Muscular rheumatism is common in dogs. It is most common and most marked
in the back and loins, though the neck may suffer, or the disease may be
generalized. It is painful to move and the subject seeks to be as much
as possible undisturbed. He walks stiffly and slowly, carrying the limbs
with as little movement of the joints as possible, and in bad cases
yelps occasionally from sudden pain. He can no longer be tempted to go
up or down stairs or to make any special effort. When touched on the
back or loins he will wince, cry out, or even snap at the offender. In
some cases the pain is so acute that even a feint to touch the back will
draw out a yelp. If the neck is affected it may be held so stiffly that
the dog can barely reach the ground to find his food, or if unilateral
the head is turned to one side. Even the muscles of the jaws may be
affected, causing prehension and mastication to be difficult and
imperfect. Defecation and urination are also interfered with and the
straining may draw forth plaintive cries.
The rapid shifting of the morbid process from one group of muscles to
another is often very striking, and if one pronounces on the exact seat
of the disease, it is liable to be speedily rendered inexact by a sudden
change of place. There is further a great disposition to the implication
of the heart and especially the valves. This is shown by irregularity
and inequality of the pulse by intermissions and palpitations, by a
blowing murmur with the first heart sound and by oppressed breathing.
Short, shallow breathing is also caused when the intercostal muscles are
attacked (pleurodynia). Various digestive troubles are also common, to
which the difficult defecation and impacted rectum largely contribute.
Emaciation makes more or less progress, and the muscles of the hind
parts especially become weak and atonic until marked paresis or actual
paraplegia sets in, and the hind limbs are extended backward and dragged
helplessly. In fat, sluggish, overfed and pampered animals the lack of
control of the hind limbs may come on at an early stage. Stiffness due
to strongylus gigas in the kidney or stephanurus or cysticercus
cellulosa in the lumbar muscles must not be mistaken for rheumatism.