Nervous system

Question 1

General considerations

Answer 1

Is it necessary to use life-saving methods
Is it a nervous system problem or is it a kindey/ liver problem
Is it cerebral, spinal or a peripheral dysfunction
Acute or chronic
Infectious disease? herpes type 1, rabies, WNV

Question 2

Types of neurological diagnosis

Answer 2

Functional or symptomatic
Anatomical
Pathological
Aetiological

Question 3

The importance of history

Answer 3

Because of the limitations of the examination
Characteristic of neuropathies e.g epilepsy the clinical signs are not always present– put in cameras
Missing subjective info
Infectious diseases! vaccines and epidemics

Question 4

The disturbing factors that could change the horses behaviour and therefore the clinical signs

Answer 4

Restraints
Sedatives
Environment

Question 5

Methods of physical exam

Answer 5

Inspection
Palpation
Postural reactions 
Vertebral reflexes 
Cranial nerves 
Sensitivity
Pain perception: supf vs deep

Question 6

Ancillary diagnostic methods

Answer 6

Neuroradiography
Nuclear scintigraphy
Computed tomography 
MRI
Electroencephalography 
Lab tests

Question 7

Neuroradiography

Answer 7

Plain
Myelography- compression of SC
Angiography- bvs both cerebral and vertebral

Question 8

Lab tests

Answer 8

Blood is NB to see if another organ system is involved
Urine
CSF!!! NB can do cultures and PCR

Question 9

Structure of the physical exam

Answer 9

Head!! always start here and check:
Behaviour 
Mental status 
Head posture and coordination
Cranial nerves 

Gait and posture 
Neck and forelimbs 
Trunk and hindlimbs 
Tail and anus 
Cerebrum
Brain stem 
Cerebellum
SC
Peripheral nerves and the muscles they supply

Question 10

Lesion at C1-C5

Answer 10

Tetraparesis and neck pain

Normal-exaggerated spinal reflexes

Question 11

Lesion at C6-T2

Answer 11

Tetraparesis and neck pain
Decreased/absent thoracic limb spinal reflexes
Normal-exaggerated spinal cord reflexes on the pelvic limbs

Question 12

Lesion at T3-L3

Answer 12

Paraparesis and back pain
Normal thoracic limb spinal reflexes
Normal- exaggerated pelvic limb spinal reflexes

Question 13

Lesion at L4-S3

Answer 13

Paraparesis and lower back pain
Normal thoracic limb spinal reflexes
Decreased/absent spinal reflexes on the pelvic limbs

Question 14

Caudal lesions

Answer 14

Paresis of tail
Decreased tail tone
Decreased tail sensation

Question 15

Localisation of lesions

Answer 15

Use the foramen magnum as a gauge
Anything cranially will be a brain issue

Assume central lesion and look at clinical sign, check if they are explicable with lesions in front of the FM.. if not, go one level caudally and try again until you can explain the signs.

Question 16

What can cranial nerve signs be an indication of?

Answer 16

Cerebral, cerebellar or brainstem disease

Question 17

Cerebral disease

Answer 17

Seizures
Blindness
Dementia
Mild ataxia or weakness

Question 18

Cerebellar disease

Answer 18

Hypermetria
Intention
Tremors
Weakness

Question 19

Brainstem disease

Answer 19

Gait deficits
Altered consciousness
Tetraparesis

Question 20

Head posture and coordination

Answer 20

Movements at the antlantooccipital joint

Control of the cerebrum, cerebellum and vestibular system

Question 21

Head posture and coordination: vestibular lesion

Answer 21

Head tilt

Question 22

Head posture and coordination: cerebral lesion

Answer 22

Deviation toward the side of the lesion

Head and neck are not in the body axis so there is circling

Question 23

Head posture and coordination: cerebellar lesion

Answer 23

jerky movements during voluntary movements and fine tremor when at rest

Question 24

What does a left head tilt usually indicate?

Answer 24

skull injury

Question 25

Cranial nerves

Answer 25

``` Olfactory Optic Oculomotor Trigeminal Facial Vestibulocochlear Glossopharyngeal, vagus and acc Hypoglossal ```

Question 26

Olfactory

Answer 26

use food to examine

Question 27

Optic

Answer 27

Menace: rapidly approaching- should blink | Test for vision: different obstacles

Question 28

Oculomotor

Answer 28

Pupillary light reflex Simple: light in one eye and see how same pupil reacts Consensual: light in one eye and check the pupil of the other eye, the nerve crossing the optic chiasm-- anisocoria if different pupil sizes

Question 29

Disturbances of the oculomotor nerve

Answer 29

Strabismus: abnormal position of the eyeball Nystagmus: abnormal movement of the eye can be physio during movement of the head and superficial anaesthesia ``` Horner's syndrome: Damage of sympathetic nerves miosis ptosis (hanging upper lid) enophthalmos Localized sweating in the cervical area ```

Question 30

What is the normal position of the eye

Answer 30

line btw medial and lateral canthus to angle of the pupil

Question 31

Trigeminal nerve

Answer 31

Facial cutaneous sensation- stick fingers into nares Palpebral reflex- the sensory component- touch upper eyelid Corneal reflex- sensory- use cotton to touch Chewing and movements of the jaw

Question 32

Facial nerve

Answer 32

Facial symmetry and movement so paralysis is easy to see | Palpebral and corneal reflexes- the motor activity

Question 33

Vestibulocochlear nerve

Answer 33

hearing and balance

Question 34

Vagus group (glossopharyngeal, vagus and acc)

Answer 34

Swallowing reflex Thoraco-laryngeal adductor test= slap test to diagnose laryngeal nerve paralysis Slap withers on one side and then palpate larynx on the opposite side, more common left-sided paralysis

Question 35

Hypoglossal nerve

Answer 35

Tongue function

Question 36

Ataxia

Answer 36

lack of coordination | graded from 1-5, 5 being lateral recumbency

Question 37

Dysmetria

Answer 37

hypo or hypermetria due to abnormal range or force of motion

Question 38

Hypometria

Answer 38

voluntary movement shorter than intended goal too little joint movement dragging of hooves

Question 39

Hypermetria

Answer 39

voluntary movements overreaching the intended goal excessive joint movement e.g WNV encephalitis with held-up tail

Question 40

Paresis

Answer 40

muscle weakness resulting from neurologic dysfunction

Question 41

Paralysis

Answer 41

cannot move voluntarily

Question 42

Evaluation of the neck and forelimbs

Answer 42

1. With food 2. Cervicoauricular reflex- tap neck at C2 and ear on the same side moves 3. Cervical cutaneous sensation- hemostat 4. Deep pain perception- press coronary band- not reliable 5. Sway reaction- lateral pressure on withers 6. Dorsal pressure on withers- stability and balance 7. Postural reactions/ Correction tests: crossing limbs put legs into wider stance sideways hopping if safe! lift up one leg

Question 43

Evaluation of the trunk and hind limbs

Answer 43

similar to forelimb! Sway reaction- push tuber coxae laterally, if doing it while walking pull the tail pressure on the lumbar region

Question 44

Recumbent horses: forelimb tests

Answer 44

flexor reflex: thermostat pinching biceps reflex: hammer in front of shoulder joint Triceps reflex: just above olecranon

Question 45

Recumbent horses: hindlimb flexors reflexes

Answer 45

Tibial- plantar aspect of the metatarsus Peroneal- dorsal part of tarsus and metatarsus Femoral- medial thigh Patellar: lift leg a bit and tap on the ligament

Question 46

Recumbent: ability to lift head, neck and limbs used for localization of the lesion

Answer 46

Can only lift head: cranial cervical region Head and neck: caudal cervical region 'Dog-sitting'- lesion in cervical cord Functional thoracic limbs- caudal to T2 Deficit in trunk/hindlimbs- between T2 and S2 Localised sweating- desc symp tracts