1. immediately before (pre-ictal) the episode

2. during the event (ictus)

3. after the event (post-ictal).

A suggested method of history taking

Begin by asking the patient the following questions:

Keep asking questions in this manner until the entire episode has been described and there is a clear understanding of the exact nature and distribution of each and every symptom and the time course of the episode. Then ask the patient to describe another episode(s) using the same technique.

The value of such a painstaking approach is highlighted by the following cases seen by the author over the years.

Cases involving single episodes

On the surface this does appear to be an epileptic seizure preceded by an olfactory aura (see Chapter 8, ‘Seizures and epilepsy’, for further discussion of the term ‘aura’, which is used to describe the initial symptom(s) of a seizure, often referred to as the warning symptoms). However, this doctor was too quick in jumping to the diagnosis of epilepsy and used only the nature of the symptoms to make a diagnosis, recalling that some seizures are associated with an altered smell. The correct diagnosis was apparent when a detailed history was obtained.

The non-fluent dysphasia indicated involvement of the frontal speech area in the dominant hemisphere. The fact that she was right-handed meant it was most likely (90% chance) it was the left hemisphere. The sudden onset suggested a vascular, mechanical or an electrical problem. A more detailed history established that, in addition to the inability to speak, the patient had noticed that the jaw had clenched shut involuntarily during the episode. This is a positive phenomenon and indicates that the problem was a focal seizure affecting the speech cortex related to the meningioma and not a transient ischaemic attack (TIA). Positive phenomena such as transient jaw clenching do not occur with cerebral ischaemia.

Cases involving recurrent episodes or transient symptoms

In patients with recurrent episodes or transient neurological symptoms, establish whether all episodes were identical and whether the symptoms varied from one episode to another by asking: ‘Are all your turns the same or are some different to the others?’ If the episodes varied, it is more rewarding to ask about several individual episodes. This is most relevant in some patients with epilepsy who may have multiple types of seizures (see Chapter 8, ‘Seizures and epilepsy’). If the events were all identical, it is possible to use the approach of asking the patient to imagine having an episode right now in front of you and using the questioning technique described above to obtain a detailed description of each and every symptom. This approach could miss the diagnosis when the circumstances under which these episodes occurred provide the vital clue to the diagnosis. This is highlighted by the next two cases.

Note the same error: only the nature of the symptoms was obtained. The weakness in all four limbs combined with true vertigo (the room spinning), diplopia (double vision) and dysarthria (slurred speech) clearly points to involvement of the brain stem. The intermittent nature of the symptoms combined with the age of the patient suggests the diagnosis of vertebrobasilar insufficiency (VBI, transient cerebral ischaemia in the posterior circulation). To the experienced clinician the transient loss of consciousness (LOC) in two of the episodes is atypical and would raise doubts about this being primarily related to cerebral vascular disease. (LOC is extremely rare in patients with VBI. See Chapter 10, ‘Cerebrovascular disease’.)

A more detailed history obtained the vital clue.

The detailed description of the three individual events revealed that they all occurred with exercise, and cerebral ischaemia related to vascular disease does not occur in such a predictable manner.¹ Examination of the patient demonstrated severe aortic stenosis, and the explanation for her symptoms was exercise-induced hypotension due to poor cardiac output with initial selective involvement of the posterior circulation causing the focal symptoms and the subsequent global cerebral ischaemia resulting in LOC.

The patient described in Case 7.4 alerted this author to the importance of obtaining a blow-by-blow description of each of the episodes. She had recently been discharged from hospital without a clear diagnosis and after having undergone extensive investigation over a 2-week period. The patient was an 85-year-old woman who would be called in the trade ‘a poor historian’.

It was evident after 10 minutes that this line of questioning was getting nowhere and that a different approach was required. The remainder of the consultation went along the following lines.

After the patient described two further episodes it became clear that every one occurred about midday and only when she stood up. Six months beforehand she had been placed on prazosin, a drug for hypertension and one that is often associated with postural hypotension. Her blood pressure fell from 170/100 lying to 110/65 on standing and her symptoms resolved upon cessation of this drug.

In each of these four cases the crucial clue(s) were missed because a very detailed history was not obtained.

• fall (or slump if seated) or do not fall

• have a ‘blackout’ or they do not, whether they fall or not

• may or may not experience abnormal movements under any of these circumstances

• may experience episodes that vary in duration from seconds to minutes or even hours.

• the very rare prolonged tonic–clonic seizure lasting many minutes

• syncope with a prolonged aura

• a secondary head injury causing LOC complicating the fall, whatever the cause.

Falling with loss of consciousness

The four most common causes of transient LOC with falling are given in Figure 7.3. A complete summary of the numerous causes of transient LOC associated with a fall are listed in Table 7.1. Table 7.2 summarises the main clinical features of the common causes. Note that all are brief in duration.

Syncope (fainting, vasovagal or neurocardiogenic syncope)

Although syncope can afflict anyone of any age it tends to occur more commonly in young adults [2]. The patient is almost invariably standing, occasionally sitting and very, very rarely in a recumbent position. There is often, but not always, a trigger such as pain, alcohol, stressful situations, the sight of blood or being in a hot crowded environment.

Unlike epilepsy, many patients who suffer from syncope can prevent LOC by lying or sitting down quickly when they experience the warning symptoms. This is an important diagnostic clue. Where there is uncertainty advise the patient to lie down immediately when the episode next occurs to see if LOC can be prevented by elevating the legs so that they are above the level of the head. There is a very rare condition in elderly patients where syncope can be related to carotid sinus sensitivity [4].

Tonic–clonic seizures

Only a few brief principles are discussed here, as Chapter 8, ‘Seizures and epilepsy’, deals with the subject of epilepsy in detail.

Stokes–Adam’s attack

This predominantly occurs in the elderly, although very rarely Stokes–Adam’s attacks can occur in younger patients. These episodes are usually related to a bradyarrhythmia or complete heart block, although similar symptoms can occur with a tachyarrhythmia if it results in sudden hypotension [7].