- This has been a digression from the main
theme of our discussion. Vaso-vagal attacks are
not faints, nor are they in any ordinary sense
fits, but the observations which I have put
forward support Kinnier Wilson's argument that
they may be epileptic.
-
- Perhaps the most important distinction
between faint and fit is the setting of the
attack. Faints very rarely occur except in the
erect posture. If an attack occurs after long
unaccustomed standing, or as the result of
sudden emotion or pain, in a hot and stuffy
atmosphere, or aftet loss of blood, it may be
presumed to be a faint unless there is evidence
to the contrary. If it occurs without any of
these causes it is probably a fit. Yet again,
however, the distinction is imperfect. Epileptic
attacks may be precipitated by various causes of
which emotion is one. The malaise of infection
may be another. In the following case both
precipitants were evident.
-
- The patient was a man of 61, whom I saw for
an entirely different complaint, and the details
which follow were obtained from his past
history. He had as he said "fainted" on many
occasions. The first was in his teens when he
was taken to the doctor with influenza, the
second at 19 after a cycle accident. He was not
injured, but very much upset, and lost his
senses suddenly fifteen minutes later. The next
occasion was a year afterwards when he went to
have a tooth out, and, feeling, as he said, in a
blue funk, lost his senses and fell before
getting into the dentist's chair. In this attack
he passed urine. There was a similar episode at
the dentist's a year later. Again he passed
water. There were no more attacks precipitated
by emotion, but on about a dozen occasions he
had fainted at the onset of a febrile illness,
influenza or bronchitis. The sequence was always
the same. He would begin to yawn and
continue yawning for ten to twenty
minutes. If he could keep walking about this
might end without further incident, but if he
gave way and sat down his vision would suddenly
become grey and he would lose his senses for a
minute. In almost all these attacks he passed
urine.
-
- These attacks, I believe, were epileptic for
two reasons. The first is the occurrence of
involuntary micturition in nearly all the
attacks. This may occur in a faint if the
bladder happens to be full at the time, but its
regular occurrence always suggests an epileptic
discharge involving the centres for micturition.
The second reason is the prodromal
yawning, recognized by Gowers
(1901) and again by Kinnier
Wilson (1928) as a precursor of epileptic
attacks. I have several examples of this in my
own notes of undoubted epileptics.
-
- There is next to be considered a rare but
important group of patients who begin by having
attacks in childhood or adolescence which we
diagnose confidently as faints, but who go on to
have attacks which we are sure, are epileptic.
The earlier attacks have the usual causes for a
faint, but the liability appears
èxcessive, the attacks are more frequent
than usual and continue to a later age and when
they have continued long enough we are not
altogether surprised when we are confronted
'With the story of an attack this time without
cause and characteristic of epilepsy. In these
cases then we observe excessive liability to
fainting followed by an excessive liability to
epilepsy. The word excessive may be equally
applied to both. Anyone may faint or have a fit
with sufficient cause. Why do some persons have
faints or fits with so little cause or no
apparent cause? The answer in the case of the
epileptic is that there are nervous centres
which are unstable. This is the trigger
mechanism for the attack. Of the causes that
operate to pull the trigger we know very little.
In the case of the fainter on the other hand we
know a good deal about the causes that pull the
trigger, and we know that when the trigger is
pulled there is bradycardia or fall of blood
pressure to explain the symptoms that follow.
But where is the trigger itself? Probably in the
central nervous system. Fainting in response to
emotion clearly suggests this localization.
Again in a faint which results from prolonged or
unaccustomed standing what is it that gives,
way? Surely the reflex mechanisms responsible
for maintenance of heart-rate and blood
pressure, and where are these except in the
central nervous system? In the syndrome of
postural hypotension, which provides the extreme
example of postural fainting, there is a good
deal of evidence for the existence of a trigger
mechanism at or near the hypothalamus (East and
Brigden, 1946). It seems probable, therefore,
that for faints as well as fits an essential
link in the chain of causation is an unstable
nervous mechanism. If this be so it would not be
surprising if we sometimes found both kinds of
instability present in the same person. Nor I
think would it be surprising to find that with
the passage of time the instability responsible
for fainting became less and that responsible
for epilepsy greater. This kind of thing
sometimes happens in persons who have migraine
in their youth and as they grow older exchange
it for epilepsy.
-
- The carotid sinus syndrome is also of
interest in relation to the occurrence of faints
and fits in the same person. In this malady
pressure upon the sinus, according to Ferris and
others (1935), may produce faints, with
bradycardia or fall of blood pressure
sufficiently abrupt to cause loss of
consciousness and sometimes convulsions: or it
may cause these symptoms without any adequate
cardiovascular derangement to explain them. Thus
it would appear that the specific stimulus in
this syndrome may produce either reflex fainting
or reflex epilepsy.
-
- The general trend of these remarks has been
towards the conclusions, first, that there is no
absolute means of distinguishing between a fit
and a faint unless the attack can be observed in
detail with estimations of pulse-rate and blood
pressure before and during the episode, and
second, that even though fits and faints may be
clinically distinguishable they are closely
related in their dependence upon the instability
of nervous mechanisms.
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