Contemporary Neurology

Contemporary Neurology compiles a large series of papers on the commonest neurological problems. This book discusses the management of epilepsy, involuntary movements, nerve and muscle diseases, and multiple sclerosis. The areas on infections, cerebrovascular disease, trauma, intracranial pressure, and vertebral column are also elaborated. This text likewise describes medical procedures on how to do a lumbar and cisternal puncture. Other topics include headache in children, hyperventilation, dizziness, funny turns—neurological, dysarthria, facial pain, and nystagmus. The weakness of the legs, loss of memory, coma, brain death, complications of alcoholism, and stupor and akinetic mutism are also covered. This publication is valuable to clinicians and examination candidates preparing for the DPM, MRCP (UK) and Neurology/Psychiatry “Boards.

• Language: English
• Publisher: Elsevier Science
• Release date: Oct 22, 2013
• ISBN: 9781483182612

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Chapter 1

Headache

James W Lance,     The Prince Henry and Prince of Wales Hospitals and the University of New South Wales, Sydney, Australia

Publisher Summary

This chapter discusses the diagnosis of headache, which is a clinical problem usually solved by taking a careful medical history. Diagnosis depends on the recognition of the pattern of headache, the time and mode of onset, the nature of the associated symptoms, and the factors that precipitate, aggravate, or relieve it. The classification of headache that has the greatest practical application is one based on the length of time the headache has been troubling the patient and the pattern of recurrence. The headache that follows concussion must be distinguished from that of cerebral compression caused by an extradural or a subdural hematoma. The vascular headache associated with the exanthems of childhood or other generalized infections, or with acute sinusitis or a hangover, does not usually present any diagnostic difficulty. The first episode of migraine that is experienced in the life of a patient may give rise to unnecessary alarm, particularly if it is accompanied by focal neurological symptoms such as aphasia or unilateral paraesthesiae. As a general rule, any headache that has been present for more than 5 years is a muscular-contraction headache or migraine.

The diagnosis of headache is a clinical problem that is usually solved by taking a careful medical history. It does not depend upon the availability of electroencephalography, isotope brain scanning, or computerized axial tomography (CAT) except in the small number of cases where a brain tumour or similar lesion is suspected. In general, the shorter the history of headache the greater the reason for concern.

Diagnosis depends on recognition of the pattern of headache (its site, quality, frequency, and duration), the time and mode of onset and the nature of the associated symptoms, and the factors that precipitate, aggravate, or relieve it. For example, any headache that is made worse by coughing, sneezing or straining is associated with dilatation or displacement of intracranial vessels. The response to alcohol is useful in the differential diagnosis between chronic vascular headaches and those caused by muscular contraction (tension headaches). The latter are commonly improved by taking alcohol whereas the former are almost always made worse.

The classification of headache that has the greatest practical application is one based on the length of time the headache has been troubling the patient and the pattern of recurrence.

Acute single episodes of headache

This group includes the serious intracranial causes of headache such as subarachnoid haemorrhage, encephalitis, and meningitis, in which the headache is usually bilateral, of rapid onset, and associated with photophobia, impaired consciousness, and neck rigidity. It is for this group that hospital admission is usually urgently required and lumbar puncture is an important diagnostic test.

The headache that follows concussion must be distinguished from that of cerebral compression caused by an extradural or a subdural haematoma. Any patient who becomes drowsy after a head injury should be investigated. If one pupil starts to dilate or any other component of a third nerve palsy appears, investigation is a matter of urgency because this sign indicates that the brain is being forced downwards through the tentorial opening by an expanding lesion and is thus compressing the third cranial nerve. Immediate action must be taken by a neurosurgeon under these circumstances. Hours or even minutes may be of importance. Such a patient should not be subjected to lumbar puncture because the removal of CSF usually increases pressure on the midbrain from above and may cause death. CAT as an emergency procedure is helpful in this post-traumatic group.

The vascular headache associated with the exanthems of childhood or other generalized infections, or with acute sinusitis or a hangover, does not usually present any diagnostic difficulty. Sinusitis is sometimes not suspected when there is no obvious blockage of the nostrils. A constant unilateral frontal pain or a boring pain in the centre of the forehead should suggest infection of one frontal sinus or of the ethmoidal and sphenoidal sinuses, respectively. The onset of closed-angle glaucoma may also be neglected if a misting of the vision in one eye with unilateral ocular or frontal headache is dismissed as migrainous. A severe loss of central vision with retro-ocular pain suggests acute retrobulbar neuritis. Occasionally, pain may be referred to the eye and forehead from an acute compression of one of the upper four cervical roots as a result of cervical spondylosis.

The first episode of migraine that is experienced in the life of a patient may give rise to unnecessary alarm. particularly if it is accompanied by focal neurological symptoms such as aphasia or unilateral paraesthesiae. If the headache is on the side of the head consistent with the symptoms (for example a left-sided headache with right-sided paraesthesiae and aphasia), investigations are usually indicated even if the subsequent history shows that they were unnecessary. If the headache is on the inappropriate side (the right side in the above example), the chances are higher that the episode is migrainous and not caused by any intracranial lesion.

Acute headaches without neck stiffness may also be of intracranial vascular origin. Blood pressure may increase rapidly in acute nephritis, toxaemia of pregnancy, malignant hypertension, and the crises caused by phaeochromocytoma or by a patient on monoamine oxidase inhibitors taking sympathomimetic drugs or tyramine-containing foods. The blood pressure is usually secondarily elevated in patients with subarachnoid or intracerebral haemorrhage. Obstruction to the CSF pathways may also present as acute bilateral headache.

Acute recurrent episodes of headache

Some of the conditions mentioned above, such as sinusitis, pressor reactions, and acute internal hydrocephalus, may recur periodically. Repeated episodes of meningitis suggest the possibility of CSF rhinorrhoea. If clear fluid drips from the nostril when the head is bent forward, the fact that it is CSF rather than a nasal secretion can be determined rapidly by using a Clinistix to detect glucose in the fluid. The repeated recurrence of subarachnoid haemorrhage is most commonly caused by an intracranial (or occasionally intraspinal) angioma rather than an aneurysm because the bleeding is from the venous side of the angioma and hence the prognosis of each episode is better.

The headache resulting from cerebral vascular insufficiency is usually mild and the clinical picture is dominated by focal neurological symptoms of transient ischaemic attacks. The headache of internal carotid artery insufficiency is unilateral while an occipital headache accompanies vertebrobasilar insufficiency.

Intermittent hydrocephalus is a rare cause of recurrent headache but should be considered if the headaches are precipitated by bending forwards or are associated with obscured vision, impaired consciousness, myoclonic jerks, or weakness of the legs. The occurrence of headache only on physical exertion or coughing leads to the suspicion of an intracranial tumour, but some patients slowly improve and lose their headaches over a period of about 10 years without any intracranial lesion becoming apparent.

Migraine is the commonest of the acute recurrent headaches. There is often a reluctance to diagnose migraine unless the headache is unilateral, associated with nausea, vomiting and photophobia, and preceded by fortification spectra or other symptoms of neurological disturbance. This is the case in classic migraine but there are many more patients with common or nonclassic migraine in whom the headaches may be bilateral and severe but unaccompanied by any of the classic symptoms other than mild nausea. There are variations of migraine which may present difficulties, such as facial migraine, hemiplegic migraine, and vertebrobasilar migraine. In the last of these, brainstem symptoms such as vertigo and ataxia are associated with visual disturbance and a tendency to faint at the time of migraine headache.

The pattern of cluster headache is quite distinctive. This condition has been called migrainous neuralgia because of the unilateral distribution of pain, radiating upwards or downwards from one eye. It affects males more often than females, and occurs in bouts or clusters each lasting 2–8 weeks and recurring after weeks, months, or even years of freedom from headache. The severe pain appears once, twice, or more often during each 24-hour period and lasts between 15 minutes and 2 hours. It is characterized by watering of the eye and blockage of the nostril on the affected side.

Investigations are required in migraine or cluster headache only when the clinical history is atypical and it becomes necessary to exclude the presence of an aneurysm or other intracranial disorder.

Headaches of subacute onset

The development and progression in severity of headache in a patient who has never before been subject to headaches is always a cause for concern. If the pattern of headache is not typical of migraine or tension headache, the possibility of an intracranial lesion such as cerebral abscess or tumour or subdural haematoma must be considered. If the patient is drowsy, if the headache is aggravated by coughing or head movement, or if there is any neurological deficit, the chance of an intracranial lesion is much higher. Isotope brain scanning and CAT play a very useful part in the diagnosis of this group of disorders. In patients over the age of 55 years temporal arteritis must be excluded. The scalp arteries may be thickened and tender to palpation and the erythrocyte sedimentation rate is usually greater than 40 mm/h. The uncommon syndrome of benign intracranial hypertension as the result of hormonal changes, metabolic disorders such as hypocalcaemia, or drug idiosyncrasy may require full investigation to elucidate the cause.

Chronic headache

As a general rule, any headache that has been present for more than 5 years is a muscular-contraction headache or migraine. If there is no paroxysmal quality to the headache, so that it recurs every day like a tight band or pressure sensation, the diagnosis of muscular-contraction headache is almost certain. Such patients usually have an underlying state of anxiety or depression but it is important to exclude eyestrain or imbalance of the bite as causes of frowning or jaw clenching.

Conclusion

Most of the patients seen in general practice or in hospital require nothing more than a careful history and examination to establish the diagnosis (Table 1.1)with confidence. Special investigations are used sparingly for patients in whom the clinical picture suggests a progressive disease.

TABLE 1.1

The differential diagnosis of headache

(data from Lance, 1982)

References

Lance, J W. The Mechanism and Management of Headache, 4th edn. London: Butterworths, 1982.

Chapter 2

Headache in children

Judith M Hockaday,     John Radcliffe Hospital, Oxford

Publisher Summary

This chapter discusses some of the more common or more serious causes of headache in childhood. Although investigation by questionnaire is inaccurate, all studies of headache prevalence in children agree in finding it high. Headache is an accompaniment of fever of any cause. Drowsiness, irritability, and photophobia can occur in any child with fever. In subacute and chronic meningitis, headache is more insidious. In younger children with head injury, trauma may not be remembered and this is the case at any age when there is retrograde amnesia. Every child should have a skull X-ray, and his condition should be reassessed after an interval. The nature of the headache is less important as a guide to investigation than associated symptoms and signs and, most important, the general well-being of the child.

"Headache is a banal* symptom" (Northfield, 1968) for which there is always a reason.

Headache is common in childhood. The principles of diagnosis and management are essentially the same as in adults but there are some important qualifications. First, the younger the child the more likely it is that the headache is organic. Secondly, headache may be the only complaint in a child febrile from a systemic illness such as pyelonephritis. Thirdly, important historical detail, for example of head trauma, may be lacking. These difficulties are to some extent balanced by the advantages that young children rarely (and then inexpertly) assume symptoms they have not got, and that parents are usually keen observers and if asked will describe circumstantial details not so easily obtained from adult patients.

Headache is often judged according to whether it is an acute new symptom or one in a series of recurring attacks. There are obvious dangers in this approach in children. Earlier symptoms are frequently forgotten by the child or have not been noticed by the parents. More important is that the child and his parents, accustomed perhaps to migraine, may be slow to recognize the significance of symptoms of meningitis. Finally, in childhood, recurrent symptoms, however trivial, can interfere with normal development and schooling, so the risk of significant and possibly permanent harm is greater than in adults with comparable symptoms.

In this review only some of the more common or more serious causes of headache in childhood are discussed.

Incidence

Although investigation by questionnaire is inaccurate, all studies of headache prevalence in children agree in finding it high (Table 2.1). The corollary of this must be that almost always the complaint is trivial (Figure 2.1). However, in two different schools, Waters (1974) found that about 14 per cent of children with headaches had consulted their doctor and Sparks (1978) found that over 50 per cent of children with migraine had done so. This constitutes a sizable problem in the school health service and in general practice. The importance of the symptom is drawn in the analysis by Jerrett (1979) of 200 new patients of all ages presenting with headache to a group practice in Wales over 2 years: three were found to have cerebral tumour and two of these were children (age 8 and 11 years; Table 2.2).

TABLE 2.1

The incidence of headache and of migraine in schoolchildren (published series)

*Ascertained on differing criteria

†Same school

TABLE 2.2

Causes of headache among children in a series of 200 new patients (all ages) presenting in a general practice with headache or pain in the head

(data from Jerrett, 1979)

Figure 2.1 The occurrence and type of headache among 8993 schoolchildren in Uppsala, and percentage distribution between the ages of 7 and 15 ( Bille, 1968).

Acute headache in a previously healthy child

With constitutional upset

This is probably the commonest cause of headache in childhood. Headache is an accompaniment of fever of any cause (Dalessio, 1980). Usually, although it may be the only symptom voiced, headache is just part of a recognizable clinical picture, such as childhood exanthem or nasopharyngeal infection, which is revealed by full examination. Less commonly headache of this sort proves to be the first symptom of less overt chronic disorders, of which subacute bacterial endocarditis and brucellosis are important examples.

Intracranial infection

Drowsiness, irritability and photophobia can occur in any child with fever. They also, especially in a child with headache, suggest intracranial infection. If no satisfactory alternative explanation presents itself, then investigation is essential. Any delay in starting therapy in bacterial meningitis is critical (Swartz and Dodge, 1965) and with newer remedies may become so in viral encephalitis (Longson, 1980): headache is a common early (prodromal) symptom in herpes simplex encephalitis. Symptoms of raised pressure (vomiting or alteration of conscious level) or any evidence of focal neurological involvement suggests intracranial abscess and the need for immediate neurosurgical investigation. Failure to demonstrate an infection source does not rule out brain abscess; sometimes all that is found is sinusitis and in a fifth of cases the source remains unknown (Idriss et al, 1978).

In subacute and chronic meningitis, headache is more insidious. Tuberculous meningitis is now rare (although there have been four cases in this hospital in the last 2 years) but it has its highest incidence in boys between the ages of 2 and 4 years (Office of Populations, Censuses, and Surveys, 1978). In approximately a quarter of cases in this age group the length of history before admission exceeds 3 weeks (Fitzsimons, 1963). Anorexia and lethargy may be the only clues to the constitutional upset.

Trauma

In younger children with head injury trauma may not be remembered and this is the case at any age when there is retrograde amnesia. Every child presenting with headache must therefore be carefully examined for bruising. Nonaccidental injury should be considered if the circumstances are unclear (Franklin, 1975). If there is any doubt about the circumstances and if headache continues or increases or if there are any associated symptoms of neck stiffness, drowsiness, or vomiting, then the possibility of intracranial haemorrhage must be urgently pursued even if the head injury was slight. Very occasionally haemorrhage from an underlying vascular malformation is provoked by minor trauma.

Sometimes relatively minor trauma will cause disruption of CSF dynamics and lead to symptoms of headache, drowsiness, and vomiting for the first time in children with a previously balanced hydrocephalus either in relation to a space-occupying lesion or with so-called arrested congenital hydrocephalus (Gordon, 1977). The underlying diagnosis may then be obscured. Demonstration of a large head is an important guide to the latter possibility.

Head injury (sometimes without obvious fracture) is a known predisposing cause of pneumococcal meningitis in children (Swartz and Dodge, 1965), perhaps by spread of infection across disrupted meninges; this possibility should be considered in a child whose headaches start or increase a few days after head trauma.

Haemorrhage

Spontaneous intracranial haemorrhage is rare in childhood. The Carlisle survey (Brewis et al, 1966) did not identify any cases of subarachnoid haemorrhage in the 0–19 age group in a 5-year period, and in a review of the literature found that only eight (0.5 per cent) of 1624 patients with subarachnoid haemorrhage were under 10 years old. In a large series of childhood cases (Sedzimer and Robinson, 1973) the causes were rupture of saccular aneurysm (17), vascular malformation (16), and unknown (24). Typical presentation is with headache of increasing severity and unresponsiveness to analgesics, followed by deterioration of conscious level.

Recurrent or chronic headaches

Probably the majority of recurrent headaches in children are unexplained (migraine, muscle tension, or psychogenic) or are caused by relatively minor pathological lesions (ocular muscle imbalance or sinusitis). A few are the result of serious neurological disease (cerebral tumour or intracranial hypertension). The distinction is often difficult, and generally much more care has to be taken in children, and clinical investigation should be done more often and sooner than in adults (Heyck, 1968). Heyck considers that every child with recurrent headaches should have a skull X-ray (Heyck, 1968). A normal skull X-ray does not on its own, however, rule out brain tumour as a cause of headache.

Cerebral tumour

Although cerebral tumour is rare (average annual incidence 5.2/100000 population aged 0–9 years in the Carlisle study; Brewis et al, 1966) it is second only to leukaemia as a cause of childhood malignancy (deaths in 1978 in population aged 0–15 years in England and Wales: leukaemia 262, brain tumour 149; Registrar-General’s Annual Report, 1978). At all ages except infancy, headache is the most eloquent symptom of brain tumour (Heyck, 1968), especially of those in the posterior fossa (Northfield, 1938).

Some studies have found infratentorial tumours slightly commoner than supratentorial (Slooff and Slooff, 1975). Koos and Miller (1971) noted the incidence to be equal but varying with age, so that between 1 and 12 years posterior fossa tumours were more common. This, together with the observation that in childhood most tumours (whether above or below the tentorium) are localized to midline structures (83 per cent; Bergstrand et al, 1958), accounts for early interference with CSF circulation and the common finding in childhood that symptoms of raised intracranial pressure tend to precede localizing neurological features (Table 2.3).

TABLE 2.3

Incidence of early prominent, and initial, symptoms in 69 children with brain tumour

(modified from Table 2.2; data from Bergstrand et al, 1958)

The headache of brain tumour can be the result of local traction and of the indirect distorting effects of the hydrocephalus. This is generally present by the time of diagnosis: papilloedema existed on admission in 57 per cent of children with supratentorial and 64 per cent of those with infratentorial tumours (Bergstrand et al, 1958), and in 88 per cent of children with celebellar astrocytoma (Geissinger and Bucy, 1971).

There may not be any specific features about the headache of brain tumour. Localization is almost always frontal in supratentorial lesions (95 per cent) but also commonly frontal in infratentorial lesions (75 per cent; Northfield, 1938). The course can be intermittent with long remissions (Bergstrand et al, 1958) and the headache is often mild. Distinction from migraine or muscle tension headache is often not possible from the character of the headache alone. The circumstances in which it occurs are more helpful and include any cause of altered intracranial pressure such as cough, sneezing, straining, exercise, recumbent posture, and sleep; thus morning headache or headache that actually wakes a child can be ominous. The characteristics of brain tumour headache in 132 patients (all ages) are shown in Table 2.4.

TABLE 2.4

Characteristics of brain tumour headache in 132 patients

(data from Raskin and Appenzeller, 1980)

In older children associated warning symptoms are often absent or not noticed until vomiting supervenes. In younger children and infants headache at first presentation is more likely to be accompanied by irritability, restlessness, crying, dislike of having the head touched, a bulging fontanelle, head enlargement, and a cracked-pot note on skull percussion; papilloedema is uncommon in early infancy. Earlier, almost universal and therefore more important, accompaniments of raised intracranial pressure from cerebral tumour in childhood are the psychic changes: cerebration is slowed, learning is interfered with, and there may be change in personality, appearance of depression, increased fatigability, failure of attention, and apathy. There may be only a slowing of intellectual development rather than regression. In addition, slowing of growth and other endocrine effects can occur. Bed-wetting should arouse suspicion of diabetes insipidus.

The possibility of excellent outcome makes it all the more important to diagnose cerebral tumour in childhood. In a series of 238, Matson (1958) found that 46 per cent were histologically benign and that nearly half of these were cerebellar astrocytomas—a fully curable lesion in the majority of cases.

Benign intracranial hypertension

Intracranial hypertension without hydrocephalus or space-occupying lesion is well recognized in childhood; three new cases presented in this hospital in 1980. Grant (1971) reviewed 71 children aged 4 months to 14 years. The cause(s) is not understood (Reid et al, 1980), although many apparently provoking factors are recognized.

Hydrocephalus

The more severe forms of hydrocephalus and those associated with neural tube defects present in infancy, but some of the congenital and postinflammatory types may not present until well into childhood; poor intellectual and motor performance generally pre-date headache in such children, but their significance may not be fully appreciated unless the large head size is noticed. In some patients, for example those with narrowing of the aqueduct of Sylvius (whether previously shunted or not), there may be periodic decompensation and presentation with recurrent severe paroxysms of headache and vomiting. Others may have a more gradual build-up in pressure with low grade chronic headache, not always obvious in very young children.

Ocular causes of headache

Extraocular muscle imbalance with or without refractive error can cause ocular discomfort, with headache in and around the eyes and radiating to the frontal and temporal areas (Behrens, 1978). The frequency of headache attributable to these causes is probably overestimated, but ophthalmic examination is important in unexplained childhood headache. The commonest findings are uncorrected hyperopia, astigmatism, and convergency insufficiency. These are all easily correctable.

Sinusitis

Acute sinusitis is usually self-evident, and accompanying local pain and tenderness reveal the site of infection. Headache with catarrh or chronic sinusitis—especially frontal—is more difficult to evaluate; many turn out to be of muscle tension type in children with allergic rhinitis (Birt, 1978). Finally nasopharyngeal malignancy, although very rare, can occur in children.

Other

Other important conditions that may present as recurrent headaches include arterial hypertension, phaeochromocytoma, psychomotor and other forms of epilepsy (Swaiman and Frank, 1978), and insulinoma. The relationships between hypoglycaemia and headache are discussed by Hockaday (1975).

Unexplained recurrent headaches

Most studies agree in regarding unexplained recurrent headaches in children as most likely to be migraine or the headache of muscle tension. Headache as a true psychogenic (or conversion) symptom is rare before puberty. The common school refusal morning headache should not be regarded in this way nor should imitative headache—both are common expressions of normal childhood behaviour. Occasionally, unexplained headache is a manifestation of depression in childhood.

Migraine

Migraine is a clinical diagnosis (World Federation of Neurology, 1969; Table 2.5) and the only essential criterion is recurrent headaches. It is overdiagnosed or underdiagnosed according to which of its many characteristic features are regarded as prerequisites (Pearce, 1969). So far, epidemiological studies give little evidence that these actually identify a distinct syndrome (Waters, 1973). Usually, migraine is diagnosed by identifying recurring headaches which are unilateral, associated with nausea, and preceded by focal neurological aura. This is difficult at first presentation in childhood when symptoms are often overshadowed by accompanying abdominal pain or are not accurately reported and when, because headache always arouses concern, referral is likely to be made before a recurring pattern is clear.

TABLE 2.5

Definition of migraine

A familial disorder characterised by recurrent attacks of headache widely variable in intensity, frequency and duration. Attacks are commonly unilateral, and are usually associated with anorexia, nausea and vomiting. In some cases they are preceded by, or associated with, neurological and mood disturbances.

All the above characteristics are not necessarily present in each attack or in each patient.

(World Federation of Neurology, 1969)

A simpler approach is to accept all recurrent headaches that are clearly paroxysmal as migraine, provided that there is return to full normal health between attacks and that other causes of headache have been excluded. In one study where cases were selected on this basis (Hockaday, 1979) it was found that one or more of three chief features identifying migraine were actually present in almost every case (Table 2.6), and that the headaches in the remainder appeared in no way different.

TABLE 2.6

Characteristic features of migraine in 122 children with headache

(data from Hockaday, 1979)

It is most important to note that there is no clear-cut line dividing migraine from symptomatic headache and ultimately the diagnosis rests on exclusion of other causes. The diagnosis in childhood should not be made on the basis of one visit, but only after a period of observation has shown that growth, behaviour, and intellectual development are proceeding normally (or after full investigation has excluded a neurological cause).

Another special factor in childhood migraine is that the relationship between headache and schooling is complex. Information about this must always be obtained before final appraisal of unexplained headache (Table 2.7). The school will at any rate almost certainly need to be involved in management if migraine is diagnosed. Enquiry may reveal bullying or a specific cognitive failure as the real cause of the child’s referral and attention to this often leads to remission without medication.

TABLE 2.7

Relationships between headache and school failure

Two further points arise in children. The first is the danger of accepting a parental history of migraine as any guide to diagnosis. The evidence favouring a hereditary factor is substantial (Raskin and Appenzeller, 1980), but Waters (1971) could not show a significantly higher prevalence of migraine in the families of migraine subjects than in those either of nonmigraine subjects or of headache-free controls. The other difficulty is when to investigate for an underlying vascular malformation. Occasionally, patients found in later life to have such a lesion have had headaches from early childhood, but they are usually distinguishable (Lees, 1962). In one large series of 500 patients presenting with headache of vascular type, no example of a vascular malformation was found (Selby and Lance, 1960). The possibility should be considered if headaches are always confined to, or maximal, on the same side, if the aura is stereotyped or shows a march, or if there are any abnormal neurological signs or a cranial bruit.

Among studies (mostly by self-administered questionnaire and based on differing diagnostic criteria) in healthy groups of children, widely different prevalence rates (Table 2.1) are found. Even at the lowest estimate migraine is common. This is borne out by the early age of onset described by most adults presenting with migraine. Selby and Lance found 21 per cent onset before 10 years and 25 per cent between 10 and 20 years. In a childhood series, Hockaday (1979) found onset by age 7 years in 62 per cent and by age 10 years in 86 per cent. Congdon and Forsythe (1979) had similar findings. Onset in infancy is well known but diagnosis is then best made only retrospectively. All series in younger childhood show a higher incidence in boys.

The clinical features of migraine in schoolchildren are well summarized by Sparks (1978), and are compared with those in adults by Prensky (1976; Table 2.8). Basilar artery migraine with posterior cerebral and brainstem symptoms is a common form of classical migraine in childhood (Table 2.9), constituting at least 24 per cent of all cases in one series (Hockaday, 1979). Migraine can present as an acute confusional state (Ehyai and Fenichel, 1978). Classic migraine can be triggered, typically in young men, by minor blows to the head as in footballer’s migraine (Matthews, 1972), but other more severe neurological syndromes (hemiparetic, amaurotic, and somnolent-irritable) which are probably migraine can follow minor head trauma in younger children (Haas et al, 1975). Other special forms of migraine are well recognized in childhood, for example familial hemiplegic migraine (Glista et al, 1975) and ophthalmoplegic migraine (Raymond et al, 1977).

TABLE 2.8

A comparison of migraine in children and adults

(Prensky, 1976; data from 12 published series)

TABLE 2.9

Distribution into common and classical migraine, and site of origin of aura, in 122 children with headaches

(data from Hockaday, 1979)

It has been suggested that there is a migrainous basis for some other recurrent disorders of childhood where headache may be a feature, such as the so-called alternating hemiplegia syndrome (Krageloh and Aicardi, 1980) and transient global amnesia (Jensen, 1980). The links with cyclical vomiting (Reinhart, 1977), recurrent vomiting of childhood (Hammond, 1974), and recurrent abdominal pain (Christensen and Mortensen, 1975) are not established. Migraine and epilepsy, both common disorders, sometimes coexist (Lancet, 1969) but in addition there may be an association between the two conditions and certainly apparently intermediate cases, with prominent headache, arise (Serratrice et al, 1973).

The outlook for permanent cessation of attacks of migraine is not very optimistic; however, long remissions can occur (Hinrichs and Keith, 1965) and boys particularly may outgrow their attacks (Hockaday, 1978).

If possible, treatment should be restricted to mild analgesics; if specific prophylaxis is really essential, propranolol is probably the most satisfactory remedy in childhood (Børgesen, 1976). Most attention should be directed to removing the causative factors.

If symptoms continue despite treatment, the diagnosis of migraine must be reconsidered.

Tension headache

There is a tendency, because of lack of clear definitions, to assume that unless there is organic disease or the specific features of migraine, the diagnosis must be headache caused by muscle tension. The distinction can be difficult and, importantly, may not be very real (Raskin and Appenzeller, 1980).

Typically the pain of muscle tension headache is nonparoxysmal, very frequent, bilateral, and described as like a band or heavy weight or fullness. Often the child is pale and anorexic, but vomiting is rare. The response to analgesics may be unsatisfactory. Ill-defined dizziness is common, but in children care should be taken to distinguish true vertigo. The main characteristics of tension headache and migraine are compared in Table 2.10: the overlap is considerable. For practical purposes, and especially in children where the management of the two conditions is very similar (with emphasis on removal of anxiety in both), the distinction between muscle tension headache and migraine is less important than distinguishing both from other causes of headache. The provoking factors are very similar and both forms of headache often coexist.

TABLE 2.10

Characteristics of migrainous and tension headaches in 2000 cases

(modified from Figure 1; data from Friedman et al, 1954)

Investigation in a child with unexplained headaches

1. Every child should have a skull X-ray, and his condition should be reassessed after an interval

2. Every headache that interferes with ordinary activity must be seriously regarded unless or until it is shown to follow a pattern acceptable as migraine.

Investigation should be pursued if

1. Headaches are not relieved by mild analgesics

2. There are any accompanying focal symptoms, alteration of consciousness, or relationship to posture, straining, exercise, or sleep

3. The frequency or severity increases

4. There is any change in the child’s personality, behaviour, or performance

5. The child fails to grow physically or to advance in intellectual and motor development

6. The centile of head growth exceeds that of height

7. There is a cranial bruit

8. The child is under the age of 5 years.

The nature of the headache is less important as a guide to investigation than associated symptoms and signs and, most important, the general well-being of the child.

References

Behrens, M M. Medical Clinics of North America. 1978; 62:507.

Bergstrand, C G, Bergstedt, J, Herrlin, K M. Acta paediatrica. 1958; 47:688.

Bille, B. Ibid. 1962; 51

Bille, BVinken, P J, Bruyn, G W, eds. Handbook of Clinical Neurology; 5. North-Holland Publishers, New York, 1968:239.

Birt, D. Medical Clinics of North America. 1978; 62:523.

Borgesen, S E. Postgraduate Medical Journa. 1976; 52

Brewis, M, Poskanzer, D C, Rolland, C, Miller, H. Acta neurologica Scandinavic. 1966; 42

Christensen, M F, Mortensen, O. Archives of Diseases in Childhood. 1975; 50:110.

Congdon, P J, Forsythe, W I. Developmental Medicine and Child Neurology. 1979; 21:209.

Dalessio, D J. Wolff’s Headache and Other Head Pain, 4th edn. London: Oxford University Press, 1980.

Dalsgaard-Nielsen, T, Engberg-Pedersen, H, Holm, H E. Danish Medical Bulletin. 1969; 17:138.

Ehyai, A, Fenichel, G M. Archives of Neurology. 1978; 35:368.

Fitzsimons, J M. Tubercle. 1963; 44:87.

Franklin, A WConcerning Child Abuse. Edinburgh and London: Churchill Livingstone, 1975.

Friedman, A P, Von Storch, T J C, Merritt, H H. Neurology. 1954; 4:773.

Geissinger, J D, Bucy, P C. Archives of Neurology. 1971; 24:125.

Glista, G G, Mellinger, J F, Rooke, E D. Mayo Clinic Proceedings. 1975; 50:307.

Gordon, N. Developmental Medicine and Child Neurology. 1977; 19:540.

Grant, D N. Archives of Diseases in Childhood. 1971; 46:651.

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*Commonplace, trivial (Shorter Oxford English Dictionary)

Chapter 3

Funny turns—neurological

T Fowler,     Brook General Hospital, London

Publisher Summary

This chapter elaborates about the transient episodes of disturbed neurological function where there is brief loss of consciousness or altered awareness. Vasovagal or syncopal episodes are the most common types of simple faint and arise from a fall in cerebral blood flow. Difficulties arise if a patient becomes incontinent in an attack, as may occur if the bladder is full. Many patients show a relatively low blood pressure and it is worth checking the blood pressure with the patient standing and lying to see if there is a significant postural drop. In the elderly, basilar ischemia may arise with complaints of vertigo, drop attacks, visual upsets (perhaps bilateral), diplopia, dysarthria, or even alternating hemipareses or hemisensory disturbances. The other main cause of transient loss of consciousness is epilepsy. The diagnosis of patients with disturbed awareness or loss of consciousness rests on the description of the attack.

Patients differ in their interpretation of neurological symptoms and it is important to establish what they understand by their complaint. For example, a blackout may indicate loss of consciousness or loss of vision. This chapter considers transient episodes of disturbed neurological function where there is brief loss of consciousness or altered awareness. Table 3.1 outlines some of the causes. Prolonged loss of consciousness is not covered, nor are mechanisms of purely focal neurological disturbance as may occur in some transient episodes of cerebral ischaemia.

TABLE 3.1

Causes of transient episodes of disturbed consciousness or awareness

Drop in cerebral perfusion

Simple faints

Vasovagal or syncopal episodes are the most common types of simple faint and arise from a fall in cerebral blood flow. There are many triggers (for example) injections, pain, and blood loss) and the circumstances leading to the attack often aid diagnosis (for instance in the case of an adolescent standing in a crowded school assembly). Usually patients are aware of warning symptoms from the lowered cerebral perfusion. These may include visual disturbance with blurring vision, hearing upset with sounds becoming muffled or distant, giddiness, and feelings of faintness. They may also be associated with feelings of heat or cold and with perspiration. Many patients recognize such warnings and by taking avoiding action (such as lying down or putting their head between their knees) may prevent loss of consciousness.

Difficulties arise if a patient becomes incontinent in an attack, as may occur if the bladder is full. Furthermore, a patient who faints and is propped up or supported in an upright position may suffer more prolonged cerebral anoxia. This sometimes leads to features suggestive of a fit (such as stiffening, twitching, convulsions, or incontinence), although such patients are not epileptic.

Many patients show a relatively low blood pressure and it is worth checking the blood pressure with the patient standing and lying to see if there is a significant postural drop. If this is present it may suggest an autonomic neuropathy (as in some diabetics) or that the patient is being treated with certain drugs (particularly hypotensives).

Micturition syncope

This describes a loss of consciousness that occurs usually in men emptying their bladders at night. Its recognition and the advice to empty the bladder at night while sitting may prevent further attacks.

Carotid sinus syncope

This may occur in middle-aged and older patients with a hypersensitive carotid sinus (Hutchinson and Stock, 1960). Stimulation of this by head turning in a tight collar or by digital massage may produce temporary asystole with loss of consciousness. Patients should be tested lying down.

Cough syncope

This sometimes follows bouts of prolonged coughing which interfere with venous return to the heart and stimulate baroceptors, reflexly causing a drop in cerebral perfusion. Such cardiac aspects are covered in another article. However, cough seizures may also appear in patients with cerebral lesions associated with tumours or vascular disease (Morgan Hughes, 1966).

Basilar ischaemia

Migraine

This, particularly in the basilar territory, may cause impairment of consciousness (Bickerstaff, 1961). Such patients, commonly adolescent girls or young women, usually have warning with the development of visual symptoms, ataxia, dysarthria, tingling in the face or limbs, or confusion. These may be followed by a loss of consciousness that is slow in onset and usually lasts only a few minutes. On recovery there is commonly an intense throbbing headache, often occipital in site. The warning symptoms suggest basilar ischaemia and many patients also have a history of more classic prostrating hemicranial headache with associated vomiting.

Thromboembolic

In the elderly, basilar ischaemia may arise with complaints of vertigo, drop attacks, visual upsets (perhaps bilateral), diplopia, or dysarthria, or even alternating hemipareses or hemisensory disturbances. Some attacks may suggest a mechanical link being triggered by head turning but in many fibrin-platelet emboli may be responsible. The latter may arise from atheromatous plaques in the extracranial arteries. Emboli may also arise from a mural thrombus in the heart. The prognostic importance of recognizing such attacks lies in the fact that they may herald a more catastrophic stroke.

Transient global amnesia

This may also arise from cerebral ischaemia. Usually older patients or their relatives describe episodes of confusion for which patients have complete amnesia. These may last hours and some appear to be precipitated by exercise. Personal identity is retained but commonly patients repeatedly ask what they are doing, where they are, or what time it is. Occasionally, repeated attacks may leave a permanent memory deficit.

Epilepsy

The other main cause of transient loss of consciousness is epilepsy. Many different patterns of epileptic seizure are recognized and a number of classifications have been proposed (Parsonage, 1979). Basically these aim to differentiate seizures that are generalized (centrencephalic) from those that are partial or focal (Table 2.3). There is overlap because many seizures that start focally may spread and become generalized. However, the importance of partial epileptic seizures is that they suggest a local site of origin where a structural lesion may lie, for instance an area of scarring, tumour, or malformation.

TABLE 3.2

Classification of epileptic seizures

*Note that partial seizures may become generalized

(data from Parsonage, 1979)

Grand mal

The commonest form of epileptic seizure is a grand mal (tonic/clonic, major) attack. If witnessed, it is easy to recognize from the convulsive features and the duration. If not witnessed, often the absence of warning and the sequelae—incontinence, tongue biting, postictal confusion, headache, injuries, and drowsiness—may give strong support to the diagnosis.

Temporal lobe

The second most common type of epileptic seizure is due to temporal lobe epilepsy. This involves complex partial seizures. Here there may be a wide variety of warning auras. These include cognitive upsets with memory changes—familiarity (déjà vu) or unfamiliarity (jamais vu)—and psychosensory disturbances with hallucinations of smell or taste (usually unpleasant) or of hearing or vision (either simple or complex), vertigo, and affective upsets (with feelings of acute anxiety, panic, or fear). Acute anger as an ictal event is rare. However, a proportion of patients with temporal lobe epilepsy have outbursts of seemingly uncontrolled aggressive behaviour for which they may show little or no remorse (Lishman, 1978).

The auras may be accompanied by a typical epigastric aura rising to the throat. Usually there is a fairly brief loss of awareness, with staring but without falling. Motor disturbances include simple facial movements such as grimaces, lip smacking, swallowing, or chewing. Patients may drop what they are holding, pluck at their clothes with their hands, or show brief limb shaking. Sometimes they walk about or perform more complex movements. Usually they break off speech or make nonsensical utterances. These features are very brief but may be followed by a longer period of confusion.

Ictal and postictal motor automatisms may occur: patients perform actions, usually out of context, of which they have no recollection. Such automatisms can lead to medicolegal problems, particularly if theft is alleged to have occurred during the episode. Automatisms are brief, commonly lasting less than 5 minutes (80 per cent of cases in the series of Knox, 1968). Furthermore, some two thirds of patients with temporal lobe epilepsy also have major epileptic seizures.

Focal

In focal epilepsy, simple partial seizures produce symptoms related to their cerebral site of origin. Jacksonian motor seizures arise in the motor strip and start with involuntary movements in the thumb, big toe, or corner of the mouth. These then spread, either to one side or become generalized. Many patients do not lose consciousness unless the attacks become generalized. Postictally there is often a transient hemiparesis (Todd’s paralysis). Sensory attacks may show a similar distribution anatomically with complaints of tingling, altered sensation, shocks, and even pain and distortions of body image. Again there may be no loss of consciousness. Such sensory attacks may be difficult to differentiate from transient ischaemic episodes. Transient sensory symptoms may also appear in patients with multiple sclerosis. These symptoms are commonly associated with brief episodes of speech disturbance and unsteadiness, sometimes accompanied by complaints of a woolly head or dizziness (Espir et al, 1966).

Seizures arising in the frontal lobe may cause turning of the eyes and head away from the site of origin (aversive attacks) and if the discharge spreads posteriorly the contralateral arm may be involved. Some attacks have auras similar to those of temporal lobe epilepsy. Unusual variants, often of temporal lobe origin, include laughing, crying, and running epilepsy.

Petit mal

True petit mal occurs in children, usually between the ages of 5 and 15. The episodes or absences consist of brief loss of awareness usually accompanied by staring. They last 5–15 seconds and as patients recover they may blink. They do not fall. It is important to differentiate these attacks from temporal lobe epilepsy and other minor forms of epilepsy because too often many of these variants are mislabelled petit mal. Most petit mal attacks cease as patients grow older but in a significant proportion they may be replaced by more major seizures. Petit mal status may occur where successive attacks produce a confused unsteady child, often with slurred speech and salivary dribbling.

Minor

Minor seizures describe attacks of varying pattern. Many lead to diagnostic difficulties. Commonly there is transient loss of consciousness or awareness. Gowers (1901) described 155 such patients. In nearly one third there was sudden falling with loss of consciousness of brief duration but no convulsive features. Nearly one third had sensations suggestive of brief auras common to partial complex seizures, 16 per cent complained of giddiness, and 11 per cent experienced jerks or starts in the limbs. Some of these attacks would now be labelled drop attacks or myoclonic jerks.

Myoclonic jerks or starts may herald a more major attack or arise alone, often shortly after waking. Sometimes they are so forceful that they throw the patient (commonly a child) to the ground. Myoclonic jerks may follow anoxic brain damage or uraemia and may occur in rare progressive degenerative forms of brain disease and in Jakob–Creutzfeldt disease.

A salaam attack, infantile spasm, hypsarrhythmia, or West’s syndrome describes a type of seizure that affects babies and commonly starts between the ages of 3 and 9 months. The baby flexes the body in a salaam, drawing up the legs. These attacks are repeated. There are a number of prenatal, perinatal, and postnatal causes but there is a high incidence of mental retardation in these children and many of them develop other forms of epilepsy.

Breath-holding attacks in children

In children between the ages of 6 months and 3 years breath-holding attacks may cause diagnostic difficulties. Here a frightened or frustrated child starts to cry. Suddenly breathing appears to stop and after a few seconds the child becomes cyanosed and limp; this is followed by clonic jerking. A further type triggered by pain or fear may produce pallor, collapse, and asystole. These are not epileptic attacks: the EEG is normal and they are self-limiting.

Intermittent obstructive hydrocephalus

There are also a number of rare neurological conditions that may produce disturbed awareness or consciousness. Intermittent obstructive hydrocephalus may induce attacks of loss of consciousness preceded by crescendo headache or episodic sudden weakness of the legs with falling but no loss of consciousness (Northfield, 1973). This may occur for example when a colloid cyst of the third ventricle obstructs the foramen of Monro. Usually such patients have signs of elevated intracranial pressure and some show mental changes.

Trauma

Head injuries may cause brief loss of consciousness. Furthermore, they may cause amnesia for the actual injury and this may lead to diagnostic difficulties.

Prostrating vertigo

Such attacks are commonly accompanied by nausea, vomiting, and fear. In severe episodes there may be falling and disturbed awareness.

Cryptogenic drop attacks of women

Drop attacks sometimes occur in middle-aged women causing them to fall suddenly without warning. They may sustain injuries in such falls and extensive investigations show no abnormality. These have been labelled benign cryptogenic drop attacks (Stevens and Matthews, 1973). They do not respond to anticonvulsants or anticoagulants and often settle spontaneously.

Narcolepsy

This causes brief episodes of an overwhelming desire to sleep. The age of onset is commonly 15–35 years and there may be a family history. Such patients usually show disturbed nocturnal sleep (Zarcone, 1973). During attacks they are easily aroused and there are no sequelae. In some patients attacks are associated with cataplexy, sleep paralysis, and hypnagogic hallucinations. True narcolepsy responds to amphetamine derivatives.

Metabolic causes

Metabolic disturbances rarely may present with neurological symptoms.

Hypoglycaemia

This usually follows insulin overdosage, less commonly oral hypoglycaemic drugs, and very rarely insulinomas. Generally the blood glucose level is less than 2 mmol/litre and this may cause symptoms that are mistaken for alcoholic intoxication. They include disturbed behaviour, confusion, irritability, slurred speech, unsteadiness, diplopia, and even focal limb weakness. The low blood glucose level also stimulates adrenaline release causing sweating, pallor, fear, palpitations, tremor, and even circumoral tingling. A blood glucose level taken during an attack confirms the diagnosis and patients respond to 20–40 ml of 20 per cent glucose given intravenously (Turner et al, 1981).

Hypocalcaemia

This may follow parathyroid gland loss, malabsorption, or vitamin D deficiency. It may present with mental symptoms—anxiety, depression, and even hallucinations. Many patients complain of muscle stiffness, tetany, cramps, and tingling in the extremities and around the mouth. Some patients may show papilloedema and cataracts. A serum calcium level of less than 2 mmol/litre suggests the diagnosis and such low levels may trigger epileptic fits. In an acute attack 10–20 ml of a 10 per cent solution of calcium gluconate administered intravenously may reverse the symptoms.

Hyperventilation

Hyperventilation may also cause tingling in the extremities and around the mouth. If it is continued, muscular twitching, carpopedal spasm, and loss of consciousness may follow. A trial with overbreathing may provoke an attack.

Hysteria

Patients with hysteria may present with episodes of claimed loss of consciousness. These may be difficult to diagnose, particularly since some patients with true epileptic seizures also have hysteroid attacks. Many such patients show hysterical features and are immature and dependent with a past or family history of psychiatric illness.

The attacks themselves are often bizarre with marked opisthotonos and forceful movements. The severity of the latter may appear proportional to the degree of restraint. Incontinence and tongue biting do not occur. The plantar responses remain flexor. During an episode it may prove difficult to open the patient’s eyelids and if they are opened the eyes turn towards the ground even if the patient is turned from side to side (Henry and Woodruff, 1978). Usually trained observers can differentiate true from hysterical seizures, but if there is doubt Trimble (1978) has shown that after true major seizures there is a significant rise in the serum prolactin level 15–25 minutes postictally. Such a rise does not follow hysterical attacks. Where diagnostic difficulty remains, inpatient observation with if necessary continuous EEG telemetry and simultaneous video recording on closed circuit television usually differentiates true from false attacks (Bowden et al, 1975).

Investigation and management (Table 3.3)

The diagnosis of patients with disturbed awareness or loss of consciousness rests on the description of the attack. The account of an eyewitness is the most important evidence. This may be supported by the patients’ own observations. In most patients neurological examination shows no abnormality. In a few there may be focal neurological signs or those of elevated intracranial pressure indicating the need for further investigation. Rarely patients may show skin stigmata or asymmetries of limb size—the latter may indicate a degree of cerebral hemiatrophy. General examination should always include a full assessment of the circulation and a search for any primary neoplasm.

TABLE 3.3

Tests used to investigate patients with loss of consciousness or impaired awareness

*If indicated

In attacks where diagnostic doubt remains, various investigations may be necessary and these may also be indicated where the question of cause arises, particularly in epilepsy of later onset. To some degree the extent of the investigations is linked with the reliability of the diagnosis, the age of onset, and the severity of the complaint (Fowler, 1980).

Simple screening investigations include a blood sample, a urine sample, X-rays of the skull and chest, and an EEG. If there is diagnostic doubt then the blood sample should include a full blood count, erythrocyte sedimentation rate, blood glucose (preferably taken during an attack), urea, electrolytes, and calcium levels, liver function tests, and Wassermann reaction (or equivalent). Urine should be tested routinely and for porphyrins. In infants an amino-acid chromatogram and more detailed tests for sugars in the urine may be necessary.

An ECG at rest detects disorders of rate and rhythm but recognition of paroxysmal disorders may require a 24-hour ambulatory tape (McAllen and Marshall, 1973; Goldberg et al, 1975).

An EEG may prove helpful although this has its limitations. Many patients with epilepsy have so-called normal interseizure records so a normal trace does not exclude epilepsy. Conversely some 10–15 per cent of the population with no history of seizures may have an abnormal record. However, a spike focus or paroxysmal discharges give strong support to the diagnosis of epilepsy and in certain conditions such as petit mal the typical 3/s spike-and-wave pattern may confirm the diagnosis. A slow-wave focus may indicate a structural lesion such as a tumour or abscess and suggests the need for further investigation. The EEG may appear diffusely abnormal in metabolic disturbances and occasionally be diagnostic, for example in Jakob–Creutzfeldt disease.

Plain X-rays of the skull may show intracranial calcification, the features of raised intracranial pressure (an eroded dorsum sella), or even asymmetries in the vault size which might support the presence of a long-standing hemiatrophy. In adults a chest X-ray may indicate primary lung pathology, metastases, or abnormalities of the cardiac contour.

If there is any suspicion of an underlying structural lesion a CT brain scan is the investigation of choice. This shows tumours (Figures 3.1 and 3.2), abscesses (Figure 3.3), areas of scarring as from infarcts (Figure 3.4), and atrophy. Where CT scanning is not available isotope brain scans show most meningiomas, abscesses, and metastases.

Figure 3.1 CT brain scan showing a right-sided sphenoid wing meningioma. This patient gave a history of classic temporal lobe seizures. (Courtesy of Dr C. Penney)

Figure 3.2 CT brain scan showing a tumour producing swelling in the corpus callosum and displacing the frontal horns. This was a glioma. The patient gave a history of aversive attacks accompanied by mental slowing and papilloedema. (Courtesy of Dr C. Penney)

Figure 3.3 CT brain scan showing a biloculated cerebral abscess with ring enhancement situated in the posterior part of the right hemisphere. There is surrounding oedema. This patient presented with headache, drowsiness, a hemianopia, focal fits, and progressive left-sided signs. (Courtesy of Dr C. Penney)

Figure 3.4 CT brain scan showing a low density area in the right parieto-occipital region. This was an infarct. The patient presented with late onset epileptic seizures and mild focal signs. (Courtesy of Dr C. Penney)

In cases where epileptic seizures might be the presenting symptom of meningitis, an encephalitis, or a subarachnoid haemorrhage, examination of the CSF is necessary. In the very young and very old meningism is sometimes minimal.

In patients with proven epileptic seizures who have had more than one attack and in whom any trigger factor has been eliminated and any reversible cause treated, control of the seizures with anticonvulsants is necessary.

Most types of seizure can be controlled by the use of a single anticonvulsant preparation in an appropriate dose (Reynolds, 1978; Shorvon et al, 1978). Most drugs can be given twice daily and some once daily which greatly aids compliance. Usually the smallest dose that provides effective control is used (Table 3.4). If that fails the anticonvulsant level in the blood should be checked. If it is below the therapeutic level (Table 3.4) the dose should be increased providing patients are known to be taking their tablets.

TABLE 3.4

Anticonvulsant drugs; first-choice indications are in italics

*Varies with the dose

†Primidone is broken down into phenobarbitone and phenylethylmalonamide

**Considerable variation between different reports

All anticonvulsants may have side effects: dose-related intoxications, allergic manifestations, or (rarely) more serious toxic effects such as marrow depression or liver damage. However,