fundamentals of neurology

Question 1

how will a pt who has a lesion in their brainstem present (in terms of side of body affected)

Answer 1

affected side of the face is opposite to affected side of the body (e.g R sides facial symptoms but L sided rest of the body)

Question 2

who does a brainstem lesion present with this specific mixed distribution

Answer 2

most peripheral nerves dessucate in the brainstem while cranial nerves do not decussate (apart from trochlear) - i.e. a lesion on the right side of the brain stem will result in R facial defecit but L body deficit

Question 3

what distribution of abnormal nuerological function may be seen with severe alcoholism

Answer 3

glove and stocking (longest nerves affected first)

Question 4

if there is a sudden neurological deficit (seconds-minutes) what is the likley cause

Answer 4

vascular (stoke, subarach etc.)

Question 5

if the onset of neurological deficit is hours-days, what is the likely cause

Answer 5

inflammatroy (MS flare up, abcess)

Question 6

if the onset of neurological deficit is weeks-months, what is the likely cause

Answer 6

space occupying lesion (tumour, subdural)

Question 7

if the onset of neurological deficit is months-years, what is the likely cause

Answer 7

degenerative (AD, PD)

Question 8

what to ask about when testing CN I

Answer 8

change in smell AND TASTE

Question 9

what are 2 examples of an abnormal optic disc

Answer 9

1. pale optic disc
2. swollen optic disc

Question 10

what 2 nerves are tested by shining a light in the eyes

Answer 10

CN II (sensory input of light) and CN III (pupil reflex motor output)

Question 11

what other area of the brain (not cranial nerves) can be tested by shining a light in the eye

Answer 11

brainstem - no pupil reaction is seen

Question 12

which muscles are controlled by CN III and what is their function (6)

Answer 12

superior rectus - eyeball up;
Levator palpabrae superioris - raises upper eyelid;
inferior oblique - elevates, abducts and laterally rotates the eyeball;
inferior rectus - depresses the eyeball;
medial rectus - adducts the eyeball;
sphincter pupillary - pupil constriciton;
cilliary muscles - causes lens to become more symmetrical;

Question 13

which muscle is controlled by CN IV and what is their function

Answer 13

superior oblique - move the eye in the down-and-out position and intort the eye

Question 14

how does CN IV palsy present

Answer 14

vertical diplopia

Question 15

which muscle is controlled by CN VI and what is their function

Answer 15

Lateral rectus muscle - abducts the eye

Question 16

why is the medial longitudinal fasiculus clinically significant and how will a pt w a lesion here present

Answer 16

it is a heavily myelinated interneuron and so it is often affected by demyelinating disorders e.g. MS;

presents with Internuclear ophthalmoplegia

Question 17

what is Internuclear ophthalmoplegia

Answer 17

interruption of the neural communication to the CN III subnuclei; leads to inability to perform conjugate lateral gaze (inability to move both eyes together in a single horizontal) and ophthalmoplegia (weakness of eye muscles)

Question 18

what reflex can be used to test for CN V

Answer 18

corneal reflex (dont acc perform in OSCE but offer it)

Question 19

what are the 3 sensory divisions of CN V

Answer 19

ophthalmic - Forehead and scalp; Frontal and ethmoidal sinus; Upper eyelid and its conjunctiva
Cornea; Dorsum of the nose
maxillary - Lower eyelid and its conjunctiva; Cheeks and maxillary sinus; Nasal cavity and lateral nose
Upper lip; Upper molar, incisor and canine teeth and the associated gingiva
Superior palate
mandibular nerves - Mucous membranes and floor of the oral cavity; External ear; Lower lip; Chin; Anterior 2/3 of the tongue (only general sensation not taste);
Lower molar, incisor and canine teeth

Question 20

what should be looked at when assessing for CN VII palsy (vs higher defecit)

Answer 20

eye closure (rather than forehead sparing) - CN VII palsy will not allow for complete eye closure on affected side (e.g. bells palsy)

Question 21

what tests are performed to check hearing loss and what nerve is being tested

Answer 21

CN VIII

a combination of
Weber’sand Rinne’s test is performed

Question 22

what is Rinne’s test and what does it indicate

Answer 22

bone conduction - tuning fork placed on mastoid process and then moved in front of ear to check if air conduction hearing is better - if air conduction is not better (i.e.the sound cannot be still heard) then there is conductive hearing loss

Question 23

what is Weber’s test and what does it indicate

Answer 23

tuning fork placed on the center of forehead and pt is asked where they hear the sound - it should be heard equally in both ears;
Sensorineural hearing loss: sound is heard louder on the side of the intact ear.
Conductive hearing loss: sound is heard louder on the side of the affected ear (due to lower environmental noise and this higher conductive ability)

Question 24

what test can be used to assess vertigo

Answer 24

HiNTS

Question 25

what nerves does uvula deviation test for and what is the finding

Answer 25

IX and X

Uvula away from affected side, tongue towards

Question 26

if there is acute CN II presentation what other structures should be checked

Answer 26

carotids (listen for bruits)

Question 27

if a painful CN III palsy is seen, what may have caused it (2)

Answer 27

1. direct compression of the nerve by an aneurysm;
2. subarachnoid hemorrhage in the vicinity of an aneurysm

Question 28

what anatomical position is known for tumour growth and what nerve can this affect

Answer 28

meckel’s cave, this an affect CN V

Question 29

what is the initial investigation for acute vertigo

Answer 29

also needs a scan

Question 30

what are the efferent pathways in the DH (motor - 6)

Answer 30

pyramidal tracts: lateral corticospinal, anterior corticospinal
extra pyramidal: rubrospinal, reticulospinal, oticospinal, vestibulospinal

Question 31

what are the afferent tracts in the DH (sensory - 3)

Answer 31

1. dorsal column (medial lemniscus)
2. spinocerebellar
3. anterolateral

Question 32

why is the anatomy of the DH important clinically

Answer 32

it explains why damage to the SC may only result in certain sensations/motor actions being affected

Question 33

why might a lesion on one side of the DH cause different symptoms in different legs of the body

Answer 33

dessucation occurs in the DH for some sensations/actions (e.g. pain, temp) but it occurs higher up for other e.g. power, vibration => a lesion in one side will affect different halves of the body differently (e.g. R sided lesion may cause L sided affected pain but R sided affected power)

Question 34

what is brown-sequard syndrome

Answer 34

a rare neurological condition that happens when damage to your spinal cord causes muscle weakness or paralysis on one side of your body and a loss of sensation on the opposite side