ICL 6.5: Localization of Brainstem Lesions Flashcards

Question

what is the fourth rule of 4?

Answer 1

4 CN in medulla, 4 in pons and 4 above pons midbrain = CN 3 and 4 (CN 1 and 2 arise from the brain) pons = CN 5, 6, 7, 8 medulla = 9, 10, 11 and 12

Answer 2

1. corticospinal tract --> contralateral weakness 2. DCML --> contralateral proprioception/vibration loss 3. medial longitudinal fasciuculus --> ipsilateral internuclear ophthalmoplegia 4. motor nucleus and nerve --> ipsilateral CN function loss

Answer 3

a disorder of conjugate lateral gaze in which the affected eye shows impairment of adduction so if the right eye wants to look right, the right CN 6 will activate the LR to do so and at the same time it will send information via the medial longitudinal fasciculus to the contralateral CN 3 to activate the left medial lectus (the MLF is on the same side as CN 3) if there's a problem with the MLF, then the left eye will not follow and you'll have double vision!! the right eye will look right but the left eye will get stuck in the middle and look straight = discordant gaze due to a lesion in the MLF

Answer 4

patients with MLF problems can perform convergence, so the medial rectus will activate when doing convergence! but if they have a CN 3 palsy then they won't be able to do convergence since the medial rectus is knocked out so INO patients have **preserved** convergence iNO = internuclear ophthalmoplegia

Answer 5

1. spinocerebellar --> ipsilateral ataxia because spinocerebellar tract goes to the ipsilateral cerebellum 2. spinothalamic --> contralateral pain and temperature sensory loss 3. sensory nucleus of CN V --> ipsilateral pain and temperature loss in the face 4. sympathetic pathway --> ipsilateral horner's syndrome

Answer 6

1. CN 9 glossopharyngeal --> ipsilateral pharyngeal sensory loss 2. CN 10 vagus --> ipsilateral palatal weakness (CN 10 pulls the uvula to the same side so if there's R sided weakness the uvula will deviate left away from the lesion) 3. CN 11 spinal accessory --> ipsilateral shoulder weakness 4. CN 12 hypoglossal --> ipsilateral weakness of the tongue (CN 12 pushes the tongue to the opposite side)

Answer 7

1. CN 5 trigeminal --> ipsilateral facial sensory loss 2. CN 6 abducens --> ipsilateral abduction weakness due to lateral rectus weakness 3. CN 7 facial --> ipsilateral facial weakness; incomplete eye closure, pulling of the face towards the normal side, loss of naso-labial fold on weak side 4. CN 8 vestibulocochlear nerve --> ipsilateral deafness

Answer 8

ACS-LIMiT auditory nerve--> cochlear nucleus --> contralateral superior olivary nucleus --> lateral leminiscus tract --> inferior colliculus --> medial geniculate body --> temporal cortex M(IC) like microphone because the inferior colliculus is what does sound!

Answer 9

CN 1 and CN 2 are not in the brainstem 1. CN 3 oculomotor --> ipsilateral eye would be turned out and down with ptosis because no levator palpebrae and the superior oblique supplied by CN 4 and lateral rectus supplied by CN 6 would be unopposed; there would also be an absent pupillary reflex 2. CN 4 trochlear --> eye unable to look down when looking towards nose because superior oblique isn't working = no intorsion

Answer 10

if CN 4 is knocked out, then you can't do intorsion = look down and in their eye will be up and out so to compensate the patient will tilt their head opposite to the side of weakness

Answer 11

1. does the patient have crossed clinical signals = head/neck signs opposite the trunk and limb --> most likely a brainstem problem if there's opposite signs 2. what is the location on the y axis based on which cranial nerves are involves = medulla, pons or midbrain? 3. what is the location on the x axis --> is it on the left or right side of the brainstem; is it a medial or lateral lesion based on which spinal tracts are involved

Answer 12

left medial midbrain lesion = Weber syndrome 1. patient has crossed clinical signs = brainstem lesion 2. CN 3 is effected with loss of pupillary reflex = midbrain 3. left body corticospinal tract is effected = medial

Answer 13

a stroke that effects the medial midbrain in the area of the cerebral peduncle/cruz cerebri this would involve the corticospinal and corticobulbar tracts so you'd have ipsilateral loss of pupillary light reflex and ophthalmoplegia along with contralateral body paralysis so it's a stroke characterized by the presence of an ipsilateral oculomotor nerve palsy and contralateral hemiparesis or hemiplegia patients will also experience UMN cranial nerve motor weakness, exaggerated gag reflex, tongue spasticity (no wasting), and spastic dysarthria from effects on the corticobulbar tract slide 122

Answer 14

left medial midbrain lesion = Benedikt's syndrome 1. patient has crossed symptoms = brainstem lesion 2. CN 3 is effected with the left ipsilateral ophthalmology = midbrain 3. left DCML tract is effect with loss of right proprioception = left, medial located there is involuntary movements due to the involvement of the red nucleus which is responsible for coordination --> without the red nucleus, you'll have ataxia and involuntary movements on the contralateral side

Answer 15

stroke of the medial midbrain in the central part that effects the medial lemniscus and red nucleus it leads to: 1. ipsilateral ophthalmoplegia 2. contralateral proprioception loss in the body 3. involuntary movements slide 122

Answer 16

WEBER'S 1. CN 3 2. corticospinal tract 3. corticobulbar tract 4. medial midbrain BENEDIKT'S 1. CN 3 2. medial lemniscus 3. red nucleus 4. medial midbrain even though both are medial midbrain lesions, weber's has contralateral weakness while benedikts has contralateral sensation loss

Answer 17

usually due to a *pineal gland tumor* in the midbrain or some other dorsal midbrain lesion that effects the superior colliculus and pretectal area clinical presentation includes: 1. patients will be unable to look upwards*** this signifies that the superior colliculus is involved since it controls vertical gaze 2. nystagmus when asked to perform convergence and loss of pupillary reflex 3. pineal tumor can also cause cerebral aqueduct obstruction which can lead to non-communicating hydrocephalus!

Answer 18

right medial pons lesion = Foville syndrome 1. patient has crossed signs = brainstem problem 2. CN 6 damage: medial deviation indicates they can't abduct so LR is weak CN 7: facial weakness both indicate right pon damage 3. medial lesion because CN 6 nucleus is medially located. also there is body weakness which is the corticospinal tract which is medially located too

Answer 19

inferior medial pontine stroke that involves the corticospinal tract and potentially also the nuclei of CN 6 and 7 clinical presentation includes: 1. contralateral weakness 2. ipsilateral medial eye deviation because of CN 6 palsy 3. ipsilateral facial weakness

Answer 20

internuclear ophthalmoplegia = medial, right MLF involvement in the pons/midbrain 1. no crossed signs, all the signs are in the head and neck 2. left eye can abduct but the right eye doesn't follow = right medial longitudinal fasciculus problem it's not a CN 3 problem because there is preserved convergence which means nothing is wrong with the MR of the right eve

Answer 21

left, lateral medullary syndrome = Wallenberg syndrome due to PICA stroke 1. left CN 10 problems because the uvula is decimated to the right which indicates left sided CN 10 weakness 2. CN 10 = medulla 3. left sided ataxia = left lateral lesion because the spinocerebellar tract is involved 4. left sided Horner's syndrome = sympathetic tract = lateral lesion

Answer 22

stroke in the lateral medulla usually from a PICA stroke this would effect the spinocerebellar, spinothalamic, spinal nucleus of V and sympathetic tracts = ataxia and Horner's syndrome also CN 9 would be effected so so you'd have horseless and dysphagia

Answer 23

right medial medullary syndrome due to stroke in the anterior spinal artery 1. crossed signs 2. CN 12 is involved with tongue deviation = medulla 3. tongue deviates to the right which indicates the right CN 12 is weakened 4. left hemiparesis and proprioception loss = right DCML and corticospinal tract problems = medial

Answer 24

sometimes the tonsils of the cerebellum and the medulla can herniate into the spinal cord through the foramen magnum this results in a blockage of CSF from the 4th ventricle which leads to internal hydrocephalus this is associated with craniovertebral anomalies or various forms of spina bifida symptoms are related to pressure on the cerebellum and the medulla which would involve the last 4 cranial nerves: 1. dysphagia 2. dysarthria 3. dizziness

Answer 25

left, medial midbrain lesion that is causing Cushing's triad! this is when increased intracranial pressure causes hypertension, bradycardia and irregular breathing this is because there is a hemorrhage on the left side of the brain that is causing a transtentorial herniation = the brain is herniating over the tentorium cerebelli and compressing on the brainstem which causes midbrain problems and Cushing's triad! 1. unreactive left pupil = left CN 3 problem = midbrain 3. right body weakness = medial lesion involving corticospinal tract

Answer 26

Parkinson's parkinson's usually effects the midbrain because it's the substantia nigra in the midbrain that normally secretes dopamine but with Parkinson's the substantia nigra is destroyed so this isn't happening and the patient presents with jerky movements and tremors because they can't initiate fluid movement treatment is dopamine replacement to counteract lost substantia nigra

Answer 27

CN 5 pushes jaw to the opposite side --> weakness would cause the jaw to deviate to the weak side CN 7 pulls the face to the same side --> weakness would cause the face to be pulled to the normal side CN 10 pulls the uvula to the same side --> weakness would cause the uvula to be pulled to the normal side CN 12 pushes the tongue to the opposite side --> weakness would cause the tongue to be pushed to the weak side