DISEASES OF THE BRAIN AND MEMBRANES
Pyogenic diseases--Meningitis: _Varieties_--Abscess:
_Varieties_--Sinus phlebitis--Intra-cranial tuberculosis.
Cephaloceles--_Meningocele_--_Encephalocele_--
_Hydrencephalocele_--Traumatic cephal-hydrocele--Hydrocephalus;
_Varieties_--Micrencephaly. Cerebral tumours. Tumours of the
pituitary body. Epilepsy--Hernia cerebri. Surgical affections of
cranial nerves--Cervical sympathetic.
PYOGENIC DISEASES
The most important intra-cranial conditions that result from infection
with pyogenic bacteria are: meningitis, abscess of the brain, and
phlebitis of the venous sinuses.
The organisms most frequently associated with these conditions are the
staphylococcus aureus and the streptococcus, but it is not uncommon
to meet with mixed infections in which other bacteria are
present--particularly the pneumococcus, the bacillus foetidus, the
bacillus coli, the bacillus pyocyaneus, and the diplococcus
intracellularis.
By far the most common source of intra-cranial infection is chronic
suppuration of the middle ear and mastoid antrum, the organisms
passing from these cavities to the interior of the skull directly
through a perforation of the tegmen tympani or of the wall of the
sigmoid groove, or being carried in the blood stream by the emissary
veins. In some cases the infection travels along the sheaths of the
facial and acoustic nerves.
Less frequently infective conditions of the nasal cavity and its
accessory air sinuses, and compound fractures of the skull,
particularly punctured fractures, are followed by intra-cranial
complications; or infection is conveyed to the inside of the skull, by
way of the emissary veins, from wounds of the scalp, or from such
conditions as erysipelas of the face and scalp, malignant pustule,
carbuncles, or boils.
At the bedside there is often difficulty in discriminating between the
various pyogenic intra-cranial complications, because many of the
symptoms are common to all the members of this group, and because
more than one condition is frequently present. Thus a localised
meningitis spreading to the brain may set up a cerebral abscess; a
sinus phlebitis may give rise to a purulent lepto-meningitis; or a
cerebral abscess bursting into the sub-arachnoid space may produce
meningitis.
MENINGITIS
#Pachymeningitis.#--This term is applied when the infection involves
the dura mater--a condition which is usually due to the spread of
infection from a localised osseous lesion, such as erosion of the
tegmen tympani in chronic suppuration of the middle ear, of the wall
of the sigmoid groove in mastoid disease, or of the posterior wall of
the frontal sinus in suppuration of that cavity. It also occurs in
relation to septic lesions of the cranial bones such as a broken-down
gumma, after operations on the cranial bones, and in cases of compound
fracture attended with a mild degree of infection and with imperfect
drainage. In contusion of the skull without an external wound, the
infection may take place through the blood stream.
The layer of the dura in contact with the affected portion of
bone is inflamed, thickened, and covered with a layer of
granulations--_external pachymeningitis_--and between it and the bone
there is an effusion of fluid. Up to this point the process is largely
protective in its effects, and gives rise to no symptoms, beyond
perhaps some pain in the head.
In the majority of cases, however, suppuration occurs between the dura
and the bone--_suppurative pachymeningitis_--and leads to the
formation of an _extra-dural abscess_ (Fig. 192). When this happens
in association with disease in the middle ear or frontal sinus, it is
attended with severe headache referred to the seat of the abscess, a
sudden rise of temperature preceded by shivering, and other evidence
of the absorption of toxins. Over the situation of the abscess, the
scalp becomes swollen and oedematous--a condition which Percival Pott,
in 1760, first observed to be characteristic of extra-dural
suppuration, hence the name, _Pott's puffy tumour_, applied to it
(Fig. 193). Under these circumstances the abscess is seldom of
sufficient size to cause a marked increase in the intra-cranial
tension, or to give rise to localised cerebral symptoms by pressing on
the brain.
[Illustration: FIG. 192.--Diagram of Extra-Dural Abscess.]
[Illustration: FIG. 193.--Pott's Puffy Tumour in case of extra-dural
abscess following compound fracture of orbital margin; infected with
road-dust; operation; recovery. At the time of the photograph the man
was unconscious.]
When associated with a punctured wound implicating the skull, an
extra-dural abscess may develop within a few days of the injury, or
not till after the lapse of several weeks, and it may spread over a
wide area and come to encroach on the cranial cavity sufficiently to
raise the intra-cranial tension and cause symptoms of compression, or
even to press upon cortical centres and produce localised paralyses.
As discharge can escape from the wound in the scalp, the puffy tumour
does not necessarily form.
_Treatment._--When the abscess is secondary to middle ear disease, the
mastoid must be opened, the eroded bone exposed, and sufficient of it
removed with rongeur forceps to admit of free drainage. When the
infection has spread from the frontal sinus, the skull is trephined in
the frontal region, the precise site being indicated by the oedematous
area in the scalp, and the diseased bone is removed. In cases of
compound fracture, drainage is established by enlarging the scalp
wound, and removing loose, depressed, or inflamed portions of bone; if
the bone is comparatively intact, it must be trephined, and further
bone is removed with rongeur forceps over the entire area in which the
dura has been separated.
#Lepto-meningitis.#--If the infection spreads to the adjacent
arachno-pia (_localised lepto-meningitis_), adhesions usually form,
and shut off the infected area from the general arachno-pial space.
Pus may form among these adhesions, constituting a _sub-dural
abscess_, and may infiltrate the superficial layers of the cortex
(_purulent encephalitis_, or _meningo-encephalitis_) (Fig. 194). The
symptoms are similar to those of extra-dural abscess, but may be more
severe; and it is seldom possible to distinguish between them before
exposing the parts by operation. The treatment is carried out on the
same lines.
[Illustration: FIG. 194.--Diagram of Sub-Dural Abscess.]
_Acute General Lepto-Meningitis._--In bone lesions, particularly
compound fractures, infection of the arachno-pia may take place
before protective adhesions form, and a diffuse lepto-meningitis
results. The open structure of the arachno-pial membrane favours the
rapid spread of the infection, which may extend over the surface of
the hemispheres, or downwards towards the base (_basal meningitis_),
or in both directions. The process is at first attended with a copious
effusion of cerebro-spinal fluid into the arachno-pial space and into
the ventricles (_serous lepto-meningitis_), but this fluid tends to
become purulent, the pus forming in a thin layer over the surface of
the brain, and in the sulci between the convolutions (_purulent
lepto-meningitis_). The membranes are congested and thickened, the
veins of the arachno-pia engorged, and the superficial layers of the
cortical grey matter may share in the process (_encephalitis_).
_Clinical features._--The earliest and most prominent symptom is
violent pain in the head, often referred to the frontal region, or, in
cases starting from middle ear disease, to the temporal region. This
is accompanied by a sudden rise of temperature, usually without an
antecedent rigor; the temperature remains persistently elevated (102 deg.
to 105 deg. F.), and the pulse is small, rapid, and irregular both in rate
and force. The patient, especially if a child, is extremely irritable,
all his sensations are hyper-acute, and he periodically utters a
peculiarly sharp, piercing cry.
Vomiting of the cerebral type--that is, unattended with nausea and not
related to the taking of food or to gastric disturbance--is common,
and persists through the illness. The bowels are usually constipated.
There is an increase in the number of leucocytes in the cerebro-spinal
fluid, and organisms also are found in the fluid. As this does not
occur in cerebral abscess, examination of the cerebro-spinal fluid may
be useful in differential diagnosis. There is a higher leucocytosis in
the blood in meningitis than in cerebral abscess.
When the inflammation is most marked over the cerebral hemisphere,
there may be paralysis of the side of the body opposite to the seat of
the original lesion; sometimes there is erratic rigidity of the limbs,
sometimes clonic spasms of groups of muscles. The superficial reflexes
disappear early on both sides; the abdominal reflexes being lost
sooner than the knee-jerks. In basal meningitis, temporary squinting
due to irritation of the ocular muscles, retraction of the head, and
an excessively high temperature are usually prominent features. The
pupils at first are equally contracted; later they become dilated and
fixed. Both optic discs are oedematous and swollen.
Gradually the patient becomes unconscious, shows signs of increasing
intra-cranial tension, slowing of the pulse, and laboured respiration,
and the condition almost always proves fatal within three or four
days.
_Treatment._--The treatment consists in removing the source of
infection when this is possible, but as a rule little can be done to
arrest the spread of the meningitis or to ward off its effects. In
cases resulting from a sub-dural abscess in relation to a compound
fracture, a sinus phlebitis, or an erosion of the tegmen tympani, an
attempt should be made, after exposing this, to purify and drain the
meningeal spaces. Temporary relief of symptoms sometimes follows the
withdrawal of cerebro-spinal fluid by repeated lumbar puncture,
bleeding by leeches or cupping, or the use of an ice-bag or Leiter's
tubes. The bowels should be freely moved by purgatives or enemata.
_Cerebro-spinal Meningitis._--This form of meningitis, which is due to
the _diplococcus intracellularis_, may occur sporadically, but is more
frequently met with in an epidemic form. It is attended with the
formation of a profuse sero-purulent exudate, which covers the brain,
the cord, the nerves, and the membranes.
The clinical features are similar to those of acute general
lepto-meningitis, and in sporadic cases the diagnosis is only
completed by discovering the diplococcus intracellularis in the fluid
withdrawn by lumbar puncture. Although recovery sometimes takes place,
the disease is attended with a high mortality. In the early stages,
before the exudate has become too thick, repeated lumbar puncture
followed by the injection of Flexner's serum has proved beneficial.
Recovery may be attended with paralysis of one or other of the cranial
nerves.
CEREBRAL AND CEREBELLAR ABSCESS
#Abscess due to Middle Ear Disease.#--The most common cause of abscess
in the brain is chronic middle ear disease, and the majority of
cerebral abscesses are therefore situated in the temporal lobe. Some
are due to direct spread from a collection of pus in relation to an
erosion of the tegmen tympani, either inside or outside the dura,
others to infection carried by the veins, and in this way the
infective material reaches the white matter; less frequently infection
from the middle ear takes place along the peri-vascular lymph spaces.
Macewen has pointed out that cerebral abscess never occurs from
pyogenic organisms passing from the middle ear by way of the internal
auditory meatus, although lepto-meningitis may do so. Cerebral abscess
is much more frequently met with in the white matter of the centrum
ovale than in the cortex, and in the majority of cases the abscess is
single.
The _pus_ is often of a greenish-yellow colour, or it may be dark
brown from admixture with broken-down blood-clot; in some cases it is
thin and serous and contains sloughs of brain matter, and it
frequently has a foetid odour. In quantity it varies from a few drops
to several ounces.
The _arachno-pia_ over an abscess usually has a turbid and milky
appearance.
In an acute abscess the surrounding _brain tissue_ is engorged and
infiltrated with pus; in a chronic abscess it is condensed, and the
pus may be encapsulated by the formation of a zone of young fibrous
tissue round its periphery. In this condition the abscess may remain
"latent," giving rise to no symptoms for many weeks or even months.
_Clinical features._--The _initial_ formation of pus in the cerebral
tissue is associated with the sudden onset of severe pain in the head,
shivering and well-marked cutis anserina, and vomiting of the cerebral
type. The discharge from the ear usually diminishes or may even cease.
As a _localised abscess_ develops the patient gradually passes, into a
stuporous condition; he does not lose consciousness, but, his
cerebration is slow, he seems unable to sustain his attention, for any
length of time, and he answers questions "slowly, briefly, but, as a
rule, correctly" (Macewen). The pain in the region of the ear becomes
less intense, but the mastoid and temporal areas on the affected side
are tender on percussion. The temperature falls, and, as a rule,
remains subnormal. Rigors are unusual: their occurrence usually
indicating the development of some complication such as sinus
phlebitis. The pulse is full, regular, and slow (40 to 60). Vomiting
frequently occurs, and the bowels are often obstinately constipated.
There is no actual paresis, but there is a "gradual diminution of the
ability to apply his strength." The superficial reflexes are late of
disappearing and the disturbance is unilateral. The optic discs are
moderately swollen. "The face is expressionless, passive, and cloudy.
It may assume a meaningless smile, with which the features are not
lit; it is too mechanical" (Macewen).
_Differential Diagnosis._--In the early stages it is often difficult
to distinguish between meningitis and cerebral abscess. The chief
points on which reliance is to be placed are that in meningitis the
pulse shows an irregularity, both in rate and force, which is wanting
in cases of uncomplicated abscess. In meningitis the temperature is
raised, while in abscess it is persistently subnormal. The
superficial reflexes, particularly the abdominal reflexes, disappear
early in meningitis and the disturbance is bilateral; in abscess they
are slower to disappear, and one side only is affected. Retraction of
the neck, when present, is a characteristic sign of meningitis. In
meningitis the optic discs are highly oedematous and are more swollen
than in abscess, and the condition is equally marked on the two sides.
_Localisation of Cerebral Abscess--Temporal Abscess._--The existence
of middle ear disease is always presumptive evidence that the abscess
is in the temporal lobe on the same side. A small abscess in this lobe
may produce no localising symptoms; one of large size may press
indirectly on the motor cortex, on the fibres passing through the
internal capsule, or on individual cranial nerves.
It is important to observe the order in which paralysis of the
opposite side of the body comes on. When it begins in the face and
passes successively to the arm and leg, the pressure is on the
cortical centres. When the paralysis progresses in the opposite
direction--leg, arm, face--the pressure is on the nerve fibres passing
through the internal capsule (Fig. 195). The paralysis may be spastic
in lesions of the cortex or internal capsule; if it is flaccid the
lesion is almost certainly cortical.
[Illustration: FIG. 195.--Diagram illustrating Sequence of Paralysis,
caused by abscess in temporal lobe. (After Macewen.)]
Motor aphasia may result from pressure on the left inferior frontal
convolution; auditory aphasia from abscess in the posterior part of
the superior temporal convolution. Ptosis and lateral squint, with a
fixed and dilated pupil, indicates pressure on the oculo-motor nerve
of the same side.
Abscess in the _parietal lobe_ gives rise to paralysis of the face and
limbs on the opposite side of the body. Abscess in the _occipital
lobe_ produces interference with the visual functions. An abscess in
the _frontal lobe_ may give rise to no localising symptoms, but if it
is on the left side, the power of making co-ordinated movements may be
lost--apraxia--or the motor speech centre may be implicated.
_Terminal Stage._--If left to itself, a cerebral abscess usually ends
fatally by causing gradually increasing stupor and coma, or by
bursting, either into the ventricles or into the sub-arachnoid space,
and setting up a diffuse purulent lepto-meningitis.
When the _abscess bursts into the ventricles_, the patient suddenly
becomes much worse and dies within a few hours. "The pupils become
widely dilated, the face livid, the respiration greatly hurried, and
either shallow or stertorous. The temperature rises within a few hours
with a bound from subnormal to 104 deg. to 105 deg. F.; the pulse from 40 or
50 per minute quickly reaches 120 and over. There are muscular
twitchings all over the body, possibly associated with convulsions and
tetanic seizures, and these are followed by coma and speedy death"
(Macewen).
Spontaneous evacuation of a temporal abscess may take place through
the middle ear.
#Cerebellar Abscess.#--Next to the temporal lobe, the cerebellum is
the most common seat of abscess. Cerebellar abscess is usually due to
spread of infection from a thrombosed sigmoid sinus, either directly
from a sub-dural abscess formed in relation to the walls of the sinus,
or by extension of the thrombotic process along the cerebellar veins.
While the abscess is small, it may give rise to few symptoms, and the
patient may be able to go about, but as it increases in size serious
symptoms develop. There may be nystagmus, and the patient suffers from
vertigo, and is unable to co-ordinate his movements. If he attempts to
walk, he reels from side to side; even when sitting up in bed, he may
feel giddy and tend to fall, usually towards the side opposite to that
on which the abscess is situated. The head and neck are retracted, the
pulse is slow and weak, and the temperature subnormal. There is
frequent yawning, and the speech is slow, syllabic, and jerky. There
may be optic neuritis and blindness. There is sometimes unilateral or
even bilateral spastic paralysis of the limbs from pressure on the
medulla oblongata. The respiration may assume the Cheyne-Stokes
character, occasionally being interrupted for a few minutes, while the
heart continues to beat vigorously. This arrest of respiration is
especially liable to occur during anaesthesia.
_Treatment._--The abscess having been localised, the skull must be
opened and the pus removed.
#Abscess from causes other than Middle Ear Disease.#--From the _nasal
passages_, infection may spread to the interior of the skull directly
through the walls of the frontal, ethmoidal, or sphenoidal air
sinuses, or indirectly by way of the veins, and give rise to a
cerebral abscess, usually in the frontal lobe. The symptoms are
similar to those of abscess following middle ear disease, but focal
symptoms are seldom present. When the abscess is on the left side,
apraxia and motor aphasia may be present. Spontaneous evacuation may
take place by the abscess bursting into the nose through the
cribriform plate.
The treatment consists in trephining through the frontal bone or
through the temporal fossa, according to the site of the abscess and
its seat of origin. The primary focus of infection must also be dealt
with.
In _infected compound fractures_, an abscess may form in the cortical
grey matter within a few days of the injury from direct spread of
infection from the bone and membranes. This is usually associated with
a spreading lepto-meningitis, the symptoms of which predominate. The
condition usually proves fatal, but by opening up the original wound,
removing depressed fragments of bone, and establishing drainage, the
patient's life may be saved.
There is evidence that an abscess may form in the brain after a simple
contusion without fracture or other external injury (Ehrenvooth).
An abscess may develop in the white matter of the centrum ovale some
weeks, or even months, after an injury, particularly if a fragment of
bone or a foreign body has been driven into the brain. If the
infection has spread along the track of the missile, the abscess is
usually near to the seat of the brain injury, but if it is due to
spread of a thrombo-phlebitis it may be a considerable distance from
it, even on the opposite side of the head. These chronic abscesses are
usually in the parietal or frontal lobes, and as the pus is
encapsulated they may remain latent for long periods, during which
they may cause some degree of headache, neuralgic pains in the
distribution of the trigeminal nerve, and occasional rises of
temperature. When the abscess becomes active, general symptoms similar
to those of other forms of abscess develop, and there may be localised
paralysis of the opposite side of the body, the distribution of which
depends upon whether the cortical centres or the motor fibres are
implicated.
The treatment consists in opening up the original wound, removing any
depressed bone or foreign body that may be present, and establishing
drainage.
_Bronchiectasis_ and other infective diseases of the lungs are less
common causes of cerebral abscess, which is usually single, and may
occur in any part of the brain.
_Disease of the bones of the skull_, such as osteomyelitis or
syphilis, may be followed by cerebral abscess.
Abscesses of _pyaemic_ origin are usually multiple, and may occur both
in the cerebrum and in the cerebellum; they are not amenable to
surgical treatment.
SINUS PHLEBITIS
Inflammation of the intra-cranial venous sinuses is due to the spread
of infection from a local focus of suppuration; by far the most
frequent cause is chronic suppuration in the middle ear. Less common
sources of infection are erysipelas of the face or scalp, infective
conditions of the mouth or nose, and diseases of the bones of the
skull.
The organisms may reach the affected sinus directly by continuity of
tissue, as, for instance, when the transverse (lateral) sinus becomes
infected from a focus of suppuration in the mastoid process spreading
through the bone to the sigmoid groove and involving the walls of the
vessel; or they may reach it by extension of thrombosis in a tributary
vein--for example, when the superior sagittal (longitudinal) sinus is
infected from an anthrax pustule of the lip, which has caused
thrombosis of the emissary vein that passes through the foramen caecum.
The pathological changes are the same as occur in the suppurative form
of thrombo-phlebitis in the peripheral veins (Volume I., p. 285). The
soft clot that forms adheres to the inflamed wall of the sinus, and,
being infected with pyogenic bacteria, it soon undergoes purulent
disintegration.
The infective process may spread backward along tributary vessels, and
so give rise to cerebral or cerebellar abscess, or to purulent
meningitis; or it may spread into the internal jugular vein and lead
to the development of a diffuse purulent cellulitis along its course.
General pyaemic infection may take place from pus or bacteria getting
into the circulation, either directly or by reversed flow through
tributary veins. Infective emboli are liable to lodge in the lung or
pleura, and set up pulmonary abscess, gangrene of the lung, or
empyema.
_Clinical Features._--In all cases, pain in the head, referred to the
region of the affected sinus, and so severe as to prevent sleep, is an
early and prominent feature. The patient is usually excited,
hypersensitive, and irritable in the early stages, and becomes dull
and even comatose towards the end. Rigors, followed by profuse
perspiration, occur early and increase in frequency as the disease
progresses. The temperature is markedly remittent, varying from 103 deg.
to 106 deg. F. (Fig. 196). The pulse is rapid, small, and thready. Loss of
appetite, vomiting, and diarrhoea are almost constant symptoms.
[Illustration: FIG. 196.--Chart of case of Sinus Phlebitis following
middle ear disease in a boy aet. 13.]
#Phlebitis of Individual Sinuses.#--The _transverse_ (_lateral_ or
_sigmoid sinus_), from its proximity to the middle ear and mastoid air
cells, is that most commonly affected, especially in young adults.
With the onset of the phlebitis the discharge from the ear stops;
there is severe pain in the ear and violent headache. The temperature
rises, but shows marked remissions, and rigors are common. Vomiting is
frequently present. Turgescence of the scalp veins draining into this
sinus, and oedema over the mastoid, are occasionally observed; but as
these signs may accompany various other conditions, they are of little
diagnostic value. Not infrequently phlebitis spreads to the internal
jugular vein, which may then be felt as a firm, tender cord running
down the neck, and the head is held rigid, sometimes in the position
characteristic of wry-neck.
Three clinical types of sinus phlebitis are recognised--pulmonary,
abdominal, and meningeal--but it is often impossible to relegate a
particular case to one or other of these groups. Many cases present
symptoms characteristic of more than one of the types.
In the _pulmonary type_ evidence of infection of the lungs appears
towards the end of the second week, in the form of dyspnoea, cough,
and pain in the side, coarse moist rales, and dark foetid sputum.
Death usually takes place from gangrene of the lung. The brain
functions may remain active to the end.
In the _abdominal type_ the symptoms closely resemble those of typhoid
fever, for which the condition may be mistaken. The absence of a rash
and the coexistence of middle ear disease are important factors in
diagnosis.
When the disease is of the _meningeal type_, symptoms of general
purulent lepto-meningitis assert themselves, and soon come to dominate
the clinical picture. Evidence of the presence of meningitis may be
obtained by lumbar puncture. The mind at first is clear, but the
patient is irritable; later he becomes comatose.
The _prognosis_ is always grave, on account of the risk of general
infection.
_Treatment._--The primary focus of infection must first be removed,
and this usually involves clearing out the middle ear and mastoid
process. The sigmoid sinus is then exposed, and after any granulation
tissue or pus that may be in the groove has been cleared away, the
sinus is opened and the thrombus removed. With the object of
preventing the dissemination of infective material, a ligature should
be applied to the internal jugular vein in the neck before the sinus
is opened, as was first recommended by Victor Horsley. If the
phlebitis is accompanied by other intra-cranial infections, these are,
of course, treated at the same time.
The _superior sagittal_ or _longitudinal sinus_ is liable to be
infected from pyogenic lesions of the scalp. There are no symptoms
that are pathognomonic, but oedema of the scalp with turgescence of
its veins, epistaxis, and convulsions followed by paralysis, are those
most likely to be met with.
The _cavernous sinus_ is usually implicated by spread of the process
from other sinuses--for instance, from the petrosal or transverse
(lateral) sinuses--or from the ophthalmic veins in cases of orbital
cellulitis. Although at first unilateral, the thrombosis usually
spreads across the middle line to the sinus of the opposite side. The
special symptoms--exophthalmos, oedema of the eyelids, and paralysis
of the ocular nerves--are due to pressure on the structures entering
the orbit.
Operative interference is seldom feasible in phlebitis of the superior
sagittal (longitudinal) or cavernous sinuses.
#Intra-cranial Tuberculosis.#--_Tuberculous meningitis_ is most
frequently met with in patients below the age of twenty, and the
infection takes place by the blood stream from some focus elsewhere in
the body or from the spinal membranes. In cases of tuberculous disease
of the middle ear infection may spread to the membranes by way of the
internal auditory meatus (Macewen). The arachno-pia, especially at the
base, is studded over with miliary tubercles, and an excess of fluid
collects in the arachno-pial space and in the ventricles (_acute
hydrocephalus_).
At first the _symptoms_ of irritation of the brain predominate: severe
headache, photophobia, inequality of the pupils, stiffness of the
neck, cutaneous hyperaesthesia, vomiting and convulsions. Kernig's
sign--pain on flexing the hip while the knee is extended, and
inability to extend the knee while in the sitting posture--is present.
There is usually obstinate constipation, and the abdomen is retracted.
Later, signs of increased intra-cranial tension develop:
unconsciousness deepening into coma, paralysis of ocular muscles,
rapid pulse, Cheyne-Stokes respiration, and sometimes hyperpyrexia. An
excess of mono-nuclear lymphocytes and, sometimes, tubercle bacilli
may be discovered in the cerebro-spinal fluid withdrawn by lumbar
puncture. The absence of the diplococcus intracellularis helps to
differentiate the disease from cerebro-spinal meningitis, which it may
closely simulate.
The only surgical measure that is justifiable is lumbar puncture,
which often affords marked relief of symptoms, although the benefit is
only temporary.
_Localised tuberculous nodules_ sometimes develop in the brain and
form definite tumours. They vary in size from a pea to a hen's egg,
are rounded and encapsulated. Sometimes the centre is caseous,
sometimes fibrinous or calcified. In children they are usually
multiple; in adults they may be single--the so-called "solitary
tubercle." They are most common in the pons, basal ganglia, and
cerebellum, but occur also in the cerebral cortex and sometimes in the
centrum ovale. They usually originate in the pia and invade the brain
substance, but do not as a rule involve the dura. The membranes in the
vicinity of the growth are often the seat of tuberculous disease.
As these nodules give rise to the same symptoms as other forms of
cerebral tumour, and as their nature can be diagnosed only in
exceptional cases, their clinical features and treatment are described
with tumours of the brain.
#Intra-cranial Syphilis.#--_Syphilitic meningitis_ is usually
secondary to cario-necrosis of the bones of the vault or to a
localised gumma of the brain. When primary, it usually affects the
inter-peduncular region of the base, and takes the form of a diffuse
gummatous infiltration of the membranes which gives rise to symptoms
referable to the parts pressed upon, and especially paralysis of one
or other of the cranial nerves. As in other intra-cranial syphilitic
lesions, the symptoms show a variability in intensity which is
characteristic. The diagnosis is made by the history, and the
treatment is carried out on the same lines as in other syphilitic
lesions.
_Localised gummata_ are described with tumours of the brain.
CEPHALOCELES
The term "cephalocele" is applied to a protrusion of a portion of the
cranial contents through a congenital deficiency in the bones of the
skull. This malformation is believed to be due to an irregularity in
development, whereby a portion of the primary cerebral vesicle remains
outside the mesoblastic layer of the embryo. It is usually associated
with adhesion of the membranes in the region of the fourth ventricle,
and with internal hydrocephalus. Cephaloceles are covered by the
scalp, and are most commonly met with in the occipital region and at
the root of the nose; less frequently at the anterior inferior angle
of the parietal bone, and in the line of the sagittal suture. Very
rarely they occur at the base of the skull and project into the
pharynx, the mouth, or the nose, where they are liable to be mistaken
for polypi. Cephaloceles vary greatly in size, some being so small as
almost to escape detection, while others are larger than a child's
head. In many cases the condition is incompatible with life.
Several varieties are recognised. They are known as (1)
_meningocele_, which consists of a protrusion of a cul-de-sac of the
arachno-pial membrane, containing cerebro-spinal fluid; (2)
_encephalocele_, in which a portion of the brain is protruded in
addition to the membranes; and (3) _hydrencephalocele_, in which the
protruded portion of brain includes a part of one of the ventricles.
_Clinical Features._--The _meningocele_ is commonest in the occipital
region, where it escapes through a cleft in the bone between the
foramen magnum and the occipital protuberance (Fig. 197). It forms a
tense, smooth, translucent globular swelling, which may be sessile or
pedunculated, and is usually covered by thin, smooth skin in which the
vessels are dilated and naevoid. The tumour does not pulsate, but
increases in size and tension when the child cries or coughs. It may
be diminished in size or even made to disappear by pressure, and so
permit of the opening in the bone being felt. This manipulation,
however, may be followed by slowing of the pulse, vomiting, loss of
consciousness, or convulsions.
[Illustration: FIG. 197.--Occipital Meningocele.
(From a photograph lent by Sir George T. Beatson.)]
Small meningoceles may remain stationary for a long time, or may even
undergo spontaneous cure. Those of larger size usually progress till
they eventually burst, and death results from the escape of the
cerebro-spinal fluid or from meningitis. Infection may also occur
from eczema or from excoriation of the overlying skin.
_Encephaloceles_ are much commoner than meningoceles, and usually
occur in the frontal region, where they form broad-based, elastic, and
pulsatile tumours, which vary greatly in size.
The _hydrencephalocele_ is usually met with in the occipital region,
and is generally so large and associated with such great cerebral
deformity as to be inconsistent with life. It does not as a rule
pulsate (Fig. 198).
[Illustration: FIG. 198.--Frontal Hydrencephalocele.
(From a photograph lent by Sir George T. Beatson.)]
Cephaloceles have to be diagnosed from dermoid cysts, naevi (Fig. 199),
cephal-hydrocele, and cephal-haematoma. Their recognition is seldom
attended with difficulty. If the margins of the gap in the skull can
be distinctly felt, or the gap in the bone can be shown by the X-rays,
the diagnosis is greatly simplified.
[Illustration: FIG. 199.--Naevus at Root of Nose, simulating
Cephalocele.
(From a photograph lent by Sir George T. Beatson.)]
_Treatment._--Only small cephaloceles are amenable to surgical
treatment; those that are large and contain brain substance are best
left alone, being merely protected from irritation and infection.
While the immediate effects of operation are, on the whole,
satisfactory, the ultimate results are disappointing, as the essential
cause of the intra-cranial pressure persists, and the child develops
hydrocephalus. The method of tapping the sac and injecting iodine has
nothing to recommend it.
#Traumatic Cephal-hydrocele.#--Certain rare cases of simple fracture
of the vault occurring in early childhood have been followed by the
development beneath the scalp of a localised fluid swelling, which
varies in size from time to time and is partly reducible by pressure.
The swelling results from laceration of the membranes, and sometimes
of the brain substance, so that the cerebro-spinal fluid of the
sub-arachnoid space, or even of the lateral ventricle, escapes through
the opening in the skull and bulges beneath the scalp. In a majority
the swelling pulsates synchronously with the heart, and becomes tense
on exertion. A distinct opening in the skull may sometimes be felt.
When associated, as it frequently is, with mental deficiency or the
occurrence of fits, the cyst may be tapped or its neck ligated
(Hogarth Pringle). Otherwise it should be left alone.
HYDROCEPHALUS
An excess of cerebro-spinal fluid may collect in the arachno-pial
space surrounding the brain, or in the interior of the ventricles,
constituting in the former case an _external_, and in the latter an
_internal hydrocephalus_. Hydrocephalus may be acute or chronic.
#Acute hydrocephalus# is practically synonymous with tuberculous
meningitis, although it may result from other forms of meningeal
infection. The excess of fluid is found both in the arachno-pial space
and in the ventricles. This condition only calls for mention here as
attempts have been made to treat it by surgical measures, such as
lumbar puncture, or drainage through the occipital fossa. The results,
however, have not been encouraging.
#Chronic Hydrocephalus.#--_Chronic external hydrocephalus_ is rare,
and usually results from some definite intra-cranial lesion, such as
meningitis, tumour, or cerebral atrophy. It is not amenable to
surgical treatment.
_Chronic internal hydrocephalus_, on the other hand, is a
comparatively common condition. It may be of congenital origin, or may
develop in young rickety children, usually as a result of some chronic
inflammatory process in the membranes at the base, the choroid
plexuses, or the ependyma of the ventricles, causing obstruction to
the outflow of blood through the internal cerebral veins of Galen. In
the acquired form the communication between the ventricles and the
sub-arachnoid space, by way of the foramen of Magendie, is obstructed,
so that the cerebro-spinal fluid is pent up in the ventricles and
gradually distends them. The pressure causes the head to enlarge, the
fontanelles to bulge, and the bones to be separated from one another,
the interval between the bones being occupied by a thin translucent
membrane.
The cerebral tissue is greatly thinned out, but the cerebellum and
cranial nerves usually remain unaffected.
The appearance of the patient is characteristic (Fig. 200). The
enormous dome of the skull surmounts a puny and preternaturally old
face; the eyes are pushed downwards and forwards by the pressure on
the orbital plates, and the eyebrows are displaced upwards. The head
rolls helplessly from side to side; the child moans and cries a great
deal; and vomiting is often a prominent symptom. In most cases the
intelligence is defective, and epileptic seizures and other functional
disturbances of the brain may be present.
[Illustration: FIG. 200.--Hydrocephalus in a child aet. 3-1/2.]
In mild cases, especially when associated with rickets or syphilis,
recovery sometimes takes place, but in the majority the condition
progresses, and death results either from convulsions or from some
intercurrent disease. Few hydrocephalic subjects reach adult life.
_Treatment._--Hydrocephalus being a symptom rather than a disease, no
method of treatment which does not remove the primary cause can be
permanently curative. Anti-syphilitic treatment should be tried in the
hydrocephalus of infants and young children. The rachitic element,
when present, must also be treated.
In congenital hydrocephalus, as there is no blocking of the passages
at the fourth ventricle, the foramina being as a rule much larger than
normal, no form of drainage is beneficial. Ligation of the common
carotids, one some weeks after the other, has been successful in
restoring the balance which normally exists between the secretion and
absorption of the cerebro-spinal fluid (H. J. Stiles). In acquired
hydrocephalus, puncture of the ventricles is sometimes followed by a
remarkable improvement in the symptoms, and may even result in
apparent cure. An exploring needle is introduced at the lateral angle
of the anterior fontanelle, to avoid the superior sagittal
(longitudinal) sinus, and from a half to one ounce of cerebro-spinal
fluid withdrawn. This is repeated once a week for several weeks.
Continuous drainage of the fourth ventricle through an opening made in
the occipital region (Parkin), and the establishment of a
communication between the ventricle and sub-arachnoid space
(Watson-Cheyne), or between the sub-arachnoid space of the spinal cord
and the peritoneal cavity, or the retro-peritoneal space (Cushing),
have been tried, with little more than temporary benefit in the
majority of cases. Operative treatment, if it is to do good, must be
undertaken early, before permanent changes in the brain have taken
place.
#Micrencephaly.#--This condition is due to defective development of
the brain, and not to premature closure of the cranial sutures and
fontanelles, and as the subjects of it are mentally deficient, and
often blind, deaf and dumb, the removal of segments of the skull with
a view to enable the brain to develop have proved futile.
CEREBRAL TUMOURS
As a comparatively small proportion of tumours of the brain--using the
term "tumour" in its widest sense--are amenable to surgical treatment,
it is only necessary here to refer to those aspects of this subject
that have a distinctively surgical bearing.
Various forms of growth occur in the brain, the most common being
tuberculous nodules, syphilitic gumma, endothelioma, glioma, and
sarcoma. Less frequently fibroma, osteoma, and parasitic, haemorrhagic,
and other cysts are met with. The growth may originate in the brain
tissue primarily, or may spread thence from the membranes, or from the
skull. In relation to operative treatment, it is an unfortunate fact
that those forms that are well defined and do not tend to infiltrate
the brain tissue, usually occur at the base, where they are difficult
to reach; while those that develop in more accessible regions are for
the most part infiltrating growths of a gliomatous or sarcomatous
nature, and are therefore irremovable.
_Clinical Features._--The presence of a tumour in the brain inevitably
results sooner or later in an increase in the intra-cranial tension,
and to this the symptoms are chiefly due.
The earliest and most prominent of the _general symptoms_ are severe
paroxysmal headache, optic neuritis, with choked disc and limitation
of the field for blue, amounting sometimes to blue-blindness
(Cushing). The relative degree of neuritis in the two eyes is a
reliable guide to the side on which the tumour is situated (Horsley).
The symptoms are seldom absent, and are common to all forms of tumour,
wherever situated. Vomiting, which is without relation to the taking
of food and is usually unattended by nausea, is a characteristic
symptom when present, but it is wanting in two-thirds of the cases
(Cushing). Vertigo, general convulsions, and signs of mental
deterioration are also present in a considerable proportion of cases.
In addition, certain _localising symptoms_ may be present. When, for
example, the tumour is situated in the _cortex of the Rolandic area_,
attacks of Jacksonian epilepsy, preceded by an aura, which is usually
referable to the centre primarily implicated, are common. The group of
muscles first involved, and the order in which other groups become
affected, are important localising factors. As the tumour increases in
size, these irritative phenomena are replaced by localised paralyses.
The tactile and muscular sensations are also disturbed, and motor and
sensory aphasia may be present. In some cases localised tenderness on
percussing the skull may be of assistance in indicating the site of
the tumour.
When the tumour is _sub-cortical_, that is, in the centrum ovale,
there are no Jacksonian spasms, the motor paralysis is more
widespread, and sensation also is lost on the opposite side of the
body. There is no special tenderness on percussion. It is not always
possible, however, to distinguish between cortical and sub-cortical
tumours, and in many cases both areas are invaded.
Tumours situated in the region of _the internal capsule_, and _in the
deeper parts of the brain_, are not attended with Jacksonian spasms,
paralysis develops more rapidly than in cortical and sub-cortical
tumours, and there is complete loss of sensation on the opposite side
of the body. The cranial nerve-trunks also are liable to be pressed
upon.
Tumours and cysts _in the cerebellum_ give rise to symptoms similar to
those of cerebellar abscess (p. 381).
Tumours _in the cerebello-pontine angle_, in addition to the special
symptoms associated with cerebellar lesions, give rise to symptoms of
interference with nerve-roots of the same side. The facial and
acoustic nerves are most frequently affected, resulting in facial
weakness, tinnitus, loss of perception for high-pitched notes, as
tested by Galton's whistle, or absolute unilateral deafness. Any of
the other cranial nerves from the fifth to the twelfth may be either
irritated or paralysed. Pressure on the pons may produce hemiplegia of
the opposite side, with spasticity and exaggeration of reflexes.
Sudden death may occur from crowding of the cerebellum into the
foramen magnum.
With the growth of the tumour the symptoms become aggravated, the
optic neuritis is followed by optic atrophy and blindness, the patient
gradually becomes stuporous, and finally dies in a state of coma. The
severity of the symptoms depends to a large extent on the rapidity of
growth of the tumour; thus an osteoma growing slowly from the inner
table of the skull and implicating the brain may reach a considerable
size without producing cerebral symptoms, while a comparatively small
sarcoma or syphilitic gumma of rapid growth may endanger life. A
sudden and serious aggravation of symptoms may result from haemorrhage
into a soft tumour, such as glioma.
The _diagnosis_ of the pathological nature of a cerebral tumour is
generally "hardly more than a guess" (Gowers). At the same time it may
be borne in mind that _syphilitic gummata_ occur in adults, from forty
to sixty years of age, who have suffered from acquired syphilis, and
who may present other evidence of the disease. They tend to increase
somewhat rapidly. A negative Wassermann reaction does not necessarily
exclude a diagnosis of brain syphilis. Severe nocturnal pain which
interferes with sleep is often a prominent symptom. Gummata are
generally situated on the surface of the brain; they often originate
in the dura mater, and when exposed are easily enucleated. Improvement
in the symptoms may follow the administration of iodides and mercury,
or organic arsenical salts of the salvarsan group, but in many cases
the growth is very resistant to anti-syphilitic treatment.
_Tuberculous masses_ occur most frequently in children and
adolescents, and other signs of tuberculosis are usually present. The
cerebellum is a common seat of these tumours, and they are often
multiple. Their growth may be rapid at first, and then become arrested
for a time. Spasmodic growth of a tumour strongly suggests its
tuberculous nature, and superadded signs of basal meningitis confirm
the diagnosis.
_Endothelioma_ grows from the dura mater, and in so far as it is a
well-defined and non-infiltrating growth it lends itself to removal by
operation. Unfortunately, however, it is usually located at the base
of the brain and is not readily accessible.
_Glioma_ is usually met with in the young; it tends to grow slowly at
first, but may take on a rapid growth at any time, and haemorrhage is
liable to occur into the substance of the tumour, causing a sudden
aggravation of the symptoms.
_Sarcoma_ occurs between puberty and middle life; it grows slowly, and
compresses rather than destroys the brain tissue. It is sharply
defined from the surrounding cerebral tissue, and is therefore more
favourable for operation than glioma.
The _prognosis_ is grave in all forms of brain tumour. Even in
syphilitic growths, although the more urgent symptoms may be
ameliorated by the use of drugs, recurrence is liable to occur, and
the structural changes induced in the cerebral tissue, and the
contraction of the cicatrix which results, may permanently interfere
with the functions of the brain, or may induce Jacksonian epilepsy.
Tuberculous tumours also may become arrested, and may cease for a time
to cause symptoms, but permanent cure is extremely rare. We have known
a sarcoma to recur as late as five years after removal. Death
sometimes occurs suddenly from haemorrhage, from acute oedema, or from
implication of vital centres.
_Treatment._--It is to be borne in mind that gummatous growths in the
brain are seldom influenced to any extent by anti-syphilitic remedies,
and time should not be wasted in trying this form of treatment.
The question of removal by operation arises in cases in which there is
reason to believe that the tumour is situated near the surface of the
brain and that it is circumscribed and of moderate size. Unfortunately
it is only in a small proportion of cases that these conditions are
present and can be recognised before opening the skull.
In many cases in which there is no hope of being able to remove the
tumour, it is advisable to relieve symptoms due to excessive
intra-cranial tension, such as blindness, severe headache, and
persistent vomiting, by performing a "decompression operation"
(_Operative Surgery_, p. 108). The relief that follows such operations
is often remarkable.
Lumbar puncture, frequently repeated, has also been practised for the
relief of tension in inoperable cases, but it is not free of danger
and is not to be looked upon as a substitute for a decompression
operation.
When surgical treatment is contra-indicated, all that can be done is
to palliate the symptoms by bromides, opium, phenacetin, caffein, and
other drugs.
#Tumours of the Pituitary Body# or #Hypophysis Cerebri#.--The tumours
most frequently met with in the pituitary body are of the nature of
adenoma with hyperplasia and cystic degeneration; carcinoma and
sarcoma also occur. They develop slowly and give rise to comparatively
slight increase in the intra-cranial tension. When the anterior lobe
is implicated and there is a pathological increase in the functional
activity of the gland (_hyperpituitarism_), signs of acromegaly may
ensue. Diminution of function (_hypopituitarism_) is attended with
infantilism, a rapid deposition of fat in the subcutaneous tissue, and
a decrease or loss of the genital functions. In women, amenorrhoea is
an early and constant symptom. Intense drowsiness is a marked feature
in some cases.
From their position close to the back of the optic chiasma these
growths affect the fibres passing to the nasal half of each retina,
and so give rise to bilateral temporal hemianopsia, and although there
is no choked disc, the optic nerves undergo primary atrophy from
pressure, and there is failure of sight.
Marked temporary benefit has followed the administration of thyreoid
extract. Operative treatment has been successful in a number of cases,
but as the anterior lobe is essential to life, the operation is merely
directed towards the relief of pressure on the optic chiasma with a
view to preventing loss of vision. We have seen marked relief follow a
temporal decompression operation.
#Epilepsy.#--The surgical aspects of Jacksonian epilepsy following
head injuries have already been considered (p. 358). For the cure of
those forms of epilepsy in which there is no gross lesion of the
brain, numerous surgical procedures have been suggested, but from none
of these have the results been encouraging.
#Hernia Cerebri.#--This term is applied to a protrusion of brain
substance through an acquired opening in the skull and dura mater,
such as may result from a compound fracture or a gun-shot wound. The
protrusion is due to increased intra-cranial tension, and is almost
invariably associated with infection of the brain and its membranes,
and with the presence of a foreign body or fragments of bone. Other
things being equal, a hernia is more likely to occur through a small
than through a large opening in the skull.
So long as the extruded portion of brain matter is small, it pulsates,
but as it increases in size and is pressed upon by the edges of the
opening through which it escapes, the pulsation ceases, and the
herniated portion may become strangulated and undergo necrosis.
In cases of compound fracture, and in other conditions associated with
necrosis of bone, masses of redundant granulation tissue growing from
the soft parts outside the skull may simulate a hernia cerebri.
The _treatment_ consists in counteracting the septic infection by
purifying the protruding mass, and if necessary by enlarging the
opening in the skull with rongeur forceps to admit of the removal of
foreign bodies or bone fragments and to relieve the inter-cranial
tension. Steps must also be taken to prevent meningitis, which, if it
occurs, is usually fatal. Pressure over the hernia, with the object
of returning it to the skull, is to be avoided, and the herniated
portion should not be cut away unless it is sloughing, or has become
pedunculated. It may be got rid of by painting it with 40 per cent.
formalin, which causes a dry, horny crust to form on the surface; this
is picked off, and the formalin re-applied.
After the hernia has disappeared and the wound is aseptic, steps
should be taken to close the gap in the skull. This may be done by an
osteo-plastic operation in which a flap, comprising a segment of the
outer table, is raised from an adjacent part of the skull and placed
in the gap; or by transplanting a portion of periosteum-covered bone
from the scapula, tibia, or other suitable source. An alternative
method is to implant a plate of celluloid, silver or other metal, or a
portion of the fascia lata, in the gap. When a permanent hole is left
in the bone, the patient should wear over it a leather or metal shield
to protect the brain.
The protrusion of brain resulting after a decompression operation
deliberately performed for the relief of intra-cranial tension, unless
it becomes infected, has nothing in common with a hernia cerebri.
SURGICAL AFFECTIONS OF THE CRANIAL NERVE
Irritation, or paralysis, of one or more of the cranial nerves may
result from lesions implicating their centres or trunks.
When the trunk of the nerve is affected, the paralysis is on the same
side as the lesion, and is of the lower neurone type; when the
cortical centre or the upper axons are involved, it is on the opposite
side, and is of the upper neurone type (p. 334). The lesions of the
cerebral centres with which nerve symptoms are most frequently
associated are: laceration of the brain, haemorrhage, meningitis,
tumour, and syphilitic gumma.
The nerve-trunks may be contused or torn across, especially in basal
fractures which traverse their foramina of exit; blood may be effused
into their sheaths as a result of injuries not attended with fracture;
or they may be pressed upon by an inflammatory effusion, a tumour, a
gumma, or an aneurysm invading the base of the skull. When the nerve
is merely contused, or pressed upon by blood-clot, the paralysis tends
to pass off in the course of a few days. When it is torn across, or
compressed by a new growth, the paralysis is permanent. In some
traumatic cases paralysis does not come on until a few days after the
injury, and is then due either to gradually increasing pressure from
blood-clot, or more probably to the onset of meningitis or of
ascending neuritis.
I. The branches of the _Olfactory Nerve_ may be ruptured as they pass
through the cribriform plate in fractures implicating the anterior
fossa of the skull, and there results complete and permanent loss of
smell (_anosmia_). Haemorrhage into the nerve sheath or contusion of
the nerve may cause a transitory loss of smell. The trunk of the nerve
may be implicated also in tumours and meningitis in the anterior
fossa. In all cases in which anosmia results there is also
interference with the power of recognising different flavours, thus
greatly impairing the sense of taste.
II. _Optic Nerve._--Temporary paralysis of one or both optic nerves is
a comparatively common result of traumatic effusion of blood into
their sheaths; the resulting blindness may pass off in a few days, or
may last for some weeks. When a large effusion takes place, the
prolonged pressure on the nerve may result in optic atrophy and
permanent blindness. Complete severance of the nerve by a bullet, the
point of a sharp instrument, or a fragment of bone, results in loss of
sight in the eye on the same side. In cellulitis of the orbit,
intra-orbital tumour, gumma and aneurysm in the region of the
cavernous sinus, also, the optic nerve may be implicated.
Lesions implicating the cortical centre for sight in the occipital
lobe give rise to hemianopia--that is, loss of sight in the lateral
halves of the fields of vision of both eyes--colour-blindness,
subjective sensations of light and colour, and other eye symptoms.
Double optic neuritis, followed by optic atrophy, is one of the most
constant effects of the growth of a tumour within the skull, and is
not uncommon in cases of cerebral abscess and meningitis. Pressure on
the optic chiasma, for example by a tumour of the pituitary body, is
associated with bilateral temporal hemianopsia.
III. _Oculo-Motor Nerve._--One or more of the branches of this nerve
may be compressed by extravasated blood, or be contused and lacerated
in fractures implicating the region of the sphenoidal fissure. Fixed
dilatation of one pupil may result from pressure by blood-clot,
without other functional disturbance of the nerve. A tumour or an
aneurysm growing in this region also may press upon the nerve.
Sometimes both nerves are involved--for example, in fracture
implicating both sides of the anterior fossa, and in tumours,
particularly gumma, growing in the region of the floor of the third
ventricle. In lesions of the cerebral hemispheres the third nerve is
frequently paralysed. Its cortical centre lies in close proximity to
the centre for the face (Fig. 179).
The most prominent symptoms of complete paralysis are ptosis or
drooping of the upper eyelid, lateral strabismus, and slight downward
rotation of the eye with diplopia. There are also dilatation of the
pupil from paralysis of the circular fibres of the iris, and loss of
accommodation and reaction to light from paralysis of the ciliary
muscle.
Paralysis of the muscle supplied by the third nerve is frequently
associated with paralysis of other ocular muscles. When all the
muscles of the eye are paralysed, the condition is known as
"opthalmoplegia externa"; it is usually due to syphilitic disease in
the floor of the third ventricle.
IV. The _Trochlear_ or _Patheticus Nerve_, which supplies the superior
oblique muscle, may suffer in the same way as the oculo-motor nerve.
When it is paralysed, there is defective movement of the eye downward
and medially, and the patient may complain of diplopia when he looks
downward.
V. _Trigeminal Nerve._--The most important surgical affection of this
nerve is "trigeminal neuralgia," which has already been described
(Volume I., p. 373). One or other of the divisions of the nerve may be
torn in fractures of the base of the skull, and there results
anaesthesia in the area supplied by it. In fractures crossing the apex
of the petrous portion of the temporal bone, the great and small
superficial petrosal nerves may be ruptured, and the soft palate and
uvula are paralysed and there is difficulty in swallowing; there are
also painful sensations in the ear. When the ophthalmic division is
implicated, the conjunctiva is rendered insensitive, and
conjunctivitis, which may be followed by ulceration of the cornea,
results from exposure to dust and other foreign bodies, which, on
account of the anaesthetic condition of the eye, are allowed to remain
and cause irritation.
VI. _Abducens Nerve._--This nerve, which supplies the lateral rectus
muscle, has the longest course within the skull of any of the cranial
nerves. In spite of this fact, it is comparatively seldom torn in
basal fractures; but it is prone to be pressed upon by tumours,
gummas, or aneurysms in the region of the base of the brain. When it
is paralysed, medial strabismus results.
VII. _Facial Nerve._--Paralysis of the facial muscles, more or less
complete, is the most characteristic symptom of lesions of this nerve.
_Paralysis of the Cerebral Type._--When the fibres of the nerve are
implicated in any part of their course between the cortical centre
and the nucleus in the lower part of the pons, the paralysis is of the
upper neurone (cerebral) type. It affects the side of the face
opposite to that of the lesion, and the defective movement is more
marked in the lower than in the upper half of the face.
This form of facial paralysis may be due to the pressure of an
intra-cranial tumour, abscess, or haemorrhage, or to degenerative
processes in the cerebral tissue, and as a rule other cranial nerves
are also affected. Its recognition is chiefly of diagnostic and
localising importance.
_Paralysis of the Peripheral Type._--When the trunk of the nerve is
implicated between the pontine nucleus and its peripheral
distribution, the paralysis is of the lower neurone (peripheral) type,
the muscles on the same side as the lesion being flaccid and
atrophied.
The majority of cases are of the so-called "rheumatic" variety, and
are attributed to exposure to cold. Others result from fractures
implicating the middle fossa of the skull, or are associated with
chronic suppuration in the middle ear.
In fractures passing across the petrous temporal, the nerve may be
torn at the time of the injury, or may become pressed upon by a
traumatic effusion or by callus later, but considering the frequency
of these fractures it is comparatively seldom damaged.
Suppurative disease of the middle ear is a more common cause of facial
paralysis. The nerve, as it traverses the facial canal (aqueductus
Fallopii), may be pressed upon by inflammatory effusions or
granulations, or may be destroyed by the suppurative process,
particularly in young children, as in them the osseous wall of the
aqueduct is very thin. It may also be involved in tuberculous and in
malignant disease of the middle ear.
The nerve may be injured also in the course of operations on the
mastoid or middle ear, or in the removal of tumours or glands in the
parotid region. As the nerve breaks up into numerous branches soon
after it leaves the stylo-mastoid foramen, the paralysis may be
confined to one or more of its branches.
Temporary paralysis may result from inflammatory conditions such as
parotitis, or from blows or pressure over the nerve, for example by
the forceps in delivery.
_Symptoms._--In complete unilateral _facial paralysis_ (Bell's
paralysis) the affected side of the face is expressionless and devoid
of voluntary or emotional movement. The muscles are flaccid, the cheek
is flattened and smooth, all its folds and wrinkles being
obliterated. When the patient speaks or smiles, the face is drawn to
the sound side (Fig. 201). The eye on the affected side cannot be
closed, and on making the attempt the eyeball rolls upwards and
outwards. The lower lid droops, the patient cannot wink, and the
conjunctiva therefore becomes dry, and is irritated by exposure to
cold and dust. The tears run over the cheek. From paralysis of the
buccinator muscle there is inability to whistle or to puff out the
cheeks and food collects between the cheek and the gums. The
orbicularis oris being also paralysed, the patient is unable to show
his upper teeth, and the labial consonants are pronounced
indistinctly. The sense of taste is often impaired from involvement of
the chorda tympani nerve.
[Illustration: FIG. 201.--Patient suffering from left facial
Paralysis. Note smoothness of left side of face, imperfect closure of
left eye, and deviation of face to right side.
(From a photograph lent by Dr. Edwin Bramwell.)]
When the paralysis is bilateral, the symmetrical appearance of the
face renders the condition liable to be overlooked.
_Treatment._--In addition to removing the cause, when this is
possible, recovery of function may be promoted by the administration
of drugs, such as potassium iodide, strychnin, or iron, by the
application of blisters, or by massage and electricity. These measures
are most useful in cases due to blows or exposure to cold. When the
nerve is accidentally divided in the course of an operation on the
face, it should immediately be sutured. So long as the electrical
reactions of the affected muscles indicate an incomplete lesion,
recovery may be confidently expected (Sherren). When the reaction of
degeneration is present and the paralysis has lasted for more than six
months, there is little hope of recovery, and recourse should be had
to operation, to restore the function of the nerve by grafting its
distal end on to the trunk of the hypoglossal nerve. To prevent
paralysis of the tongue the lingual nerve may be divided, and its
proximal end anastomosed with the distal end of the hypoglossal.
The facial may be grafted on the accessory nerve, but the associated
movements of the face which then accompany movements of the shoulder
often prove inconvenient.
_Facial Spasm._--Clonic contraction of the facial muscles (histrionic
spasm) occasionally results from irritative lesions in the cortex or
pons. Sometimes all the muscles are involved, sometimes only one, for
example the orbicularis oculi (palpebrarum)--blepharospasm. This
condition may be induced reflexly from irrigation of the trigeminal
nerve, notably of branches that supply the nasal cavities and the
teeth.
The _treatment_ consists in removing any source of peripheral
irritation that may be present, in employing massage, and in
administering nerve tonics, bromides, and other drugs. In severe
cases, the facial nerve may be stretched with benefit, either at its
exit from the stylo-mastoid foramen or on the face.
VIII. _Acoustic_ or _Auditory Nerve_.--The acoustic nerve is liable to
be damaged along with the facial in tumours of the cerebello-pontine
angle, and in fractures which traverse the internal auditory meatus.
Both nerves also may be torn across just before they enter the meatus
in severe brain injuries apart from fracture. Complete and permanent
deafness results. Effusion of blood into the nerve sheath, or into the
internal or middle ear, causes transitory deafness, and the patient
suffers from noises in the ear, giddiness, and interference with
equilibration.
IX. The _Glosso-pharyngeal Nerve_ is comparatively seldom injured.
When it is compressed by a tumour in the region of the medulla, there
is interference with speech and deglutition, ulcers form on the
tongue, and oedema of the glottis may supervene.
X. The _Vagus_ or _Pneumogastric Nerve_ is seldom injured within the
cranial cavity.
In the neck, it is liable to be divided or ligated in the course of
operations for the removal of malignant or tuberculous glands, for
goitre, or for ligation of the common carotid. Division of the nerve
on one side, or even removal of a portion of it, is not as a rule
followed by any change in the pulse or respiration. If it is
irritated, however, for example by being grasped with an artery
forceps, there is inhibition of the heart, and if it is accidentally
ligated, there may be persistent vomiting.
Division of the main trunk, or of its recurrent branch on one side,
results in paralysis of the corresponding posterior crico-arytaenoid
muscle--the muscle that opens the glottis. This condition is known as
unilateral _abductor paralysis_, and is accompanied by interference
with inspiration and phonation. If both nerves are divided, bilateral
abductor paralysis results: the vocal cords flap together, producing a
crowing sound on inspiration and embarrassment of breathing, and
tracheotomy may be necessary to prevent asphyxia.
The vagus and recurrent nerves have been successfully sutured after
having been divided accidentally.
XI. _Accessory_ or _Spinal Accessory Nerve_.--This nerve is seldom
damaged within the skull. It supplies the sterno-mastoid and
trapezius; but as these muscles usually have an additional nerve
supply from the cervical plexus, the accessory may be divided, or a
considerable portion of it resected, as, for example, in the treatment
of spasmodic torticollis, without any serious disablement resulting.
It is liable to be accidentally divided in excising malignant or
tuberculous glands in the neck. When, however, the accessory is the
only source of supply to these muscles, its division is followed by
considerable disablement, which appears to depend almost entirely on
the _paralysis of the trapezius_. The head is inclined slightly
forward, the shoulder is depressed, the arm hangs heavily by the side
and is slightly rotated forward, the scapula is drawn away from the
spine and rotated on its horizontal axis, and there is slight cervical
scoliosis with the concavity towards the affected side. The trapezius
is markedly wasted, and is, therefore, less prominent in the neck than
normally, and the functions of the arm and shoulder are impaired,
especially in making overhead movements. In time other muscles
compensate in part for the loss of the trapezius.
When divided accidentally, the nerve should be immediately sutured.
Even when the paralysis has lasted for some time, secondary suture
should be attempted; if this is impossible, the peripheral end should
be anastomosed with the anterior primary divisions of the third and
fourth cervical nerves (Tubby). Massage, electricity, and the
administration of tonics are also indicated.
XII. _Hypoglossal Nerve._--This nerve has been ruptured in fractures
passing through the canalis hypoglossi (anterior condylar foramen). It
is also liable to be divided in wounds of the submaxillary region--for
example, in cut throat, or during the operation for ligation of the
lingual artery, or the removal of diseased lymph glands.
The paralysed half of the tongue undergoes atrophy. When the tongue is
protruded, it deviates towards the paralysed side, being pushed over
by the active muscles of the opposite side. Speech and mastication are
interfered with, the tongue feeling too large for the mouth; in time
this disability is to a large extent overcome.
#The Cervical Sympathetic.#--The cervical sympathetic cord and its
ganglia may be injured in the neck by stabs or gun-shot wounds, or in
the course of deep dissections in the neck; and in injuries of the
lower part of the cervical enlargement of the spinal cord (p. 417) or
of the first dorsal nerve root.
Paralysis of the cervical sympathetic is characterised by diminution
in the size of the pupil on the affected side. The pupil does not
dilate when shaded, nor when the skin of the neck is pinched--"loss of
the cilio-spinal reflex." The palpebral fissure is smaller than its
fellow, and the eyeball sinks into the orbit. There is anidrosis or
loss of sweating on the side of the face, neck, and upper part of the
thorax, and on the whole upper extremity of the affected side.