Brain Lesions Flashcards
Disinhibition (gambling, spending, fighting, hyper-sexual etc.) and deficits in concentration, orientation, judgment;
may have reemergence of primitive reflexes
Frontal Lobe Lesion
Destructive lesions of Frontal Eye Field disrupts conjugate horizontal gaze leading to eyes looking ___ brain lesion side caused classically by MCA stroke
(aka: away from side of hemiplegia/paralysis)
toward
Eyes look away from brain lesion (constantly looking to one side, but can’t look to the other side)
(aka toward side of hemiplegia)
Ex) LEFT side brain lesion = Eyes can only look RIGHT = Hemiplegia/paralysis on the RIGHT.
Paramedian pontine reticular formation
lesion in the PONS
Internuclear ophthalmoplegia (impaired adduction of ipsilateral eye; nystagmus of contralateral eye with abduction)
Ex) LEFT eye can move to the left, but the right eye stops at midline (nystagmus) so lesion on the LEFT side). LEFT eye can’t adduct, but right eye can abduct).
Medial Longitudinal Fasciculus
Buzzword for Multiple Sclerosis
Agnosia (can’t acknowledge it) of the contralateral side of the world causing Hemi-neglect Syndrome
NONDOMINANT parietal Cortex
aka left handed person has a left handed lesion
Anterograde amnesia—inability to make new memories
BILATERAL Hippocampus
May result in tremor at rest, chorea, athetosis
Basal Ganglia lesion
Substantia Nigra Pars compacta damage (Basal Ganglia)
Parkinson’s
Cuadate Nucleus damage (Basal Ganglia)
Huntington Disease
Subthalamic Nucleus damage (Basal Ganglia)
Contralateral Hemiballismus
Confusion, Ataxia, Nystagmus, Ophthalmoplegia, memory loss (anterograde and retrograde amnesia), confabulation, personality changes
BILATERAL MAMMILLARY BODIES damage
Wernicke-Korsakoff syndrome
disinhibited behavior (ex: hyperphagia, hypersexuality, hyperorality) HSV-1 ENCEPHALITIS
BILATERAL AMYGDALA damage
Klüver-Bucy syndrome
vertical gaze palsy, pupillary light-near dissociation, lid retraction, convergence-retraction nystagmus
Superior Colliculi in DORSAL Midbrain
Parinaud Syndrome
Stroke, Hydrocephalus, Pinealoma can compress
Superior Colliculi in DORSAL Midbrain
No more vertical gaze
Reduced levels of arousal and wakefulness or
Coma
may precede a tear of Middle Meningeal artery
Reticular Activating System (midbrain)
Intention tremor, limb ataxia, loss of balance;ipsilateral deficits; fall toward side of lesion
Lateral Cerebellar Hemisphere (so NOT the vermis)
Truncal ataxia (wide-based,“drunken sailor” gait even with eyes open), nystagmus Degeneration associated with chronic alcohol use
Cerebellar Vermis degeneration
Decorticate (flexor) posturing—flexion of upper extremities and extension of lower extremities
lesion above red nucleus (midbrain)
Ex: cerebral hemispheres, internal capsule
Decerebrate (extensor) posturing—extension of upper and lower extremities
lesion at or below red nucleus
Ex: midbrain to pons
Which posturing (Decorticate/Decerebrate) has a worse prognosis?
Decerebrate
Wernicke’s Aphasia: impaired language comprehension, fluent, but non-sensical speaking.
DOMINANT
Superior Temporal Gyrus lesion
Prosopagnosia (unable to recognize faces)
Fusifrom Gyrus lesion
runs along the bottom of the brain from the temporal to the occipital lobe
irreversible neuron damage occurs after how many minutes of hypoxia?
5 minutes
What are the 4 most vulnerable areas to hypoxia in order of most to least?
HIPPOCAMPUS
Neocortex
Purkinje Cells (Cerebellum)
Watershed Areas
(Vulnerable hippos need pure water)
24 hours or less after brain ischemia shows what?
2
EOSINOPHILIC
Pynknotic nuclei
(aka Red Nuclei)
2-3 days after brain ischemia shows what?
2
Necrosis
Neutrophils
4-5 days after brain ischemia shows what?
1
Macrophages (Macroglia)
1-2 weeks after brain ischemia shows what?
2
Reactive Gliosis (astrocytes, microglia etc proliferation) Vascularization
> 2 weeks after brain ischemia shows what?
1
Fibrotic Glial Scar
Decreased pain/temp from CL body and IL face Horner Syndrome Dysphagia Hoarseness decreased gag reflex
PICA
Wallenberg
*don’t PICA wHORe that can’t Eat or Sing
PICA lesion - MEDULLA
1. Dysphagia/Dysarthria:
Nucleus ambiguous CN IX and X
2. Ipsilateral facial anesthesia/thermanesthesia: Spinal nucleus and tract of Trigeminal nerve
3. Contralateral anesthesia/thermanesthesia: ALS
4. Vertigo & ocular disturbances: Vestibular nuclei
5. Ipsilateral ataxia: Inferior cerebellar peduncle
6. Ipsilateral Horner syndrome
neuropathic pain d/t thalamus. Initial paresthesias followed by allodynia and dysesthesia
Central post-stroke pain syndrome
spastic hemiparesis of CL side and weakness of lower two thirds of the face
internal capsule lesion
Agraphia
Acalculia
Finger agnosia
L–R disorientation
Dominant parietal cortex
(Dominant Angular & Supramarginal gyri)
Gertsmann syndrome
stroke affecting nucleus ambiguus is specific for a lesion to which artery?
PICA
Homonculus (medial vs lateral)
medial = limbs lateral = face
Epidural Hematoma looks like a ___ on CT
Lens (bioconvex/Lentiform)
Subdural Hematoma looks like a ___ on CT
Crescent moon (banana)
Subarachnoid Hemorrhage looks like a ___ on CT
Diffuse Hyperdensity deep in the deep brain or periventricular
Intraparenchymal Hemorrhage looks like a ___ on CT
Well circumscribed hyperdense blob in the deep brain
Due Long term Hypertension & 2nd most common cause of elderly dementia
Intraparenchymal Hemorrhage
Increased risk due to Marfan, Ehler Danlos, Polycystic Kidney disease, Smoking, or HTN
Subarachnoid Hemorrhage
Due to Rupture of Bridging veins
Subdural Hematoma
Crescent moon
Has a lucid interval. often involves a fractured pterion (lateral skull).
Epidural Hematoma
lens shaped
Can progress to transtentorial herniation and CN III palsy
Epidural Hematoma
lens shaped
a completely closed eyelid and deviation of the eye outward and downward. The eye cannot move inward or up, and the pupil is typically enlarged and does not react normally to light.
CN III palsy
Seen in shaken babies
Subdural Hematoma
Crescent moon
Bleed crosses suture lines
Subdural Hematoma
Crescent moon
Bleed does NOT cross suture lines
Epidural Hematoma
lens shaped
Alcoholism can cause chronic rupture of bridging veins leading to a hypodense ____ on CT
Subdural Hematoma
Crescent moon
