SA Neuro Exam Flashcards
Does the size of the lesion correlate well with severity of dz in neuro?
no, speed of onset more telling of severity
- eg. slow growing tumour, brain can compensate for a long time
When localizing the lesion, what different options do we have?
> Brain - Forebrain - Brainstem - Cerebellum > Spinal cord - C1-C5 - C6-T2 - T3-L3 - L4-Cd > Neuromuscular
What are the 2 main aims of the neuro exam?
- Is the patient neurologically normal or abnormal?
2. Localisation
What should be done before the neuro exam? Which parts hould be left until the end?
- full PE and musculoskeletal exam
- leave noxious parts to the end
What are the 8 parts of the neuro exam?
- Mentation
- Posture
- Gait
- Postural Reactions
- Spinal Reflexes
- Cranial Nerves
- Palpation
- Nociception
How is mentation described?
> Level - alert - obtunded - stupor - coma (unresponsive to pain) > quality - appropriate - innapropriate (compulsion, dementia/delerium)
What can be looked at to judge posture?
- Hed position
- tilt (vestibular disease)
- turn (forebrain disease) - Limb position
- wide base (proprioceptive loss)
- narrow base (weakness)
- v weight bearing (pain) - Body
- Decerebrate (both pairs of limbs spastic extension, neck dorsally stretched out, not fully concious)
- Decerebellate (forelimbs extended, hid limbs flexed, neck slightly up, concious)
- Shiff-Sherrington (spinal cord lesion, concious, forelimbs normal but stiff, voluntary control still present and withdrawal, hindlimbs paralysed and no withdrawal reflex)
What can be assessed when looking at gait?
> Normal or abnormal? > Limbs affected? - paresis - ataxia - lameness - combination
What is paresis? What are the 2 forms? What should also be assesed when looking at potential paresis?
> decreased voluntary movement
- UMN or LMN (NOT based on severity)
- Also assess postural reactions, spinal reflexes and muscle tone
How can UMN paresis be identified?
- UMN = ^ muscle tone and spinal reflexes caudal to the lesion
- stride length normal/increased
- spasticity
How can LMN paresis be identified?
- LMN = v muscle tone and decrease/loss of spinal reflexes in limbs with a reflex arc containing the lesion
- stride length normal/decreased, stiff, bunny hopping, +- collapse
+- ataxia (sensory) knuckling and slappy gait
Signs of sesnroy/proprioceptive/spinal ataxia
- wide based stance
- ^ stride length
- swaying/floating gait
- knuckling
Signs of cerebellar ataxia
- disorder of rate and range of movement
- hypermetria
- intention tremor
- postural tremor
Signs of vestibular taxia
> unilateral - falling/leaning/circling - head tilt > bilateral - wide excursions of the head \+- tilt - crouched posture > strabismus and nystagmus
What do postural reactions require to be intact?
- proprioceptive AND motor systems
- similar pathways to gait
- senstivie but non-specific
- interpret with gait, spinal reflexes and muscle tone
How do sensory tracts relate to the brain?
- ipsilateral sensory tract to midbrain, then crosses to forebrain of contralateral side
- eg. absent paw positioning reflex on L = R forebrain lesion
Give examples of postural reactions
- hopping
- wheelbarrow
- hemiwalking
- placing (tactile/visual)
- extensor postural thrust
What nerve does biceps tendon spinal reflex test?
Musculocutaneous n. C6-8
What nerve does triceps tendon spinal reflex test?
Radial n. C7-T2
What nerve does patellar tendon spinal reflex test?
Femoral n. L4-6
What nerve does gastroc tendon spinal reflex test?
Sciatic n. L6-S2
What nerve does thoracic limb withdrawal reflex test?
Multiple nn C6-T2
What nerve does pelvic limb withdrawal reflex test?
Sciatic n. L6-S2
What nerve does perineal reflex test? What should happen with this test?
Pudendal n. S1-3
- bilateral response to a unilateral stimulus
Cutaneous trunci
Look up
What do decreased/absent spinal reflexes indicate?
- lesion within the reflex arc
- physcial limitation of movement (joint fibrosis, muscle contracture)
- excitement/fear
- spinal shock (complete loss of reflexes caudal to the lesion which gradually return over few days )
What do increased/exaggerated spinal reflexes indicate?
- lesion to UMN pathways cranial to spinal cord segment tested
- excitement/fear
- pseudohyperreflexia d/t loss of antagonism
What are the cranial nerves?
1- olfactory 2- optic 3- occulomotor 4- trochlear 5- trigeminal 6- abducens 7- facial 8- vestibulocochlear 9- glossopharyngeal 10- vagus 11- accessory (trapezius m.) 12- hypoglossal
What must be remembered when testing cranial nerves?
Afferent and efferent pathways differ
How do sharks differ from most animals?
10 cranial nerves as caudal 2 not encorporated into skull
How can the optic nerve (II) be tested?
- vision (II -> forebrain)
- menace (II -> forebrain -> cerebellum -> brainstem -> VII)
- PLR (II -> brainstem -> III) Direct and consensual
- Fundic exam
What is Horner’s syndrome?
> Sympathetic denervation of the orbit
- miosis
- ptosis
- enopthalmus
- hyperaemia
What do III, IV and VI nn. do?
> III (oculomotor) IV (trochelar) VI (abducens)
- motor to extraocular mm
- strabismus eye position (VIII -> central vestibular/brainstem -> III, IV, VI)
- nystagmus eye movement (VIII -> central vestibular/brainstem -> III, IV, VI)
What does CN V provide?
> facial sensation
- palpebral reflex (V-> brainstem -> VII blink)
- corneal reflex (V-> brainstrem -> VI globe retraction)
motor mm. mastication
- atrophy and inability to close jaw
What does CN VII provide?
> motor to muscles of facial expression
-facial paralysis/paresis, asymetry
- palpebral reflex (V-> brainstem -> VII)
- menace (II-> forebrain -> cerebellum -> brainstem -> VII)
autonomic innervation of lacrimal glands
- STT
What does CN VIII provide?
(vestibulocochlear) > cochlear - auditory > vestibular - ataxia - head tilt - strabismus - abnormal nystagmus (physiological nystagmus VIII -> brainstem -> III, IV, VI)
What do IX and X provide?
(glossopharyngeal and vagus)
- sensory and motor to pharynx
- gag reflex (IX and X -> brainstem -> IX and X)
- change in bark and swallowing
What does CN XII provide?
> motor to tongue
- paresis of tongue
- atrophy/assymetry
Which speices is CN XI important in?
fish
otherwsie not
What can you find on palpation?
- swelling and atrophy
- deep pain
> focal or diffuse?
What is nociception?
Concious perception of pain
- receptors -> brain
> superficial (skin) and deep (bone periosteum)
Does limb withdrawal indicate pain?
NO!!!!
- behavioural changes yelp or attempts to bite you indicate pain!
How can nociceptive testing be carried out methodically?
Cutaneous autonomous zones for each nerve on the limbs, trunk and head
Can all lesions be explained with one lesion?
Remember lesion can be focal, diffuse or multifocal
