Neuro- week 4

Question 1

Ischaemic stroke

Answer 1

an episode of neurological dysfunction caused by focal cerebral, spinal or retinal infarction

Question 2

Silent CNS infarction

Answer 2

only visible through imaging or neuropathological evidence

Question 3

Stroke caused by intracerebral hemorrhage

Answer 3

Rapidly developing clinical signs of neurological dysfunction attributable to a focal collection of blood within the brain parenchyma or ventricular system that is not caused by trauma.

Question 4

Silent cerebral hemorrhage

Answer 4

A focal collection of chronic blood products within the brain parenchyma, subarachnoid space, or ventricular system on neuroimaging or neuropathological examination that is not caused by trauma and without a history of acute neurological dysfunction attributable to the lesion

Question 5

Subarachnoid hemorrhage

Answer 5

Bleeding into the subarachnoid space (the space between the arachnoid membrane and the pia mater of the brain or spinal cord).

Question 6

Stroke caused by subarachnoid hemorrhage

Answer 6

Rapidly developing signs of neurological dysfunction and/or headache because of bleeding into the subarachnoid space (the space between the arachnoid membrane and the pia mater of the brain or spinal cord), which is not caused by trauma.

Question 7

Stroke caused by cerebral venous thrombosis

Answer 7

Infarction or hemorrhage in the brain, spinal cord, or retina because of thrombosis of a cerebral venous structure. Symptoms or signs caused by reversible edema without infarction or hemorrhage do not qualify as stroke.

Question 8

Stroke, not otherwise specified

Answer 8

An episode of acute neurological dysfunction presumed to be caused by ischemia or hemorrhage, persisting ≥24 hours or until death, but without sufficient evidence to be classified as one of the above.

Question 9

what is the global lifetime risk of stroke

Answer 9

25% and rising

Question 10

what are the internal carotid arteries referred to as?

Answer 10

anterior circulation

Question 11

what type of circulation are the vertebral arteries

Answer 11

posterior circulation

Question 12

what percentage of patients do not have a complete circle of willis

Answer 12

50%

Question 13

describe total anterior circulation stroke (TACS)

Answer 13

large cortical stroke

anterior or middle cerebral arteries

15% of strokes

symptoms
    unilateral weakness and/or sensory deficit of the 
    face and/or arms and/or legs
    homonymous heminopia
    higher cerebral dysfunction

Question 14

describe partial anterior circulation stroke (PACS)

Answer 14

cortical stroke

anterior or middle cerebral arteries

35% of strokes

2/3 of the TACS criteria:
    unilateral weakness and/or sensory deficit of the 
    face and/or arms and/or legs
    homonymous heminopia
    higher cerebral dysfunction

Question 15

lacunar stroke (LACS)

Answer 15

subcortical stroke

small deep perforating arteries

25% of all strokes

1. pure motor, sensory or sensorimotor (Min 2; face, arm, leg)
2. ataxic hemiparesis

Question 16

posterior circulation stroke (POCS)

Answer 16

cortical, cerebellum, brainstem stroke

posterior cerebral artery, vertebral artery, basilar artery and branches

25%

1. cerebellum or brainstem syndrome
2. loss of consciousness
3. isolated homonymous heminopia

Question 17

define apraxia

Answer 17

Inability to perform purposeful movement despite motivation, and preserved overall neurological function – typically left hemisphere localization

Question 18

define ‘Executive’ apraxias

Answer 18

Deficit in ‘sequencing’ complex movements - SMA & PMA in frontal cortex

Question 19

define ‘Posterior’ apraxias

Answer 19

Deficit in the spatial construction of complex movements – posterior parietal cortex

Question 20

describe whats involved in the corticospinal tracts and what does dysfunction cause

Answer 20

motor regions of cerebral cortex
brainstem
spinal cord
motor response

weakness and spasticity

Question 21

describe whats involved in the basal ganglia loop and what does dysfunction cause

Answer 21

motor regions of cerebral cortex
thalamus
basal ganglia

movement disorder

Question 22

describe whats involved in the cerebellar loop and what does dysfunction cause

Answer 22

motor regions of cerebral cortex
thalamus
cerebellum

coordination disorders

Question 23

Spasticity – “clasp knife”

Answer 23

• Pyramidal tract disorder – upper motor neurone
• Most tone at beginning and end of range of movement
• Deep tendon reflex primed to contract but usually you have descending inhibition from the cortex – problem with UMN leads to increase in these reflexes when stretch is max – beginning and end of range of movement

Question 24

Rigidity

Answer 24

• Extra-pyramidal – basal ganglia
• Increased tone throughout movement
• “lead pipe”

Question 25

Paratonia (you keep forgetting one thing)

Answer 25

* Voluntary resistance * Executive system pathology * Typical seem in delirium/ dementia

Question 26

what are UMN lesion signs

Answer 26

spasticity brisk reflexes pyramidal pattern weakness (strong biceps and weak triceps (extensors). Opposite for legs where HAMS (flexors) are weaker than the quads

Question 27

what are extrapyramidal signs

Answer 27

rigidity tremor normal reflexes no weakness

Question 28

describe parkinsons

Answer 28

A lack of dopamine supply to the basal ganglia - male 2:1 female Alpha-synucleinopathy - build up of alpha synuclein Bradykinesia Rigidity Tremor Postural instability + ‘non-motor’ symptoms Parkinson’s treatment includes giving L-DOPA and a DOPA decarboxylase inhibitor to make sure its only converted to dopamine in the CNS

Question 29

what are the pathways from the basal ganglia

Answer 29

Basal Ganglia structure receive signals from, and project to, the motor cortex Direct pathway The “accelerator”: pro-movement D2 receptors for dopamine Indirect pathway The “brake”: anti-movement D1 receptors for dopamine

Question 30

what are some jerky hyperkinetic disorders?

Answer 30

tremor chorea tics

Question 31

what are some non-jerky hyperkinetic disorders?

Answer 31

dystonia myoclonus stereotypies

Question 32

where do the spinal nerves pass out?

Answer 32

upper 7 cervical nerves pass through the intervertebra; foramen above the appropriate vertebra Other spinal nerves pass through the intervertebral foramen below the appropriate vertebra. This results in there being 8 cervical spinal segments and nerves while there are 7 cervical vertebrae.

Question 33

what is the conus medullaris

Answer 33

the lower limit of nervous tissue

Question 34

what is the filum terminale

Answer 34

a cord of connective tissue connecting the conus medullaris and the 1st coccygeal vertebra

Question 35

what is caused by an upper spinal cord lesion

Answer 35

* Spastic tetraplegia * hyperreflexia * extensor plantar responses * incontinence * sensory loss below lesion * Proprioception problems

Question 36

what is caused by a lower cervical cord lesion

Answer 36

* UMN - lower limbs affected * LMN – upper limbs affected * Sensation affected

Question 37

what is caused by hemisection of the spinal cord

Answer 37

Brown-Séquard • Ipsilateral loss of proprioception • Contralateral loss of pain and temperature

Question 38

what does anterior spinal artery thrombosis cause

Answer 38

supplies 2/3 of the blood to the spinal cord – can cause damage to spinal cord – first LMN signs then UMN signs – preservation of proprioception

Question 39

describe brachial plexus lesions

Answer 39

• Traction lesions o Upper roots (C5 & C6) – Erb’s palsy – “waiters tip” o Lower roots (C8 & T1) – claw hand • Neoplastic involvement • Radio-therapy related

Question 40

describe radial nerve lesions

Answer 40

* C6 – C8 * Damaged by fractures to the mid shaft of the humerus * Compression at this site leads to “Saturday night paralysis” – loss of extension of wrist and fingers (wrist drop)

Question 41

describe median nerve lesions

Answer 41

* C5-T1 (maintly C6) | * Carpal tunnel syndrome – predominantly sensory but there can be wasting of thenar muscles

Question 42

describe ulnar nerve lesions

Answer 42

* C7, C8, T1 * May be damaged at the medial epichondyle or at the medial aspect of the wrist. * Characteristic claw hand deformity

Question 43

describe femoral nerve lesions

Answer 43

* L2 – L4 * May be damaged by hip dislocation, pelvic fracture or tumours * Leads to weakness of knee extension (inability to lock knee while walking) and some wasting of quads

Question 44

describe sciatic nerve lesions

Answer 44

• L4-S3 • This is composed of two trunks which are bound together and separate in mid thigh o Tibial nerve o Peroneal nearve • Damage can be due to trauma, neoplasm or operative complication * Much more common is compression or irritation of a spinal root which comprises the sciatic nerve (sciatica) * Symptoms dependant on the nerve root • Common o L5; sensory- pain in posterolateral thigh and leg, numb inner foot  motor- weakness of dorsiflexing foot and toes o S1; sensory- pain in posterolateral thigh and leg, numb lateral foot  motor- weakness of foot dorsiflexion and loss of ankle jerk • Rare o L3+L4- diminished knee jerk, pain in anterior thigh Sciatica can be caused by: • Prolapsed intervertebral disk – typically posteriorly o Can be treated by microdiscectomy to remove prolapsed material

Question 45

describe common peroneal nerve lesions

Answer 45

* L4-S2 * This can be damaged as the nerve winds round the head of the fibula. This can be a fracture or a tight cast * Results in weakness of foot dorsiflexion and eversion

Question 46

describe the occulomotor nerve

Answer 46

• Motor • oculomotor nucleus in midbrain (LMN), innervates most extra-ocular muscles • Parasympathetic motor • arise from Edinger-Westphal nucleus in the brainstem and pass to the ciliary ganglion. Post-ganglionic fibres innervate the pupil (constrict). * Damage results in the ipsilateral eye being deviated downward and laterally (“down and out”), ptosis, and a fixed dilated pupil. * May be damaged in raised intracranial pressure with tentorial herniation, or disorders involving the cavernous sinus. Oculomotor nerve supplies all these muscles apart from the superior oblique and lateral rectus

Question 47

describe the trochlear nerve

Answer 47

* Only cranial nerve to arise from the dorsal surface of the brainstem. * Motor * Supplies the superior oblique muscle • Damage results in diplopia when looking downward and medially (direction globe moves when sup. oblique contracts).

Question 48

describe the abducens nerve

Answer 48

• Motor – supplies the lateral rectus muscle. • Damage results in diplopia when looking laterally.

Question 49

describe the trigeminal nerve

Answer 49

• Motor supply – Supplies the skeletal muscles of mastication which all develop from the first branchial arch. Fibres arise from the trigeminal motor nucleus and join the mandibular division of the trigeminal nerve. • Sensory supply – the trigeminal ganglion is the equivalent of a dorsal root ganglion and receives sensory input from three branches; ophthalmic, maxillary and mandibular. There are three sensory nuclei; • mesencephalic; proprioception from jaw • chief sensory nucleus and spinal nucleus – Fibres decussate and pass to thalamus.

Question 50

describe the facial nerve

Answer 50

• Motor – supplies the muscles of facial expression which develop from the second branchial arch, and stapedius, stylohyoid and part of digastric • Parasympathetic motor – pre-ganglionic fibres arise in the sup. salivatory nucleus and pass to; • pterygopalatine ganglion (lacrimal gland) • submandibular ganglion (submandibular and sublingual salivary glands) • Sensory – cutaneous sensory information from the external ear. 1st order neurones lie in the geniculate ganglion (middle ear) and axons pass to the spinal trigeminal nucleus. • Special sensory – the chorda tympani nerve innervates (taste) the anterior 2/3rds of the tongue. 1st order neurones lie in the geniculate ganglion (middle ear) and pass to the nucleus solitarius (also receives fibres from IX and X). • Conditions affecting VIIth nerve include; – Bell’s palsy; unilateral facial paralysis – Geniculate herpes zoster (vesicles in ear drum) * UMN lesion- upper facial muscles are relatively well preserved due to bilateral innervation of the facial nucleus. * LMN lesion- paralysis of both upper and lower facial muscles.

Question 51

describe the vestibulocochlear nerve and some conditions that would affect it

Answer 51

• Special sensory – sensory information relating to hearing (cochlear nerve) and balance (vestibular nerve). 1st order neurones in the vestibular and cochlear ganglia pass to vestibular (4) and cochlear nuclei (2) in the medulla. • Symptoms of VIIIth nerve damage – deafness, tinnitus – dizziness, vertigo • Conditions involving the VIIIth nerve include; – Acoustic schwannoma – labyrinthitis – Meniere’s disease

Question 52

describe the glossopharyngeal nerve

Answer 52

• Motor – fibres arise from the nucleus ambiguus and innervate a single pharyngeal muscle which arises from the third and fourth branchial arches (stylopharyngeus). • Parasympathetic motor – fibres arise from the inf. salivatory nucleus and pass to the otic ganglion, from where post-ganglionic fibres innervate the parotid gland. • Sensory – provides sensory information from the pharynx, posterior 1/3rd of the tongue and the middle ear. 1st order neurones lie in the ganglion and pass to the trigeminal sensory nucleus. Important in the gag reflex. • Special sensory – taste information passes from posterior 1/3rd of the tongue and the pharynx to the nucleus solitarius. – information from the carotid body and carotid sinus passes to the nucleus solitarius.

Question 53

describe the vagus nerve

Answer 53

• Motor – fibres arise from the nucleus ambiguus and innervate muscles of the soft palate, pharynx, larynx and oesophagus which arises from the third and fourth branchial arches . Important in swallowing and speech. • Parasympathetic motor (MAIN PARASYMPATHETIC NERVE IN THE BODY) – fibres arise from the dorsal motor nucleus and pass to a number of ganglia within the cardiovascular, respiratory and gastrointestinal systems. • Sensory – provides sensory information from the pharynx, larynx, tympanic membrane and part of outer ear. 1st order neurones lie in the ganglion and pass to the trigeminal sensory nucleus. Important in the gag reflex. • Special sensory – Taste information passes from the pharynx to the nucleus solitarius. – information from the aortic body and aortic arch passes to the nucleus solitarius.

Question 54

describe the accessory nerve

Answer 54

• Motor – LMN’s are in the nucleus ambiguus and in the anterior horn of the upper cervical cord. They innervate trapezius and sternomastoid. (ask patient to shrug shoulders)

Question 55

describe the hypoglossal nerve

Answer 55

• Motor • This innervates both the extrinsic and intrinsic muscles of the tongue. LMN’s are in the hypoglossal nucleus. • Unilateral lesions result in weakness and atrophy of the tongue on the affected side. When protruded the tongue deviates towards the affected side.

Question 56

describe bulbar and pseudobulbar palsy

Answer 56

• Bulbar refers to the motor nuclei of the brainstem (strictly the medulla[“bulb”]). Corticobulbar fibres pass from the cortex to brainstem nuclei. As with elsewhere in the motor system there are UMN (pseudobulbar) and LMN (bulbar) lesions. – Bulbar (LMN); atrophy and fasciculation of the innervated muscles. – Pseudobulbar (UMN); usually have to be bilateral lesions due to bilateral innervation. Exaggerated reflexes (jaw) and spastic paresis of the tongue. – Dysphonia, dysphagia and dysarthria are seen in both. * Bulbar palsies are most commonly seen in MND (chronic) and Guillain-Barre (acute). * Pseudobulbar palsies are most commonly seen in vascular disease and demyelination.

Question 57

whats imprtant about the jugular foramen

Answer 57

The lower cranial nerves (IX, X, XI) may all be affected at the base of the skull (jugular foramen) by tumour, trauma or an inflammatory process. XII leaves the skull via the hypoglossal foramen and is only affected by large tumours.

Question 58

what is the reticular formation

Answer 58

Periaqueductal grey matter (midbrain) has ascending arousal pathways, and descending pain suppression pathways