Neurology Flashcards
What is scotoma
Small patch of visual loss
What causes monocular visual loss
Lesion at the optic nerve
What causes bitemporal hemanopia
Lesion at optic chiasm
What causes homonymous hemaninopia
Lesion at right optic tract
What causes lower homonymous quadrantanopia
Lesion at left parietal radition
What causes upper homonymous quadrantanopia
Lesion at left temporal
What causes homonoymous hemianopia with central sparring
Lesion at right occipital pole
What does compression of median nerve cause
Carpal tunnel (abductor pollicis brevis weakness)
What does compression of the ulnar nerve cause
Abductor digiti minimi weakness
What does compression of the radial nerve cause
Saturday night palsy
What is ankle clonus
tested by rapidly flexing the foot into dorsiflexion, inducing a stretch to the gastrocnemius muscle. Subsequently beating of foot will result, but only a sustained clonus (5 beats or more) is considered abnormal.
What is a LMN lesion
flaccid, hypotonic, hyporeflexic, denervation atrophy (atrophy occurs early on, and much quicker), -Babinski
What is an UMN lesion
spastic (muscle is spasm), hypertonic, hyperreflexive, disuse atrophy (lack of use even though muscle is in spasm), Babinski. Everything above the anterior horn. Lose the ability to send a spinal pathway from the upper cortical centre down to the anterior horn. Muscle has unregulated innervation.
Where does the spinal cord terminate
L1 vertebra - conus medullaris, everything below conus is LMN (cauda equine)
What is the course of CN III, IV, V (I, II), VI
Cavernouse sinus
What goes through the cerebellopontine angle
V, VII, VII
What goes the the base of the skull (jugular/hypoglossal foramine)
IX, X, XI, XII
What is the Edinger–Westphal nucleus
parasympathetic pre-ganglionic nucleus that innervates the iris sphincter muscle and the ciliary muscle
What is Babinski’s sign
in normal adults, the plantar reflex causes a downward response of the hallux. An upward response of the hallux is a sign of upper motor neurone disease
What does Freiderich’s ataxia affect
Lateral corticospinal, dorsal columns, spinocerebellar. Bilateral spastic paresis, bilateral loss of proprioception and vibration, bilateral limb ataxia + cerebellar taxia
What does syringomyelia affect
Ventral horns, lateral spinothalamic tract. Flaccid paresis, loss of pain and temperature sensation
What is Guillain Barre Syndrome
Immune reaction of demyelination of the peripheral nervous system - often caused by Campylobacter Jejunii (gram negative)
Cross reaction of antibodies in the gangliosides and the peripheral nervous system
Anti-GM1 antibodies in 25% of px
What do parietal lobe lesions cause
Sensory inattention, apraxias, astereognosis, inferior homonymous quadrantopia
What do occiptal lobe lesions cause
Homonoymous hemaniopia, cortical blindness, visual agnosia
What do temporal lobe lesions cause
Wernicke’s aphasia: area involved with word formation. Lesion results in word substitution
Superior homonoymous quadrantopia
Auditory agnosia
Prosopagnosia
What do frontal lobe lesions cause
Expressive (Broca's Aphasia): on posterior aspect of the frontal lobe. Speech is non-fluent laboured, and halting Disinhibition Preservation Anosmia Inability to generate a list
What do cerebellum lesions cause
Midline: gait and trunctal ataxia
Hemisphere: intention tremor, past pointing, nystagmus
What is an extradermal ahematoma
Bleeding into the space between the dura mater and the skull. Trauma or blow to side of the head. Temporal region -> cause rupture of MCA
Raised intracranial pressure
What is a subdural haematoma
Bleeding into the outermost meningeal layer. Most common and frontal and parietal lobes.
What is a subarachoid haemorrhage
Occurs spontaneously in the context of ruptured cerebral aneurysm.
What is the minimal cerebral perfusion
70mmHg in adults
40-70 mmHg in children
What do C fibres transmit
Slow transmission of mechanothermal (unmyelianted)
What do A gamma fibres transmit
High intensity mechanical stimuli
What does the medullary resp centre do
: Inspiratory and expiratory neurones. Has ventral group which controls forced voluntary expiration and dorsal group controls inspiration
What does the apneustic centre do
lower pons. Stimulates inspiration- activates and prolongs inhalation. Overridden by pneumotaxic centre to end inspiration.
What does the pneumotaxic centre do
Upper pons. Inhibition of inspiration.
What is the short synacthen test
Test for cortisol production
