Neurological Dysfunction Equine Flashcards
1
Q
What are some neurological disorders?
A
- Congenital Lesions
- Trauma
- Cervical Vertebral Stenotic Myelopathy
- Inflammatory/Infectious Conditions
- Degenerative Conditions
- Neoplasia (new or abnormal growth of tissue)
- Neuromuscular Diseases
- Peripheral Nervous System Disorders
2
Q
What are congenital lesions?
A
- Congenital hydrocephalus
- Rare (3% congenital abnormalities)
- Possibly hereditary
- Often aborted or stillborn
- Cerebral disease
- Dullness
- Blindness
- Strabismus (wall eye)
- Nystagmus (increases eye movement)
- Seizures
born with it
•Diagnosis:
•Radiography/Ultrasonography
3
Q
Where can congenital lesions occur? (three examples)
A
- Occipito-atlanto-axial malformation
- Developmental abnormalities of occipital condyles, atlas and axis
- Hereditary in Arabian horses
- Clinical signs:
- Stillborn
- Ataxic at birth
- Progressive ataxia
- Extended neck carriage
- Diagnosis
- Radiography
- Malformation of the spine
- Kyphosis
- Scoliosis
- Lordosis
- Incidence 2.9%
- Rarely neurological
- Butterfly vertebrae
- Dorsal to ventral cleft
- Hemivertebrae
- Wedge-shaped
- Block vertebrae
- Fused ventral bodies
- Rarely neurological
- Neonatal Maladjustment Syndrome – also known as barker syndrome, dummy foal syndrome, wander foal.
- Caused by a lack of oxygen to the brain during birth
- Symptoms
- Loss of sucking reflex
- Seizures or convulsions
- Emitting of strange, unusual whinnies or barking sounds
- Lack of coordination
- Weakness
- Respiratory distress
- Circulatory stress
- Recumbency
- Coma
- Signs of blindness
- Erratic movements and behaviour
4
Q
What is trauma?
A
- 22% equine neurologic disorders
- 1:3 brain:spinal cord
- Diagnosis
- Radiography
- Brain injury
- 50% head trauma cases
- Haemorrhage
- Brain swelling
- Coup/contracoup
- Spinal cord injury
- Usually cervical
- Proprioceptive deficit
- Degree of trauma
- Site of damage
- Sudden onset ataxia
- Reluctance to move
- Recumbency
- Stiff painful neck
- Sweating
- Spinal cord ischaemia = 2y injury
5
Q
What is cervical vertebral stenotic myelopathy- wobblers?
A
•Leading cause of non-infectious spinal cord ataxia •Affects 2% of TB horses •Chronic and/or repetitive trauma •Conduction block due to axonal loss neurological signs •Insidious in onset •Typically progressive •Acute exacerbation after what may seem a minor trauma
6
Q
What is Cervical Vertebral Stenotic Myelopathy?
A
- Developmental disease of the cervical vertebrae
- Malformation
- Malarticulation
- Multi-factorial disease
- Genetic predisposition
- Environmental influences
- Risk factors
- Young horses (1-2 y/o)
- Rapid growth
- High carbohydrate ration
- Zinc excess
- Copper deficiency (defective lysyl oxidase)
- Calcium/phosphorus imbalance
- Similar to other developmental orthopaedic diseases: OCD
- Second class of horses is generally older
- Osteoarthritic enlargement of articular processes (mainly caudal cervical)
- External trauma
- Soft tissue changes
- Thickening of the surrounding ligaments
- Thickening of the joint capsules
- Synovial cyst formation
- Only a few develop clinical signs
- Diagnosis
- Radiography
- Myelography
- Post Mortem
- Surgery – ‘Seattle Slew’
- 80% improve
- 63% return to athletic function
- 15% suitable for breeding
- 10% pasture sound
- 12% failure to improve
- Non-surgical treatment
- Anti-inflammatory drugs
- Steroids
- NSAIDs
- Older horses (Grade 0-2)
- Peri-articular joint injection
- Steroids
- Hyonate
- <1yo
- Restricted diet
- Reduced protein
- Reduced carbohydrate
- Balanced zinc and copper
- Restricted exercise
7
Q
What is Viral- Equine herpesvirus (1,4)?- inflammatory/ infectious conditions
A
- EHV-1
- Respiratory disease
- Abortion
- Neonatal death
- Neuropathy (nerve pain)
- EHV-4
- Milder respiratory form
- Rarely abortion
- Not linked to neuropathy
- Viral - Equine Herpesvirus (1,4) cont.
- Mainly spinal cord
- Ataxia
- Dysmetria
- Weakness
- Paralysis
- Spastic bladder
- Supportive treatment
- Mild case => fair prognosis
- Recumbent case => guarded, residual deficits
- Vaccination
8
Q
What viral infections are not present in the uk?- inflammatory/ infectious conditions
A
- Rabies
- Togavirus - Eastern/Western/ Venezuelan equine encephalitis
- Equine Infectious Anemia
- Equine Protozoal Myeloencephalitis (EPM)
9
Q
What bacterial infectious/ Inflammatory conditions are there and what do they do?
A
- Bacterial
- Foals
- E. coli
- Salmonella
- Septicaemia and immunosupression
- Adults
- Streptococcal species
- Sinusitis
- Meningitis
10
Q
What infectious/ Inflammatory conditions are there?
A
- Foals
- Depression
- Disorientation
- Loss of suckle reflex
- Recumbency
- Seizures
- Adults
- Local lesions (abscess)
- Ataxia
- Dementia
- Blindness seizures
11
Q
How do you treat infectious/ Inflammatory?
A
- Antibiotics
- Anti-inflammatory therapy
- Symptomatic therapy
12
Q
What is tetnus?-inflammatory/ infectious conditions
A
- Clostridium tetani - bacteria
- Common soil organism (spores)
- Deep penetrating wounds
- Produces 3 potent biological neurotoxins
- Tetanospasmin
- Haemolysin
- Peripheral acting non spasmogenic toxin
- Neurotoxins affect signals at the nerve synapses
13
Q
What are the onset signs of 2-21d tetnus? and what are the treatments? -inflammatory/ infectious conditions
A
- Onset of signs 2-21d
- Hyperaesthesia – excessive reaction to stimulation
- 3rd eyelid prolapse
- Stiff gait
- ‘Anxious’ expression
- ‘Sawhorse’ stance
- Dysphagia – loss of swallowing function
- Trismus – lock jaw
- Recumbency
- Treatment
- Antibiosis
- Tetanus antitoxin
- Muscle relaxants
- Diazepam
- Supportive therapy
- Vaccination very effective
14
Q
What is botulism and what are its treatments?-inflammatory/ infectious conditions
A
- Botulism
- Clostridium botulinum
- Soil organism
- Forage stored in plastic bags
- Forage poisoning
- Wound botulism
- Treatment
- Antitoxin
- +/- antibiosis
- Supportive therapy
- Incubation: 12h-10d
- Diffuse flaccid paralysis
- Symmetrical loss of muscle strength
- Sudden death
- Dysphagia
- Slow, shuffling gait
- Toe drag
- Mydriasis – prolonged dilation of pupils
- Drooping eyelids
- Reduced tongue tone
- Muscle fasciculations/trembling
15
Q
What are parasites and how do you treat?-inflammatory/ infectious conditions
A
- Parasites
- Strongylus vulgaris
- Hypoderma spp.
- Habronema spp.
- Signs reflect migration path
- Treatment
- wormer with rapid kill to minimise progression
- Possible acute worsening due to inflammatory response to parasite death
- Anti-inflammatory therapy
