Lecture 23: Diagnostic Procedures & Tx Options in Equine Neurology

What bloodwork should be performed in a neuro case?

• CBC: inflammation, dehydration, other disease

• Biochemistry: metabolic disorders, electrolyte abnormalities, enzymes, ammonia, vitamin E

• Serology, ELISA, PCR

What are the three methods of CSF collection?

How is CSF analyzed?

GROSS

• Pressure

• Appearance (color, turbidity)

• Xanthochromia

LAB ANALYSIS

• TP

• TCC

• Cytology

• Enzymes

• Immune testing for specific diseases

Why is a nasal swab performed during a neuro exam?

EHV1

What are the possible complications of myelograms?

Complications possible

- Seizure, blindness

- Fever

- Neck pain

- Horse cannot rise

Recovery of neuro horse from general anesthesia is difficult

What are the neuroelectrodiagnostics?

• Electromyography - EMG

• Nerve conduction studies -NCS

• Brainstem auditory evoked response - BAER

• Electroencephalography

What is the difference between EMG and NCS and what do they evaluate?

• EMG: electrical activity by muscle

• NCS: electrical conduction by nerve

• Evaluate LMN: Positive sharp waves, Fibrillation potential

What are the human concerns when caring for the neurologic horse?

1. Always consider rabies ➔ gloves, contact tracing

2. Careful handling

• Exit strategy, buddy strategy

  • Always be able to exit the stall

  • Do not examine the horse by yourself

• Prevent falls, kicks etc.

  • Steady horse by tail if standing

  • Be nowhere close to the legs

  • Even a horse in a sling may not be safe…

What are the horse concerns when caring for the neurologic horse?

a. Protect from self-injury

b. Provide nutrition & support

c. Avoid secondary injuries & loss of function

When does recumbency decrease prognosis significantly in a neurologic horse?

if > 48-72 hours

What are the injury and secondary issues risked with recumbency?

How can you protect a neurologic horse from self-injury?

• Head: helmet

• Eyes: ointment, helmet

• Legs: bandage, support

• Adapt bedding: Absorbent, nonabrasive, comfortable, Good footing

• Padded stall

How should hydration and nutrition be altered for a neurologic horse?

Hydration:

• Easy access to water

• Nasogastric intubation

• IV fluids

Nutrition:

• No additional support

• Pellet gruel

• Liquid diet

• Parenteral nutrition

What in the GI tract and urinary tract needs to be evaluated in a neurologic horse?

GI:

• Can the horse defecate? Rectal exam

• Empty rectum regularly

• Monitor fecal output & GI sounds

• Complications: impaction, ileus

Urinary:

• Can the horse urinate? Rectal exam

• Empty bladder regularly

• Consider catheter

• Complications: cystitis

What are the concerns with the lungs and the eyes in a neurologic horse?

Lung:

• Is the horse dysphagic? Prevent aspiration

• Positioning: up > sternal > lateral

• Broad spectrum antimicrobials

• Complication: pneumonia

Eyes:

• Protection: padding, helmet, bandage

• Lubrication: eye ointment

• Daily exam

• Complication: ulcers, keratitis

What physiotherapy should be considered in a neurologic horse?

• Some horses are smarter than others

• Encourage movement

• Controlled exercise (standing horse)

• Sling (even if for brief periods)

• Recumbent horse: manipulate limb: passive flexion, extension, Massage, Therapeutic ultrasound

What are the benefits of using slings in a neurologic horse?

➔ Better assessment, diagnosis, prognosis

➔ Improved supportive care for horse

➔ Physiotherapy

• Supervision

• Not every horse tolerates the sling

• Not every condition is amenable for a sling

What are the different types of slings?

• Simple: Breast piece and body part, ! can slide out backwards (i.e. EquiSling)

• Advanced: Tail piece around hind quarters, adjustable straps (i.e. Liftex sling)

• Complex and smart slings: Anderson Sling

How should a neurologic horse be transported?

1. Protect from self-injury

a. Empty trailer without supporting bars

b. Wide door (i.e. stock trailer)

c. Consider heavy sedation or anesthesia

2. Bandage head and limbs

3. Padding or deep bedding

4. Call ahead

What drugs are used for seizure control in horses?

• diazepam

• midazolam

• phenobarbital

• potassium bromide

• sodium bromide

What drugs are used to control seizures if diazepam or phenobarbital NOT available?

• xylazine

• detomidine

• butorphanol

• pentobarbital

What NSAIDs are commonly used for a neurologic horse?

• phenylbutazone

• flunixin meglumine

• ketoprofen

• firocoxib

What steroids are used for neurologic horses?

• dexmethasone

• dexmethasone SP

• methyprednisolone sodium succinate

• prenisolone

What are the common complications of steroids in neuro cases?

• use controversial

• laminitis

• infection

What antioxidants are used for neurologic horses?

• DMSO: controversial but cheap

• Vitamin E

• Thiamine

• coenzyme 10

What is used to treat neuro head trauma?

• hypertonic saline

• mannitol

• thiamine

What antimicrobial drugs are used for neuro horses?

• Trimetoprim-sulfamethoxazole

• Penicillin, 3rd generation cephalosporins

• Gentamycin

What are 3 FDA approved EPM treatments?

1. Sulfadiazine – Pyrimethamine

2. Ponazuril

3. Diclazuril

What are the risk based vaccines in horses?

• botulism

• EHV1, but no EHM protection