SINUS THROMBOSIS
Lateral sinus thrombosis.
Soon after entering on its course across the mastoid process the lateral sinus presents a well-marked S-shaped curve. This sigmoid sinus bulges markedly forwards—especially on the right side—towards the region of the mastoid cells and antrum, so much so that a mere shell of bone intervenes between the sinus on the one hand and the antral region on the other. Indeed, the relations are so intimate that one would expect a more frequent occurrence of lateral sinus thrombosis. Furthermore, the sinus receives numerous venous communications from the mastoid cells, antrum, and other parts of the temporal bone, conspicuous amongst the last-named group of vessels being the mastoid emissary vein which, passing inwards at the upper and posterior border of the mastoid process, connects the posterior auricular and occipital veins with the lateral sinus.
From these considerations it is obvious that any acute or chronic infective process originating either in the aural region or in the neighbourhood can readily infect the sinus by direct propagation of organisms along one or more of these inter-communicating vessels (thrombo-phlebitis).
The sinus may also become infected in middle-ear disease by the more gradual process of mining and sapping, the osseous barrier between the antrum and sinus being progressively destroyed by the backward progress of the aural disease. The sinus may erect an additional barrier by throwing out granulations (external pachymeningitis) against the invading host, but, in the event of the attack overcoming the defence, sinus thrombosis may result, at first perhaps of a non-infective type but soon becoming definitely septic, the clot softening and disintegrating (osteo-phlebitis).
There can be no question that middle-ear disease is responsible for the very great majority of cases of lateral sinus thrombosis, and whether the infection takes place by extension of thrombus along the connecting veins (thrombo-phlebitis), or after destruction of the osseous barrier (osteo-thrombosis), the results are more or less identical.
Thrombosis first occurs in that part of the sinus which is in closest relation to the primary cause of the infection, the clot rapidly increasing in size until the lumen of the sinus is entirely obliterated. In its early stages the thrombus is of a chocolate colour, softening at a later date and breaking down into a purulent material. Many varieties of bacteria may be present though the infection is mainly dependent on the presence of the streptococcus pyogenes.
Two changes may now occur:—(1) the central portion of the thrombus, having softened into a purulent material, may be limited by the firmer thrombus in front and behind; and (2) the thrombus may extend into the neighbouring and connecting venous channels downwards along the course of the internal jugular vein, backwards along the course of the lateral sinus, inwards along the course of the superior petrosal sinus, outwards along the line of the mastoid emissary vein, downwards through the posterior condyloid foramen, and inwards along meningeal veins.
The symptomatology may be considered as follows:—
(1) Symptoms dependent on the extension of the thrombus to neighbouring venous and lymphatic channels.
(2) Symptoms resulting from toxic absorption or dependent on the transmission of infected material to other parts of the body.
1. Symptoms dependent on the extension of the thrombus to neighbouring venous and lymphatic channels. When the thrombus spreads downwards along the course of the internal jugular vein, there is swelling and tenderness along the line of the vein. The vessel, though thrombosed in its upper part—perhaps throughout its whole extent—is itself seldom palpable, the cervical swelling usually being dependent on associated lymphadenitis and lymphangitis. In those few cases where the thrombosed vein can be felt, resembling a ‘buried lead pencil’, the thrombus is sometimes of the non-infective type.
The combined venous and lymphatic involvement causes œdema of the tissues, pain, and rigidity on attempted movement. The anterior and external jugular veins may become engorged from the extra strain thrown upon them. Subsequently, the inflamed parts may break down and extensive cervical suppuration result.
When the thrombus spreads backwards along the course of the lateral sinus, the coagulation process may extend as far as the torcula and even further. Evidence as to the nature and extent of the process is not always apparent, though one expects to find some œdema of the overlying scalp tissues.
When the process spreads inwards along the course of the superior petrosal sinus there is considerable risk of involvement of the corresponding cavernous sinus, possibly of the opposite sinus also (see [p. 288]).
When the process spreads outwards along the course of the mastoid emissary vein, œdema, and dilatation of veins in the post-auricular region are observed, associated with tenderness on palpation. This is most apparent at the upper and posterior border of the mastoid process.
When the thrombus spreads downwards along the course of the posterior condyloid vein, there may be some œdema and pain on pressure in the upper part of the posterior triangle of the neck, associated with glandular enlargement in the region. These symptoms are dependent on the connexion established by the posterior condyloid vein between the sigmoid sinus and the deep veins of the neck.
When the thrombus extends inwards along the meningeal veins, meningitis, meningo-cerebritis, and cerebral abscess result.
2. Symptoms resulting from toxic absorption or dependent on the transmission of infected material to other parts of the body.
Optic neuritis is present, according to Hunter Tod, in about 50 per cent. cases. It develops rapidly and attains a high degree of intensity.
Headache is usually intense in character, persistent, but little remedied by drugs and presenting marked exacerbations. It is often most acute over the affected region.
The mental condition of the patient is subject to variation. In the average case mental symptoms are quite disproportionate to the severity of the disease. Sometimes the patient is cheerful, perhaps rather excited, retaining his faculties to the last, in other cases—as the result of excessive toxic poisoning—he lies in a stuporose, typhoid-like state. When the thrombus is associated with meningitis, meningeal symptoms predominate.
Vomiting is often a conspicuous feature, generally of the so-called ‘cerebral’ type, a regurgitation without nausea and retching.
The pulse is rapid, the rhythm irregular, and the tension lowered.
The temperature. The formation of the thrombus is usually notified by the advent of one or more severe rigors, the temperature rising to 103° or more. During the height of the illness the temperature is high but remittent, and rigors are frequent. The occurrence of a series of rigors is almost certainly indicative of sinus thrombosis. Any marked remission of temperature is succeeded by profuse sweating, but, with this exception, the skin remains dry and burning.
Each rigor implies the extension of the thrombus to other venous channels or the transference of infected particles, by means of the blood-stream, to other parts of the body. In the young general convulsions are often observed.
The tongue is brown and dry, the breath foul and diarrhœa of common occurrence. The skin may be jaundiced, and septic rashes are prone to develop. The liver and spleen may be enlarged and tender. Cough and foul sputum point to pulmonary infarction.
Treatment.
The mastoid antrum is rapidly exposed and the conditions investigated. The bone is then chiselled away in the backward direction, with the hammer and gouge, so as to expose the lateral sinus. The question then arises as to the condition of the sinus. This is a matter that may require considerable experience. The surgeon should be guided, not so much by exploratory puncture as by the surroundings and general appearance of the sinus. Thus, the absence of bleeding from the mastoid emissary vein during the process of exposure is very significant of sinus thrombosis. Again, whilst the normal sinus pulsates, is of dark blue colour and presents a shining surface, the thrombosed channel may be covered with pale granulations or obscured by fibrinous deposit, it does not pulsate, and appears of a yellow or deep purple colour. Between it and the bone there may be a collection of purulent matter. In the event of doubt, the surrounding regions should be carefully protected with gauze, after which the sinus may be punctured with a needle. The absence of fluid blood is conclusive of thrombosis.
Fig. 85a. Diagram to show the usual Points at which the Lateral Sinus is primarily infected. A, High up; from the posterior mastoid cells. In this case it may not be necessary to tie the jugular vein. B, Low down; involving the jugular bulb. This necessitates ligature of the vein. (After Hunter Tod.)
Fig. 85b. The Lateral Sinus exposed and opened. The lumen of the sinus is obliterated above and below the region of the infected thrombus by plugs of ribbon gauze pressed in between the sinus wall and the overlying bone. In this case it is not necessary to tie the jugular vein. (After Hunter Tod.)
In the event of the surgeon concluding that thrombosis is present, subsequent procedures vary according to the extent of the thrombus. Thus, when the clot appears to terminate above the jugular bulb, a strip of gauze is inserted between the bone and the parietal wall of the sinus so as to obliterate the lumen of the sinus on the cardiac side of the clot.
The danger of further extension of the clot being thus obviated, the bone is nibbled away in the backward direction till at least half an inch of healthy vessel is exposed on the occipital side of the thrombus. A second gauze plug is then introduced so as to obliterate the sinus lumen in that region also.
In the interval between the two plugs the sinus is freely laid open, all clot and granulations being gently curetted and washed away. Some bleeding may take place during these procedures, from the mouths of certain vessels entering the sinus between the two compressed regions. This is in itself a favourable symptom, insomuch as it proves that the thrombotic process has not extended in those directions. This hæmorrhage may be controlled with gauze plugs. The parietal sinus wall in direct relation to the thrombus is freely cut away, after which the whole field is lightly packed with gauze and the ear sewn back into position. The main portion of the wound is left open, the sinus plugs being brought to the surface whilst those inserted into the combined middle ear and antrum emerge from the external auditory meatus.
All gauze-plugs may be withdrawn after twenty-four to thirty-six hours, the wound cleansed and lightly repacked. This process is continued daily till all is healed.
When the clot extends into the jugular bulb, and when the jugular vein appears to be involved, it is necessary to expose and ligature the vein in the neck, thus preventing further extension of coagulation and diminishing the risk of general infection. This measure should be carried out before the lateral sinus is laid open. With fresh gloves and another set of instruments, the vein is exposed so as to allow the application of two ligatures, and the division of the vessel between those two ligatures. If possible, the ligatures should be applied above the level of the entrance of the common facial vein. In all cases, however, the application must be carried out, if possible, below the lower limit of the thrombus. After the vein has been divided, the upper end may be dissected in such a manner as to allow of its being brought to the surface of the wound and there anchored.
Elsewhere the neck-incision is sewn up and protected with collodion gauze. The surgeon then returns to the mastoid and sinus regions, completing the exposure of the sinus and laying it open freely to the surface. At the termination of these procedures, an attempt may be made, by irrigation between the open sinus above and jugular vein below, to wash away all thrombus contained in the intervening portion of the vessel.
Finally, both sinus and aural regions are packed with gauze, in a manner similar to that described above. Dressings are reapplied as circumstances demand, and the wounds allowed to heal by granulation.
The great frequency of a streptococcus pyogenes infection justifies one in the early administration of anti-streptococcic serum (20 to 40 c.c. of Burroughs Wellcome’s ‘Pyogenes’) followed by an autogenous vaccine as soon as that can be prepared.
Main Points in the Differential Diagnosis between
| Brain Abscess | Meningitis | Lateral Sinus Thrombosis | |
|---|---|---|---|
| Onset | Insidious. | Acute. | Acute. |
| Temperature | Subnormal (see [p. 255]). | First a rigor, then high and continuous temperature, usually intermittent. | First a rigor, then high and continuous temperature, usually remittent. Frequent rigors. |
| Pulse | Slow (see [p. 255]). | Rapid. | Rapid. |
| Mental condition | Often apathetic. In the later stages, stupor and loss of consciousness. | Very restless and delirious. Sometimes maniacal. Coma towards the end. | In the early stages, the mind is clear. This condition may persist till near the end when delirium and coma become evident. |
| Special symptoms | Paresis or paralysis, according to the site of the lesion. | Squints, retraction of the head and neck. Irregular palsies. | Œdema over mastoid, pain along course of internal jugular vein. Enlarged cervical glands. |
| Blood and cerebro-spinal examination | Progressive leucocytosis. Increased leucocytes in cerebro-spinal fluid. | Increased leucocyte count and organisms in fluid withdrawn by lumbar puncture. | Blood infection frequent. |
In typical cases no great difficulty will be experienced in diagnosing between brain abscess, meningitis, and lateral sinus thrombosis. In many cases, however, two or more of these conditions may be co-existent. Thus, both brain abscess and lateral sinus thrombosis are often complicated by the presence of a meningeal infection. Again, the undue prominence of abdominal, cardiac, or pulmonary symptoms—more especially in cases of lateral sinus thrombosis—demand the full consideration of enteric fever, endocarditis, and pneumonia. Thus, in a case recently under my care at the hospital, and in which I had the benefit of the wide experience of my Aural colleague, Mr. West, operative procedures were carried out on the mastoid region, the patient dying some days later from enteric fever. Again, the question of differential diagnosis between tuberculous meningitis, brain tumour and brain abscess is always cropping up. Thus, a short time ago, I explored both temporo-sphenoidal lobes in a boy suffering from double otitis media and presenting well-marked general cerebral symptoms, only to find that he was a subject of tuberculous meningitis.
The diagnosis is often difficult, and no trouble must be spared in the complete investigation of the case. Lumbar puncture should invariably be carried out, the fluid being examined both cytologically and bacteriologically. In all cases of doubt one would be wise to call in further advice before undertaking exploratory operation.
Cavernous sinus thrombosis.
Thrombosis of the cavernous sinus arises either as an osteo-phlebitis or as a thrombo-phlebitis. In the former case, the thrombus is dependent on disease of the bones related to the sinus—arising more especially as the result of prolonged sphenoidal sinusitis—whilst, in the latter instance, the sinus becomes infected through one of the many vascular communications connecting it with other neighbouring regions. Thus the radicles of the ophthalmic vein, by means of their communication with orbital, ethmoidal, and upper nasal vessels, and their connexion at the inner canthus of the eye with radicles of the angular vein, afford the most ready means of infection. Again, infection may spread from the auditory region along the superior petrosal sinus, and from the tonsillar and pharyngeal regions along the various emissary veins connecting the cavernous sinus on the one hand with the deep cervical vascular system on the other.
The two cavernous sinuses intercommunicate by means of the circular sinus, and consequently thrombosis of the one sinus is liable to involve its fellow. According to Macewen,[57] bilateral trouble occurs in 50 per cent. cases, the infection often spreading from one sinus to the other within twenty-four to thirty-six hours.
Thrombosis of the cavernous sinus is often associated with meningeal infection or brain-abscess.
Symptomatology.
(a) Symptoms dependent on the formation of the thrombus and its extension to neighbouring venous and lymphatic channels.
The presence of the thrombus and its extension into ophthalmic, angular, and retinal veins leads to proptosis, paresis of the ocular muscles, disturbances of vision, and œdema. Proptosis is of rapid development, frequently reaching its maximum within a few hours, the globe being protruded in the downward and outward direction. With respect to ocular palsies, the movements of the globe are greatly restricted with squints, ptosis, and perhaps complete ophthalmoplegia. The pupil may be contracted during the earlier stages, becoming fully dilated and insensitive at a later date. The vision suffers in proportion to the degree of paralysis of ocular muscles and associated retinal hæmorrhages and thrombosis. The veins of the lids, conjunctivæ, and upper part of the face and forehead are engorged, with corresponding œdema of the soft parts. The conjunctivæ may be chemotic.
The spread of the thrombus to the opposite sinus results in the development of bilateral symptoms, whilst the involvement of the petrosal sinus may bring about thrombosis of the lateral and sigmoid sinuses, with corresponding developments.
In other cases the meningeal veins are affected at an early date, in which case the symptoms dependent on the cavernous thrombus are obscured by those resulting from the meningeal infection.
(b) Symptoms dependent on toxic absorption or resulting from the transference of infected particles to other parts of the body.
These more general symptoms closely resemble those enumerated when discussing lateral sinus thrombosis (see [p. 283]). Headache, however, is of the most intense type, and pain, of a severe neuralgic character, is referred along the course and distribution of the first and second divisions of the fifth nerve.
Treatment.
It has been suggested that exploration could be carried out, the thrombus evacuated, and the cavernous sinus region drained from the naso-ethmoidal region or by approach along the floor of the middle fossa of the skull—an exaggerated Gasserian ganglion operation. Both these methods have been tried, but the difficulties encountered and the want of success tended to show that cavernous sinus thrombosis was beyond the reach of the surgeon. However, of recent date, more hopeful views have been entertained, it being suggested that the globe should be removed, the sinus explored, and the orbital cavity packed with gauze. It is doubtful, however, whether the end justifies the means.
The prognosis in brain abscess, meningitis, and sinus thrombosis.
A patient may be expected to recover from brain abscess, whether temporo-sphenoidal, cerebellar, or frontal, if an early diagnosis be made, if the case be uncomplicated by meningeal infection or sinus thrombosis, and if the evacuation be carried out without any great difficulty. As Sir William Macewen[58] pointed out, ‘an uncomplicated brain abscess may be regarded as the most hopeful of all cerebral affections.’ In fatal cases, death results from general meningeal infection or from the bursting of the abscess into the lateral ventricles.
In meningitis the prognosis is bad, more especially when the process is widespread. Early exposure of the affected region and the supply of adequate drainage offer the only hope of recovery. This, even under the most favourable circumstances, is a desperate remedy.
The prognosis in lateral sinus thrombosis hinges to a large extent on the time at which operative procedures are carried out. When the case is seen and operated on at an early date in the history of the disease, recovery may be anticipated in about 50 per cent. cases. Hunter Tod states that, when all cases are considered of whatever grade, about one-third recover. Death results from pyæmia, septicæmia, meningitis, or brain abscess.
Cavernous sinus thrombosis of the infective variety almost necessarily terminates fatally. Death results from causes similar to those observed in cases of lateral sinus thrombosis.