[Ill.u.s.tration: 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 dema 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 dyspna, cough, and pain in the side, coa.r.s.e moist rales, and dark ftid 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 a.s.sert 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 dema 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, dema 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 s.p.a.ce 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 a.s.sociated 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.
[Ill.u.s.tration: 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 a.s.sociated with such great cerebral deformity as to be inconsistent with life. It does not as a rule pulsate (Fig. 198).
[Ill.u.s.tration: 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.
[Ill.u.s.tration: 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 s.p.a.ce, 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 a.s.sociated, 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 s.p.a.ce surrounding the brain, or in the interior of the ventricles, const.i.tuting 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 s.p.a.ce 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 s.p.a.ce, 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.
[Ill.u.s.tration: FIG. 200.--Hydrocephalus in a child aet. 3-1/2.]
In mild cases, especially when a.s.sociated 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 pa.s.sages 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 s.p.a.ce (Watson-Cheyne), or between the sub-arachnoid s.p.a.ce of the spinal cord and the peritoneal cavity, or the retro-peritoneal s.p.a.ce (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.