Pus, when present, is commonly also manifested by the usual signs of its existence. There will be pitting on pressure or edema of the overlying parts, while an acutely inflamed joint may be at any time so swollen as to impede return circulation and lead to edema of the parts beyond. To the local signs of phlegmon, then, we simply have to add in greater detail those mentioned above. Along with these there will be constitutional septic disturbances, usually proportionate to the gravity of the local condition. The opportunities for absorption afforded by a large synovial surface are great, and the lymphatics are sure to carry toxins in abundance. The signs, then, of septicemia, sometimes even of pyemia, are often pronounced. In the presence of a joint full of pus the prognosis may be regarded as exceedingly grave. Pain and tenderness seem to bear but little relation to the swelling. Usually pain is an expression of distention, yet some of the non-inflammatory forms of apparently milder type are extremely painful. Pain is influenced by the position of the joint, and the patient instinctively seeks that position in which suffering is minimized. In a joint disorganized by the presence of pus there is less sensitiveness, except on rough handling, unless the trouble have extended far beyond the joint limits, and cellulitis be present, with suppuration threatening. In metastatic joint abscess tenderness rather than pain is the common rule.
In the presence of an acute inflammation in the joint end of a long bone the other joint structures will participate to an extent proportionate to its acuteness. With an acute osteomyelitis—e. g., near the articular surface—the synovial membrane will participate, just as does the pleura in many cases of pneumonia, and we may look for fluid in the joint in one case as we do for fluid in the chest cavity in the other. Moreover, pictures of acute or chronic tuberculous affections of the synovia correspond very closely to those of the pleura. Tuberculous disease is liable to spread in every direction in both diseases. The reverse of this, however, is not true in all diseases of the chest, and there are many synovial as well as pleural affections which are confined to their respective sacs.
Fig. 193
Pneumococcus infection of ankle; rapid destruction of all joint structures. Child aged nine months. (Lexer.)
The same statement, almost, can be made concerning the bursæ and tendon sheaths in proximity to infected joints. Particularly is this true when any of these connect with joint cavities.
The metastatic forms of pyarthrosis, as a collection of pus within the joint capsule is called, are more insidious, though sometimes equally destructive. They are by no means confined to one joint, and in pyemia especially many of the joints will become involved. (See [Pyemia].) These secondary affections seem to be purulent from the outset. In gonorrhea the effused fluids will often be found nearly pure cultures of the gonococcus; after typhoid they contain typhoid bacilli, etc. Such expressions are less frequent after pneumonia, influenza, and the acute exanthemas, but may be seen even after smallpox. It is often in these severely destructive joint lesions that spontaneous dislocation occurs ([Fig. 193]).
Treatment.
—In the presence of a single joint lesion indications for treatment are quite clear. When we have multiple and pyemic or gonorrheal pyarthrosis it is often exceedingly difficult to determine what is for the best interest of the patient. In general it may be said that pyemia progressed to this extent will almost certainly be fatal, and we may rest content with aspirating the affected joints, or perhaps in leaving them alone; because we may feel that they constitute but a small proportion of the metastatic foci which eventually determine death. On the other hand, in other infections with pyarthrosis it would be better to aspirate or to open and drain, because these cases are slow and chronic, and the exudate is sometimes so rich in fibrin as to lead to quite firm spurious ankylosis.
Thus gonorrheal synovitis is usually monarticular, although several joints may be involved. It is readily recognized in the presence of the active disease, but there are times when recognition is made difficult by the latency of urethral symptoms or the concealment of their existence. The knee is usually the joint most often involved; next the joints about the foot, and sometimes the tendon sheaths and bursæ adjoining them.