  
• Deep venous thrombosis and pulmonary embolism: use graduated compression stockings and consider low molecular weight heparin prophylaxis.
  
• Pressure sores: avoidance requires careful positioning, regular turning and use of appropriate pressure-relieving mattresses.
  
• Urinary infections/septicaemia: especially in those requiring catheterisation.
  
• Seizures: (5% patients) may require treatment with anticonvulsants.
  
• Hyponatraemia: may complicate intravenous fluid use or reflect syndrome of inappropriate antidiuretic hormone secretion.

Venous Infarction

Transient Ischaemic Attack (TIA)

A scoring system such as ‘ABCD²’ may identify patients who need immediate specialist assessment (within 24 h) and those requiring assessment within 1 week (Table 15.3). A score of ≥ 4 is deemed ‘high risk’ (> 4% risk of stroke over the next week) and requires immediate referral to a specialist unit. For patients with a score of < 4, aspirin should be commenced immediately and the patient referred for specialist review as soon as possible.

Table 15.3 The ‘ABCD²’ Score for Assessment of risk of Stroke Following Transient Ischaemic Attack (TIA)

NB Scoring systems such as ‘ABCD²’ may fail to identify some ‘high risk’ patients (e.g. those suffering recurrent events (‘crescendo TIA’ = ≥ 2 TIAs in a week) or receiving treatment with anticoagulation) who merit urgent evaluation. In addition, their relevance to patients who present late is unclear.

Management

Acute Management

• Exclude hypoglycaemia: this is an important mimic of stroke/TIA – correct the blood sugar and reassess the patient.
  
• Confirm no ongoing/residual neurological deficit.
  
• Check full blood count (± ESR), electrolytes/renal function, glucose/HbA1c, fasting lipids, ECG.
  
• Commence aspirin (300 mg/day, unless contraindicated).
  
• Establish ‘high’ or ‘low risk’ – i.e. do they need specialist review within 24 h or within 1 week?

Specialist Management

• Confirmation of the diagnosis.
  
• Assessment/treatment of risk factors (e.g. hypertension, diabetes mellitus, dyslipidaemia, smoking, atrial fibrillation) and institution of secondary prevention measures/advice.
  
• Early pharmacological therapy.
  
• Timely referral for brain and carotid imaging.

Brain imaging is recommended when the diagnosis remains unclear, when the vascular territory affected is uncertain and the patient is a potential candidate for carotid endarterectomy, and to exclude intracerebral haemorrhage.

Diffusion-weighted MRI is the imaging modality of choice for patients with suspected TIA. It should be performed within 24 h of onset of symptoms if the patient is deemed at ‘high risk’ (‘ABCD²’ score ≥ 4) of subsequent stroke, and within 1 week in other cases. Patients with anterior circulation events who are deemed potential candidates for carotid endarterectomy should be referred for carotid imaging within 1 week.

Medical Treatment

Aspirin reduces the risk of stroke, myocardial infarction and vascular death in patients with a history of TIA. Clopidogrel is an alternative in those who are aspirin intolerant. In the absence of risk factors for cardioembolism there are no conclusive data to support the routine use of oral anticoagulants.

Surgical Treatment

The decision to perform carotid endarterectomy depends on several factors, including the severity of the stenosis and the extent of comorbidities. In centres with low surgical morbidity/mortality, endarterectomy is of proven benefit in patients with a severe stenosis (70–99% according to the European Carotid Surgery Trial (ECST) criteria) and should be undertaken within 2 weeks of symptom onset.

Extracerebral Haemorrhage

Dementia

Causes (Table 15.4)

Many diseases including infective, inflammatory, metabolic/endocrine and neurodegenerative disorders may predispose to cognitive impairment which may be reversible – hence the need to ascertain the underlying cause wherever possible.

Table 15.4 Causes of Dementia

Clinical Assessment

The history should include information from a knowledgeable relative or friend. A full physical examination and cognitive assessment should be performed.

Investigation

This is aimed at establishing the diagnosis and excluding treatable causes. The following should be considered:

• full blood count and ESR
  
• creatinine and electrolytes, glucose, liver, bone and thyroid function tests, vitamin B₁₂
  
• chest X-ray (for bronchial carcinoma)
  
• CT/MRI scan of the head.

In other patients additional investigations may be required, including:

• serological tests for syphilis and HIV (human immunodeficiency virus)
  
• functional imaging (e.g. with PET) may be useful in cases where diagnostic uncertainty persists
  
• EEG (useful if Creutzfeld–Jacob disease (CJD) or epileptic amnesia suspected)
  
• CSF analysis
  
• genetic testing (in patients with a relevant family history or appropriate clinical phenotype)
  
• tissue biopsy (very rarely indicated).

Alzheimer’s Disease

Alzheimer’s disease (AD) is the most common form of dementia in all age groups, with increasing prevalence with advancing age.

Aetiopathogenesis

AD is a neurodegenerative disorder. The so-called amyloid hypothesis proposes that altered metabolism of the transmembrane amyloid precursor protein (APP; genetic locus 21q21–22) results in the production of amyloid β-peptides (Aβ). Studies of patients with Down syndrome (trisomy 21) also support a pathogenic role for amyloid, where a ‘gene dosage effect’ has been implicated in early onset AD in this setting. Understanding of the pathogenesis of AD has been aided by the study of rare familial (autosomal dominant) cases, arising as a consequence of mutations in three different genes: APP, presenilin-1 and presenilin-2, all of which alter Aβ production. However, even when taken together, mutations in these genes account for < 1% of all AD. Susceptibility to AD is also conferred by genetic variation at other loci, the most important to date being the ε4 allele of the lipid transport protein apolipoprotein E (ApoE). Genome-wide association studies have identified other potential susceptibility genes, several of which may influence Aβ metabolism.

Two characteristic pathological features are found in the brain of patients with Alzheimer’s disease:

1. Senile plaques, consisting of extracellular deposits of Aβ.

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