Stroke

Question 1

What causes lateral medullary syndrome (Wallenberg’s)?

Answer 1

Occlusion of PICA

Question 2

What happens if PICA is occluded?

Answer 2

Lateral medullary syndrome:

• Vestibular nuclei and inferior cerebellar peduncle –> ataxia, diplopia, vertigo, muldirectional nystagmus
• Sympathetic tract –> ipsilateral Horner’s
• Spinothalamic tract –> contralateral loss of pain/temperature sensation
• Lateral CN nuclei in the medulla: 9, 10 and 11 –> weakness of speech and swallowing, sternocleidomastoid and trapezius

Question 3

What causes lateral pontine syndrome?

Answer 3

Occlusion of AICA or perforating branches of the basilar artery

Question 4

Symptoms of lateral pontine syndrome?

Answer 4

• Corticospinal tract –> contralateral hemiplegia
• Spinothalamic tract –> contralateral loss of pain/temperature/crude touch sensation
• Sympathetic tract –> ipsilateral Horner’s syndrome
• Spinocerebellar tracts and middle cerebellar peduncle –> ipsilateral limb ataxia
• Vestibular nuclei: vertigo and vomiting, nystagmus
• CN nuclei: 5, 7, 8 –> ipsilateral facial paralysis (LMN as it is the VII nucleus, not above), ipsilateral loss of facial sensation+mastication, ipsilateral SNHL and vertigo

Question 5

What symptoms would you expect in a right MCA stroke affecting the superior branch?

Answer 5

Left-sided hemiparesis affecting the face and arm and sparing the leg
Left homonymous hemiopia (unable to see left side of the visual field)
Left-sided neglect

Question 6

Left MCA stroke, inferior branch

Answer 6

Right homonymous hemianopia (–> right visuospatial ‘dysfunction’)
Wernicke’s aphasia (or global aphasia)

Question 7

Left MCA stroke, superior branch

Answer 7

Right homonymous hemianopia
Broca’s aphasia (or global aphasia)
Right-sided hemiparesis affecting face and arm

Question 8

Other strokes causing contralateral homonymous hemianopia aside from MCA?

Answer 8

Posterior cerebral artery (often has macular sparing); other concurrent symptoms are lethargy (bilateral medial thalamic infarction; if large infarct can also have contralateral hemiplegia and hemisensory loss), visual agnosia, anterograde amnesia (if infarction of medial temporal lobe). Also, if large, a left PCA stroke can cause aphasia, and a right PCA stroke can cause left-sided neglect.

Question 9

What vessels come off the basilar artery?

Answer 9

• AICA (–> lateral pons, middle cerebellar peduncle, antero-inferior cerebellum); AICA also gives off labyrinthine artery
• SCA (–> superior cerebellum)
• Penetrating arteries (–> lateral pons)

Question 10

Do you get contralateral hemiparesis in stroke of the lateral pons or medulla?

Answer 10

Lateral pons

Question 11

You get a patient in an OSCE that has a history and examination consistent with acute stroke; what investigations would you ask for next?

Answer 11

Plain CT head ASAP
Bloods including clotting profile and serum glucose
BM glucose in meantime
ECG (AF embolus?)

Question 12

Aside from investigations how would you manage a patient presenting with a stroke?

Answer 12

ABC and IV access
Find out whether it has been >4.5h since onset of symptoms and whether there are CIs to thrombolysis
Mention you need a CT head before thrombolysis to see if it’s ischaemic
If CT-confirmed ischaemic stroke, no CI and <4.5h, thrombolyse with tPA (alteplase)
Give aspirin 24h post-thrombolysis
Supportive treatment: oxygen, fluids, NBM and NGT if swallow impaired