Page 543 - The Veterinary Care of the Horse

Investigation of back pain

By now, the cause of the pain may be obvious or further investigations may be necessary.
VetBooks.ir They may include the following.

BLOOD TESTS

When there is severe muscle spasm and soreness, the vet may take a blood sample to check
for muscle damage. The level of the muscle enzymes creatine kinase (CK) and aspartate

aminotransferase (AST) in the blood increases if muscle damage has occurred.

RADIOGRAPHY

Powerful X-ray machines are needed to take X-rays of the horse’s back. Even then, only

limited parts of the spine can be seen. Radiographs are useful to identify conditions such as
impingement or overriding of the dorsal spinous processes (DSPs) and arthritic changes of
the facet joints and vertebral bodies.

LOCAL ANALGESIA

Once a potential problem has been identified, e.g. impingement of DSPs, local anaesthetic
can be infiltrated around and between the suspect processes, sometimes using ultrasound

guidance. If the horse is much more comfortable when ridden after a period of approximately
20 minutes, the impingement is confirmed as the source of the pain.

SCINTIGRAPHY (BONE SCAN)

Scintigraphy is useful for locating lesions such as vertebral fractures which are too deep in
the body to be seen on X-rays. It shows up any areas of bone remodelling and can be useful

to confirm the presence of inflammation of the dorsal spinous processes. However, many
horses with no signs of back pain have abnormal patterns of uptake of the radioactive drug.
The results therefore have to be interpreted with great care even by vets experienced in this

technique.

ULTRASONOGRAPHY
Ultrasound is useful for examining the spinous processes and attached ligaments. The

articular and transverse processes can also be seen with this technique.

THERMOGRAPHY

Thermography is sometimes used as part of the examination of a horse with back pain.