The etiology of classic stringhalt is idiopathic. One theory relates the clinical signs of stringhalt to trauma or compression of the nerve. Other theories state that compression of the spinal cord in the C5-T1 region due to OCD or arthritis can cause symptoms of stringhalt. Another theory states that the muscle spindles or golgi tendon organs in the hind limb muscles aren’t working correctly resulting in the over flexion of the limb. Classic stringhalt is seen worldwide. Australian stringhalt is caused by the ingestion of dandelions, flat weed, sweet peas and other plants causing that targets the longest peripheral nerves of the hindquarters. Sometimes the laryngeal nerve is also affected that innervates the larynx. Australian stringhalt often occurs in outbreaks in horses in the same pasture especially during dry weather or . It has been reported most commonly in Australia, New Zealand & North America. Clinically stringhalt is seen as the sudden, exaggerated, involuntary flexion of one or both , with delayed protraction. If the presentation is bilateral the horse seems to have a “goose-stepping” movement in the hind limb. The amount of flexion seen varies from mild lifting of the foot to extreme flexion where the dorsal metatarsus and pastern hit the ventral abdomen. Atrophy of the lateral thigh muscles is associated with stringhalt. The signs of stringhalt generally are increased when the horse is backed up or asked to make a , but ease with rest. Diagnosis of stringhalt can be made thorough clinical signs and symptoms, case history, x-rays , ultrasound, nuclear scintigraphy and EMG. The elimination of other diseases such as shivers, EPM, upward fixation of the patella and wobbler’s disease should also be included when making a diagnosis. Treatment of stringhalt is variable depending on the severity and suspected cause of the condition. In cases where toxicity is suspected the horse should be removed from the pasture and the pasture should be searched for known sources of neurotoxicity. With toxicity there may be spontaneous resolution of the clinical signs within two weeks to two years once the source of toxicity is removed. Average recovery time for Australian stringhalt is 6-9 months. In cases where compression of the tibial nerve or other trauma to the dorsolateral gaskin and hock are suspected to be the cause, of the lateral digital extensor muscle is recommended. No matter the cause, the administration of high doses of thiamine, vitamin B1, and phenytoin, an anticonvulsant and anti-seizure medication, may be of use in controlling the clinical signs and symptoms of stringhalt and in lessening the concussive damage to the cannon and abdomen in severe cases. Muscle relaxants can also be given.
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