Page 424 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

Musculoskeletal system: 1.9 Muscle disorders of the horse 399

VetBooks.ir 1.766 1.767

Fig. 1.766 Post-anaesthetic myopathy affecting the Fig. 1.767 Same horse as in 1.768. There is focal
left shoulder mass. Note the swollen supraspinous swelling and patchy sweating.
muscle on the left side (arrow) compared with the
right side.
• Generalised form. This occurs spontaneously
or as a result of prolonged recumbency, perhaps
as a consequence of a localised myoneuropathy.
1.768
Affected animals are recumbent and show
an inability to stand up. Most muscle masses
are affected, as noted above, with increased
heart and respiratory rates, myoglobinuria to
anuria, profuse sweating, distress and possible
cardiovascular shock and death.

Differential diagnosis
Other orthopaedic injuries, such as fractures, occur-
ring during recovery; post-anaesthetic neuropathy;
other causes of prolonged recumbency including
myelomalacia of the spinal cord.

Fig. 1.768 Localised, post-anaesthetic myopathy- Diagnosis
induced lameness due to loss of the shoulder muscle History, clinical signs and significant increases in
mass and triceps functions. The horse is unable to muscle enzyme activity following general anaes-
extend its shoulder and elbow. thesia will confirm the diagnosis. CK will peak at