Neuropathology 1 Flashcards
What are lacunar infarcts
- A stroke of the deep brain structures (, thalamus, basal ganglia, internal capsule). It leaves small cavities in the brain, or lacunes, hence the term. They often occur due to chronic hypertension which leads to charcot-bouchard microaneurysms that rupture causing a small hemorrhagic stroke in deep brain structures.
- Assoc. w/ hypertension and diabetes
Neural Tube defects
Congenital failure of neural folds and coverings to fold during development
Need folate - necessary for DNA synthesis
Carbamazepine and valproic acid - developments of neural tube defects as they inhibit intestinal folate absorption
Valproic acid is a folate antagonist
Wernicke-Korsakoff syndrome
Thiamine deficiency secondary to EtOH use. Acute symptoms include ataxia, sluggish pupils, anisocoria (unequal pupils). Chronic symptoms include amnesia, confabulation. Associated with polyneuritis (dry beriberi) or dilated cardiomyopathy (wet beriberi).
Cardinal signs of hydrocephalus
Headache
Vomiting without nausea
Papilledema
Enlarged calvarium if cranial bones have not fused
Dandy Walker malformation
Malformation of posterior fossa structures - hypoplasia of cerebellar vermis
Massive hydrocephalus with enlargement of fourth ventricle (posterior fossa ‘cyst’)
Associated defects: Aqueductal stenosis, Agenesis of corpus callosum, polymicrogyria, herniation of vermis into vertebral canal - trouble walking
Riboflavin inhibitors, viral infection (rubella, CMV),posterior fossa trauma - linked to DWM
Arnold Chiari Malformation
Downward displacement cerebellar tonsils and medulla thru foramen magnum
Feutures: hydrocephalus, cervical syringomyelia, myelomeningocoele, herniation and unrolling of vermis into vertebral canal
Syringomyelia
Loss of pain and temp sensation in a cape-like pattern (over arms) due to injury of anterior white commissure in spinal cord
Usually assoc. with Arnold Chiari syndrome
Segmental amyotrophy
Hydrocephalus ex vacuo
In elderly - ventricular dilation due to neuronal loss (AD, stroke)
Communicating hydrocephalus
Cognitive deficits
Use MRI, CT for diagnosis
Meningitis
Inflammation of meninges in CNS from bacterial, viral, fungal, parasites infections
Decrease reabsorption of CSF at arachnoid granulations - ICP increase
Symptoms: meningismus (pain touching chin to chest), nuchal rigidity, headache, fever, and signs of ICP
Epidural Hematoma
Middle meningeal artery - fast
Lucid interval in 50% (talk and die syndrome)
Lens shaped on imaging
Due to skull fractures, can increased ICP, herniation, death
CN III affected - pupil dilation
Sub dural hematoma
More common than epidural
Cortical atrophy in elderly patients - tension in bridging veins
Maybe be associated with contusion. subarachnoid and other hemorrhages
Subarachnoid hematoma
Raptured berry aneurysm
“Worst headache of my life”
Sudden onset of “thunderclap headache”
Assoc: Marfan syndrome, Ehler-danlos type 4, autosomal dominant PCKD, HTN, smoking, blacks, age
Xanthochromic CSF- yellow discoloration due to breakdown of RBCs
Normal Pressure hydrocephalus
Due to meningitis, subarachnoid hemorrhage, and atherosclerosis
Decreased resorption of CSF
Triad of “wet, wacky, wobbly” - urinary incontinence, dementia, and ataxia
Magnetic gat - attempts to initiate several times before taking a small step
ICP normal - treatment shunt
Thrombotic Stroke- Causes?
Due to platelet thrombus in middle of MCA or ICA
Liquefactive necrosis -remains pale, wedge shaped at periphery of cortex 1-2 days after, no reperfusion
Edema develops, loss of dermacation between gray and white matter, myelin breakdown, cystic area and reactive gliosis (astrocyte proliferation)
Thrombotic stroke - Presentation and treatment?
Patients have focal neurological deficits -unilateral arm, face, leg weakness, slurring speech, trouble walking, or visual disturbances
TREATMENT: IV tPA within 3 hours to dissolve thrombus and enable reperfusion
Risk - bleeding
Do CT: to rule out hemorrhagic stroke
MRI- choice for ischemic brain injury
Embolic stroke (Hemorrhagic Infarction)
Due to lysis of emboli after arterial occlusion and ischemic necrosis causing reperfusion injury
Emboli originates from the heart or proximal plaque in the ICA
TREATMENT: Treat underlining conditions causing emboli: atrial fibrillation, bacterial/nonbacterial endocarditis, rheumatic heart disease
Anticoagulants (warfarin) are preventive
Binswanger Disease
-multi-infarct dementia
-degeneration of white matter secondary to vascular lesion from hypertension or atherosclerosis, multiple strokes
-dementia, gait disorder, pseudobulbar state
Treatment-treat hypertension and atherosclerosis
What are lacunar infarcts? Associations?
- A stroke of the deep brain structures (, thalamus, basal ganglia, internal capsule). It leaves small cavities in the brain, or lacunes, hence the term. They often occur due to chronic hypertension which leads to charcot-bouchard microaneurysms that rupture causing a small hemorrhagic stroke in deep brain structures.
- Assoc. w/ hypertension and diabetes
- Treatment: reduce BP using statins, ACE inhibitors
Thalamic lacunar stroke
pure sensory loss stroke with tingling, numbness, pain, or burning sensations without motor symptoms
Posterior limb of Internal Capsule lacunar stroke or basis pontis
Pure motor hemiparesis
Face, arm, legs always involved as opposed to occlusion of the MCA (face, arm worse than leg) or ACA (leg worse than face and arm)
Ataxic hemiparesis?
Dysarthria?
Lacunar infarct in base of pons, combination of motor and cerebellar symptoms
Dysarthria or clumsy hand due to infarcts in base of pons or genu of internal capsule
Pure motor hemiparesis with Broca aphasia lacunar infarct?
thrombotic occlusion of the lenticulostriate branch supplying the genu, and the anterior limb of the internal capsule, and adjacent white matter of the corona radiata
MCA stroke presentations Parietal lobe? Frontal lobe? Temporal lobe? Dominant vs. nondominant hemisphere
Parietal lobe: contralateral hemianesthesia (loss of pain and temp. face and arm worse than leg)
Frontal lobe: contralateral hemiparesis (weakness in face and arm worse than leg)
Temporal lobe - homonymous quandrantanopia
Dominant hemisphere (usually left) - aphasia will develop
Nondominant (usually right) - left sensory neglect and apraxia
ACA stroke presentations
Parietal lobe?
Frontal lobe?
Medial frontal midline?
Parietal lobe: contralateral hemianesthesia (loss of pain and temp. leg worse than face and arm)
Frontal lobe: contralateral hemiparesis (weakness in leg worse than face and arm)
Medial frontal - urinary incontinence, grasp reflex returns
PCA stroke presentations?
occipital causes homonymous hemianopia with macular sparing
AICA infarcts (lateral pontine syndrome)
Ipsilateral: CNVII lesion- facial paralysis, CNVI lesion- paralysis of conjugate gaze, spinal trigeminal nucleus/tract - facial pain/temp loss, horner syndrome (descending sympathetics), hearing loss, vertigo, nausea, and vomiting/nystagmus from CNVIII lesion, dystaxia and difficulty controlling voluntary mvments: ICP, MCP
Contralateral - loss of pain and temp. in body (spinothalamic)
PICA infarcts (Wallenberg/lateral medulla syndrome)
Ipsilateral: limb ataxia and intention tremor (ICP), vertigo, nausea, vomiting/nystagmus away from lesion (vestibular nuclei), paralysis of larynx/pharnyx/palate – hoarseness (nucleus ambiguus), facial pain and temperature loss (spinal V), horner syndrome (descending hypothalamics)
Contralateral - loss of pain/temp in body (spinothalamic)
Name three causes of vascular dementia?
- Multiple infarcts - large artery atherosclerosis in circle of willis and corotids
- Binswanger leukoencephalopathy - loss of white matter secondary to HTN-related atherosclerosis
- Lacunar infarcts- small infarcts of the striatum and thalamus related to arteriosclerosis
Balint’s syndrome: Features? Triad?
- Disruption of parietal part of visual association cortex - spatial problems
- TRIAD: can have either one of the 3 to be diagnosed
- -> simultagnosia: inability to perceive more than one object simultaneously
- -> optic apraxia: inability or problems controlling voluntary eye movements
- -> optic ataxia: problems controlling voluntary motor movements e.g. reaching for the object
- Pts. have no experience of space, or spatial relations, no idea where objects are in space, and can only see 1 object at the time. Cannot locate the object they report seeing, and cannot reach for it
- inability to report if an object moves towards them or away from them
What is decorticate posture? Causes? Indications?
-Laying with hands close to chest
-1) disinhibition (loss of cortical inhibition)
of rubrospinal tract to arms –> increased flexor tone, overwhelms vestibulospinal
input
2) decreased corticospinal input to legs, vestibulospinal (extensor) tone predominates.
–> Indicates damage to cerebral hemispheres, the internal capsule, thalamus, or midbrain.
What is decerebrate posture? Causes? Indications?
-Laying with hands prone to the side
-indicates brain stem damage, specifically damage below the level of the red nucleus. -With the rubrospinal pathway destroyed,
extensor tone predominates in all extremities.
