Brainstem Lesions

Question 1

lesion of dorsal motor nucleus of X

Answer 1

transient parasympathetic deficits

Question 2

lesion of descending motor nucleus of V

Answer 2

ipsilateral loss of pain and temp sensations from 1/2 of face

Question 3

lesion of posterior columns

Answer 3

ipsilateral loss of prop, 2 pt tactile, and vibratory sensations

Question 4

lesion of lateral lemniscus

Answer 4

bilateral diminution of hearing which is most predominant in contralateral ear

Question 5

cranial Ns 5, 7, 9, 10, 11 and spinal lemniscus

Answer 5

these cranial Ns exit the brainstem close to the spinal lemniscus
-as a result, a lesion in one of these may involve the N and the spinal lemniscus so causes ipsilateral CN deficits and contralateral loss of pain and temp from body

Question 6

alternating hemiplegias

Answer 6

involve 3, 5, 6, 12 b/c of their close association with the corticospinal tract
-yields ipsilateral CN deficits and contralateral motor paralysis or paresis

Question 7

alternating hypoglossal hemiplegia

Answer 7

1. destruction of hypoglossal N–ipsilateral paralysis of Ms of tongue and atrophy of ipsilateral Ms of tongue
2. destruction of CST–contralateral spastic hemiplegia

Question 8

alternating hypoglossal hemiplegia and destruction of contralateral CST

Answer 8

1. destruction of hypoglossal N–ipsilateral paralysis and atrophy of tongue Ms
2. destruction of ipsilateral CST–contralateral spastic hemiplegia
3. partial destruction of contralateral CST–some degree of ipsilateral spastic paralysis

Question 9

alternating hypoglossal hemiplegia and destruction of ipsilateral medial lemniscus

Answer 9

1. destruction of hypoglossal N–ipsilateral paralysis and atrophy of tongue Ms
2. destruction of ipsilateral CST–contralateral spastic hemiplegia
3. destruction of ipsilateral ML–contralateral loss of proprioception, 2 pt tactile, and vibratory sensations from body

Question 10

alternating abducens hemiplegia

Answer 10

1. destruction of abducens N–ipsilateral paralysis of lateral gaze/internal strabismus
2. destruction of CST–contralateral spastic hemiplegia

Question 11

Millard Gubler’s Syndrome

Answer 11

A6H+7

1. destruction of abducens N–ipsilateral paralysis of lateral gaze/internal strabismus
2. destruction of CST–contralateral spastic hemiplegia
3. destruction of facial N–ipsilateral facial palsy, loss of taste sensations from anterior 2/3 of tongue, decreased lacrimation, and hyperacusis

Question 12

Syndrome of Foville

Answer 12

A6H+ML

1. destruction of abducens N–ipsilateral paralysis of lateral gaze/internal strabismus
2. destruction of CST–contralateral spastic hemiplegia
3. destruction of ML–contralateral loss of proprioception, 2 pt tactile discrimination, vibrations
4. destruction of medial longitudinal fasciculus (MLF)–internuclear ophthalmoplegia
5. facial N may be involved
6. destruction of CROSSED corticobulbar fibers results in denervation of ipsilateral nucleus ambiguus and hypoglossal N–dysarthria, dysphagia, protrusion of tongue
   
   • this is not due though to a problem with CN 9, 10, or 12 but instead due to the crossed CBF and the highest CN involved (CN 6)

Question 13

alternating trigeminal hemiplegia

Answer 13

1. destruction of trigeminal N–ipsilateral loss of all sensations from half of face and scalp and ipsilateral paralysis of Ms of mastication
2. destruction of CST–contralateral spastic hemiplegia

Question 14

alternating trinomial hemiplegia with dorsal expansion

Answer 14

A5H+ML

1. destruction of trigeminal N–ipsilateral loss of all sensations from half of face and scalp and ipsilateral paralysis of Ms of mastication
2. destruction of CST–contralateral spastic hemiplegia
3. destruction of ML–contralateral loss of prop, 2 pt tactile, vibration from body and limbs
4. destruction of UNCROSSED corticobulbar fibers results in denervation of contralateral CN nuclei
   
   • abducens nucleus
   • 1/2 of facial nucleus results in paralysis of mimetic Ms on lower half of face–supranuclear facial palsy
   • hypoglossal nucleus
   • nucleus ambiguus

Question 15

Weber’s Syndrome

Answer 15

• alternating oculomotor hemiplegia
  1. destruction of oculomotor N–external strabismus, pupillary dilation, complete ptosis
  2. destruction of CST–contralateral spastic hemiplegia
  3. destruction of substantia nigra–contralateral resting tremor
  4. destruction of UNCROSSED CBF–contralateral brainstem motor nuclear palsy including supra nuclear facial palsy

Question 16

lesion of nucleus ambiguus and spinal lemniscus

Answer 16

1. destruction of nucleus ambiguus–dysphagia, dysarthria, hoarseness, paresis of ipsilateral palatal Ms
2. destruction of SL–contralateral loss of pain and temp sensations from body
3. lesion may extend medially to include the medial lemniscus and solitary nucleus
   
   • ML: contralateral loss of prop/2 pt tactile hemianesthesia of body
   • solitary nucleus: ipsilateral anesthesia of palate and pharynx, loss of taste sensations from 1/2 of tongue and pharynx

Question 17

Lateral Medullary Syndrome

Wallenburg’s Syndrome

Answer 17

1. destruction of spinal lemniscus–contralateral hemianalgesia
2. destruction of descending tract of V–ipsilateral loss of pain and temp from face
3. alternating hemianalgesia–ipsilateral loss of pain and temp sensations from face and contralateral loss of pain and temp from body
4. destruction of glossopharyngeal and vagus Ns–DYSPHAGIA
5. destruction of nucleus ambiguus
6. destruction of solitary nucleus–ipsilateral anesthesia of palate and pharynx, loss of taste sensations from 1/2 of tongue and pharynx
7. destruction of spinocerebellar tracts–asynergia or hypotonia
8. irritation of vestibular nuclei resulting in nystagmus

Question 18

Cerebellopontine Angle Syndrome (CPA)

Answer 18

-common tumor of posterior cranial fossa in adults is acoustic neurinoma–as tumor enlarges it compresses the lateral aspect of pons, cerebellum, and medulla

1. destruction of vestibulocochlear N–DEAFNESS and vestibular disturbances
2. destruction of facial N–Bell’s Palsy
3. alternating hemianalgesia–ipsilateral loss of pain and temp sensations from face and contralateral loss of pain and temp from body
   
   • destruction of descending tract of V–ipsilateral loss of pain and temp from face
   • destruction of spinal lemniscus–contralateral hemianalgesia of body
4. involvement of cerebellar peduncles results in some degree of ipsilateral cerebellar ataxia, intention tremor, dysmetria, and dysdiadochokinesia

Question 19

Benedikt’s Syndrome

Answer 19

• lesion of midbrain tegmentum
  1. destruction of oculomotor N–external strabismus, pupillary dilation, complete ptosis
  2. destruction of ML–contralateral loss of prop, 2 pt, and vibratory sensation from body and limbs
  3. lesions of red nucleus, superior cerebellar peduncle, and midbrain tegmenjtum–ipsilateral oculomotor palsy, contralateral motor dysfunction–tremor, ataxia, or choreiform movements

Question 20

Parinaud’s Syndrome

Answer 20

• lesion of superior colliculus which contains a center for controlling upward gaze
• principal sign of this syndrome–paralysis of upward gaze
• may be due to pineal tumor or varix of Great V of Galen
• lesions may destroy posterior commissure and concomitant loss of consensual light reflex

Question 21

unilateral lesion of VPM and VPL

Answer 21

• results in contralateral hemianesthesia
  
  • loss of pain and temp on opposite side of face and body
  • prop and tactile discrimination from contralateral body
  • prop, tactile discrimination, and taste sensations from ipsilateral head

Question 22

thalamic syndrome (Dejerine-Roussy Syndrome)

Answer 22

• usually due to thrombosis of PCA
• pts exhibit:
  
  • state of constant spontaneous pain w/o appropriate external strabismus
  • modification of emotional control–pt exhibits extreme mood swings from laughter to sobbing in a short time
  • may involve contralateral hemihypalgeia (crawling ant sensations), hemiparesis, homonymous hemianopsia, auditory deficits