Stroke Localization

Aug 26, 2023

Stroke Localization

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Content

0 ->

1.09 -> Welcome to the presentation

2.86 -> of stroke localization.

5.32 -> My name is Il Fan.

7.01 -> I will be presenting this topic

8.71 -> together with Dr. Pang Yee Hau.

11.92 -> We are both from the National

13.24 -> Neuroscience Institute.

14.62 ->

17.66 -> The objective of this session

19.64 -> includes physical signs

22.04 -> and clinical syndromes

23.6 -> relevant to stroke,

25.7 -> to correlate

26.33 -> the physical findings

27.65 -> with neuroanatomy and vascular

30.29 -> supply,

32.02 -> and enhance understanding

33.41 -> of localization.

35.84 -> Basic neurological examination

37.875 -> technique is not in the scope.

39.95 ->

43.01 -> The presentation will be divided

45.05 -> into the anatomy of motor

48.14 -> and sensory tracts,

49.94 -> clinical syndrome, and stroke

51.95 -> localization

53.03 -> according

53.57 -> to clinical presentation

55.37 -> and correlated with vascular

57.041 -> supply.

57.54 ->

60.784 -> Stroke is a vascular event that

63.41 -> happens hyperacutely.

65.93 -> There is an acute infarct lesion

68.33 -> affecting certain tracts

69.92 -> in the central nervous system,

71.9 -> producing the symptoms

73.4 -> and signs.

75.42 -> Listed are the presenting signs

77.5 -> of stroke.

79.11 -> It is important to identify

81.13 -> the signs.

82.92 -> This can help to localize

84.57 -> the site of the infarct,

86.87 -> determine the vessel involved,

89.25 -> and subsequently plan

90.87 -> the investigation

92.13 -> and management.

94.38 -> The list is not exhaustive,

96.66 -> but it covers the common to less

98.79 -> common signs encountered

100.53 -> in clinical practice.

103.38 -> Generally, the signs can be

105.12 -> divided into, number one,

108.23 -> interior circulation infarcts

110.91 -> and posterior circulation

112.47 -> infarcts--

113.91 -> number two, cortical size

116.31 -> and lacunar syndromes.

119.17 -> In subsequent slides,

121.18 -> we will explain the signs

122.68 -> and syndromes with explanation

125.29 -> on corresponding neuroanatomy

127.69 -> for understanding localizations.

130.25 ->

133.29 -> Before landing on localization,

135.599 -> one should be

136.14 -> familiar with understanding

137.73 -> of the anatomy and physiology

140.25 -> of the nervous system

141.48 -> and its blood supply.

143.5 -> The long tracts consist

145.2 -> of corticospinal tracts,

147.14 -> medial motor tracts,

149.21 -> spinothalamic tracts, which mean

151.69 -> the sensory tracts,

153.95 -> and posterior column tracts.

156.63 -> The efferent pathway, also known

158.73 -> as "descending pathway"

160.74 -> involve motor tracts, which

162.75 -> originate from the brain

164.82 -> or brain stem descending down

167.49 -> to the spinal cord to control

169.11 -> motor neurons.

171.06 -> Some of the efferent pathways

173.28 -> are pyramidal cortical tracts,

176.68 -> extrapyramidal, and cerebellar

179 -> pathways.

180.53 -> The picture on the right hand--

182.61 -> color demonstrates

184.07 -> the corticospinal tract that

185.97 -> originates

186.57 -> from the primary motor cortex.

189.24 -> It passes

189.84 -> through the internal capsule,

192.51 -> enters the cerebral peduncle

194.37 -> in the midbrain, then the pons

198 -> and medulla.

200.01 -> The fibers then decode it

202.08 -> and descend

203.07 -> into the spinal column

205.48 -> and terminate

206.32 -> in the ventral horn.

208.57 -> From there, the lower motor

210.37 -> neurons go to supply the muscles

212.59 -> of the body.

213.27 ->

216.46 -> The afferent pathway is also

218.65 -> known as the "ascending pathway"

221.83 -> that involves sensory tracts.

225.45 -> It carries sensory modalities

227.79 -> from the skin

229.11 -> and the spinal cord.

231.92 -> The spinothalamic tracts

234.18 -> decussate at two to three

236.6 -> spinal segments above the entry.

240.26 -> It then ascends up

241.87 -> to the thalamus

243.32 -> and ends

244.09 -> at the somatosensory cortex

246.25 -> of the postcentral gyrus.

250.2 -> There are also other tracts,

251.85 -> such as the posterior column

254.04 -> and spinocerebellar tracts.

255.71 ->

258.94 -> Every tract from

260.5 -> and to the brain

261.7 -> passes through the brainstem.

264.01 -> The additional feature

265.15 -> of the brainstem

266.37 -> is it consists of 10 pairs

268.36 -> of cranial nuclei

270.64 -> and, importantly, the reticular

272.94 -> formation,

274.1 -> which regulate sleep

275.6 -> and wakefulness

276.98 -> and cardiorespiratory control.

280.29 -> The diagram shows the three

282.06 -> major parts of the brainstem,

284.81 -> namely, the midbrain, pons,

287.01 -> and medulla.

288.66 -> They consist

289.44 -> of different cranial nuclei

291.9 -> arranged in pairs, except, oddly

295.59 -> enough, all cranial nerves have

298.01 -> motor and sensory supply

300.1 -> to the ipsilateral part

301.37 -> of the head.

302.83 -> The long tracts are arranged

304.92 -> in different regions

306.32 -> in each part.

308.58 -> In fact, it's caused

309.81 -> by occlusion

310.57 -> of the large vessels,

312.45 -> such as posterior cerebellar

314.05 -> arteries, the vascular artery,

316.44 -> and vertebral arteries.

318.68 -> Its branches-- such

320.55 -> as the posterior inferior

322.1 -> cerebellar artery, anterior

324.64 -> inferior cerebellar artery--

327.15 -> imperforate thus.

329.5 -> The infarct lesion usually

331.2 -> involves the nucleus

333.04 -> and its vesicles

334.63 -> in the long tracts,

336.04 -> producing classical cross-signs.

338.315 ->

341.66 -> The next few slides, we will

343.66 -> discuss on the syndrome

345.3 -> of stroke, namely,

347.065 -> lacunar syndromes,

349.2 -> cortical syndromes,

351.16 -> and brainstem syndromes.

353.78 -> This is concurrently discussed

355.82 -> on localizations and vascular

358.43 -> supply.

360.35 -> Let's begin with lacunar

362.39 -> syndromes.

363.88 -> As per the picture shown

365.71 -> on the slide, typically, we have

368.35 -> six lacunar syndromes, such

371.26 -> as pure motor, pure sensory,

375.421 -> sensorimotor, dysarthria--

377.94 -> clumsy hand--

379.66 -> ataxic hemiparesis,

382.09 -> and hemiballismus or hemichorea.

386.91 -> The localization of lacunar

389.15 -> syndrome is usually

391.03 -> at the subcortical region

393.61 -> in the brainstem.

394.852 ->

397.45 -> This diagram shows the anatomy

399.49 -> of small perforators originating

402.85 -> from major arteries.

405.67 -> The left diagram shows anterior

408.24 -> circulation.

410.09 -> A is the basilar artery.

413.7 -> B are thalamoperforators, which

416.63 -> originate

417.57 -> from the posterior cerebral

419.87 -> artery.

422.25 -> C is the anterior choroidal

423.84 -> artery.

425.34 -> And E are

426.51 -> lenticulostriate arteries, which

429.82 -> originate from D, which

432.09 -> is the medial cerebral artery.

436.1 -> At posterior circulation,

438.2 -> as shown on the middle and right

441.11 -> diagrams, at the pons level,

443.96 -> for example, there are, A,

447.78 -> midline large median arteries,

451.44 -> B, paramedian penetrators--

455.37 -> C, penetrating arteries

458.07 -> into the lateral tegmentum

460.56 -> of the pons.

462.88 -> The occlusion

463.99 -> of the perforators,

466.72 -> either along anterior

468.61 -> or posterior circulations,

470.85 -> may produce lacunar syndromes.

473.04 ->

476.23 -> Next, we are going to talk

478.21 -> about hemispheric syndrome.

480.94 -> The syndrome consists of one

482.6 -> or more of the cortical signs.

485.126 -> It includes neglect, aphasia,

489.03 -> hemianopia, and conjugated

491.77 -> gaze deviation.

494.55 -> Certain patterns,

495.79 -> such as brachiofacial and upper

498.66 -> limb or lower limb monoparesis,

501.04 -> are

501.54 -> specific to cortical infarcts,

503.7 -> as well.

505.37 -> This is due to a distribution

506.93 -> of a motor homunculus,

509.09 -> as shown here,

510.59 -> at the coronal view

511.94 -> of the cerebrum

513.289 -> along the precentral gyrus.

517.36 -> The trunk and lower limb area

519.28 -> are supplied

520.22 -> by the anterior cerebral artery,

524 -> whereas the upper limbs and face

527.03 -> are supplied

528.26 -> by the middle cerebral artery.

530.73 ->

534.15 -> The middle cerebral artery

535.84 -> is the largest artery

537.75 -> and supplies the largest area

539.58 -> of the brain.

541.75 -> Occlusion at different parts

543.63 -> produces a combination

545.4 -> of certain signs.

548.14 -> On the table,

549.82 -> there are different depths

551.58 -> of arterial occlusion, which

555.05 -> produce different extents

557.2 -> of infarcts and hence

560.01 -> their clinical manifestations.

562.08 ->

565.22 -> Now we move

565.97 -> on to the posterior circulation

568.16 -> syndromes.

569.57 -> There are medullary syndromes,

572.99 -> pontine syndromes, midbrain

575.69 -> syndromes, cerebellar syndromes,

579.65 -> top of the basilar,

582.4 -> and lock-in syndrome.

583.45 ->

586.81 -> As shown on the anatomy

588.55 -> of posterior circulation,

590.92 -> a single basilar artery supplies

593.38 -> the majority of the brainstem.

598.45 -> Syndromes of basilar artery

600.97 -> occlusion can be various,

603.4 -> and there is a possibility

604.96 -> that the sign can be

606.5 -> bilateral or generalized.

609.75 -> This makes the early diagnosis

612.16 -> challenging.

614.26 -> As listed here,

616.4 -> it can have paraplegia, bulbar

620.16 -> involvement, and nystagmus.

623.68 -> Dysconjugated eye movement poses

626.44 -> can be presented

627.79 -> as classical internuclear

630.45 -> ophthalmoplegia, one

632.83 -> and a half syndrome,

634.93 -> and isolated cranial nerve four

638.77 -> and six palsies.

641.77 -> And lastly,

643.24 -> coma or unconsciousness or even

646.78 -> apnea and cardiorespiratory

649.66 -> collapse due to extensive

652.42 -> reticular formation impairment

655.09 -> might occur.

657.25 -> It is critical not to miss

659.77 -> and to identify early,

661.57 -> as prompt treatment will improve

664.21 -> morbidity and mortality.

666.37 ->

669.4 -> In the subsequent few slides,

671.76 -> we will show

672.31 -> some common brainstem syndromes.

675.85 -> As mentioned earlier, most

677.74 -> cranial nerve nuclei supply

679.72 -> ipsilaterally,

681.4 -> but pyramidal and spinothalamic

683.71 -> tracts decussate below the lower

687.09 -> medulla.

688.51 -> Hence, a lesion

689.26 -> in the brainstem,

690.88 -> if a large extent enough,

693.11 -> will produce

694.09 -> classic cross-signs.

696.72 -> The most common clinically

698.05 -> encountered syndrome is

700.05 -> lateral medullary syndrome.

703.65 -> It has

704.31 -> dysphagia, dysarthria,

706.31 -> dysphonia, absent or impaired

709.06 -> gag reflex, and ipsilaterally,

712.3 -> it will produce Horner's

714.12 -> syndrome, fifth cranial nerve

716.31 -> palsy, cerebellar sign,

719.74 -> and impairment of pain

721.14 -> and temperature

722.17 -> in touch over the V2 and V2

726.31 -> areas.

728.91 -> Contralateral deficits are

731.21 -> impaired pain and temperature

733.55 -> over the body.

734.27 ->

737.33 -> Another less common medullar

739.82 -> syndrome is medial medullary

741.92 -> syndrome.

743.73 -> It produces

744.9 -> ipsilateral 12th nerve palsy

747.97 -> and loss of proprioception

749.74 -> and vibration sense.

752.2 -> The contralateral deficit

754.16 -> is pyramidal weakness.

755.815 ->

759.17 -> Moving on to the pons

760.61 -> are Millard-Gubler syndrome

763.46 -> and Marie-Foix syndrome,

766.29 -> but these syndromes are rarely

768.42 -> seen in clinical practice.

769.83 ->

773.22 -> Then, certain midbrain syndromes

775.61 -> are shown here.

776.43 ->

779.59 -> The arterial supply

780.75 -> of the cerebellum

782.37 -> is provided by the posterior

784.02 -> circulation and is divided

786.24 -> into three arteries.

788.44 -> The posterior inferior

789.54 -> cerebellar artery arises

791.86 -> from the intracranial vertebral

793.76 -> artery,

795.35 -> the anterior inferior cerebellar

797.36 -> artery from the basilar artery,

800.26 -> and the superior cerebellar

801.84 -> arteries near the basilar artery

804.81 -> bifurcation.

807.22 -> Cerebellar infarcts have

808.84 -> their own list of syndromes,

811.38 -> as listed there.

813.146 -> Please bear in mind paralysis

815.87 -> usually does not occur.

817.7 ->

821.04 -> Finally, stroke

822.88 -> is a clinical diagnosis.

825.47 -> Identifying a clinical syndrome

827.6 -> will help us to localize

829.17 -> a lesion.

830.92 -> Neurological examination

833.02 -> in correlation with imaging

835.33 -> helps to localize the stroke

837.365 -> syndrome.

837.865 ->

841.29 -> We hope that you have more

842.67 -> understanding on stroke

843.93 -> syndromes and localization

846 -> from this presentation.

848.08 -> Thank you, and have a nice day.

850.7 ->

Source: https://www.youtube.com/watch?v=UOlEoJJ3B80