This form of the disease most frequently results from wounds which injure or puncture the capsule of the joint, and especially such as are contaminated with septic matter at the time of or after infliction.

The size of the wound is no measure of the danger which may attend it. A dirty stable-fork entering a joint may prove as destructive as a wound inches in length. Pyaemia is a common cause of acute synovitis in foals, and less frequently in young horses when suffering from strangles.

Severe blows and sprains, and acute attacks of rheumatism, especially when following upon influenza, are also fruitful causes of it.

Symptoms

Lameness more or less severe is the first noticeable symptom of the disease. The joint becomes distended with synovia, and bulges at points where there is least resistance. The swelling thus formed is tense and fluctuating, and when pressed acute pain is evinced. Soon the outer structures of the joint become enlarged, hot, and tender. The animal stands with the leg in a semi-flexed condition, imposing little or no weight on it. The local suffering soon gives rise to constitutional disturbance, attended with considerable fever and prostration.

As the disease progresses the joint becomes filled with pus, the inflammation spreads to structures round and about it, one or more abscesses form and break, and the purulent contents of the joint escape.

In those cases where joint abscess develops, the articular cartilage undergoes softening and displacement, and the underlying bone becomes exposed and diseased. In such circumstances the function of the joint is seriously impaired or altogether destroyed, and should the patient recover, his or her services can only be reckoned on for breeding purposes.

Treatment

The first concern should be directed towards providing conditions for affording rest and relief from pain. To this end the floor should be covered with peat-moss, tan, or saw-dust, and the patient should be placed in slings.

A dose of physic at the outset will prove beneficial, and the diet should be light and sparing. Scalded bran with a little chaff, and some roots or green meat will be most suitable for the purpose.

The limb should be supported and its movements restricted by the application of bandages.

The joint should then be irrigated with cold water four or five times a day, and in the intervals the bandages should be repeatedly soaked with it.

If a wound exists it should be thoroughly cleansed, freely irrigated with five-per-cent solution of carbolic acid, and kept aseptic by suitable dressing.

Where the pain is acute and the suffering great, the affected joint should be anointed twice a day with belladonna and glycerine, in the proportion of one part of the former to two of the latter, and if necessary an opiate may be given from time to time to alleviate pain and ensure rest.

When the acute symptoms have subsided, the part may be vigorously rubbed with weak soap liniment, and gently-increasing pressure applied to the swollen joint by means of a bandage.

This may require to be followed up by one or more blisters, and a course of iodide of potassium administered to effect removal of the swelling.