Thrombus

“ Thrombosis and Embolism.
A blood-clot formed within a blood-vessel during life is called a thrombus. The entire process of which the thrombus is the essential element is designated thrombosis.
These terms were introduced by Virchow17 to avoid the confusion which resulted from regarding the process and result as synonymous with inflammation of the vessel. All writers, even at present, do not adhere to this strictness of meaning. For a thrombus of the vulva indicates a clot of extravasated blood within the connective tissue of the labium ”

“ 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. ”

“ LIII) . In this instance, the thrombus originated in the right iliac veins; and, although no attempt was made to demonstrate the primary vascular lesion, so many similar cases are recorded (7, 82) , and vascular damage is so frequent in this disease, that the hypothesis attributing pulmonary embolus to a thrombus initiated by a phlebitis is strongly supported.
Parenchymatous and skeletal lesions of hemorrhagic type, although variable quantitatively, are frequent and involve the muscles, the parenchymatous organs,—the adrenal especially,—and the mucosa of the alimentary canal. ”

“ A thrombus, however, is slower in its formation, and may produce gradually increasing anæmia of the region of brain supplied before it is absolutely complete, with a gradually increasing paralysis and loss of consciousness slowly approaching. Thus we may have the early symptoms in the form of headache, vertigo, heaviness, and drowsiness, peculiar sensations in the limbs about to be paralyzed or in the head, delirium of various kinds, or hysterical manifestations. ”

“ The occurrence of thrombi is favored and, now and again, a thrombus plugs an artery which supplies an important and even vital part of the brain. The arteries of the brain are end arteries, hence there is no chance for collateral circulation. ”

“ When not developing with extreme rapidity the symptoms are very similar to those caused by stenosis of the pulmonary artery, and in the suddenly fatal cases they are almost identical with rupture of the heart or rupture of a thoracic aneurism, or even angina pectoris. The history of an antecedent thrombus or of a disease of the heart which is likely to be accompanied by thrombus, together with the absence of physical signs, render a diagnosis many times probable. ”

“ In a great number of cases the thrombus of the worm-aneurism is continued past the mouth of the anterior mesenteric artery, into the lumen of the aorta, and, as such, is the exclusive cause of the embolisms of the pelvic and crural arteries which bring about the intermittent hobblings (the author says “intermitterenden Hinken,” not “Hahnentritten,” the usual equivalent term for stringhalt) . ”

“ A suddenly-developed, complete hemiplegia or other paralysis may be considered as in all probability either hemorrhagic or produced by a thrombus so large that the results will be disorganization of the brain-substance, and a future no more hopeful than that of a clot. ”

“ PHLEBITIS AND PHLEBO-THROMBOSIS.—The formation of thrombi in the uterine and pelvic veins is sufficiently common during the puerperal period. The coagulation may result from compression or from enfeeblement of the circulation. A predisposition to its occurrence is created by relaxation of the uterine tissue. A normal thrombus is in itself harmless. In time it becomes organized, and the occluded vessel is converted into a connective-tissue cord, or a channel may form through it which permits the passage of the blood-stream. ”

“ Comparison of operations for lateral sinus thrombosis. Except when the thrombus is limited to the upper part of the sigmoid sinus, it is undoubtedly wiser to tie the jugular vein than to be content with curetting out the clot after obstructing the sinus above and below by means of gauze plugs. Exposure of the jugular bulb is so difficult an operation and requires so much time, especially if the whole length of the upper portion of the jugular vein is also dissected out, that it is seldom advisable to perform it ”

“ When a vein is inflamed the blood in it is apt to form a clot, or thrombus, which, if loosened and displaced from its original position, may be carried as an embolus towards the heart and there be arrested ”

“ A thrombus of the basilar artery may lead not only to rapid, but even to sudden, death. A phthisical patient died suddenly while eating his supper, and a thrombosis of the basilar artery, with softening of the pons, was found. Of course the lesion must have been of older date.50 Bright51 thought that when symptoms pointing to disease of the intracranial vessels were present the diagnosis was confirmed, and the location of the lesion in the vertebral arteries rendered highly probable, by a persistent occipital [p. 971] pain. ”

“ By the irritative character of the thrombi themselves, they excite inflammatory action in the adjoining tissues; in this way are produced multiple abscesses. Therefore, we find in persons who die under such conditions, abscesses in the brain, heart, lungs, kidneys and intestines; further we may find purulent inflammation and abscesses in the connective tissues.
It is now necessary to explain the nature and composition of both the thrombus and embolus, and how, through their mechanical agency, the process of embalming may become seriously impaired, if not altogether arrested. ”

“ The more rapidly the obstructing thrombus extends, the earlier and more extreme is the oedema likely to become, while the slower the advance of the thrombus, the more favorable is the opportunity for an enlargement of the collateral vessels through which a sufficient flow of blood is permitted to check oedema and preserve nutrition. ”

“ All thrombi may become softened. When the process of organization advances normally, the softened parts are absorbed as rapidly as the formation of vascularized fibrous tissue progresses. If this formation is checked or stopped, the process of disintegration still continues. White corpuscles undergo fatty degeneration; red corpuscles give up their coloring matter and become converted, like the fibrin, into granules, and there results a granular detritus. This is present as a viscid, semi-fluid material, either red, gray, or yellow, according to the color of the thrombus. ”

“ Thrombi in the veins produce inflammation in and around the vein, thickening of the skin and connective tissue, gangrene and hemorrhage.
The consequences of embolism vary with the character of the embolus and its situation. A simple plug of fibrine in a vessel only produces changes in the circulation, but a plug from a gangrenous thrombus has a tendency to excite suppurative inflammation wherever it lodges.
The size of the artery thus obstructed, and the character of its collateral circulation also lead to a variety of results. If a large artery is stopped, the part becomes empty ”

“ When the superficial veins are emptied, the blood flowing by those deep-seated is to be directed to the wound by muscular action; with this view the patient is made to grasp the lancet-case, or any other solid body, in his hand, and turn it round. If the opening in the integument is too small, the flow gradually diminishes, and at length stops, in consequence of blood being insinuated into the cellular tissue, coagulating, and so forming what is termed a405 thrombus, which plugs the wound. ”

“ At the post-mortem examination the pulmonary artery was found occluded with clot and the ovarian vein contained a thrombus (Byron Robinson) .
It is important to note that these fatal cases of pulmonary embolism occur when they are least expected, and it is an unusual sequence in patients with obvious thrombosis of the femoral and saphenous veins.
The most constant symptoms are urgent dyspnœa accompanied by great distress; in some instances the patient becomes pallid and in others cyanotic. Death may follow in a few minutes ”

“ The bruising of the vessel wall, especially if it is diseased, may result in the formation of a thrombus which occludes the lumen temporarily or even permanently, and in rare cases may lead to gangrene of the limb beyond.
Subcutaneous Rupture.#--An artery may be ruptured subcutaneously by a blow or crush, or by a displaced fragment of bone. This injury has been produced also during attempts to reduce dislocations, especially those of old standing at the shoulder. It is most liable to occur when the vessels are diseased. ”

“ 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. ”

“ Prognosis and Treatment.—In the majority of instances, when there is occasioned serious inconvenience, the outcome is not likely to be favorable, according to Möller. Detachment of a portion of the thrombus, according to Hoare, may result in the lodgment of an embolus in the brain or kidneys. The latter authority also states that muscular atrophy may occur owing to lack of blood supply in some of these cases. Möller states that moderate exercise or work stimulates the establishment of collateral circulation. Massage per rectum is condemned as dangerous by Cadiot.
Fracture of the Patella. ”

“ The most significant symptoms of thrombosis of the portal vein are the sudden formation of ascites, which quickly assumes a very high grade, and equally sudden passive congestion of the gastro-intestinal mucous membrane, enlargement of the spleen, and distension of the superficial veins of the abdominal parietes. When these symptoms succeed to cirrhosis of the liver, or appear after the formation of a tumor in the hepatic region, or come on in the course of phthisis or chronic inflammation of the hepatic peritoneum, the existence of thrombus of the portal vein may be reasonably suspected. ”

“ Sometimes, indeed, there are no clinical symptoms, the condition perhaps only being discovered whilst performing the complete mastoid operation as a prophylactic measure. The sinus is generally exposed accidentally whilst following out a tract of carious bone, and, to the surprise of the surgeon, pus or granulations may be seen to exude or protrude from an opening in its outer wall. On further exposure of the sinus on each side of the thrombus, the dura mater may appear to be of a dark colour for a short distance, but beyond this to be of normal appearance. ”

“ Percussion and auscultation may remain negative. The patient may have a succession of similar accidents, and yet finally recover. According to Ball, pulmonary embolism and pulmonary thrombosis cannot be distinguished during life. In one case which he reports where pulmonary embolism should have been present without question the autopsy showed the presence of a thrombus in the pulmonary artery. A succession of chills, general malaise, febrile excitement, the localized phenomena of pneumonia or gangrene of the lung, point indubitably to the existence of septic emboli. ”

“ The danger of an embolus plugging one of the smaller arteries is great and probably happens more often than we think. The collateral circulation is able to supply the thrombosed area. Should the thrombus be on the carotid arteries, hemiplegia may result from cerebral embolism. On microscopic examination of the arteries there is seen extreme degeneration of all the coats, the degeneration of the media leading almost to an obliteration of that coat. On seeing such arteries as these one wonders how the circulation could have been maintained and the organs nourished. ”

“ Pieces of disintegrated coagula from the systemic veins, the contents of echinococcus cysts ruptured into the venous current, fragments of new growths, are carried to the heart and pass into the pulmonary artery, or large thrombi may be detached from their position in a vein and lodge in the trunk or main branches of the pulmonary artery.
Primary thrombosis of the pulmonary artery is very uncommon. In certain septic conditions, in parturient women, in typhoid fever, and in extreme anæmia thrombosis of the pulmonary artery may occur. ”

“ Such symptoms are dependent upon circulatory interference, but resolution should take place without untoward results with judicious treatment, unless the operator has been negligent by injecting one or more blood vessels, in which case the resultant thrombosis may cause breaking down of the subcutaneous tissue, abscess, evacuation of the mass, and possibly death in part of the integument. The precautions referred to in avoiding any such possibility have been fully given heretofore.
Never should the operator hyperinject the cheeks, even if the patient insists upon looking like a puffed ball. ”