The neuro horse with normal mentation miscellaneous Flashcards
What is head shaking in horses?
What is the cause?
Involuntary sudden violent repetitive movements of the head dorso-ventrally, horizontally or rotatory
Also see:
* Nose rubbing on stationary objects /floor/scratching
* Lower head carriage
* Snorting, sneezing, snoring
* Excessive nasal discharge
90% are considered idiopathic
Persistent: Trigeminal-mediated (most?): Facial/head noxious sensations: V-trigeminal nerve
How is head shaking graded?
Grade 0 – there is no headshaking.
Grade 1 – there is headshaking, only at exercise but sufficiently mild that the horse may be ridden.
Grade 2 – there is headshaking at exercise to a severity as to make ridden exercise unsafe or impossible.
Grade 3 – there is headshaking even at rest
What types of horses are predisposed to head shaking?
what are the triggers?
Young geldings 5-12yo (Ross et al. 2018)
Pleasure horses and sport horses
April - Summer
Identified triggers
* Photic: bright light, photoperiod, cystic corpora nigra, floaters in the posterior/anterior chamber
* Allergic: rhinitis.
* Sinusitis, otitis (Trombicula autumnalis),GP mycosis
* Structural: skull fractures, dental disease, THO, TMJ
* Bit/bridle
*
What is the diagnosic plan for a horse that is head shaking?
Identification of potential triggers CRITICAL
* Physical exam/environment/ management
* Ocular exam
* Dental exam
* Upper airway endoscopy including GP
* Nerve blocks (infraorbital and maxillary)
* Skull x-rays/CT
* Otoscopy
What is the treatment for head shaking?
Medical treatment:
* Cyproheptadine 0.3mg/kg PO BID
* + Carbamazepine (4mg/kg)
* Gabapentin (25mg/kg q 8h)
* Steroids (inhaled)
* Magnesium sulphate 40mg/kg
* Antihistamine drugs
* Melatonin 4 mg/kg BW, qốh
* Nose nets
* Ocular sunglasses
* Bridles bit
Surgical therapy - low success adn high complication rate
* Infraorbital neurectomy with cryotherapy
* Chemical sclerosis of the infraorbital with phenol
* Caudal compression of the infraorbital nerve
Other treatment:
* EquiPENNS ( Percutaneous nerve stimulation) - moderate results
What is narcolepsy?
What causes it?
What breeds are predisposed?
- Spectrum of CND disorders characterized by episodes of excessive sleepiness, muscular weakness and REM onset sleep
- Caused by Dysfunctional orexin system: hypocretins 1-2 and hypothalamic GABA neurons
- shetlands, minature horses
What is sleep deprevation in horses what is it caused by?
E pisodes of collapse due to lack of regular resting/sleep
Caused by: Chronic arthritis, Chronic pain, Fear to environment
What are the clinical signs of sleep deprivation?
- Staggering, lowering the head and neck, buckling of the thoracic limbs, kneeling posture, flaccidity of lips…
- Unexplained abrasions wounds: knees, lips…
- Kneeling when tightening the girth
How do you diagnose sleep deprivation in horses?
What is the Treatment for sleep-deprivation in horses?
- Age, recent changes in environment, stable, barn, premisses, wildlife….
- Concurrent disease: arthritis: back, hocks, carpus…PPID…
- Quality of bedding, tight rungs in winter
- True narcolepsy: rule out dx
Treatment:
* Bute-trial: oral phenylbutazone
* Thick bedding: straw
* Large stable
* Inside barn
* Remove rugs
*
What is shivers in the horse?
what is the cause?
Progressive, chronic neuromuscular disease in horses characterized bygait abnormalities when backing up, trembling of the tail while held erect, trembling of the thigh muscles and a flexed and trembling hind limb when held
Cause: Damage of the Deep cerebellar Nuclei: fine-tune of planned movements: Flex & Ext activated at the same time
What are the clinical signs of shivers in the horse?
What is the diagnosis and treatment?
Backing manoeuvre: hyperextension of hindlimbs, inability of picking up the hind limbs: offers contralateral limb, hyperextension…
* But normal ambulation otherwise: walk forward, trot, cantering, performing
- Normally starts around 5 years of age
- Normally progressive and performance limiting
- Rule out other conditions: upper fixation of patella, stifle OA, Sacro-iliac pain..
No treatment: guarded prognosis
