Synovitis

“ Septic synovitis and infectious arthritis are always serious affections even in young animals and much depends upon individual resistance and early rational treatment in such cases, if recovery is to follow.
The same general plan of treatment is indicated in this kind of septic synovitis as is employed in all cases of infective synovitis and septic infection in open joints. There is to be considered, however, the fact that the young animal is more agile, a better self-nurse, and in a general way more apt to recover than is the adult, under similar conditions. ”

“ But if the individual or the joint were at that time in a state of imperfect nutrition, the effects are likely to be more serious. As a rule, it is the synovial membrane lining the fibrous capsule of the joint which first and chiefly suffers; the condition is termed synovitis. Synovitis may, however, be due to other causes than mechanical injury, as when the interior of the joint is attacked by the micro-organisms of pyæmia (blood-poisoning) , typhoid fever, pneumonia, rheumatism, gonorrhœa or syphilis. ”

“ Rheumatic Synovitis may arise from exposure to cold, from some injury, or from intemperance in eating. The beginning of the disease may be distinctly marked, or it may come on so gradually that the time of its commencement cannot be noted. The pain is of a dull, steady character, and less severe in the night. This form of the disease sometimes terminates favorably, but in scrofulous systems it is liable to end in the destruction of the joint. It is more common in early life, rarely occurring after the thirtieth year. ”

“ There is often a good deal of heat of the surrounding skin and of pain accompanying the synovitis. In the case of a healthy individual the effects of a sprain may quickly pass off, but in a rheumatic or gouty person chronic synovitis may obstinately remain. In a person with a tuberculous history, or of tuberculous descent, a sprain is apt to be the beginning of serious disease of the joint, and it should, therefore, be treated with continuous rest and prolonged supervision. In a person of health and vigour, a sprained joint should be at once bandaged. ”

“ If the synovitis or arthritis remains non-infected and the wound, traumatic or surgical, is not too large, healing by granulation occurs, and the discharge of synovia ceases. However, if synovial discharge persists too long because of tardy closure of an open joint, there is great danger of infection gaining entrance into the synovial cavity, or in some instances, desiccation of endothelial cells of the articulation occurs, in areas, and the reactionary inflammation eventually results in ankylosis. ”

“ The subsidence of a chronic synovitis generally leaves a weak and impaired joint, though pain may be absent. Movements, especially in extension, are restricted, and grating or cracking remain as evidences of the roughened membrane. ”

“ Non-infective wounds which may cause open joint are not necessarily productive of an active carpitis—a synovitis may be the extent of the disturbance. Unlike synovitis, which may characterize a non-infectious penetrative wound of the capsular ligament, septic arthritis which may supervene is a very painful inflammatory disturbance. It is characterized by all of the symptoms which attend the case of open joint and synovitis plus the obvious manifestation of great pain. There is an elevation of temperature of from two to five degrees above normal; circulation is accelerated ”

“ Teno-synovitis Crepitans.—In the simple or traumatic form of teno-synovitis, although the most prominent etiological factor is a strain or over-use of the tendon, there would appear to be some other, probably a toxic, factor in its production, otherwise the affection would be much more common than it is: only a small proportion of those who strain or over-use their tendons become the subjects of teno-synovitis. The opposed surfaces of the tendon and its sheath are covered with fibrinous lymph, so that there is friction when they move on one another. ”

“ Mild synovitis and arthritis have been induced in rabbits and rats by massive intravenous or intraarticular injections with nonliving whole cells or fractions of the organism (White et al. 1975; Hermanns et al. 1982) , but the lesions were not as severe as those typically caused by infection. White et al. (1975) suggested that the mild response induced by such antigens may predispose the joint to infection during a subsequent transient septicemia. ”

“ The general symptoms arise from the absorption into the circulation of either bacteria or their toxins, and vary greatly in severity. There is either a toxemia or a septicemia, with the usual symptoms of a general sepsis.
The local symptoms are those common to synovitis and arthritis: pain, tenderness, swelling, heat, redness and loss of function. From these alone a differential diagnosis between synovitis and arthritis cannot be made. If, however, there is a sensation of crepitus conveyed to the examiner’s [Pg 89] hand upon passive motion, there is an arthritis present beyond doubt. ”

“ As a result of acute synovitis a chronic synovial distension of the tarsal sheath occurs. Bog spavin is often present in case of thoroughpin but the two conditions are separate and distinct excepting in that both may occur simultaneously and as the result of the same cause. Some animals are undoubtedly predisposed to disease of synovial structures. The average horse that has been subjected to hard service on pavements or hard roads at fast work suffers synovial distension of bursae, thecae or of joint capsules. ”

“ The commonest type is a chronic synovitis or hydrops, in which the joint—very often the knee—becomes filled with a serous or sero-fibrinous exudate. There are no reactive changes in the synovial membrane, cellular tissue, or skin, nor is there any fever or disturbance of health. The movements are free except in so far as they are restricted by the amount of fluid in the joint. ”

“ Joint lesions are comparatively common in scarlet fever, and were formerly described as scarlatinal rheumatism. The most frequent clinical type is that of a serous synovitis, occurring within a week or ten days from the onset of the fever. Its favourite seat is in the hand and wrist, the sheaths of the extensor tendons as well as the synovial membrane of the joints being involved. It does not tend to migrate to other joints, and rarely lasts longer than a few days. ”

“ Examples of such a condition are to be found in bog-spavin, in hygroma of the stifle, and sometimes in the fetlock. From a study of these, we know that they may be induced by frequent attacks of acute synovitis, from repeated slight injuries or bruises, or from strains to the ligaments of the joint; or that they may be chronic from the outset. We know, too, that in such cases the synovial membrane becomes thickened, and that in places it may have extended somewhat over the edges of the articular cartilages. It is only fair to suppose that such changes occur also in the pedal articulation. ”

“ As severe a lesion as suppurative synovitis always is, and as frequently fatal as it proves to be, still cases arise in which, the inflammation assuming a modified character and at length subsiding, the lesion terminates favorably and leaves the animal with a comparatively sound and useful joint. There are cases, however, which terminate in no more favorable a result than the union of the bones and occlusion of the joint, to form an anchylosis, which is scarcely a condition to justify a high degree of satisfaction, as it insures a permanent lameness with very little capacity for usefulness. ”

“ In #inherited syphilis# the earliest joint affections are those in which there is an effusion into the joint, especially the knee or elbow; and in exceptional cases pyogenic infection may be superadded, and pus form in the joint.
In older children, a gummatous synovitis is met with of which the most striking features are: its insidious development, its chronic course, symmetrical distribution, freedom from pain, the free mobility of the joint, its tendency to relapse, and its association with other syphilitic stigmata, especially in the eyes. ”

“ This affection may therefore follow on a case of acute coronitis, a case of suppurating corn, a case of quittor, a severe case of tread, or may attend a case of laminitis.
Symptoms.—In our cases we get very little beyond a magnification of such symptoms as we have described under acute synovitis. The heat and the pain is perhaps greater, and the lameness more marked. It is rather to the constitutional disturbance we must look, however, for a confirmation of our opinion that arthritis is in existence. This is always severe, and of an acute febrile nature. ”

“ Otherwise, diagnosis is usually easy, as soon as lameness or synovitis, or arthritis of the lower regions of the limbs appears. Only in isolated cases are the lesions likely to be mistaken for accidental injuries, and it is also fairly easy to differentiate them from the localised lesions of rheumatism. The latter disease seems more frequently to attack the upper joints of the limbs, and is often accompanied by intense fever and cardiac disturbance. ”

“ In the Joints, a serous synovitis or hydrops may occur, chiefly in the knee, on one or on both sides.
The Affections of the Eyes, although fortunately rare, are of great importance because of the serious results which may follow if they are not recognised and treated. Iritis is the commonest of these, and may occur in one or in both eyes, one after the other, from three to eight months after infection. The patient complains of impairment of sight and of frontal or supraorbital pain. ”

“ Pyogenic diseases result from infection through the blood stream, from one of the adjacent bones, or from a penetrating wound of the joint. The commoner types include the synovitis associated with disease in the adjacent bone, acute arthritis of infants, joint suppuration in pyæmia, pyogenic arthritis following upon penetrating wounds, and the affections which result from gonorrhœal or pneumococcal infection. ”

“ Hydrops may occur apart from disease--for example, in the knee-joint from repeated sprains, or when there is a loose body in the joint--but is met with chiefly in the chronic forms of synovitis which result from gonorrhoea, tuberculosis, syphilis, arthritis deformans, or arthropathies of nerve origin. ”

“ Injuries to the scapulohumeral joint may be the result of kicks, runaway accidents or bruises from the collar, and there may result, because of such injuries, reactionary inflammation which will vary in intensity from the mildest synovitis to the most severe arthritis, causing more or less lameness. ”

“ Synovitis and arthritis of chronic SE in a hock joint 8 weeks after exposure to E. rhusiopathiae. Note hyperemia and proliferation of synovial tissue. (Courtesy National Animal Disease Center, Ames, Iowa) . Vegetative endocarditis consists of proliferative granular growths on the heart valves and may be accompanied by lesions resulting from cardiac insufficiency. Other internal organs may show chronic inflammatory changes such as infarcts of kidneys and spleen. ”

“ In chronic rheumatism, which is more often present in women and in the poorer classes, the moderately painful attacks of synovitis with crepitation, and evidence of wearing away of cartilage. In chronic rheumatoid arthritis the presence of bony outgrowths around the margin of the articulation is the main element of distinction from the latter condition. In tuberculous disease the personal and family history, the soft fusiform swelling, the tendency to breaking down of the morbid tissue, and the more or less complete destruction of the articular capsule in the later stages. ”

“ The least muscular effort when lying down often causes it to moan, as do efforts to change its position or to walk. Even when standing still, it may appear to be in pain, and patients often assume a position similar to that of a horse suffering from laminitis.
At the end of this second phase, swellings appear, due to synovitis or arthritis of the extremities, synovitis of the sesamoid or navicular sheaths or to inter-phalangeal arthritis or arthritis of the fetlock joint. Weakness becomes marked, and the appetite is very irregular. ”

“ Etiology and Occurrence.—Following strains from work in the harness or under the saddle, horses develop an acute synovitis of the hock joint, which often results in chronic synovial distension. Debilitating diseases favor the production of this affection in some animals. It is also frequently observed in young horses and in draught colts of twelve to eighteen months of age. This condition occurs while the subjects are at pasture and often spontaneous recovery results by the time the animals are two years of age. ”

“ Wounds invading the tissues adjacent to joints, when these wounds are of considerable extent, cause inflammation of such articulations by contiguous extension of inflammation. As long as an injury remains practically aseptic, or if infected and the septic process does not involve the joint proper by direct extension, no more serious disturbance than a simple synovitis will result. If, instead, a periarthritic inflammation is serious or destructive in character, the type of arthritis will be grave—even though due to an indirect cause. ”

“ Except in cases of acute synovitis, lameness is not present and in chronic distension of the capsule of the tarsal joint, no interference with the subject's usefulness occurs. In the majority of instances, the disfigurement which attends bog spavin is the principal objectionable feature. The condition is bilateral in many instances, and in such cases the subjects have a predisposition to this condition or it follows attacks of strangles or other debilitating ailments. Because of a rapid and unusual growth, bilateral affections are of frequent occurrence in some animals. ”