Neurology Flashcards
(100 cards)
what locations of the brain can a lesion be localised to?
forebrain
brainstem
cerebellum
vestibular system (central/peripheral)
what mnemonic can be used to generate a differential diagnosis list?
Vascular
Inflammatory/infectious
Trauma
Anomalous
Metabolic
Idiopathic
Neoplasia
Degenerative
what are the main four clinical signs that would localise the lesion to the forebrain?
seizure
disorientation
contralateral blindness (normal PLR)
circling
what clinical signs would suggest a forebrain lesion?
seizures
behavioural changes
disorientation, depression
contralateral blindness (normal PLR)
facial hypoasthesia
normal gait
circling (ipsilateral), head pressing, pacing
decreased postural response (contralateral limb)
what are the two main clinical signs that suggest a cerebellar lesion?
hypermetria
tremors (intention)
what clinical signs suggest a forebrain lesion?
normal mentation
abnormal menace (normal vision/PLR)
vestibular signs - head tilt…
ataxia, broad stance, hypermetria
intention tremors
decerebellate rigidity
hypermetric postural response
what are the main three clinical signs of a brainstem lesion?
cranial nerve deficits
vestibular signs
paresis (all four/ipsilateral limbs)
what are the clinical signs of brain stem lesions?
depression, stupor, coma
cranial nerve deficits
vestibular signs
paresis
decerebrate rigidity
decreased postural response
respiratory/cardiac abnormalities
what are the differentials for a focal/lateralised brain lesion?
neoplasia
vascular
what are the differentials for a multifocal brain lesion?
inflammatory
infectious
what are the differentials for a diffuse/symmetrical brain lesion?
metabolic
toxic
what contributes to intracranial pressure (ICP)?
brain
blood supply to brain
cerebrospinal fluid
what is compliance in relation to intracranial pressure?
can accommodate mild changes in ICP as when one factor contributing to it (eg. blood supply) increases the others with decrease
what happens when ICP gets too high?
herniation underneath the tentorium of through foramen magnum
what structure of the brain does formen magnum herniation effect?
cerebellum
what are the signs of raised ICP?
mental status (ARAS)
bushings reflex
pupil size and PLR
vestibular eye movement
posture - decerebrate/decerebellate
why does raised ICP effect the mental status of patients?
(ARAS - ascending reticular activation system)
awakeness centre in brainstem will decrease in activity with raised ICP causing depression, stupor and coma
what is bushings reflex?
very unwell patients with bradycardia and hypertension due to cerebral ischaemia (end stage sign)
how can pupil size change with raised ICP?
anisocoria
miosis
mydriasis
what is anisocoria?
pupils are different sizes
what is miosis?
excessive constriction (shrinkage) of pupil
what is mydriasis?
excessive dilation of pupils
how does physiological nystagmus change with raised ICP?
eyes don’t move due to a delay in connection between vestibular system and cranial nerves
what is a peracute presentation?
extremely sudden onset (change from one second to the next)