Chill, hyperthermia, lameness in fetlock, hock, knee, shoulder,
stifle, hip, elbow, tendons, sheaths, bursæ, bilateral, shifting,
swelling, heat, tenderness, decubitus, joint semi-flexed, pain on
extension or flexion, signs of cardiac disease. Course: rapid to
recovery, improvements and relapses, metastasis, debility.
The attack is usually sudden and marked by a slight chill, shivering or
staring coat with hyperthermia and lameness. The temperature may vary
from normal to 107° or 108° F. in severe attacks. In many cases the
fever and lameness appear simultaneously, the former being in ratio with
the extent and severity of the latter, but not infrequently the
elevation of temperature precedes the articular symptoms, and then it is
to be considered as concurrent with the internal lesions—cardiac,
pericardial or otherwise. In other cases the articular lesions and
lameness precede by several days the appearance of the fever. So far as
we know the fever never antedates the occurrence of some local lesion,
external or internal.
The joints affected are very varied. The fetlock is the most frequently
attacked, but some of the other larger joints, the hock, knee, shoulder,
stifle, hip and elbow are often involved or exclusively affected. The
adjacent tendons and their synovial sheaths are very often implicated;
the attack is very prone to show a bilateral symmetry, the same joints
(right and left) on the corresponding fore or hind limbs, suffering at
once, or, as in the case of the fetlocks, all four are simultaneously
attacked. A joint that is weak by reason of previous injury or disease
is especially liable to suffer, and is then less likely than joints that
had been previously healthy to undergo speedy improvement. When the
symptoms wander from joint to joint or from joint to muscle, or fascia
or tendon, the disease in its earlier seat seeming to undergo almost
complete resolution, while it advances with great intensity in the newly
affected joint or part, the occurrence is highly significant. These
transitions often take place with great rapidity. Thus the centre of
suffering may shift from one joint to another in an hour, (Megnin,
Cadeac), or from a limb to the loins in a quarter of an hour (Lewis).
The fact that the inflammation remains fixed in one or several joints,
is not, however, proof of the absence of rheumatism. A joint with a
primary weakness or injury may remain the seat of disease through even a
chronic rheumatism.
The affected joint is usually swollen, hot and tender; the tenderness
being as a rule greatest where the capsular ligament is pressed upon.
These symptoms are very evident in joints that approach the surface, and
obscure in such as are thickly covered by muscle (shoulder, hip). The
swelling is soft, or tense and elastic (especially over the synovial
membrane), or œdematous and pitting on pressure. On white skins sparsely
covered by hair there is marked redness and congestion, the veins
standing out prominently and the arteries above the joint pulsating
strongly. When the tendinous sheaths are involved, they stand out as
elastic lines following the course of the tendons, and with more or less
pasty swelling adjacent.
In some cases, however, the swelling may be entirely absent, and the
trouble is to be located only by the local tenderness and pain during
motion.
Small, hard, pea like, subcutaneous nodosities were first noticed by
Floriep, in 1843, in rheumatism in man, and have been met with in
different cases in the horse. Rodet fils met with great numbers of these
nodules crepitating under pressure, in a horse that had suffered for
months from chronic rheumatism.
Acute pain on moving the affected joint or tendon is a most
characteristic symptom. The horse goes dead lame, walks on three legs,
or with great stiffness, and avoids as far as possible all flexion of
the joint. If left alone the animal stands stock still, never moving
from the place, or in the worst cases lies down and refuses to rise. If
compelled to walk his suffering is shown by hastened breathing, dilated
nostrils, anxious, pinched countenance and low plaintive neighing. The
affected joint is held semi-flexed, to relieve the tension, the pastern
is habitually more upright, and if the foot is lifted and the affected
joint bent or extended, the animal winces, or resists, and tries to draw
away the limb and groans. The movements of the affected joint in walking
or under manipulation, are often attended by cracking which may be both
felt and heard. It has been variously attributed to lack of synovial
lubrication (Cadeac), and ulceration of the articular cartilage
(Lafosse), yet it may occur from the constrained position assumed, as in
the case of a man attempting to walk noiselessly on tip toe, and in
other cases from the extension of false membranes, or of rigid or
contracted binding ligaments.
Rheumatism of the fetlock and sesamoid pulley, as the most common form
in solipeds, demands a special notice. The swelling of one fetlock, of
the two fore, of the two hind or of all four at once, extends beyond the
limits of both joint and sesamoid pulley and may form a general
engorgement or _stocking_ which serves to hide the synovial distension.
Pressure however shows that while all is tender, the extreme tenderness
is referable to the joint, the synovial sheath of the flexors, to the
flexors or suspensory ligaments. As the general swelling subsides the
rounded or ovoid synovial distensions become more patent. The swelling
and tenderness may extend to the knee in which case the synovial
membrane of the carpal arch is especially distended and tender from the
carpus down, or in the hind limb the synovial membrane of the tarsal
arch is distended showing in this case on the inner and outer sides in
front of the calcis, and not infrequently implicating the summit of that
bone as a capped hock.
In rheumatism of the shoulder the coraco-radial tendon and pulley may be
involved, causing a diffuse swelling on the point of the shoulder. If
the hip is the seat of disease the median gluteal may suffer, causing an
indefinite swelling over the joint. If the stifle is affected the
patellar capsule suffers and not infrequently the tendon and pulley of
the flexor metatarsi are involved.
The most important internal complications, pericarditis and
endocarditis, are manifested by their usual symptoms, sharp, variable,
irregular, unequal or intermittent pulse, blowing murmur usually with
the first heart sound, oppressed breathing, and it may be muffled heart
sounds, or dropsies.
_Course._ This is exceedingly uncertain. Some cases make a rapid
progress to complete convalescence; others make partial improvements
interrupted by relapses; others have the morbid process subside in great
measure in one joint or organ only to reappear in full force in another;
others leave complications on the part of the heart especially and are
rendered permanently useless. Even should the heart escape, the health
often suffers so much in connection with the destruction of the red
globules, the malnutrition, and the local disease, swellings and
distortions of the joints that a perfect recovery seems distant and
problematical.