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.