Читать книгу Large Animal Neurology - Joe Mayhew - Страница 66

Infrared, electronic thermography is a completely noninvasive method of determining skin temperature.^174,175 Thermography should be well suited for horses because of their short, even hair coat and because radiography of the thoracolumbar vertebral column, which is so useful in smaller patients, often contributes less to the neurologic workup of large patients.

Superficial temperature primarily depends on cutaneous blood flow. Because many neurologic disorders can be associated with local alterations in blood flow, this diagnostic modality can help localize neuromuscular lesions.^174–177 In this manner, exercise‐exacerbated focal, thoracolumbar myopathies with associated pelvic limb gait abnormalities have been corroborated by focal and asymmetric thermographic patterns before and after exercise. Also, neurologic and disuse muscle atrophy have been associated with a lower overlying superficial temperature, when compared with the normal, opposite side. However, any such changes in skin temperature are very variable and not specific such that cutaneous thermography is not regarded as very useful for diagnosis and monitoring of spinal cord and nerve root diseases in humans^178,179 and large animals. Its utility in cases of back pain in horses^{175,177, 180} is also dubious.

Because loss of sympathetic innervation in the horse causes demarcated cutaneous vasodilation and hyperhidrosis, thermography can be of great assistance in localizing any lesion affecting the sympathetic nervous system, particularly those involving peripheral nerves that contain sympathetic fibers. For example, the well‐known facial hyperthermia of Horner syndrome in the horse produces a characteristic, abnormal thermographic pattern.^180–186