Brainstem Clinical Application Flashcards
Which tracts connect the spinal cord with the contralateral cerebrum?
The vertical tracts:
- Lateral corticospinal (CST) - Dorsal column/medial lemniscus (DCML) - Spinothalamic (STT)
Lesions of lateral corticospinal and dorsal column tracts in the brainstem usually cause ____lateral signs. Why?
contralateral, because these tracts cross the midline in the inferior medulla
Where is the only location where a brainstem lesion would cause ipsilateral corticospinal or DCML signs?
The corticospinal tract or dorsal column nuclei in the inferior medulla
Where does the corticobrainstem tract convey motor signals from and to?
From the cerebral cortex to cranial nerve nuclei in the brainstem
Upper motor neuron lesions are associated with muscle _____tonia.
hypertonia
Lower motor neuron lesions are associated with ___tonia
hypotonia
What does a complete motor neuron lesion of the facial nerve results in?
Flaccid paralysis of muscle in the ipsilateral face
What does a unilateral UMN lesion interrupt?
Voluntary control of contralateral facial muscles in the lower half of the face
Why are muscles in the upper half of the face spared in an UMN lesion?
Because the right and left cerebral cortices have bilateral projections to lower motor neurons innervating the muscle of the forehead and surrounding the eye
Are people with UMN lesions that prevent voluntary control of the contralateral lower face able to laugh and cry normally?
Yes, because the pathway involved in emotional vocalization is separate from the corticobraintem tract for the same activity
What does a lesion in the brainstem cause?
a mix of ipsilateral and contralateral signs
What does a lesion in the vestibular nuclei in the brainstem cause?
- vertigo
- nausea
- vomiting
- nystagmus
- tilted head position
- balance problems
What does a lesion on the lateral cuneate nucleus and inferior cerebellar peduncle cause?
ataxia
What does a lesion in the afferents to the solitary nucleus cause?
loss of taste from the ipsilateral anterior tongue
What does a lesion in the spinal tract and nucleus of the trigeminal nerve cause?
loss of pain and temperature sensation from the ipsilateral face
What does a lesion in the spinothalamic tract cause?
loss of pain and temperature sensation from the contralateral face
What does ischemia in the brainstem produce?
An abrupt onset of neurologic symptoms including dizziness, visual disorders, weakness, incoordination, and somatosensory disorders
Where is the most frequent site of brainstem stroke?
the lateral medulla
What does a stroke that affects the lateral medulla cause?
Wallenberg’s syndrome
The disruption of vital functions secondary to brainstem damage may cause what 3 things?
- Heart to stop beating
- Blood pressure to fluctuate
- Breathing to cease
Which areas of the brainstem regulate vital functions
the medulla and pons
What are the 4 D’s of brainstem dysfunction
- Dysphagia
- Dysarthria
- Diplopia
- Dysmetria
What is Dysmetria?
the inability to control the distance of movements
Lesions to what 2 structures may alter consciousness?
either the brainstem or the cerebrum
Damage to which brainstem structures will interfere with consciousness?
- reticular formation
- axons of the ARA system
Damage to which cerebral structures will interfere with consciousness?
- hypothalamic/thalamic activating areas
- the entire cerebral cortex
What are the 7 states of altered consciousness?
- coma
- stupor
- obtunded
- vegetative state
- minimally conscious state
- syncope
- delirium
How can you tell the difference between coma and vegetative state?
- spontaneous eye opening
- regular sleep-wake cycles
- normal respiratory patterns
What is stupor?
A state in which a person is only arousable by a strong stimulus
What is obtunded?
The state of being asleep more than awake and when awake they are confused and drowsy
Tumors within the cerebellum or brainstem cause increased _____ pressure
intracranial
What can increased intracranial pressure cause?
- headache
- nausea
- vomiting
- cranial nerve disorders
- hydrocephalus
