fundamentals of neurology Flashcards
how will a pt who has a lesion in their brainstem present (in terms of side of body affected)
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)
who does a brainstem lesion present with this specific mixed distribution
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
what distribution of abnormal nuerological function may be seen with severe alcoholism
glove and stocking (longest nerves affected first)
if there is a sudden neurological deficit (seconds-minutes) what is the likley cause
vascular (stoke, subarach etc.)
if the onset of neurological deficit is hours-days, what is the likely cause
inflammatroy (MS flare up, abcess)
if the onset of neurological deficit is weeks-months, what is the likely cause
space occupying lesion (tumour, subdural)
if the onset of neurological deficit is months-years, what is the likely cause
degenerative (AD, PD)
what to ask about when testing CN I
change in smell AND TASTE
what are 2 examples of an abnormal optic disc
- pale optic disc
- swollen optic disc
what 2 nerves are tested by shining a light in the eyes
CN II (sensory input of light) and CN III (pupil reflex motor output)
what other area of the brain (not cranial nerves) can be tested by shining a light in the eye
brainstem - no pupil reaction is seen
which muscles are controlled by CN III and what is their function (6)
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;
which muscle is controlled by CN IV and what is their function
superior oblique - move the eye in the down-and-out position and intort the eye
how does CN IV palsy present
vertical diplopia
which muscle is controlled by CN VI and what is their function
Lateral rectus muscle - abducts the eye
why is the medial longitudinal fasiculus clinically significant and how will a pt w a lesion here present
it is a heavily myelinated interneuron and so it is often affected by demyelinating disorders e.g. MS;
presents with Internuclear ophthalmoplegia
what is Internuclear ophthalmoplegia
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)
what reflex can be used to test for CN V
corneal reflex (dont acc perform in OSCE but offer it)
what are the 3 sensory divisions of CN V
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
what should be looked at when assessing for CN VII palsy (vs higher defecit)
eye closure (rather than forehead sparing) - CN VII palsy will not allow for complete eye closure on affected side (e.g. bells palsy)
what tests are performed to check hearing loss and what nerve is being tested
CN VIII
a combination of
Weber’sand Rinne’s test is performed
what is Rinne’s test and what does it indicate
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
what is Weber’s test and what does it indicate
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)
what test can be used to assess vertigo
HiNTS
