Brainstem Pathology: Vascular Syndrome, Lesions, Tumors Flashcards
1
Q
Are there any major syndromes in the superior cerebellar arteries?
A
No
2
Q
What arteries supply the most lateral part of the medulla
A
PICA
3
Q
What artery supplied the small portion of rostral medulla and caudal pons
A
AICA
4
Q
What is the medial zone of the medulla supplied by
A
Anteiror spinal artery
5
Q
Where do strokes normally happen
A
In the lateral most and medial most regions
6
Q
What is the lateral zone of medulla supplied by
A
- Posterior inferior cerebellar artery
- anterior inferior cerebellar artery
7
Q
Which artery is more likely to be occluded in the lateral zone of the medulla
A
PICA
8
Q
What gets knocked out with a PICA infarct
A
- aanteriolateral tract (pain and temp)
- hypothalamospinal tract (Horners syndrome)
- spinal trigeminal nucleus (pain/temp to body and face)
- cochlear and vestibular nuclei
9
Q
What does an infarct to the AICA knock out
A
Cochlear and vestibular nuclei
10
Q
Other names for anterior spinal artery infarct
A
- medial medullary infarct
- djerine syndrome
11
Q
(ASA) If there is damage to the right pyramid, what kind of motor deficit?
A
Weakness in left side. It is above decussation!
12
Q
(ASA) Right medial lemniscus damage: sensory deficit?
A
Decreased fine touch contralareal
13
Q
(ASA) Right hypoglossal nucleus/nerve (XII) damage: motor deficit?
A
Right tongue weakness. Deviation to right side
14
Q
(ASA) Medial longitudinal fasciculus damage: what happens
A
Nystagmus
15
Q
Is it possible to have a partial infarct of the ASA?
A
Yes, spares medial lemniscus
16
Q
What are other names for PICA infarct?
A
- PICA
- wallenburg syndrome
- lateral
17
Q
What structures can be damaged during PICA infarct?
A
- right hypothalamospinal projections
- right anterolateral/spinothalamic tract
- right spinal trigeminal tract/nucleus
- right nucleus ambiguus and IX/X nerves
- right vestibular nuclei
- right inferior cerebellar peduncle (restiform)
18
Q
If the right hpothalamospinal projections are damaged during PCIA infarct what will happen
A
Horners syndrome on right face
19
Q
If the right anterolateral/spinothalamic tract is damaged during a PICA infarct
A
Loss of pinprick sensation from left side of body
20
Q
If the right spinal trigeminal tract/nucleus is damaged during PICA infarct?
A
Loss of pain/temp sensation from right side of the face
21
Q
If the right nucleus ambiguus and IX/X is damaged during PICA infarct
A
Right side paralysis of palate, impaired gag reflex, pharynx, larynx
22
Q
If the right vestibular nuclei is damaged during PICA infarct?
A
Vertigo, nausea/vomitting, left beating nystagmus, imbalance toward right
23
Q
If the right inferior cerebellar peduncle is damaged during PICA infarct
A
Ataxia of right limbs
24
Q
What gets spared during a lateral medulla infarct
A
Most medial part of the PICA territory, including the solitary nucleus/tract and dorsal motor nucleus of the vagus
25
What does the PICA supply in the lateral medulla?
- anterolateral system
- spinal trigeminal tract
- restiform body
- solitary nucleus and tract
- vestibular nuclei (inferior and spinal)
26
What is the medial pons territory
- paramedical branches of basilar
- corticospinal tracts
- pontine nuclei
- pontomedullary-cerebellar fibers
- medial lemniscus
- abducens VI nerve (not nucleus)
27
Lateral pons territory
- circumferential branches of basilar
- middle cerebellar peduncle
- vestibular nuclei
- trigmeninal motor nucleus
- trigeminal main sensory nucleus
- spinal trigmeninal nucleus and tract
- anteriolateral (spinothalamic) tract
- hypothalamus-spinal projections
28
Medial pontine syndrome (infarct in the medial pons) on left causes what kind of damage to left corticospinal tracts
Spastic paralysis/paresis of right extremities
29
Medial pontine syndrome (infarct in the medial pons) on left causes what kind of damage to left medial lemniscus
Loss of two point discrimination and vibration from right body
30
Medial pontine syndrome (infarct in the medial pons) on left causes what kind of damage to left abducens nerve (not nucleus)
Left VI palsy, medial strabismus, diplopia
31
Medial pontine syndrome (infarct in the medial pons) on left causes what kind of damage to left pontine nuclei
Potential motor coordination impairment masked by weakness
32
Medial pontine syndrome (infarct in the medial pons) on left causes what kind of damage to left pont-cerebellar fibers
Motor coordination impairment masked by weakness
33
What is Foville's syndrome
A type of medial pontine syndrome that causes damage to corticospinal tracts, CN 6 nucleus/nerve, genu of CN 7 nerve and leaves the medial lemniscus intact
Full face paralysis
34
Occlusion of long circumferential arteries coursing along the borderline of the medial and lateral territories and sparing of the medial lemniscus
Foville syndrome
35
What would happen in lateral pons syndrome (AICA infarct) to the right anterolateral (spinothalamic) tract?
Loss of pain and temp on left of body
36
What would happen in lateral pons syndrome (AICA infarct) to the right spinal trigeminal nucleus and tract
Right face analgesia
37
What would happen in lateral pons syndrome (AICA infarct) to the right hypothalamo-spinal projections
Horners syndrome on the right face
38
What would happen in lateral pons syndrome (AICA infarct) to the right facial nucleus/nerve (VII)
Right upper and lower face flaccid paralysis/paresis
39
What would happen in lateral pons syndrome (AICA infarct) to the corneal blink refelx?
Neither eye blinks to cornea touch in the right eye
40
What would happen in lateral pons syndrome (AICA infarct) to the right vestibular nuclei (caudally)
Vertigo, nausea/vomitting, left beating nystagmus, imbalance toward right
41
What would happen in lateral pons syndrome (AICA infarct) to the right inferior and middle cerebellar peduncles
Ataxia, similar signs as for right lateral cerebellar lesions
42
If rostral pons has a lateral infarct what will it affect
Right anteiror/ventral trigeminothalamic tract, loss of somatosensation from left face
43
If mid level pons has lateral infarct
- right trigeminal main sensory nucleus (VO): loss of fine touch on the right face
- Right trigeminal motor nucleus (V): right paresis/paralysis of mastication muscles
44
Ventral midbrain blood supply
Medial branches of PCA
45
Blood supply of the lateral midbrain
Quadrigeminal artery (off PCA)
46
Dorsal blood supply of midbrain
Branches from SCA
47
What are some common midbrain infarct zones
- Weber
- Claude's
- Benedikt's
48
What is affected in Weber's syndrome
- left III nerve
| - left crus cerebri (cerebral peduncle)
49
What deficits are caused in Weber's syndrome from the left CNIII
Ipsilateral CNIII palsy, ptosis, failure of direct/consensual pupillary constriction in left eye.
50
What deficits would be caused by the left crus cerebri (cerebeal peduncles) in Weber's syndrome
Right hemi-paralysis/paresis of extremities and UMN for CN 4-12. Level down.
Easy to identify
51
What structures are affected in CLaude's syndrome (midbrain blood infarct)
Left CNIII nerve
| Left Red Nucleus
52
What does a deficit in left CN III nerve cause in Claude's syndrome
Ipsilateral CN III palsy, ptosis, failure of direct/consensual pupillary constriction in left eye
53
What deficits come from Left red nucleus in Claude's syndrome (midbrain infarct)
Possibly ataxia for right limbs; as if damage to right lateral cerebellar cortex, which projects to or through left red nucleus, on to left thalamus and left motor neocortex, controlling right limbs
54
Creates a flap that flutters inside the lumen and can occlude blood
Vertebral artery dissection
55
Narrowing due to atherosclerosis can lead to brainstem ischemia if systemic blood pressure falls
Vertebral or basilar artery stenosis
56
Clot can not only occlude an individual branch, but also can transiently block several major branches on the way up to the bifurcation of PCA which leads to transient brainstem signs
Vertebral or basilar artery thrombosis
57
Top-of-basilar syndrome, visual disturbances and other supratentorial problems
Occlusion of the basilar artery at bifurcation of PCA
58
Basilar pons is especially prone to hypertension-related ______ which can lead to locked-in syndrome
Hemorrhage
59
What is normal in locked in syndrome (bilateral damage to basilar pons)?
Full awareness and cognitive/emotional function, normal sleep-wake cycles, vital functions intact, sensory functions intact
60
What can cause locked in syndrome
Bilateral lesion of the BASILAR pons such as a bilateral hemorrhage or infarct, MS lesions, cnretal pontine myelinolysis
61
Degeneration of myelin causes by rapid over correction for dehydration by large amounts of water, inducing hyponatremia, low Na+
Central pontine myelinolysis
62
What gets covered in the pons when there is locked in syndrome
Most/all of BASILAR pons.
- corticospinal tract
- corticonuclear projections
Usually only CNIII function is spared!
63
What are the major deficits from locked in syndrome
Cranial motor paralysis and quadriplegia, patient can response to questions with vertical eye movements (up or down for yes/no) if CN 3 is spared. Usually permanent damage
64
Examples of cerebellopontine angle tumors
- meningioma
- cerebellar astrocytoma
- acoustic neuroma
- metastatic and other origins
65
Compression of dorsal midbrain
Parinaud's syndrome
66
Bilateral compression of midbrain tectum, the dorsal region containing the superior colliculi
Parinaud's syndrome
67
What is there disruption to in parinaud's syndrome
To the pretectal nuclei,, CN 3 nucleus, causing loss of the light reflex and disruption of vergence and accommodation
68
What are some causes of parinaud's syndrome
- pineal tumor
- hydrocephalus
- ischemic damage
- MS lesion
69
Vulnerable zone for simultaneously losing one or multiple cranial nerves, if there is an infection, embolism, tear in sinus wall allowing direct contact between venous blood and nerves
Cavernous sinus
70
What is the difference between cavernous sinus syndrome and orbital apex syndrome
Cavernous sinus just involves the CN that run through the sinus, orbital apex syndrome involves cranial nerves contained within the cavernous sinus and also the optic nerve as well
71
What nerves run through the cavernous sinus
```
III (oculomotor)
IV (trochlear)
VI (abducens)
V1 (ophthalmic)
V2 (maxillary)
```
72
Uncalled herniation into midbrain
Compression of CN III, blockade of pupillary light reflex
73
Left temporal lobe her acting across left tentorial notch
- compresses left cerebral peduncle and left CN 3
- right hemiplegia and cranial nerve motor deficits (UMN probs)
- CN 3 palsy, drooped eyelid, blown pupil
74
Right temporal lobe herniated across right notch
- pushes midbrain against contralteral clivus
| - left cerebral peduncle compresses, but right CN3 compressed
75
A general longitudinal regional, not a nucleus or tract that contains many functionally different nuclei and tracts that includes respiratory centers and baroreceptors reflex circuit
Reticular formation
76
Respiratory centers of spinal cord
Contains groups of LMNs controlling diaphragm and intercostal muscles
77
Which has more regions for respiratory control, pons or medulla?
Medulla. Damage to pons does not cause much resp problems
78
Repeated cycles of increased and decreases volume of each breath due to bilateral damage in medulla or pons
Cheyne-stokes pattern
79
If blood pressure is too high
Sensory info goes in on glossopharyngeal and out on vagus (parasympathetic)
To carotid SINUS
80
If blood pressure is too low?
In on glosspharyngeal and out via anterolateral medulla and sympathetic action
81
Unilateral lesions on brainstem
Usually do not significantly affect function, but bilateral can abolish function
82
What is the vomiting (emetic) center in the brain?
Area postrema
83
What can area postrema sense
Chemicals in CSF from 4th ventricle and in blood (no BBB here)
84
After the area postrema sense chemicals from the CSF and 4th ventricle. What does it do
Activates medulla reticular formation neuron, generate motor functions that generate vomitting: vagus, nucleus ambiguus, resp muscles
85
How can CN X act similarly to area postrema
Sensing emetics in the gut
86
Are nausea and vomitting always together?
No, can have vomitting without nausea
