Fig. 61. A Case of Traumatic Orbital Aneurysm.
The impairment of venous flow in those radicles which drain into the cavernous sinus is evidenced by the marked engorgement of palpebral, conjunctival, episcleral, and retinal veins. Obstruction to lymph flow is shown by a hazy cornea, chemosis, and œdema of the parts surrounding the orbit. The danger thus incurred by the cornea is rendered more serious by the inability on the part of the patient to close the eyelids over the protruded globe. Keratitis and sloughing of the globe are to be feared. From muscular involvement, squints and diplopia are frequently observed. The pupil may be fully dilated through paralysis of the third nerve.
Defect in vision is experienced at an early date, but perhaps the most prominent subjective symptom lies in ‘noises in the head’, compared by the patient to the thud of a steam-hammer, the whirring of wheels, the buzzing of bees, &c. These noises are more or less constant, most annoying to the patient, and increased on bending down, straining, &c.
All these symptoms tend to become more severe as time lapses, though cases have been recorded in which the symptoms remained in statu quo. In the event of failure at relief or cure, the patient runs considerable risk of losing his sight from corneal ulceration, whilst repeated hæmorrhages and secondary infection may place the patient in imminent danger of his life.
In the consideration of the treatment of this condition, the results obtained in the 26 cases investigated will afford a valuable guide.
In 4 cases an expectant attitude was adopted, the patient being kept quiet, restricted in diet, and dosed with potassium iodide. One case improved, two experienced no material benefit, and the fourth, dissatisfied, discharged himself from the hospital.
In 10 cases compression was applied to the common carotid artery, with the result that in 3 cases the conditions remained stationary whilst in the remainder, either on account of the pain produced or from complete failure to bring about any improvement, this mode of treatment was abandoned in favour of ligature of the common carotid. In some cases the carotid compression was carried out by means of tourniquets, in others intermittent digital pressure was utilized by means of relays of assistants.
In 18 cases the common carotid was ligatured, in 12 cases as a primary measure, in 6 after failure of other methods. The immediate and remote results were in all cases as satisfactory as could be anticipated. Proptosis at once diminished, the globe receding in some cases to the normal position, and the distressing subjective symptoms were almost entirely relieved. In many cases the patients were enabled to return to work.
Some defect in vision commonly persists, dependent on muscular paresis (on account of the previous stretching), retinal thrombosis, or corneal changes. The longer radical treatment was deferred the greater and more distressing were the after-effects of the lesion.
According to Sattler, however, the results obtained by ligature of the common carotid are less favourable than as stated above, and by no means devoid of danger to life. Fifty-six cases were collected with results as below:—
39 cases recovered and showed marked improvement.
11 cases experienced no benefit.
8 cases died.
It has been urged that ligature of the internal carotid artery would suffice to bring about equally satisfactory results, combined with less danger to life and diminished risk of secondary cerebral degeneration. Such, however, does not seem to be the case, for the anastomosis between the angular arteries and between the terminal branches of the ophthalmic is so free that the results obtained by ligature of the internal carotid appear to be unsatisfactory. Indeed, even when the larger trunk was tied, secondary operations have been occasionally required in order to excise some large anastomotic channel in the region of the inner canthus of the eye and over the bridge of the nose.
From these data, the following conclusions can be drawn:—
1. That by means of rest, careful dieting, and administration of potassium iodide in large doses, the progress of the case can sometimes be arrested, but that much patience is required and the ultimate result is entirely problematical.
2. That compression—digital or instrumental, intermittent or continuous—is painful, tedious, and usually quite inefficacious.
3. That ligature of the common carotid affords the best chance of cure or alleviation.
When should the common carotid artery be ligatured? How soon after the development of symptoms? This depends largely on the severity of the accident that produced the arterio-venous communication. If the blow was severe and the depth and duration of the stage of unconsciousness of a prolonged character, it may be presumed that the brain was injured. Under such circumstances early ligature of the common carotid presents an appreciable danger by reason of the development of hemiplegia on account of the further interference with the arterial supply to the brain. In such cases the patient should be confined to bed or kept quiet for not less than two months, the operation being carried out when the general condition warrants surgical interference.
In the event of early operation being imperative, periodic digital compression of the common carotid, for a few minutes at a time, may be carried out with the object of accustoming the brain to the proposed new form of circulation. In ordinary cases the sooner the common carotid is tied the better is the ultimate result.
[36] Hunterian Lectures, February 1904.
[37] It is absolutely essential that the scalp incision should lie some distance away from the outer margin of the plate. Failure to adopt this procedure impedes the healing of the wound and adds to the risk of infection.
[38] If desired, the plate may be anchored in position by means of a few small silver-plated screws.
Tumours may develop in any part of the cerebrum and cerebellum, from the sheaths of the efferent nerves, from the vascular tissues, and from the membranes of the brain. Tumours arising from the bones of the skull are considered elsewhere (see p. 325).
The regional distribution of these tumours may be estimated by reference to the following table[39]:—
| Cerebellum | 33 | cases. |
| Deep or subcortical | 32 | „ |
| Precentral | 30 | „ |
| Post-central | 25 | „ |
| Extra-cerebellar | 19 | „ |
| Pontine | 15 | „ |
| Temporo-sphenoidal | 13 | „ |
| Multiple | 7 | „ |
| Fourth ventricle | 5 | „ |
| Third ventricle | 4 | „ |
| Pituitary | 2 | „ |
Schüster,[40] from an investigation of 1,000 cases, showed that cerebellar tumours are relatively more common than cerebral, the comparative size of the two regions being taken into account. An examination of Paton’s table shows that cerebellar and extra-cerebellar tumours together form rather more than 25 per cent. in 202 cases of brain-tumour formation.
Gliomata, sarcomata, and endotheliomata are the three commonest types of tumour formation. Other forms are fibromata, tuberculomata, syphilomata, cysts, and carcinomata.
Fig. 62. A Glioma of the Brain.
Fig. 63. A Sarcoma of the Brain.
occur with almost equal frequency in cerebrum and cerebellum. They are generally primary and single, the boundaries but ill-defined, and the tumour is seldom amenable to radical surgical procedures.
Fig. 64. An Endothelioma of the Dura Mater.
Fig. 65. A Fibroma of the Dura Mater. Indenting the cortex and attached to the pia-arachnoid by fine filaments.
grow from the meninges, periosteum of cranial bones, and from the sheaths of nerves and vessels. They are either primary and then single, or secondary and then multiple (sarcomatosis). Sarcomata are often more or less encapsuled, tending in the first instance to exercise a compression force, and only in the later stages to invade the surrounding regions. It is during this early stage of development that the tumour is capable of removal.
Fig. 66. An Acoustic Tumour. Attached loosely to the seventh and eighth nerves.
grow from the meninges of the brain. They are hard, nodular, and, in their early stages, definitely non-infiltrating, and, when accessible, removable.
are especially prone to originate in the cerebello-pontine angle, usually possessing a narrow stalk representing an atrophied nerve-trunk or vascular bundle. From the frequency with which these cerebello-pontine tumours are attached to the eighth nerve they are often designated acoustic tumours. They may be as small as a pea or as large as a hen’s egg. In their early stages they are probably pure fibromata, appearing as pink-red lobulated tumours. They are of slow growth, primarily compressing the brain-substance without invasion. Later on degenerative changes are prone to occur, with invasion of the cerebellar substance and extension into the internal auditory canal. Whether growing in the cerebello-pontine angle or in other parts of the skull, fibromata are often readily removed.
Fig. 67. Symmetrical Tuberculomata. Situated on either side of the falx cerebri above the tentorium cerebelli.
are most commonly situated beneath the tentorium. They are often multiple. They cannot be considered as favourable tumours from the surgical point of view, insomuch as they are frequently associated with tuberculous lesions in other parts of the body and complicated by a tuberculous infiltration of the meninges.
occur with greater frequency in the cerebrum than in the cerebellum. Sometimes they are totally unaffected by anti-syphilitic remedies, and, under such conditions, appear as densely hard and definitely encapsuled tumours. These more chronic gummata are usually cortical or subcortical in position, and, when accessible, are readily removable.
are of frequent occurrence. They may be (1) of traumatic origin, containing a grumous material characteristic of the incompletely absorbed blood-clot; (2) of parasitic origin (e. g. echinococcus); (3) due to cystic degeneration of a sarcomatous, carcinomatous, or gummatous mass; or (4) simple arachnoid cysts (see p. 203). Many of these cysts are amenable to surgical treatment.
are always secondary to cancer in other parts of the body—more especially carcinoma mammæ. They are usually multiple, and quite unsuited to surgical procedures.
Any of these tumours may be complicated by the presence of internal hydrocephalus, this condition being dependent on the pressure exercised by the tumour on the veins of Galen, or on the interference with the normal transudation of fluid from one ventricle to another.
The symptoms resulting from tumour formation may be considered under two headings:—
1. General symptoms, dependent on the general increase of intracranial pressure.
2. Localizing symptoms, dependent on local compression.
Previous to discussing the symptomatology of brain tumours, it cannot be too forcibly urged that the surgeon is seldom justified in embarking on an extensive operation for tumour removal except after consultation with a neurologist. Ill-planned and ill-timed operations are usually disastrous in their results, and little creditable to cranio-cerebral surgery in general. On general grounds also, the symptomatology of brain tumours, as given below, must be accepted in the light in which it is offered, not representing the complete neurological aspect of the case, but affording an index to general diagnosis. For further information the reader is referred to more extensive works on brain tumours.[41]
Headache.
Mental disturbances.
Optic neuritis, &c.
Vomiting.
Alterations in pulse, respiration, and blood-pressure.
Alterations in temperature.
Headache is an almost constant symptom, and presumably dependent on general or local dural tension. It may be general or localized, intermittent or continuous, intense or comparatively mild in character. It is the more intense when the tumour develops in the confined space of the subtentorium, and when the tumour is of considerable size. In young subjects, before the skull is synostosed, some compensatory enlargement of the skull may postpone the development of headache, or diminish its intensity.
The diagnostic value of a localized headache is rather problematical, but, when constantly referred to some particular region and when associated with definite tenderness on percussion, the localization of the headache assumes considerable importance in the regional determination of the tumour. Still, too much stress must not be placed on the site of the pain. A cerebellar tumour may give rise to frontal headache, and vice versa.
In the earlier stages of tumour development the patient is irritable, depressed, or apathetic, shows his objection to his fellow mortals on all possible occasions, is unable to concentrate his attention or exhibits impairment of memory. As has rather quaintly been observed, he appears in every sense to ‘have a weight on his mind.’ Inquiry amongst relatives will show that he has ‘changed in every way’, or ‘is not the same man’.
Mental changes vary according to the site and size of the tumour. For example, it has been stated that a general air of elation or exhilaration (Witzelsucht) may be regarded as almost diagnostic of tumours situated in the anterior part of the frontal lobe.
As the tumour increases in size, somnolence becomes the marked feature, progressing on to stupor and coma. In rare cases, mania may develop.
Optic neuritis must be regarded as one of the most constant and valuable symptoms in the diagnosis of intracranial tumour formation. The degree to which it progresses depends more on the site of the tumour than on its size. In general, it may be stated that it is most constantly associated with tumours of the temporo-sphenoidal and cerebellar regions, less common in frontal tumour formation, still less frequent in post-central tumours, and perhaps least common in tumours of the pons. In this last-mentioned case optic neuritis is always late in development, and not infrequently absent throughout the whole stage of the illness.
Primary optic atrophy only occurs when the tumour exerts direct compression on the optic chiasma and tracts—for example, pituitary tumours.
Paton,[42] from a series of 252 cases treated at the National Hospital, of which 202 were accurately diagnosed, found that optic neuritis or atrophy was present in 81·2 per cent. cases. The fundus change, though usually bilateral, may be confined to the ipso- or contra-lateral side. Considerable discussion has taken place as to the localizing value of unilateral disk changes. For instance, it has been stated that a unilateral neuritis indicates that the tumour is situated on that side of the brain, and that when disk changes are bilateral the side which evidences the higher grade of inflammation is the side on which operation should be conducted. In the light, however, of the most recent research it would appear that unilateral symptoms are not to be relied on in establishing the localization of the tumour. Gowers[43] lays stress on the statement that with strictly unilateral neuritis one should always suspect a general rather than a local exciting cause.
The actual cause of the neuritis is still a matter of doubt. It is possible that the same cause is not present in every case. Still, sufficient evidence is to hand to justify the probability that neuritis is dependent on the general increase of intracranial pressure—there is, at any rate, a close relationship between the two. The cerebro-spinal fluid is forced into and dammed up within the vaginal sheaths of the optic nerve, leading, in the first instance, to an œdema, and later on, to compression of the lamina cribrosa and interference with the circulation.
The increase of intraventricular pressure may also act directly on the optic tracts and chiasma—the anterior boundaries of the third ventricle—the pressure being then transferred directly to the nerve tracts.
Furthermore, the great intensity, great frequency of occurrence, and rapid development of optic neuritis when the tumour is subtentorial in position may be explained on the hypothesis that the rigid enclosure of the cerebellum permits of the ready application of pressure to the veins of Galen or to the iter, thus leading to an increase of intraventricular pressure, this pressure being then transferred to the optic region.
The alternative theory states that the old tissue destruction and the new tissue formation sets free certain toxic substances which act on the optic nerve-fibres, leading to œdema and inflammation. Paton, however, comes to the conclusion that ‘the nature of the tumour does not play any part in determining the onset of neuritis except in so far as the nature determines its localization’.
Whatever be the localizing value of optic neuritis, it is generally accepted that it commences in the upper nasal quadrant.
Visual acuity is but little impaired in the earlier stages of optic neuritis, but so soon as atrophic changes develop, diminution in the field of vision occurs.
The pupillary changes associated with tumours of the brain are closely connected with these fundus changes. In the early stages, the pupils may be contracted with the object of protecting the inflamed surfaces exposed to light, whilst, when atrophy develops, the pupils may steadily dilate, becoming fully dilated and fixed as the atrophic changes become fully developed.
These pupil changes must therefore be taken into consideration in estimating the value of pupillary changes in general.
Vomiting is dependent on stimulation of the medullary vomiting centre, or on irritation of the dura mater in the immediate neighbourhood of the tumour. The dura is supplied by branches of the fifth cranial nerve, the stimulus being referred to the vagus centre in the floor of the fourth ventricle.
Vomiting is of the so-called ‘cerebral’ type. It is of frequent occurrence, generally irrespective of ingestion of food and seldom preceded by any nausea and retching. The attacks are often associated with exacerbation of headache, and more rarely with some slight elevation of temperature. The more severe the vomiting the more likely is the tumour to be subtentorial in position.
In the early stages there is but little alteration in pulse and respiration. Later on, the increasing intracranial pressure acts as a stimulus on the vagus and vaso-motor centres, the pulse becomes slowed and the blood-pressure raised. When the pressure is considerable, the slow pulse and deep, even stertorous, respiration evidence the effect produced on the medullary centres. In the terminal stages the imminent exhaustion of these centres is heralded by progressive acceleration of the pulse, by great fall in blood-pressure, and by the advent of Cheyne-Stokes respiration.
The more marked the alterations in pulse and respiration the more likely is the tumour to be subtentorial in position.
The temperature tends to remain subnormal throughout the progress of the case, except during the terminal stages when pyrexia is often observed. Occasional elevations of temperature during the course of the illness may be explained by transient attacks of ependymitis or cerebritis.
Differences of temperature on the two sides of the body may occasionally be observed, especially when the tumour involves the basal ganglia.
Headache tends to be localized to the frontal region, vomiting is seldom a conspicuous feature, and optic neuritis is not only rather later in development, but also less progressive than when the tumour is placed in other situations. If the tumour occupies the orbital aspect of the lobe, primary optic atrophy (from pressure) may be existent on the affected side with optic neuritis of the contralateral fundus.
The mental condition is often profoundly altered and, according to some writers, more especially so when the tumour is situated on the left side. The quality of mental change varies considerably in individual cases. In some there is an attitude of general suspicion, the patient following all points in his general examination with a curious air of suspicion, in others moral perversion is the rule, whilst in a third group of cases a state of elation and exhilaration is the predominant feature, a condition which, as previously stated, is said to be pathognomonic of a tumour frontally situated.
Anosmia—uni- or bi-lateral—may be present, but, on account of the general condition of the patient, considerable difficulty is experienced in endeavouring to demonstrate the existence of this symptom.
Fig. 68. The Cortical Motor and Sensory Areas.
Incontinence of urine has been observed, independent of the condition of the patient—in other words, without a sufficient degree of coma to account for the state.
When the tumour is of considerable size, some degree of paresis of the contralateral side of the body may result, due to backward pressure exercised by the tumour on the corona radiata preceding from the pre-Rolandic motor area. Associated with this paresis the deep reflexes may be increased with extensor plantar reflex (Babinski) and some diminution of superficial reflexes. The more posterior the tumour the greater the degree of paresis, and the more exaggerated the reflexes. When the tumour is situated on the left side the motor speech centre may be affected.
Fine tremors may be noticed, usually involving the muscles of the upper extremities, and best demonstrated by asking the patient to hold his arms horizontally with the palms downwards.
Paresis on the contralateral side may be preceded by or associated with fits, these partaking of the Jacksonian type and accompanied by conjugate deviation of the eyes towards the side opposite to that on which the tumour is situated. This association of fits suggests that the tumour occupies the second frontal convolution.
In the early stages symptoms of irritation predominate, the patient suffering from fits of a focal or Jacksonian type (see p. 189), whilst, later on, paresis of a progressive type, involving the face or extremities unequally, becomes evident. In children, however, the rapid transference of impulses from one motor area to another causes the fits to soon lose their focal character, general convulsions taking their place.
If the tumour occupies the left side of the brain (in right-handed individuals) the motor speech centre of Broca may be involved, with difficulty in or failure of the power of speech.
Apraxia may be present, a condition characterized by inability on the part of the patient to perform certain familiar purposive movements, such as sewing, turning a key in the lock, &c.
The contralateral pupil may be contracted from irritation, or dilated from paralysis; the ipsolateral is variable, more commonly dilated.
In the event of extensive tumour formation and when the growth is associated with tract degeneration, the deep reflexes will be increased on the contralateral side, with well-marked extensor plantar response.
Attacks of focal epilepsy are frequently observed when the tumour occupies the post-central convolution, such developments being probably dependent on forward pressure effects. These epileptiform attacks, however, are almost invariably preceded by some sensory auræ. Furthermore, the fits will usually be followed by ‘some degree of anæsthesia or analgesia, a loss of tactile sensation over half the body, affecting mostly the hand and foot, with loss of power and astereognosis (inability to recognize the form and consistency, and to name objects placed in the affected hand)’ (Beevor).
When situated in the left angular gyrus, word-blindness may result—inability to appreciate the meaning of written words, &c.
When the tumour presses on the optic radiation, hemianopia results, with ipsolateral temporal and contralateral nasal blindness.
When the tumour occupies the anterior part of the temporo-sphenoidal lobe, more especially when it is situated on the internal aspect of that lobe, the degree of optic neuritis is intense. Perversion or loss of smell may be noticed—a symptom of difficult determination on account of the general condition of the patient.
As the result of pressure exercised on the optic tracts hemianopia—with hemianopic pupillary reaction (the pupil not reacting to light)—may be observed. Pupillary reactions, however, are complicated by possible paralysis of the third nerve.
Some weakness of the face muscles on the contralateral side is a fairly constant symptom, presumably dependent on the upward pressure exercised on the lower motor areas.
A tumour involving the more posterior and central portions of the lobe may bring about a certain degree of word-deafness, whilst objects may be incorrectly named or named with difficulty, the patient being more or less aware of his mistakes and evidencing considerable annoyance of the same.
In whatever part of the lobe the tumour be situated, certain sensory auræ may be present. Not infrequently the patient falls into the so-called ‘dream-state’. When sensory auræ are associated with crude sensations of smell and taste, with chewing or spitting movements, the tumour is probably situated on the antero-internal aspect of the lobe.
Headache may be localized to the back of the head, and optic neuritis is usually both early in onset and intense in degree. Perhaps the most important localizing symptom is homonymous hemianopia—blindness in the temporal half of the retina on the same side as the lesion and in the nasal half of the opposite eye. This is explained by the fact that the fibres of the optic radiation, passing forwards from the affected occipital region, supply those retinal areas. The reaction of the pupil will be unaltered, for the pupillary nerve-fibres, in their course towards the third nerve nucleus, are only directed backwards as far as the anterior corpora quadrigemina. Consequently, an interruption of optic fibres between retina and third nerve nucleus brings about a loss of pupillary reflex when light is thrown on the blind portion of the retina, whilst if the lesion be situated further back, pupillary reaction is unaltered. This is Wernicke’s sign.
Certain symptoms are more or less common to all subtentorial tumours, whether they arise within the cerebellar substance (intra-cerebellar) or immediately outside the brain-substance (extra-cerebellar). Headache is very severe, and in about 50 per cent. cases, localized to the back of the head, perhaps associated with stiffness of the neck muscles and retraction of the head. Optic neuritis is early in onset and intense in degree. It is more constant in cerebellar tumour formation than in tumours located in almost any other part of the brain. The choking of the disk is marked and hæmorrhages are frequent. Vomiting and other symptoms referable to increased subtentorial pressure—slow pulse, altered rhythm of respiration, &c.—are usually well marked.
Fig. 69. The Visual Paths. O.L., Occipital lobe; O.R., Optic radiation; O.T., Optic tracts; P., Pupillary fibres from optic tract to third nerve nucleus; O.C., Optic chiasma; O.N., Optic nerve; 1, Blindness of affected eye; 2, Bitemporal hemianopia; 3, Bilateral homonymous hemianopia, with hemianopic pupillary reaction; 4, Bilateral homonymous hemianopia, pupillary reaction normal.
Vertigo is most apparent when the patient is suddenly changed in position or tries to stand or walk. It appears in two forms, either as a definite sense of movement of self (subjective vertigo) or of objects (objective vertigo), or merely as a giddy feeling. In objective vertigo the sense of displacement of objects is more commonly from the side of the tumour towards the sound side.
Vertigo is dependent on the influences exercised by the tumour on the cerebello-vestibular apparatus, and on irritation of those branches of the fifth nerve which are distributed to the dura mater in the immediate neighbourhood of the tumour, the impulses being then transferred to the bulbar nuclei of that nerve and thence to the pneumogastric nucleus.
Ataxia and inco-ordination of movement are also prominent symptoms. Ataxia results from one or more of the following causes: (1) co-existent vertigo, (2) asthenia of the muscles of the affected side, the muscular contractions being irregular in their nature, ill-timed in their action, and often in excess of actual requirements, and (3) involvement of the spino-cerebellar tracts and their terminations.
The patient, when standing with the eyes shut and one foot advanced in front of the other, is unable to maintain his balance, staggers and tends to fall. No great diagnostic value can be attached to the direction in which he sways or falls, though, from my own experience, it would appear more probable that he should lurch towards that side on which the tumour is situated. In walking, however, there is occasionally a definite tendency to deviate towards the opposite side, probably due to over-correction of the weakened muscles on the affected side. The gait should present the typical appearance of cerebellar ataxia, and the patient may walk with the head drawn down towards the shoulder of the affected side, the chin being tilted in the opposite direction.
Inco-ordination of movement is rendered most obvious during active movement of the limb, decreasing towards the termination of that movement, and ceasing so soon as the object is attained. This is most readily demonstrated by the well-known ‘finger-to-nose’ test.
Nystagmus is one of the most frequent symptoms of cerebellar tumour, usually lateral, the movements coarse or fine, and most marked when the eyes are directed towards the side of the lesion.
In the more differential diagnosis between extra- and intra-cerebellar tumours, the following points should be noted:—
Extra-cerebellar tumours situated in the cerebello-pontine angle tend to lead to compression of the eighth nerve (with deafness and tinnitus), of the seventh nerve (with paralysis of the face muscles), of the fifth nerve (with anæsthesia of the parts supplied by that nerve), and more rarely of the sixth nerve (with paralysis of the external rectus). The ninth, tenth, eleventh, and twelfth nerves are but rarely involved.
Intra-cerebellar tumours seldom give rise to pressure effects on isolated cranial nerves. On the other hand, one expects ipso-lateral paresis or paralysis, with exaggerated reflexes (see Fig. 78). Conjugate deviation of the eyes to the side opposite to that on which the tumour is placed is a fairly frequent symptom, the deviation being associated with well-marked lateral nystagmus. When the tumour is of considerable size, or placed nearer the central portion of the cerebellum, pressure may be exerted on the pyramidal fibres with paresis or paralysis on the contra-lateral side of the body.
In addition, allusion should be made to Dana’s symptom—‘cerebellar fits’—said to be almost pathognomonic of an extra-cerebellar tumour (or abscess) situated in the cerebello-pontine angle. In such cases, there may be sudden attacks of tinnitus, vertigo, and apparent loss of consciousness, during which the patient falls to the ground as if struck with lightning. The final stage of falling is said to be dependent, not so much on actual loss of consciousness, as from the absence of cerebellar innervation and a total loss of equilibrium. These attacks are brought about by sudden alterations in position.
Considerable research has recently been carried out, and much knowledge obtained as to the functions of the pituitary body and the symptoms that result from lesions of the gland.[44] As is well known, the pituitary body consists of two portions, an anterior (derived from upgrowth of buccal epiblast) and a posterior (formed from neural epiblastic downgrowth).
Complete removal of the body in animals invariably terminates fatally, the patient exhibiting a definite train of symptoms—cachexia hypophyseopriva—and dying within a few days or weeks, the younger animals living longer than the older. The symptoms of apituitarism are as follows: fall of body temperature, lowering of blood-pressure, increasing feebleness, muscular tremors, a curious attitude resembling that of defæcation, coma, and death.
On further investigation it was proved that all these symptoms were observed when the anterior portion of the gland was alone removed, whilst, on the other hand, extirpation of the posterior half created no great change in the animal’s general health.
Fig. 70. A Pituitary Tumour.
In the human being it would appear that the symptoms resulting from the development of pituitary tumour formation may be classified into two groups, those of hyper-pituitarism and those of hypo-pituitarism.
In the former case the secretion being superabundant, acromegaly and giantism are observed. Keith[45] considers that one of the substances secreted by the gland is of the nature of a hormone, rendering the osteoblasts hypersensitive to the various stresses that fall upon the human skeleton during life, and that the osteoblasts, at the origins and insertions of muscles, become increasingly sensitive to the traction of muscles. Muscular impressions and processes of the skeleton become exaggerated by the new bony matter, and if the epiphyseal lines be still open, the osteoblasts of which appear to be specially affected, giantism is produced. The skull and skeleton of the giant O’Brien are regarded as typical examples of the results due to over-secretion of the gland.
Hypo-pituitarism leads to a striking and rapid development of fat (adiposity), loss of sexual power and amenorrhœa, persistence of sexual infantilism (if the patient be attacked when young), harsh skin and œdematous tissues, subnormal temperature, and psychic disturbances.
In any case, whether the secretion of the gland be increased or decreased, the developing tumour tends to compress those cranial nerves with which it is in close anatomical relation. For instance, the gland, being situated immediately behind the optic chiasma, tends to compress the mesial nasal optic fibres producing bilateral temporal hemianopia, with primary optic atrophy as a final result. In some cases optic neuritis is observed with secondary atrophy. The third, fourth, and sixth nerves may also be affected, with consequent squints, ptosis, and perhaps complete ophthalmoplegia.
In addition, it should be noted that glycosuria and albuminuria have been observed.
In the general diagnosis of brain tumours, reference must be made to Lumbar puncture and X-ray investigation.
With respect to the desirability of carrying out lumbar puncture in brain tumours and the value of the information obtained, considerable difference of opinion exists. Lumbar puncture supplies information as to the tension of cerebro-spinal fluid and as to its bacteriological and cytological character. The evidence so obtained as to tension is of little value in view of the proved increase of intracranial pressure as evidenced by the mental condition of the patient, the headache, optic neuritis, &c. On the other hand, bacteriological and cytological examination of the fluid may point to the tuberculous or syphilitic composition of the tumour, thus offering help from the point of view of treatment. Still, information of almost equal importance can be obtained by tuberculin, Wassermann, and other tests. There is also considerable risk attendant on the process. The rapid withdrawal of cerebro-spinal fluid has been followed by disastrous results, the medullary stem being suddenly forced downwards into the foramen magnum, with corking up of that aperture, and complete upset of the medullary centres. Such a disaster is the more likely to occur when the tumour is subtentorial in position. Looking at the question from the broadest point of view, it would appear that the performance of lumbar puncture in cases of suspected brain tumour is fraught with considerable peril.
X-ray examination should always be carried out. More commonly the results are negative, the nature of the tumour seldom permitting sufficient shadow formation. Occasionally the firmer and denser tumours allow of a more definite result. When the tumour arises from the bone, or is so situated as to change the shape of the part with which it is in contact, valuable information will be obtained. For example, the hollowing out and general enlargement of the sella turcica in pituitary tumour formation.
The indications for operation must be considered under two groups:—
Those for radical operation aiming at the removal of the tumour.
Those for palliative operation aiming at the alleviation of symptoms.
According to Risien Russell,[46] the following are the main indications:—
(1) Cases in which the tumour can be accurately diagnosed.
(2) Cases in which the tumour is situated in an accessible position. The more favourable sites are the surface of the cerebrum, the lateral lobe of the cerebellum, and the cerebello-pontine angle.
(3) Cases in which there is reason to believe that the tumour is simple, and of such a nature that it can be removed from its bed.
(4) Cases in which there is reason to believe that the removal of the tumour will not greatly imperil the patient’s life, and, furthermore, will not result secondarily in the development of fits, paralysis, aphasia, &c.
The following are the main indications for operation:—
To prolong life.
To alleviate the severe and persistent headache.
To stop fits.
To save the sight.
And, in general, to benefit the patient by reducing the increased intracranial pressure, even though it may be quite impossible to remove or even locate the tumour.
Of all the considerations enumerated above, for which palliative measures are indicated, there is no symptom which more urgently demands alleviation than optic neuritis. This question of sight-saving may be accepted as a basis on which to estimate the value of palliative measures in general. It is obvious that no mere ‘decompression’ operation will save the sight when the optic inflammation has progressed to atrophy, and even in the earlier conditions of neuritis cases must be carefully chosen. Herbert Bruce[47] admirably clinches the matter in the following words: ‘As to the prediction of improvement of vision after trephining, everything depends on the condition of the disks. Yellowish white patches of exudate or white atrophic changes, especially when associated with macular changes, all indicate that the secondary changes in the disks will be permanent. In proportion to this development will the vision be impaired, whilst when the loss of vision has been dependent on the swelling of the disks, then not only will the sight be saved but largely improved. In other words, one might say, therefore, that when the neuritis has not progressed on to atrophy the sight would be saved.’ Even in the event, however, of the ocular conditions being unfavourable for palliative operation, other factors in the case still remain—the terrible and persistent headache, the fits, the emaciation from vomiting, &c., all of which require the most careful consideration, and all of which can be remedied by an efficient decompression operation.
After the usual preparatory treatment and the application of the scalp-tourniquet, the skull is opened either by craniectomy or craniotomy. The two methods—with their relative advantages and disadvantages—have already been described (see Chapter II), but there can be no question that a brain tumour should be exposed by the formation of an osteoplastic flap. Such a procedure is called for on the ground that the exact localization of the tumour is always a matter of very great difficulty, and that it is impossible to foretell with certainty as to whether it will be feasible to remove the tumour or not.