Brain lesions, strokes, aphasia, aneurysms Flashcards
What are the effects of a frontal lobe stroke?
- Disinhibition + judgement affected
- Deficits in concentration
- Orientation affected
- Possible reemergence of primitive reflexes
What way do the eyes look in a frontal eye field lesion?
Toward brain lesion
Where is the paramedian pontine reticular formation?
Nuclei in dorsal part of pons
The PPRF talks to the contralateral CNIII via what?
MLF
A lesion in the PPRF causes what?
Horizontal gaze palsy
- Eyes look away from brain lesion
What clinical finding will be found in a MLF lesion (e.g due to MS)?
Internuclear opthalmplegia
- Impaired adduction of ipsilateral eye
- Nystagmus of contralateral eye with abduction
Inability to write and perform maths (agraphia, acalculia) may occur with a lesion to where?
Dominant parietal cortex
What are the possible features of a lesion to the dominant parietal cortex?
- Agraphia
- Acalculia
- Finger agnosia
- Left-right disorientation
What syndrome may cause a dom. parietal cortex lesion (agnosia, acalculia)?
Gerstmann syndrome
Agnosia to the contralateral side of the world occurs with a lesion to where?
Non-dominant parietal cortex
- Hemispatial neglect syndrome (usually after stroke)
Anterograde amnesia or the inability to form new memories is caused by a lesion to where?
Hippocampus (bilateral)
What diseases may create lesions in the basal gnaglia?
- Parkinsons
- Huntington
- Wilson
A lesion in the subthalamic nucleus will cause what?
Contralateral hemiballismus
- Hyperkinetic involuntary movement disorder characterized by intermittent, sudden, violent, involuntary, flinging, or ballistic high amplitude movements in arms, legs
Wernicke-Korsakoff syndrome is due to a lesion where?
Mammillary bodies (bilateral)
What are the features of Wernicke-Korsakoff?
- Confusion
- Ataxia
- Nystagmus
- Opthalmoplegia
- Memory loss (anterograde, retrograde amnesia)
- Confabulation, personality changes
What part of the brain is affected in Kluver-Bucy syndrome?
- Amygdala (bilateral)
What are the features of Kluver-Bucy syndrome and what causes it?
- Hyperphagia, hypersexuality, hyperorality
- HSV-1 encephaitis
A lesion of the dorsal midbrain will produce what syndrome with what features?
Parinaud syndrome
- Vertical gaze palsy
- Pupillary light-near dissociation
- Lid retraction
- Convergence-retraction nystagmus
A reticular activating system (midbrain) lesion causes what?
Reduced levels of arousal and wakefulness (often from coma)
What are the effects of a cerebellar hemisphere lesion?
- Intention tremor
- Limb ataxia
- Loss of balance
- Ipisliateral deficits
- Fall towards side of lesion
Affects laterally
What are the effects of a cerebellar vermis lesion?
- Truncal ataxia (wide-based, drunkedn-sailor gait)
- Nystagmus
Central lesion -> affects centrally
What is cerebellar vermis lesion associated with?
Alcoholism
Decorticate (flexor) posturing (flexion of arms, extension of legs) is due to a lesion where?
Above the red nucleus
Decerebrate (extensor) posturing (extension of arms, flexion of legs) is due to a lesion where?
Below red nucleus
What are the most vulnerable areas of the brain furing hypoxia (watershed-areas)?
- Hippocampus
- Neocortex
- Cerebellum (purkinje) cells
Vulnerable Hippos Need Pure Water
What kind of necrosis occurs in the brain as a result of stroke?
Liquefactive
How soon after onset of stroke is tPA given?
3-4.5 hrs after onset (if no risk of hemorrhage)
How soon after an attack do tPAs usually resolve within?
15 mins
Where does a neonatal intraventricular hemorrhage occur?
Germinal matrix (highly vascularised layer within subventricular zone)
What will be seen on US in neonatal hemorrhage?
Blood in ventricles
Why are neonates vulnerable to intraventricular hemorrhage?
Reduced glial supprt
Impaired autoregulation of BP
Decreased vit K
What is the most common site for a thrombus to form in the brain?
MCA
What kind of hematoma may cause transtentorial herniatio and CN III palsy?
Scalp hematoma
What kind of hematoma causes a biconvex (lentiform) blood collection which does not cross suture line?
Epidural hematoma
What kind of hematoma causes a crescent shaped hemorrhage crosses suture lines?
Subdural
What kind of hematoma will have a bloody or yellow (xanthochromic) LP?
Subarachnoid
What kind of hemorrhage will may cause vasospasms due to blood breakdown or rebleed 3-10 days after infarction?
Subarachnoid
What drug is used to prevent vasospams?
Nimodipine
What can intraparenchymal hemorrhages be caused by? (6)
- Systemic HTN (most commonly)
- Amyloid angiopathy (recurrent lobar hemorrhagic stroke in elderly)
- Vascular malformations
- Vasculitis
- Neoplasms
- May be secondary to repurfusion injury in ischemic stroke
Where do intraparenchymal hypertensive (Charcot-Bouchard) hemorrhages most often occur?
- Putamen of BG (lenticulostriate vessels)
Then: - Thalamus, pons, cerebellum
What are the symptoms of a lenticulostriate artery stroke?
- Contralateral paralysis
- Absence of cortical signs (e.g. neglect, aphasia, visual field loss)
What is Central postroke pain syndrome?
Neuropathic pain due to thalamic lesions
- Initial paresthesias followed in weeks and months by:
- Allodynia (pain w/o stimuli)
- Dysthesia (altered sensation) on contralateral side
How common is central postroke pain syndrome?
~ 10% of stroke patients
What is Diffuse axonal injury due to? (what kind of injury -> what does this cause)
Rapid acceleration/deceleration of the brain i.e motor vehicle accident
Causes:
- Traumatic shearing of white matter tracts -> vegatitive state / coma
What will be seen on MRI in Diffuse axonal injury?
Multiple lesions (punctate hemorrhages) involving white matter tracts
What is the difference between aphasia and dysarthria?
- Aphasia: higher order language deficit
- Dysarthria: motor inability to produce speech
A patient is speaking in a ‘word salad’ that makes no sense what kind of aphasia do they have?
Wernicke (receptive) aphasia
- Sup temporal lobe of gyrus
Conduction aphasia is due to a lesion where>
Arcuate fasiculus
What conditions are associated with saccular aneurysms?
- Aut Dom Polycystic Kidney Disease
- Ehlers-Danlos syndrome
What kind of aneurysm will not be visible on angiography?
Charcot-Bouchard microaneurysm
- Hemorhagic intraparenchymal stokes
What temperatures will heat stroke occur at usually?
> 40 deg C (104F)
What are the complications of heat stroke?
- CNS dysfunction (eg confusion)
- End-organ damage
- Acute respiratory distress syndrome
- Rhabdomyolysis
What is the management of heat stroke patients?
- Rapid external cooling
- Rehydration
- Electrolyte correction
When can a seizure be considered status epilepticus?
> 5 mins or recurring seizures that may result in brain injury
