Climatic influences. Rheumatoid. Joints attacked. Muscles. Decubitus.
Stiff, rigid, steps on toes, grunts, swelling, heat, tenderness,
chaps, cracks, suppurations, inappetence, emaciation, metastasis,
cardiac disorder. Duration; course. Chronic form. Muscular form.
Diagnosis from trichinosis. Connection with arthritis. Metastasis.
Remissions.
The pig which shows an extreme sensitiveness to climatic vicissitudes
and cold winds, fleeing instantly to his lair on their advent, is yet
protected by his subcutaneous fat, so that he is not a frequent victim
of simple rheumatism. Leblanc attributes it to unwholesome pens.
Chaussade to too rapid fattening (overfeeding). Rheumatoid attacks are
very common at the onset of hog cholera, swine plague and other
infectious diseases, when they are probably but local manifestations of
the general infection.
The lesions are mainly concentrated in the stifle, hock, knee and
fetlock. In some cases the dorsal and lumbar muscles suffer and there is
arching of the back with great tenderness on manipulation. In other
cases the muscles of the quarter or shoulder are involved as shown by
their stiffness and extreme sensibility to touch.
The pig is found down, indisposed to rise, and when up, stands drawn
together with limbs rigid and feet resting on the toes. He will often
point one toe to the ground repeatedly, before resting on the foot, or
shift the weight uneasily from foot to foot. If moved he grunts
plaintively and if handled squeals.
The affected joints may be surrounded by hot tender swellings or they
may be nearly normal in outline, but they are always very sensitive to
pressure and above all to flexion and extension, and the skin is usually
hyperæmic and red. There may be engorgements of the lymphatics on the
inner side of the limbs, and chaps and cracks in the flexures of the
joints. Suppurations may follow (Graignard) suggesting a complex
infection.
There is little appetite and though the disease becomes subacute or
chronic there is a steady loss of condition or at least a failure to
thrive.
Benion’s reference to a coincident or sequent inflammation of the
respiratory or digestive organs and Spinola’s similar reference to
pleurisy are strongly suggestive of swine plague and hog cholera. Any
manifest disposition to shift from one part to another and any
concurrent disorder of the heart, other than simple palpitation is
strongly confirmatory of rheumatism.
The disease tends to recovery in from four to twenty days, or to pass
into the _chronic form_. In this state the symptoms are materially
mitigated. Fever is absent, but the appetite, digestion and assimilation
are poor, the animal remains stunted, emaciated or unthrifty, there is a
disposition to lie most of the time under the litter, and when up it
moves stiffly with short steps, semi-flexed joints and upright digits.
Sometimes the joints are permanently swollen and rigid by reason of
thickening and shortening of the binding ligaments, by the organization
of false membranes or by anchylosis.
=Muscular Rheumatism in Swine.= This appears to be rarely seen as an
independent disease, but appears at times to coincide with the arthritic
form. In such cases the back is arched and very sore to the touch or to
pressure. It must be distinguished from the muscular soreness of
trichinosis which occurs in infested localities, after trichinous food
or water, is preceded by digestive disorder and diarrhœa, and by the
passage of the nearly microscopic worms in the stools, and is
independent of arthritis.
Muscular rheumatism leads to atrophy of the muscles, especially those of
the quarters, and this may resemble, somewhat, partial paraplegia from
disease of the spinal cord. Its connection with arthritis, its tendency
to shift from place to place, to undergo ameliorations and relapses, and
its exquisite tenderness, serve to distinguish it from paralysis.