Flashcards in SA Neuro Exam Deck (44):
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?
> Spinal cord
What are the 2 main aims of the neuro exam?
1. Is the patient neurologically normal or abnormal?
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?
4. Postural Reactions
5. Spinal Reflexes
6. Cranial Nerves
How is mentation described?
- coma (unresponsive to pain)
- innapropriate (compulsion, dementia/delerium)
What can be looked at to judge posture?
1. Hed position
- tilt (vestibular disease)
- turn (forebrain disease)
2. Limb position
- wide base (proprioceptive loss)
- narrow base (weakness)
- v weight bearing (pain)
- 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?
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
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
Signs of cerebellar ataxia
- disorder of rate and range of movement
- intention tremor
- postural tremor
Signs of vestibular taxia
- head tilt
- wide excursions of the head
- 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
- 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
What do decreased/absent spinal reflexes indicate?
- lesion within the reflex arc
- physcial limitation of movement (joint fibrosis, muscle contracture)
- 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
- pseudohyperreflexia d/t loss of antagonism
What are the cranial nerves?
11- accessory (trapezius m.)
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
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
What does CN VIII provide?
- head tilt
- 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
Which speices is CN XI important in?
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?
- 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