It is characteristic that the symptoms develop abruptly without satisfactory cause, that they are exaggerated and wanting in harmony with one another, and that they do not correspond with the features of any of the known forms of organic disease.  In some cases the only complaint is of severe pain; more often this is associated with excessive tenderness and with impairment of the functions of the joint.  On examination the joint presents a normal appearance, but the skin over it is remarkably sensitive.  A light touch is more likely to excite pain than deep and firm pressure.  Stiffness is a variable feature—­in some cases amounting to absolute rigidity, so that no ordinary force will elicit movement.  It is characteristic of this, as of other neuroses, that the symptoms come and go without sufficient cause.  When the patient’s attention is diverted, the pain and stiffness may disappear.  There is no actual swelling of the joint, although there may be an appearance of this from wasting of the muscles above and below.  If the joint is kept rigid for long periods, secondary contracture may occur—­in the knee with flexion, in the hip with flexion and adduction.

The diagnosis is often a matter of considerable difficulty, and the condition is liable to be mistaken for such organic lesions as a tuberculous or pyogenic focus in the bone close to the joint.

The greatest difficulty is met with in the knee and hip, where the condition may closely simulate tuberculous disease.  The use of the Rontgen rays, or examination of the joint under anaesthesia, is helpful.

The local treatment consists chiefly in improving the nutrition of the affected limb by means of massage, exercises, baths, and electricity.  Splints are to be avoided.  In refractory cases, benefit may follow the application of blisters or of Corrigan’s button.  The general condition of the patient must be treated on the same lines as in other neuroses.  The Weir-Mitchell treatment may have to be employed in obstinate cases, the patient being secluded from her friends and placed in charge of a nurse.  Complete recovery is the rule, but when the muscles are weak and wasted from prolonged disuse, a considerable time may elapse before the limb returns to normal.

TUMOURS AND CYSTS

New growths taking origin in the synovial membrane are rare, and are not usually diagnosed before operation.  They are attended with exudation into the joint, and in the case of sarcoma the fluid is usually blood-stained.  If the tumour projects in a polypoidal manner into the joint, it may cause symptoms of loose body.  One or two cases have been recorded in which a cartilaginous tumour growing from the synovial membrane has erupted through the joint capsule and infiltrated the adjoining muscles. Multiple cartilaginous tumours forming loose bodies are described on p. 544.