National Hospital
for the Paralysed and Epileptic, Queen Square,
London.
Historical.
Epidemic encephalitis is now regarded as one
of the most disabling diseases of the nervous
system. Its late effects have been studied and
described with great care and an extensive
literature has arisen. Amongst the sequel,
disorders of the respiratory mechanism have been
regarded as rare after-effects. A study of the
most recent monographs (Hal, Lévy) has
shown, however, that respiratory disabilities
take quite a large and important share in the
general post-encephalitic picture.
The more frequent occurrence of these
disabilities has received confirmation from our
own recent experience, as we have observed the
existence of minor respiratory symptoms to be
not uncommon if looked for in association with
Parkinsonism and other well-recognized effects
of this disease. (...)
Clinical manifestations.
For descriptive purposes the respiratory
disorders following epidemic encephalitis may be
classified as follows
(1) Disorders of the respiratory rate
(tachypnœa and bradypnœa).
(2) Dysrhythmias, or disorders of the
respiratory rhythm (CheyneStokes breathing,
breath-holding spells, sighs, forqed or noisy
expiration, inversion of the
inspiration-expiration ratio).
It must be realized, however, that any
combination of the above types may co-exist with
or without the other sequelie of
encephalitis.
Before proceeding to a description of
respiratory manifestations it is advisable to
define the terms we propose to use.
Breathing which is faster than normal we
shall speak of as "tachypnœa." The word
"bradypnœa" we shall apply to slow
respirations. Respiratory movements which are
shallower than normal may be named "hypopnoea."
The term "hyperpnœa" should strictly
speaking be limited to those of abnormal depth.
It may be pointed out here that tachypucea is,
as a rule, accompanied by some degree of
compensatory hypopuœa. In this article we
propose to discard the word "polypnœa"
altogether.
(1) Disorders of the Respiratory
Rate.
Tachypncea constitutes one of the commonest
of the respiratory manifestations. The increased
respiration rate may be either continuous) in
which case it bears no relationship to the
output of work, or paroxysmal. The patient
usually suffers no inconvenience and cyanosis is
rare ; in the majority of cases there is no
accompanying tachycardia. The tachypnœa may
occur during sleep only, or during both sleeping
and waking states. On the other hand the
respiration rate may fall during sleep or even
when the patient is recumbent. Physical
examination of the chest usually gives negative
results, but in some cases, particularly in the
presence of the Parkinsonian syndrome, there may
be a relative immobility of part of the thorax
or of the diaphragm. The amplitude of each
expiration is usually shallower than normal and
may be saccadé or jerky in
character.
Paroxysmal tachypnœa may arise in
attacks occurring three to four times daily or
several times in the course of an hour. It is
sometimes observed that the paroxysms tend to
come on towards nightfall, each one lasting
anything from a minute to several hours. The
patient is usually conscious of the increased
respiration rate and is able voluntarily to
control it for a short time. When questioned as
to why he breathes more rapidly no very clear
reply is given, but complaint may be made of a
sensation of thoracic constriction or pulsation.
Farquhar Buzzard has pointed out that in many
cases of post-encephalitis acts which are
normally automatic in nature (swallowing,
speaking, breathing, &c.) become purely
voluntary actions. This statement is true for
certain of these paroxysmal tachypnœas. The
intensity and frequency of the attacks are
increased by emotional stimuli, and conversely
become less marked when attention is distracted.
Frequently the act of deglutition temporarily
inhibits the tachypnœa.
Of the complications of tachypnœa,
tetany is the most important, and occurs in
those cases in which the usual compensatory
hypopnœa is replaced by respirations of
full amplitude. The experiments of Collip and
Backus, Grant and Goldman, Rosett and many
others have demonstrated that tetany is a
physiological accompaniment of "over ventilation
of the lungs" due to forced respiration, the
causative mechanism arising through the altered
H'/OH' balance. Vasomotor disturbances may also
appear in the course of the tachypnœa,
giving rise to lowered arterial tension and
cyanosis of the extremities.
Children in particular are liable to display
tachypnœa. This manifestation may arise
during the acute phase, during convalescence, or
as a remote sequel. When arising as a late
result of encephalitis it is rare not to find
some other abnormality, physical or psychical.
Reference has been made to the association of
tachypncea with synchronous myoclonic
contractions of the biceps muscle.
Bradypnœa, a much rarer phenomenon, may
be continuous or paroxysmal. The respiration
rate may fall to as low as six per minute, and
pressure on the eyeballs sometimes reduces it
yet further. The amplitude of each respiration
is usually increased, and expiration tends to
become prolonged and noisy.
(2) Dysrhythmias, or Disorders of the
Respiratory Rhythm.
Sighs: This is one of the commonest
manifestations. The patient in the course of
normal breathing may suddenly give a deep sigh,
which is followed by a short period of
compensatory expiratory apnœa. These sighs
may occur only during sleep, or, on the other
hand, may come on after some slight exertion. In
certain instances the patient at the same time
may exhibit a tic-like grimace or movement, such
as opening of the mouth or shrugging the
shoulders. Occasionally the expiratory component
is broken or "cogwheel" in character. At times a
regular periodicity may be detected in the order
of their appearance, each sign occurring after a
definite number of respirations.
Apnœic pauses: Intervals in which no
breathing occurs may take place as a result of
sighing inspiration, during a spell of
breath-holding, or spontaneously in the course
of normal respiration. These pauses are
particularly prone to arise during sleep. The
resumption of respiration, unlike what is seen
in Cheyne-Stokes breathing, is not
"crescendo."
Inversion of the inspiration/expiration
formula:
inspiration is shorter than expiration with
the proportion of 5:8; during sleep the converse
is true. In certain post-encephalitic patients
the normal ratio is reversed so that the
respiration during the waking state resembles
that of normal sleep.
Cheyne-Stokes respiration. This is a rare
manifestation; Pierre Marie affirming that he
has never seen a genuine case. Goldflam, Leroy
and Dupouy, and Naville have, however, recorded
cases of abnormal breathing conforming to this
type; tachypnœa constituted a marked
symptom in their patients.
Bigeminal and trigeminal respiration.-In
certain cases, a graphic record of the
respiration reveals a regular arhythmia in the
amplitude of each effort; for example, breaths
may be alternately deep and shallow (bigeminal
or alternating respiration) ; or a deep breath
may be succeeded by two of smaller amplitude
(trigeminal respiration). These abnormal types
of breathing are frequently associated with the
occurrence of sighs or apnœic pauses.
Breath-holding spells.-This subclass
includes a great variety of interesting
manifestations which differ from the simple
apnœic pauses in that the breath is held in
almost full inspiration. It is into this class
that one must place the first and third cases
recorded by us.
The paroxysms occur at irregular intervals
and may or may not be interposed with periods of
normal breathing. They tend to come on
especially towards nightfall and in some cases
(as in our third case) may be present only
during sleep. In other instances (as in our
first case) the paroxysms occur during the
waking state only. The attacks, like those of
simple tachypnœa, are to a limited extent
under the patient's control and may be
temporarily inhibited by voluntary effort, by
deglutition or when attention is forcefully
distracted. Similarly, the attacks increase in
number and frequency when the patient is under
emotional stress or is the object of marked.
attention.
The paroxysms are ushered in by a series of
deep, forced inspiratory efforts with noisy
expirations; the patient's subjective sensations
at this stage frequently take the form of a
feeling of dizziness, or of "something in the
chest interfering with full inspiration." A deep
inspiration is then taken and maintained for a
period of ten, twenty or thirty seconds. At the
same time choreo-athetotic movements of the
limbs, bizarre attitudes or peculiar grimaces
are common. Sometimes the patient stands up and
throws back his head; others run their fingers
through their hair. Roch and Schmidt quote a
patient who would try to run away and conceal
himself. Cyanosis is unusual, but may occur. In
the severe cases, consciousness may be lost for
a moment or two, as in our first and fifth
cases. The inspiratory apnœa is terminated
bya forced and often noisy expiration which is
followed by a short period of compensating
expiratory apnoea. Breathing is then resumed,
each breath being of normal amplitude.
(3) Respiratory Tics.
(a) Hiccough is mentioned merely because
discussion of its relationship with epidemic
encephalitis would be beyond the scope of this
paper.
(b) Yawning.
Involuntary opening of the mouth is not an
uncommon feature in the post-encephalitic
Parkinsonian syndrome: during the last three
months, three patients out of twenty-five
observed by ourselves showed this symptom.
Occasionally "mouth opening" occurs in
paroxysms, is sustained for a few seconds and
amounts in degree to a wide gape. Such a
manifestation is tantamount to a yawn and may be
included amongst the respiratory tics of
post-encephalitic nature. An extreme instance is
recorded in our third case and is illustrated by
photograph. Other cases have been reported by
Sicard and Paraf, Pardee, Hinds Howell,
Abrahamson and Farquhar Buzzard.
(c) "Soufflement." The French writers have
used this word to denote tic-like expiration of
air through the nose as though in order to
dislodge a foreign body. (Babinski and
Charpentier.)
(d) Spasmodic cough. One of the most
distressing post-encephalitic "tics" consists in
a constant, short, hacking, dry cough which
persists during the daytime and often throughout
the night. Pierre Marie gives the term "toux
coqueluchoïde "to this cough. There are no
pulmonary physical signs and examination of the
larynx and pharynx is negative. This cough may
be succeeded later by some other respiratory
disorder as in Case 1 of our series.
These respiratory tics are particularly
common in children after encephalitis. They tend
to persist through the daytime, but show an
increased frequency towards nightfall.
From the study of the recorded cases it is
apparent that respiratory phenomena may arise at
any stage of epidemic encephalitis. It does not
seem possible to trace any association between
the symptomatology of the original attack and
the subsequent onset of respiratory disorders.
Thus cases which were originally characterized
by insomnia or delirium do not tend to develop
subsequent respiratory disorders any more than
cases showing lethargy. The myoclonic variety is
known also to be followed occasionally by
disorders of breathing.
Although respiratory disorders may
occasionally constitute the sole late
manifestations of encephalitis, it is more usual
for other psychical and nervous after-effects to
be present; association with inversion of the
sleep rhythm is particularly common. The nature
of the co-existing sequelie does not appear to
exer6ise any essential bearing on the nature or
severity of the respiratory abnôrmality.
It is difficult to gauge the frequency of
respiratory disorders during and after
encephalitis. It is probable that the slighter
dysrhythmias are not uncommon features, and it
is only by careful observation of the
respiration during sleep as well as in the
waking state that many of them are discovered.
Miss Anderson, in her study of forty children
recovered from encephalitis, records
"hyperpnœic" breathing in "many." Hinds
Howell mentions three cases in his series of
twenty-eight. Mlle. Lévy found ten
instances of respiratory disorders out of 129
cases. On the other hand, out of 423 surviving
cases of encephalitis recorded by Price, Bing
and Staehelin, Palitzsch, Duncan, Shrubsall,
Paterson and Spence, and Edgeworth, no mention
whatever is made of respiratory upsets; we do
not know, however, whether any such changes were
looked for.
Encéphalite léthargique
Cruchet, Moutier, Calmettes Soc méd hop
Paris 27 avril 1917
