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  Discussion on Head tilt and proprioceptive deficit
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New Member:
Pmobius

Posted on Saturday, Sep 16, 2006 - 11:56 pm:

One of my boarders has a 17 year old thoroughbred that is used for light dressage riding a few days per week. In the past three weeks we noticed he was not performing equally in both directions. She had acupuncture and chiropractic performed to treat a sore lumbar region. He has slowly gotten worse. He has proprioceptive deficit that seems to worsen when he walks in the dark barn. At times when he became unsteady, his legs would shake. That happened early on and hasn't happened recently. He leans to the left and tilts his head. He splays his hindlegs to steady himself and occasionally crosses the front legs as well. He walks as if he is drunk. She called her vet who rather quickly diagnosed EPM, after performing a few negative flexion tests and few neurological tests. He shows slight weakness on the left side when the tail is pulled and increased ataxia when walked with the head elevated. He circled pretty well in both directions, although on the lunge line, I heard his left stifle snapping and he cut to the inside of the circle. Blood was drawn and sent for EPM and WNV (he has been vaccinated) testing as well as a CBC and blood chemistry. From what I have heard the regular blood work resulted in normal ranges, and we are waiting to hear about the EPM and WNV. In the mean time the owner called in a holistic vet who diagnosed spinal arthritis and TMJ to explain the head tilt, and prescribed herbs and Vitamin E capsules. The owner was relieved to hear the diagnosis. The horse is not improving and I feel that something is being missed and enough isn't being done fast enough. I agree that he has some of the symptoms associated with EPM, but is a head tilt one of the symptoms commonly seen with EPM? And why does he become increasingly unstable in the lowly lit barn? I keep thinking that the problem is in the head, maybe inner ear or brain tumor. I don't want to let this go too long, before it is too late to help him. He is turned out every day and runs and bucks when he is out with occasional unsteadiness. Any thoughts? I would like to take him to Cornell University, but it isn't my horse.
New Member:
Upzoo

Posted on Sunday, Sep 17, 2006 - 12:20 am:

One of our horses who had EPM (diagnosed by spinal tap) had a head tilt as one of his symptoms prior to treatment and still walks with his head tilted when tired.
Moderator:
DrO

Posted on Sunday, Sep 17, 2006 - 11:06 am:

Hello Pam,
It believe it will require examination by an experienced an neurologist or someone well versed in the subject to accurately localize the lesion(s). And the best you will be able to do from physical examination is going to be to localize the lesions and not accurately diagnose the disease causing the clinical signs. However accurate localization will help establish a smaller set of likely diseases that can be pursued with serology and possibly CNS tap.

EPM tends to be a focal disease and can be in the brain and cause cranial nerve symptoms. You describe symptoms of quadrilateral proprioceptive deficits and either cerebellar or eight cranial nerve deficits. It is possible to create wide ranging neuro-musculature disease by effecting the cerebellum but the trembling, if do to weakness, is not consistent with a disease of just this location. On the other hand intention tremors accompanied with exaggerated movement are consistent with cerebellar disease. Note that neither blood work on CNS results positively diagnose EPM, see the article on EPM for more.

Though a bit technical (and I don't know how to cover this subject without being technical) we discuss your particular problem at Diseases of Horses » Nervous System » Incoordination, Weakness, Spasticity, Tremors » Diagnosing Incoordination, Ataxia and Weakness. Following localization lists of rule outs are provided.

In the meantime while waiting for a better diagnosis I see nothing wrong with treating for EPM, large doses of Vitamin E, and providing support for potential inflammatory/painful problems with NSAID's. Each of these are covered in the articles linked to in the diagnosis article referenced above.
DrO
New Member:
Pmobius

Posted on Sunday, Sep 17, 2006 - 3:23 pm:

Thank you both for your prompt replys. I have already read and printed the articles you referenced, and I will be sure to share them with the owner. I think the best thing to do is what you, Dr. O, suggested and that is take him to see an experienced neurologist. He has too many symptoms that don't seem to pinpoint one disease. I am still unsure of why his proprioceptive deficit increases with low light. Thanks again, I will be sure to share our findings.
New Member:
Pmobius

Posted on Tuesday, Sep 26, 2006 - 10:11 pm:

I just returned from a trip to Cornell where three neurologist examined the horse and came up with a diagnosis: temporohyoid osteoarthropathy. It was confirmed by endoscope and xray. The direction in which he tilted his head was the side that was most severely affected. Since my initial posting, his staggering decreased substantially, which they attribute to compensation for the lack of balance due to the head tilt. Also, cervical spine xrays showed bony proliferation between C5 and C6, which they said contributed to slight but unusual movements in the hind limbs, ie. lifting one slightly higher and the other making a larger arc when turned in a tight circle. They were able to separate the two symptoms and diagnose them individually. Upon diagnosis, I immediately retrieved your article about temporohyoid osteoathropathy and showed the owner. It was very informative to her and the illustration help her understand better. Thank you again for your advise and input.
Moderator:
DrO

Posted on Wednesday, Sep 27, 2006 - 6:14 am:

Excellent Pamela,
Great case, though I know owners hate to hear those words, in this case it may make a difference as to outcome.

Did the horse have deficits before this started? If not: I would discount the minor spinal lesions as a cause of problems; if so: sounds likely. The pressure on the eight cranial nerve from the TO would be enough to account for most of the symptomology but I have trouble with the trembling....hmmm if the horse was having a particularly difficult time dealing with the head tilt. Did they comment on this or had this symptom disappeared.

A few other questions if you don't mind. Did they see the dry eye symptom or other cranial nerve deficits and lastly do they recommend a treatment and offer a prognosis?
DrO
Member:
Pmobius

Posted on Thursday, Sep 28, 2006 - 2:07 am:

When the long necked, long legged horse first arrived at my farm in June, I thought he looked a bit clumsy in behind when I first turned him out and also noticed that his right semitendinous muscle was larger that the left. I attributed it to his age and lankiness as no one mentioned any previous or existing lameness problems. I am guessing that these slight symptoms are a result of the bony proliferation on the cervical spine. As for the trembling, I only witnessed it once, which was when the proprioceptive deficits were first occurring. He was probably trembling because he was scared of his new unsteadiness.

As for the cranial nerve deficits, the dry eye test was negative, and myself and one of the three vets saw very slight facial differences on the affected side. I thought his loose lower lip DrOoped more on the left and the vet thought that his left nostril was slightly smaller.

The treatment is 17 tablets of TMP-SMZ b.i.d. for 30 days, and bute as needed for the cervical spine. I think in an effort to reduce their risk of liability, they recommended that he not be ridden ever again. We have already seen an improvement in his head tilt and believe that if it fully resolves itself that he should be able to be ridden lightly. The vets at Cornell informed us about the surgery to remove the ceratohyoids and warned about the risk of permanent facial nerve damage. We will consider it if we don't see a complete recovery or the symptoms worsen or return.

Thank you for your interest and information. I will update you as he hopefully progresses.
Member:
pmobius

Posted on Monday, Jan 22, 2007 - 7:29 pm:

Four months have passed since this horse had his original problem and it still has not resolved completely. I would like to hear your thoughts. As prescribed by the neurologist at Cornell, the horse received 17 TMS tablets b.i.d. for 2 months. The head tilt resolved, he was being ridden, and we thought it was over. Shortly thereafter, we noticed a discharge from his left ear. The discharge was cultured and was shown to be sensitive to TMS, so we were told to treat him with the antibiotics for another 2 months. He is now on his 7th week of antibiotics and today I noticed blood coming from the affected ear. Can this be a normal progression of an ear infection?
Moderator:
DrO

Posted on Tuesday, Jan 23, 2007 - 7:04 am:

Pamela, the presence of the blood suggest unresolved tissue damage, but if there is no longer a sign of infection it may be the infection has resolved and the damaged tissue has not healed completely. Without any other information, I would continue the antibiotic for another month to give the tissues time to heal. While on such long term oral antibiotic there is some B vitamin deficiency concern that simple oral supplementation may paradoxically exacerbate. For more on this see the article on TMP/SMZ in the antibiotic section.
DrO
Member:
pmobius

Posted on Tuesday, Jan 23, 2007 - 2:17 pm:

Thank you very much. I will read the article and supplement as necessary.
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