Should we do Koenig's other reflexes?
asked Becca.Well, it would be nice to have the information
, said Dr. Smith, but in a large animal such as Koenig, it isn't practical to test what we call spinal reflexes, as this requires that the animal is lying down and relaxed – we're not about to achieve that with Koenig! If he were a dog, or even a goat, we would lay him down, and check reflexes such as his patellar reflex – your own doctor has probably tested that on you. That's the one when the examiner taps below your knee with a little hammer and your leg involuntarily strikes forward. It tells us that a certain segment of your spinal cord is intact. In horses, we have to rely on our observations during other parts of the examination.Well
, said Becca, I think that we should do a thorough physical examination. Some systemic diseases can result in neurologic disease, so we should listen to his heart and lungs carefully. We should also do a thorough ocular examination, as the optic nerve, which we can see at the back of the eye, is the only part of the central nervous system that we can view directly. Some diseases, such as equine motor neuron disease result in visible changes to the optic nerve. Finally, we should do some basic bloodwork. A complete blood count, or CBC, can tell us if there is a focus of inflammation or infection in the body.
They took blood and submitted it to the lab for testing – there were no abnormalities. Then, they dilated Koenig's eyes and looked at the back of them – everything looked normal. Well, Suzie
, said Dr. Smith. I'd like to sum up our findings for you. We've gone through a systematic, thorough neurological examination. Our goal with a neurological examination is to find out where in the central nervous system the lesion is. Then, we can have a better shot at 'who dunnit'. From our examination, we think that Koenig's neurological system is intact in all areas except the cervical spinal cord. We also find that the signs are fairly symmetric – meaning that it has affected both sides of the spinal cord evenly. We judge him to be a grade 2 out of a possible 4 – it takes challenge tests to see what is abnormal with him. We now can do several ancillary tests to try to determine the cause. Our top choices of what is wrong with Koenig include Wobbler's Syndrome, which is a type of developmental disease of the vertebral bones that sometimes doesn't show up until the horse is in hard work, and Equine Protozoal Myeloencephalopathy (EPM). In order to figure out which it is, we'll do x-rays, bloodwork, and a spinal tap. If we hadn't done our careful neurological examination, we would still have a very long list of rule-outs – and we might be quite a long way from figuring out what is wrong with Koenig. This way, we'll be pretty sure of an answer very soon
This was a hypothetical case, not a real case. There is no answer but both diseases can be the cause. For more information, please read Wobbler's Syndrome
or Equine Protozoal Myeloencephalopathy