Brain Vessel Occlusions

Question 1

What is the general cause of a “sub-arachnoid hemorrhage” what arteries are involved and where is it located?

Answer 1

Aka “Hematoma,” this bleed occurs between the arachnoid and the pia. Most commonly due to a rupture of berry aneurysms, most common artery is the anterior communicating artery.

Question 2

How do patients with sub-arachnoid hemorrhages (aka hematoma) present? What would you find in labs?

Answer 2

They present with a “thunder clap” headache or worst headache in their lives, also a stiff neck due to inflammation of the blood in the neck region. Blood will be present in the CSF.

Question 3

What causes a “subdural hemorrhage” and where is it located?

Answer 3

Located between the dura and the arachnoid, its usually induced by trauma. This is a tearing of the veins of the SUPERIOR SAGITAL SINUS leading to a VENOUS TEAR.

Question 4

How would the bleeding present in subdural hemorrhages?

Answer 4

Hemorrhage across suture lines (where the dura is attached to the calvaria), Blood will be “all over the place” not bound by sutures giving the classical “half moon appearance.”

Question 5

Where would the bleed be in an epidural hemorrhage and how would the bleed present?

Answer 5

The bleeding will be in between the skull and the dura, and the bleeding will be limited to the sutures and not extend beyond the sutures.

Question 6

Why does epidural hemorrhages occur and what happens?

Answer 6

This is almost always due to a trauma, and in this type of hemorrhage there is a tear of the artery, most commonly the MIDDLE MENINGEAL ARTERY. Bleed looks like a Biconvex Bleed.

Question 7

How do patients present with epidural hemorrhage?

Answer 7

“Talk and die syndrome,” where they are lucid before they lose consciousness and require immediate surgery.

Question 8

How many spinal arteries are there?

Answer 8

Technically 2, the anterior spinal artery will give off branches to the posterior spinal artery (there are 2 posterior arteries however). Anterior spinal artery feeds 2/3 of the spinal cord, the 2 posterior feeds the remaining.

Question 9

What are the structures that the PICA supplies blood to?

Answer 9

Dorsolateral medulla, posterior cerebellar lobe, inferior vermis, deep cerebellar nuclei, choroid plexus of the 4th ventricle. In short, bottom part of the cerebellum and a small part of the medulla on the dorsolateral side.

Question 10

Where does the AICA supply blood to?

Answer 10

Cortical and inferior surface of the cerebellum anteriorly, upper medulla and lower pons. There is some overlap between AICA and PICA.

Question 11

Describe the supply of the “short” or paramedian pontine artery? What tracts do they feed?

Answer 11

Supplies the medial basilar pons, and the medial pontine tegmentum. Feeds the corticospinal fibers, pontine nuclei and pontocerebellar fibers.

Question 12

What does the long or circumferential pontine arteries feed?

Answer 12

Whereas the paramedian pontine arteries fed the medial basilar pons and the medial pontine tegmentum, the circumferential arteries feeds the lateral pons and the lateral pontine tegmentum. Also feeds the middle cerebellar peduncle.

Question 13

What is the area that the SCA feeds?

Answer 13

Superior Cerebellar artery feeds the superior cerebellum and peduncle, as well as the rostral pontine tegmentum, deep cerebellar nuclei and the inferior colliculus.

Question 14

What does the PCA supply?

Answer 14

The lower strip of the lateral surface of the cerebral hemispheres, OCCIPITAL LOBE AND SPLENIUM (posterior 1/5 of corpus collosum) supplies all of the primary and some of the associated cortex for vision (particularly the calcarine branch of the PCA). The posterior choroidal branch and the temporal branch also supplies other parts

Question 15

What is “Locked in syndrome?”

Answer 15

Basilar artery is partially occluded, and this results in infarction of ventral pons, complete paralysis of the entire body (because the corticospinal fibers are fed by the basilar) BUT THE EYES ARE SPARED. Conscious pt. Special sensory pathway and the reticular formation is spared due to supply by the MLF.

Question 16

What artery occlusion causes “Medial Medullary Syndrome?” What structures are deprived of blood?

Answer 16

Anterior spinal artery or the medullary branch of the vertebral artery occluded. The pyramids will be infarcted (CST runs through here, as well as the DCML tract and CN 12).

Question 17

Describe the clinical presentation of the medial medullary syndrome?

Answer 17

Contralateral spastic (upper motor neuron induced, no inhibition by interneurons thus muscles are “stiff”) hemiparasis (CST infarct), loss of proprioception, vibration, and tactile sense from trunk and extremety (DCML infarct). IPSILATERAL tongue paralysis (all CN damage is ipsilateral presentation. CN 12 in this case). Tongue deviates to the side of the lesion.

Question 18

What artery is occluded in Wallenberg Syndrome, aka Lateral Medullary Syndrome?

Answer 18

Occlusion of the medullary branch of PICA.

Question 19

What are the structures affected by wallenberg syndrome?

Answer 19

Vestibular nucleus, inferior cerebellar peduncle, spinal trigeminal tract, Spinothalamic tract, nucleus ambiguous (fibers from CN 9, 10, 11) descending sympathetic fibers to the face, aka descending hypothalamic fibers.

Question 20

Clinical manifestation of wallenburg syndrome?

Answer 20

1. Nausea, Vomitting and Vertigo (vestibular nucleus), nystagmus (away from the lesion (vestibular nucleus has connection to CN 6).
2. Ipsilateral cerebellar signs such as ataxia and dysmetria (inferior cerebellar peduncle).
3. Ipsilateral loss of heat and pain sensation to FACE (Spinal Trigeminal tract, affected by 7 9 and 10).
4. CONTRALATERAL sensation of pain/temp loss (spinothalamic tract),
5. Paralysis of soft palate, pharynx and larynx, loss of gag reflex and uvula deviated away from lesion (CN induced).
6. ips Horner’s syndrome (ptosis - eye droop, miosis - pin point pupil, and anhydrosis - lack of sweat) due to descending hypothalamic tract injury.

Question 21

What artery causes Median Pontine Syndrome? What are the structures affected?

Answer 21

Occlusion of the short (paramedian) pontine artery, which feeds CN 6, CST, and possibly the DCML if deeper in pons.

Question 22

What are the clinical symptoms of Medial Pontine Syndrome?

Answer 22

Ipsilateral medial strabismus (CN 6), contralateral body spastic paralysis (CST) and contralateral loss of proprioception and vibration.

Question 23

What artery occlusion causes LATERAL PONTINE SYNDROME and what structures are affected?

Answer 23

This can be caused by AICA (caudal pons) or SCA (rostral pons). Affects the inferior cerebellar peduncle, fibers of CN 5, 7 (LMN) and 8 (caudal). Spinal tract and nucleus of CN5. Spinothalamic tract. Descending hypothalamic tracts to the face (sympathetic innervation to face).

Question 24

What are the clinical symptoms of lateral pontine syndrome?

Answer 24

1. Ipsilateral Limb Ataxia (Inferior cerebellar peduncle).
2. Ipsilateral anasthesia to the face, weak muscles of mastication and deviation of jaw towards lesion side. (Fibers of CN 5).
3. Ipsilateral facial paralysis (complete bell’s palsy) and hearing loss, nystagmus (away from lesion) and vertigo (CN 7 and 8).
4. Ipsilateral loss of pain and sensation to face (spinal tract and nucleus of CN 5).
5. Contralateral loss of pain/sensation (spinothalamic tract).
6. Ipsilateral Horner’s Syndrome (Descending hypothalamic fibers to face).

Question 25

What is the “Medial/Ventral Midbrain syndrome” caused by? What’s it called?

Answer 25

Occlusion of the PCA. Aka, Weber’s Syndrome.

Question 26

What are the structures affected and clinical presentation of this?

Answer 26

1. Ipsilateral CN 3 palsy, ptosis, lateral strabismus, and mydriasis (CN 3).
2. Contralateral hemiplagia or hemiparalysis (Descending motor fibers, CST).
3. Contralateral spastic paralysis of lower half of face (Corticobulbar tract, UMN).

Question 27

What is the key defecit of “Posterior Cerebellar Artery Syndrome?”

Answer 27

Alexia without agraphia, DISCONNECT SYNDROME. If left PCA is occluded for example, the right eye will not be able to convey the information to the left visual cortex (recall that the fibers of right eye crosses over at optic chiasm). The left eye will send info to the right visual cortex as normal, so the person will SEE something. However, if this person’s dominant hemisphere is on the left, the Wernicke’s area (located on posterior 1/5 of corpus collosum, supplied by PCA) will also be on the left and will not function. As a result, even though the left eye will send info to the right visual cortex to “see” information as it is still functional, the right visual cortex still needs to send info to Wernicke’s on left, which isnt functioning, and thus pt will see but not understand. Patient will still be able to write, because rostral 4/5 of the corpus collosum is supplied by anterior cerebellar artery.

Question 28

Besides alexia without agraphia, what are the symptoms associated with PCA syndrome?

Answer 28

1. Contralateral visual field defect and macular sparing.
2. Visual and color agnosia (unable to interpret meaning of).
3. Contralateral sensory loss and pain (thalamic pain syndrome) and involvement of the VPM and VPL nucleus of thalamus.

Question 29

What is “Raymond’s Syndrome?”

Answer 29

Similar to Medial Pontine Syndrome, because pontine branch is occluded, abducens and CST affected, leading to medial strabismus of ipsilateral eye loss of visual tracking and object fixation (abducens) and contralateral hemiparesis (cst).