9/16 Clinical Brainstem - DiCicco-Bloom

Question 1

multiple cranial nerves affected without any long tracts affected

Answer 1

prob out in the csf → extra-medullary lesion!

• meningitis
• fungus
• cancer

Question 2

mediolateral organization of brainstem

Answer 2

medial

• corticospinal
• medial lemniscus
• motor CN (III, IV, VI; VII; IX-XII)

lateral

• spinothalamic (anterolateral)
• spinocerebellar
• sensory CN (V, VIII)
• descending sympathetics (Horner’s)

Question 3

long tracts and crossed syndromes

Answer 3

long tracts (CST, STT, DCMLS) are crossed from medulla up to midbrain (except most rostrally, where they converge and cross)

crossed syndromes

• CN facial dysfx and cerebellar problems ipsilateral
• long tract body signs (sensory/motor) contralateral

Question 4

general regions served in medulla by

• ant spinal a
• vertebral a
• PICA

Answer 4

anterior spinal a → medial structures

vertebral a → ventral lateral

PICA → dorsal lateral

Question 5

lateral medullary syndrome

Answer 5

Wallenberg

usually involves PICA

lesion → symptom

1. spinal V tract and nucleus → ipsilateral loss of P/T on face
2. vestibular nuclei → nystagmus, vertigo, nausea, ataxia
3. inf cerebellar peduncle → ipsilat ataxia, nystagmus
4. nucleus ambiguus & fascicles of vagus n → dysphagia, hoarseness, deviation of uvula to contralat side
5. descending autonomics → ipsilat Horner’s syndrome
6. spinothalamic tract (anterolat system) → contralat loss of P/T on body

Question 6

medial medullary syndrome

Answer 6

Déjérine

usually related to vertebral a

lesion → symptom

1. hypoglossal nucleus & nerve fascicles → ipsilateral paralysis & fasciculations of tongue
2. pyramid/CST → contralat hemiparesis/hemiplegia
3. medial lemniscus → contralat loss of touch, vibration, position sense on body

Question 7

lateral pontine syndrome

Answer 7

AICA infarct

• sx vary depending on rostral-caudal level

lesion → symptom

1. middle cerebellar peduncle → ipsilateral ataxia, nystagmus
2. vestibular nuclei/nerve → vertigo, nystagmus, ataxia
3. auditory nerve → ipsilat deafness, tinnitus
4. spinal tract of V → ipsilateral loss of P/T on face
5. STT (anterolat system) → contralat loss of P/T on body
6. facial nucleus/nerve → ipsilat facial weakness, dysarthria
7. motor nucleus of V → jaw weakness, dysarthria
8. descending autonomics → ipsilat Horner’s syndrome

Question 8

medial pontine syndrome

Answer 8

lesion → symptom

1. CST/corticobulbar tract → contralat hemiparesis (body/face); dysarthria
2. pontine nuclei & pontocerebellar fibers → ataxia (usually contralat)
3. facial nerve fascicles → ipsilat facial weakness, dysarthria
4. PPRF; abducens nucleus/nerve → ipsilat horizontal gaze palsy, diplopia
5. medial lemniscus → contralat loss of touch, vibration, position sense
6. MLF → internuclear ophthalmoplegia (connection between III and VI interrupted)

Question 9

relationship of STT and DCMLS in rostral midbrain

Answer 9

in region of superior colliculus, the two ascending sensory pathways become much closer to one another

(previously ascending in posteromedial portion and anterolateral portion of SC)

here, possible for one lesion to knock out fx to all sensory modalities

Question 10

midbrain syndrome

Answer 10

midbrain base (Weber’s syndrome)

usually involves posterior cerebral a

lesion → symptom

1. CST/corticobulbar tract → contralateral hemiparesis (body/face), dysarthria
2. oculomotor nerve & fascicles → ipsilat CN III palsy (“down and out”)

Question 11

midbrain syndrome

Benedikt

Answer 11

Weber + Claude = Benedikt syndrome

lesion → symptom

1. CST/corticobulbar tract → contralateral hemiparesis (body/face/tongue), dysarthria
2. oculomotor nerve & fascicles → ipsilat CN III palsy (“down and out”)
3. red nucleus → contralat tremor and ataxia
4. medial lemniscus → contralat loss of position, vibration, discriminative touch