Brainstem Syndromes

Karin Johnson, MD

Brainstem arteries

Lateral Medullary Syndrome (Wallenberg)

• Vertebral a. (PICA distribution but clot in vertebral a.)

• Inf cerebellar ped, vestibular nuclei – Ipsilateral ataxia, vertigo,

nystagmus, nausea

• Trigeminal nuc and tract– ipsi face temp and pain loss

• Spinothalamic tract– contra body pain and temp

• Descending sympathetics– ipsi horners

• Nucleus ambiguus (X)– hoarseness, dysphagia

• Nucleus solitarius– ipsi decreased taste

Avellis (Medulla Tegmentum)

• CN X– Paralysis of soft palate and vocal cord

• Spinothalamic, sometimes pupillary fibers– contralateral hemianesthesia

Jackson

• CN X– Paralysis of soft palate and vocal cord

• CN XII– Ipsilateral tonglue

• Spinothalamic, sometimes pupillary fibers– contralateral hemianesthesia

Medial Medullary Syndrome

• Paramedian branches of vert and ant spinal a.

• Pyramidal tract– Contralateral arm or leg weakness

• Medial lemniscus – contralateral position and vibration loss

• Hypoglossal nucleus and nerve– ipsilateral tongue weakness

Pons

Lateral caudal pons (AICA syndrome)

•Spinothalamic tract•contra body pain and temp

•Middle cerebellar ped–ipsilateral ataxia

•Descending sympathetics•ipsi horner’s

•Trigeminal tract and nucleus•ipsi face temp and pain loss

•Vestibular nuclei–vertigo, nystagmus

•(labyrinthine artery to inner ear)–ipsi hearing loss

Marie-Foix Syndrome (lateral pons)

• Lesion in the lateral pons, including the middle cerebellar peduncle.

• 1. Ipsilateral cerebellar ataxia due to involvement of cerebellar tracts

• 2. Contralateral hemiparesis due to corticospinal tract involvement

• 3. Variable contralateral hemihypesthesia for pain and temperature due to spinothalamic tract involvement.

Dorsilateral rostral pons

• SCA

• Superior cerebellar penduncle– ipsilateral ataxia

• Other lateral tegmental structures of the AICA syndrome

Sup. Cerebellar peduncle

Foville’s syndrome (medial pons basis and tegmentum)

• Paramedian brances of the basilar artery, ventral and dorsal territories to caudal 1/3 of pons

•Corticospinal and corticobulbar tracts

–contra facce arm and leg weakness, dysarthia

•Facial colliculus–ipsi face weakness

•Abducens nucleus or paramedian pontine reticular formation

–ipsilateral horizontal gaze palsy

Millard- Gubler (medial pons basis and tegmentum)

• Paramedian brances of the basilar artery, ventral and dorsal territories to caudal 1/3 of pons

•Corticospinal and corticobulbar tracts

–contra face arm and leg weakness, dysarthria

•Fascicles of the facial nerve

–ipsi face weakness

•(6th nerve fascicles)–ipsi 6th nerve palsy

Raymond syndrome (medial pons basis and tegmentum)

• Paramedian brances of the basilar artery, ventral and dorsal territories

•Corticospinal and corticobulbar tracts

–contra face arm and leg weakness, dysarthia

•Fascicles of the 6th–ipsi 6th nerve palsy CN VI fascicles

Corticospinal tracts

Pontine wrong-way eyes (medial pons basis and tegmentum)

• Paramedian branches of the basilar artery, ventral and dorsal territories

•Corticospinal and corticobulbar tracts

–contra facce arm and leg weakness, dysarthia

•Abducens nucleus or paramedian pontine reticular formation• ipsilateral horizontal gaze palsy

PPRF

Abducens

Corticospinal tracts

Ataxia hemiparesis (medial pontine basis)

• Paramedian branches of the basilar, ventral territory

•Corticospinal and corticobulbar tracts

–contra face, arm, leg weakness, dysarthria

•Pontine nuclei and pontocerebellar fibers

–contralateral ataxia (occasional ipsilateral ataxia) Pontocerebelllar

corticospinal

Dysarthria hemiparesis (medial pontine basis))

• Paramedian branches of the basilar, ventral territory

corticospinal

•Corticospinal and corticobulbar tracts

–contra face, arm, leg weakness, dysarthria

Locked in syndrome (Bilateral ventral pons)

• Bilateral corticospinal tract– Quadriplegia

• Bilateral corticobulbar tract of lower CN – Aphonia

• Bilateral fascicles of CN VI– Impairment of horizontal eye movements

• Reticular formation is spared, so the patient is typically fully awake.

• The supranuclear ocular motor pathways lie dorsally, so that vertical eye movements and blinking are intact.

Weber’s (midbrain basis)

• Branches of the PCA and top of the basilar

•Oculomotor nerve fascicles

–ipsilateral third nerve palsy

•Cerebral peduncle–contralateral hemiparesis CN III fascicles

Cerebral peduncle

Benedikt’s (midbrain basis and tegmentum)

• Branches of the PCA and top of the basilar

•Oculomotor nerve fascicles –ipsilateral third nerve palsy

•Red nucleus, substantia nigra, superior cerebellar peduncle fibers

–contra ataxia, tremor and involuntary movements

•Cerebral peduncle–contralateral hemiparesis

CN III fascicles

Red nucleus

Cerebral peduncle

Claude’s (midbrain tegmentum)

• Branches of the PCA and top of the basilar

•Oculomotor nerve fascicles

–ipsilateral third nerve palsy

•Red nucleus•Contra tremor

• Superior cerebellar peduncle fibers

–contra ataxia

Sup cerebellar peduncle fibers and red nucleus above

CN III fascicles

Nothnagel’s Syndrome

• Branches of the PCA and top of the basilar (due to tumor)

•Oculomotor nerve fascicles

–ipsilateral third nerve palsy

•Superior cerebellar peduncle

–ipsilateral ataxia

Sup cerebellar peduncle fibers

CN III fascicles

Parinaud’s Syndrome

• Pinealoma of hydrocephalus compressing midbrain tectum

•Pre-oculomotor regions –Ocular palsies, paralysis of upgaze, pupillary abnl

•Superior colliculi

Basilar artery embolism• The embolus typically lodges at the terminal bifurcation

of the basilar artery and obstructs the posterior cerebral and superior cerebellar arteries, including the central branches from the proximal part of the posterior cerebrals. Coma (reticular formation of midbrain and rostral pons); diverging eyes with fixed, dilated pupils (bilateral fibers of III).

• In less severe cases there is recovery of consciousness, and the residual top of the basilar syndrome includes the oculomotor paralysis, together blindness or lesser visual field defects (occipital lobes) and disturbances of memory or behaviour (temporal lobes).

Posterior cerebral artery.

• Occipital lobe – contralateral hemianopia.

• Hippocampal formation – memory deficit, but this soon

recovers.

• Bilateral posterior cerebral artery occlusions can result in a permanent inability to form new memories, in addition to blindness in both eyes.

Middle cerebral artery

• Occlusion of the vessel at its origin causes contralateral upper-motor-neuron paralysis of the upper limb and face, with global aphasia if left-sided. Lower limb functions are spared.

• Infarction of the geniculocalcarine tract, deep to the parietal cortex, results in contralateral hemianopia.

• Obstruction of branches of the MCA results in fragments of the complete syndrome, such as monoplegia, upper motor neuron facial paralysis, or receptive aphasia.

Anterior cerebral artery

• Paralysis and sensory deficits in the contralateral lower limb and perineum.

• Urinary incontinence.• A proximal lesion - obstructing the origin of the

anterior cerebral artery - causes hemiplegia affecting the limbs and lower face, because an early branch, the recurrent artery of Heubner, supplies the internal capsule. Proximal lesions may also cause ipsilateral anosmia from infarction of the olfactory bulb and tract.