“Head trauma is common in horses, and a number of these cases will present with neurologic signs consistent with brain injury,” began Darien Feary, BVSc, MS, Dipl. ACVIM, ACVECC, a lecturer in equine medicine with the University of Sydney, Australia. She discussed management of these injuries at the 2007 American Association of Equine Practitioners Convention, held Dec. 1-5 in Orlando, Fla.
Due to limited research on equine brain injury, most equine recommendations come from human research, she reported.
The two most common types of equine head trauma resulting in neurologic dysfunction are injury to the frontal/parietal brain from kicks or head-on collisions and poll trauma from flipping over backward, she said. These injuries are not always associated with fractures.
Frontal trauma can result in lacerations or contusions of the cerebral cortex. Neurologic signs can include contralateral (in the opposite eye) blindness, depressed mentation (mentality), compulsive wandering, and generalized seizures.
Poll trauma tends to result in the most severe brain injuries. “Young horses are particularly susceptible to this because they tend to flip over on their heads when they don’t want to do something, and the skull bones in this area don’t fuse until they’re three to four years old,” Feary noted. Brainstem and blood vessel damage with this injury can cause head-tilt, nystagmus (involuntary, rapid, rhythmic movement of the eyeball), depressed mentation, tetraparesis (weakness of the extremities), facial nerve paralysis, and bleeding into the guttural pouches.
Brain injury takes two forms–primary and secondary. Primary injury is immediate, direct, mechanical, or structural injury occurring at impact, such as concussions, lacerations, edema (fluid swelling), or hemorrhage. Secondary injury encompasses “the cascade of loca