Trey, a 2 month old stray kitten, was presented to us for possibly being hit by a car. He was found limping across a busy street and was rescued by a group of good Samaritans. On presentation Trey’s left forelimb was hanging loosely at his side, but he was otherwise in very good health. A radiograph was taken to look for fractures, however none were found. Trey was hospitalized for monitoring; as we watched him, we noticed that he lacked pain sensation in the affected limb, and played like a normal kitten using the other forelimb. We also noticed that one of Trey’s pupils was larger than the other. Based on these signs, we diagnosed Trey with Brachial plexus avulsion.
Brachial plexus avulsion is a condition in which the nerve roots that supply the forelimb (known collectively as the brachial plexus) are damaged by a traumatic tearing or over pulling force (avulsion), which causes paralysis of the limb. How much of the limb is affected depends on where along the nerve the damage occurred. Complete avulsions, such as that suffered by Trey, causes total paralysis, loss of pain sensation to the limb, and atrophy of the muscles. Affected animals may also develop other neurological signs such as Horner’s syndrome, an eye problem resulting in a sunken eye, smaller than normal pupil, a raised third eyelid, or a drooping eyelid. Diagnosis is generally made based on the patient’s history and physical exam findings. Advanced diagnostic tools can be used to measure nerve conduction; however these tests can be cost prohibitive.
Depending on the level of damage, there is a possibility for complete or partial recovery of limb function, with long term physical therapy. The best prognostic indicator is whether the patient has any pain sensation. In cases like Trey’s, where there is no pain sensation, there is very little chance that the limb can be saved, and amputation is the only option. Following amputation animals do very well. Trey was scheduled for surgery, and his arm was successfully amputated. He recovered well and found a loving new home.