The temperature of the parts near the affected joints is higher than that of neighbouring regions. Sensibility is much more acute, and the slightest external pressure gives rise to pain.
In favourable cases the joint may appear scarcely injured. The principal symptoms are those of pain. In old-standing cases certain permanent changes may occur, such as thickening and hardening of the wall of the synovial capsule, fibrous infiltration of the tissues around the joint, or even diffuse and irregular calcareous infiltration.
Cases of false or true anchylosis are rare, the animals usually being slaughtered before such conditions can develop.
Complications. The commonest complications are endocarditis and pericarditis. Valvular endocarditis localised in the auriculo-ventricular valves is revealed by a systolic sound, and by tumultuous or irregular beating of the heart when the animals are forced to move. Pericarditis, which seems rare in bovine animals, is much commoner in sheep. This pericarditis, however, produces none of the external signs of pericarditis due to a foreign body. Like tuberculous pericarditis, it is only accompanied by a trifling amount of exudate, and is recognised by increased cardiac dulness and diminution in the cardiac sounds on auscultation.
Simple pleurisy associated with pericarditis is frequent in sheep, but unknown or little known in the ox.
If in animals other visceral complications occur, affecting the peritoneum, meninges of the brain or intestines, they are at present little recognised.
Diagnosis. Articular rheumatism can only be confused with osseous cachexia or laminitis. Osseous cachexia, however, possesses symptoms peculiar to itself, and generally extends to an entire district, whilst rheumatism appears in an isolated form. Again, the arthritis peculiar to osseous cachexia most commonly affects the joints of the extremities (fetlock and phalanges). The disease may be differentiated from laminitis by simply manipulating the joints, which are painful in rheumatism but not in laminitis, and by percussing the claws, which are painful in laminitis but not in rheumatism, and by noting the character of the gait.
Prognosis. The prognosis is grave, as in all acute diseases which are capable of assuming a protracted chronic form. It is also necessary to take into account the loss of condition, the possibility of relapse, and the complications due to prolonged decubitus.
Treatment. The first indication is to place the patients in a nearly constant temperature, to supply bedding generously, and to arrange for the animal being undisturbed. Among drugs salicylate of soda gives the best results if administered in sufficient doses—6 to 7 drams per day for oxen or cows of medium size, 45 to 75 grains for sheep.
Diuretics, like bicarbonate of soda, nitrate of potash and hay tea or infusion of couch grass, pellitory, etc., also give good results.