Manual of Surgery, Alexis Thomson [new books to read txt] 📗

Diseases caused by the Staphylococcus Aureus.—As the majority of pyogenic diseases are due to infection with the staphylococcus aureus, these will be described first.

Acute osteomyelitis is a suppurative process beginning in the marrow and tending to spread to the periosteum. The disease is common in children, but is rare after the skeleton has attained maturity. Boys are affected more often than girls, in the proportion of three to one, probably because they are more liable to exposure, to injury, and to violent exertion.

Etiology.—Staphylococci gain access to the blood-stream in various ways, it may be through the skin or through a mucous surface.

Such conditions as, for example, a blow, some extra exertion such as a long walk, or exposure to cold, as in wading, may act as localising factors.

The long bones are chiefly affected, and the commonest sites are: either end of the tibia and the lower end of the femur; the other bones of the skeleton are affected in rare instances.

Pathology.—The disease commences and is most intense in the marrow of the ossifying junction at one end of the diaphysis; it may commence at both ends simultaneously—bipolar osteomyelitis; or, commencing at one end, may spread to the other.

The changes observed are those of intense engorgement of the marrow, going on to greenish-yellow purulent infiltration. Where the process is most advanced—that is, at the ossifying junction—there are evidences of absorption of the framework of the bone; the marrow spaces and Haversian canals undergo enlargement and become filled with greenish-yellow pus. This rarefaction of the spongy bone is the earliest change seen with the X-rays.

The process may remain localised to the ossifying junction, but usually spreads along the medullary canal for a varying distance, and also extends to the periosteum by way of the enlarged Haversian canals. The pus accumulates under the periosteum and lifts it up from the bone. The extent of spread in the medullary canal and beneath the periosteum is in close correspondence. The periosteum of the diaphysis is easily separated—hence the facility with which the pus spreads along the shaft; but in the region of the ossifying junction it is raised with difficulty because of its intimate connection with the epiphysial cartilage. Less frequently there is more than one collection of pus under the periosteum, each being derived from a focus of suppuration in the subjacent marrow. The pus perforates the periosteum, and makes its way to the surface by the easiest anatomical route, and discharges externally, forming one or more sinuses through which fresh infection may take place. The infection may spread to the adjacent joint, either directly through the epiphysis and articular cartilage, or along the deep layer of the periosteum and its continuation—the capsular ligament. When the epiphysis is intra-articular, as, for example, in the head of the femur, the pus when it reaches the surface of the bone necessarily erupts directly into the joint.

While the occurrence of purely periosteal suppuration is regarded as possible, we are of opinion that the embolic form of staphylococcal osteomyelitis always originates in the marrow.

The portion of the diaphysis which has sustained the action of the concentrated toxins has its vitality further impaired as a result of the stripping of the periosteum and thrombosis of the blood vessels of the marrow, so that necrosis of bone is one of the most striking results of the disease, and as this takes place rapidly, that is, in a day or two, the term acute necrosis, formerly applied to the disease, was amply justified.

When there is marked rarefaction of the bone at the ossifying junction, the epiphysis is liable to be separated—epiphysiolysis. The separation usually takes place through the young bone of the ossifying junction, and the surfaces of the diaphysis and epiphysis are opposed to each other by irregular eroded surfaces bathed in pus. The separated epiphysis may be kept in place by the periosteum, but when this has been detached by the formation of pus beneath it, the epiphysis is liable to be displaced by muscular action or by some movement of the limb, or it is the diaphysis that is displaced, for example, the lower end of the diaphysis of the femur may be projected into the popliteal space.

The epiphysial cartilage usually continues its bone-forming functions, but when it has been seriously damaged or displaced, the further growth of the bone in length may be interfered with. Sometimes the separated and displaced epiphysis dies and constitutes a sequestrum.

The adjacent joint may become filled at an early stage with a serous effusion, which may be sterile. When the cocci gain access to the joint, the lesion assumes the characters of a purulent arthritis, which, from its frequency during the earlier years of life, has been called the acute arthritis of infants.

Separation of an epiphysis nearly always results in infection and destruction of the adjacent joint.

Osteomyelitis is rare in the bones of the carpus and tarsus, and the associated joints are usually infected from the outset. In flat bones, such as the skull, the scapula, or the ilium, suppuration usually occurs on both aspects of the bone as well as in the marrow.

Clinical Features.—The constitutional symptoms, which are due to the associated toxæmia, vary considerably in different cases. In mild cases they may be so slight as to escape recognition. In exceptionally severe cases the patient may succumb before there are obvious signs of the localisation of the staphylococci in the bone marrow. In average cases the temperature rises rapidly with a rigor and runs an irregular course with morning remissions, there is marked general illness accompanied by headache, vomiting, and sometimes delirium.

The local manifestations are pain and tenderness in relation to one of the long bones; the pain may be so severe as to prevent sleep and to cause the child to cry out. Tenderness on pressure over the bone is the most valuable diagnostic sign. At a later stage there is an ill-defined swelling in the region of the ossifying junction, with œdema of the overlying skin and dilatation of the superficial veins.

The swelling appears earlier and is more definite in superficial bones such as the tibia, than in those more deeply placed such as the upper end of the femur. It may be less evident to the eye than to the fingers, and is best appreciated by gently stroking the bone from the middle of its shaft towards the end. The maximum thickening and tenderness usually correspond to the junction of the diaphysis with the epiphysis, and the swelling tails off gradually along the shaft. As time goes on there is redness of the skin, especially over a superficial bone, such as the tibia, the swelling becomes softer, and gives evidence of fluctuation. This stage may be reached at the end of twenty-four hours, or not for some days.

Suppuration spreads towards the surface, until, some days later, the skin sloughs and pus escapes, after which the fever usually remits and the pain and other symptoms are relieved. The pus may contain blood and droplets of fat derived from the marrow, and in some cases minute particles of bone are present also. The presence of fat and bony particles in the pus confirms the medullary origin of the suppuration.

If an incision is made, the periosteum is found to be raised from the bone; the extent of the bare bone will be found to correspond fairly accurately with the extent of the lesion in the marrow.

Local Complications.—The adjacent joint may exhibit symptoms which vary from those of a simple effusion to those of a purulent arthritis. The joint symptoms may count for little in the clinical picture, or, as in the case of the hip, may so predominate as to overshadow those of the bone lesion from which they originated.

Separation and displacement of the epiphysis usually reveals itself by an alteration in the attitude of the limb; it is nearly always associated with suppuration in the adjacent joint.

When pathological fracture of the shaft occurs, as it may do, from some muscular effort or strain, it is attended with the usual signs of fracture.

Dislocation of the adjacent joint has been chiefly observed at the hip; it may result from effusion into the joint and stretching of the ligaments, or may be the sequel of a purulent arthritis; the signs of dislocation are not so obvious as might be expected, but it is attended with an alteration in the attitude of the limb, and the displacement of the head of the bone is readily shown in a skiagram.

General Complications.—In some cases a multiplicity of lesions in the bones and joints imparts to the disease the features of pyæmia. The occurrence of endocarditis, as indicated by alterations in the heart sounds and the development of murmurs, may cause widespread infective embolism, and metastatic suppurations in the kidneys, heart-wall, and lungs, as well as in other bones and joints than those primarily affected. The secondary suppurations are liable to be overlooked unless sought for, as they are rarely attended with much pain.

In these multiple forms of osteomyelitis the toxæmic symptoms predominate; the patient is dull and listless, or he may be restless and talkative, or actually delirious. The tongue is dry and coated, the lips and teeth are covered with sordes, the motions are loose and offensive, and may be passed involuntarily. The temperature is remittent and irregular, the pulse small and rapid, and the urine may contain blood and albumen. Sometimes the skin shows erythematous and purpuric rashes, and the patient may cry out as in meningitis. The post-mortem appearances are those of pyæmia.

Differential Diagnosis.—Acute osteomyelitis is to be diagnosed from infections of the soft parts, such as erysipelas and cellulitis, and, in the case of the tibia, from erythema nodosum. Tenderness localised to the ossifying junction is the most valuable diagnostic sign of osteomyelitis.

When there is early and pronounced general intoxication, there is likely to be confusion with other acute febrile illnesses, such as scarlet fever. In all febrile conditions in children and adolescents, the ossifying junctions of the long bones should be examined for areas of pain and tenderness.

Osteomyelitis has many features in common with acute articular rheumatism, and some authorities believe them to be different forms of the same disease (Kocher). In acute rheumatism, however, the joint symptoms predominate, there is an absence of suppuration, and the pains and temperature yield to salicylates.

The prognosis varies with the type of the disease, with its location—the vertebræ, skull, pelvis, and lower jaw being specially unfavourable—with the multiplicity of the lesions, and with the development of endocarditis and internal metastases.

Treatment.—This is carried out on the same lines as in other pyogenic infections.

In the earliest stages of the disease, the induction of hyperæmia is indicated, and should be employed until the diagnosis is definitely established, and in the meantime preparations for operation should be made. An incision is made down to and through the periosteum, and whether pus is found or not, the bone should be opened in the vicinity of the ossifying junction by means of a drill, gouge, or trephine. If pus is found, the opening in the bone is extended along the shaft as far as the periosteum has been separated, and the infected marrow is removed with the spoon. The cavity is then lightly packed with rubber dam, or, as recommended by Bier, the skin edges are brought together by sutures which are loosely tied to afford sufficient space between them for the exit of discharge, and the hyperæmic treatment is continued.

When there is widespread suppuration in the marrow, and the shaft is extensively bared of periosteum and appears likely to die, it may be resected straight away or after an interval of a day or two. Early resection of the shaft is also indicated if the opening of the medullary canal is not followed by relief of symptoms. In the leg and forearm, the unaffected bone