Pathoma Flashcards
What happens in severe global ischemia?
Results in diffuse necrosis - survival leads to vegetative state
How does dementia relate to Parkinson Disease?
Early-onset dementia (w/in 1 year of onset of Parkinson symptoms) is suggestive of Lewy Body Dementia, which is characterized by dementia, hallucinations and parkinsonian features. Histo reveals cortical Lewy Bodies.
What is vascular dementia?
Multifocal infarction and injury due to HTN, artherosclerosis, or vasculitis
What is an intracerebral hemorrhage?
Bleeding into brain parenchyma
Thrombotic strokes are due to and usually occur where?
Rupture of an antherosclerotic plaque and usually developes at branch points
Pale infarct at periphery
What are the clinical and radiological findings associated with epidural hematoma?
Lens-shaped lesion on CT
Lucid intervals may precede neuro signs
Herniation is lethal complication
What are the histological findings of Parkinsons?
Histology reveals loss of pigmented neurons in the substantia nigra and round, eosinophilic inclusions of alpha-synuclein (Lewy Bodies) in affected neurons.
Moderate global ischemia leads to?
Infarcts in watershed areas - damage to highly vulnerable areas
Pyramidal neurons of cerebral cortex - laminar necrosis
Pyramidal neurons of hippocampus - important in LTM
Purkinje layer of cerebellum - integrates sensory perception
The end result of the area affected by ischemic stroke?
Formation of fluid-filled cystic space surrounded by gliosis
What are the characteristics of Subacute Sclerosing Panencephalitis?
Progressive, debilitating encephalitis leading to death
Due to slowly progressive, persistent infection of the brain by the MEASELS VIRUS.
Infection during infancy and signs during childhood
Characterized by viral inclusions in neurons and oligodendrocytes
What type of necrosis results from ischemic stroke?
Liquefactive necrosis
What are the CSF findings associated with bacerial meningitis?
Neutrophils with decreased CSF glucose
Gram stain often identifies causitive organism
Embolic strokes are usually due to and involve what?
Emboli of the left side of heart (A fib)
Usually involves the middile cerebral artery
What is a berry aneurysm and what is the most common location?
Berry aneurysms are thin-walled saccular outpouchings that lack a media layer (increased risk of rupture)
Most commonly located in the anterior circle of Willis at branch points of the ACA
Associated with Marfan Syndrome
What are the molecular changes seen in AD?
Neuritic plaques made of amyloid
ABeta amyloid is derived from APP which is coded on chromosome 21 APP normally undergoes alpha cleavage, but when messed up it does beta - amyloid may also
Neurofibrillary tangles - intracellular aggregates of fibers composed of phosphorylated tau protein (microtubule associated protein)
Loss of cholinergic neurons
How is the diagnosis of MS made?
MRI reveals plaques
LP will show increased lymphocytes, increase Ig with oligoclonal IgG bands, and myelin basic protein
What are the characteristics of Progressive Multifocal Leukoencephalopathy?
JC Virus infection of oligodendrocytes (white matter)
Immunosuppression (AIDS) leads to reactivation of latent virus
Presents with rapidly progressive neuro signs
What are the major etiologies of global cerebral ischemia?
Low perfusion
Acute decrease in blood flow
Chronic hypoxia
Repeated episodes of hypoglycemia
What is Multiple Sclerosis and who does it present in?
Autoimmune destruction of the oligodendrocytes
Most common chronic CNS disease in young adults (20-30) more common in women
Associated with HLA-DR2 (HLA-DR15 accordine to Dr. Newell)
What is the pattern of change following an ischemic stroke?
Eosinophilic change in cytoplasm (RED NEURONS) - 12hrs after infarction
Necrosis (24hrs)
Infiltration of neutrophils (1-3 days)
Microglial cells (Days 4-7)
Gliosis (2-3 weeks)
What are the morphologic changes associated with AD?
Cerebral atrophy with narrowing of the gyri, widening of the sulci, and dilation of the ventricles (hydrocephalus ex vacuo)
Complications with Meningitis are usually seen with?
Bacterial meningitis
Death - caused by herniation secondary to cerebral edema
What is the classic cause of a subdural hematoma and what are the clinical and radiological signs?
Due to tearing of the bridging veins that lie between the dura and arachnoid arising from trauma
Crescent shaped lesion on CT
Presents with progressive neuro loss
What is the most common cause and site of intracerebral hemorrhage?
Complication of HTN
Basal Ganglia most common site
How will meningitis present?
Classic triad of headache, fever and neck stiffness
What is the most common cause of a subarachnoid hemorrhage?
Rupture of a berry aneurysm
What is the most common cause of an intracerebral hemorrhage?
Classically due to rupture of Charcot-Bouchard Microaneurysms of the lenticulostriate vessels
What are the CSF findings associated with Viral Meningitis?
Lymphocytes with normal CSF glucose
What is Meningitis?
Inflammation of the leptomeninges (Arachnoid and pia)
How will subarachnoid hemorrhage present and what will the CSF show?
Present as sudden “worst headache of my life” with nuchal rigidity
LP will show xanthochromia (yellow hue due to bilirubin)
How will MS present in clinic?
Relapsing neuro deficits with periods of remission
Features:
- Blurred vision in one eye
- Vertigo and scanning speech mimicing intoxication
- Internuclear opthalmoplegia (damage to MLF)
- Hemiparesis
- Lower extremity loss of sensation or weakness
- Bowel, bladder and sexual dysfunction
What is Amyotrophic Lateral Sclerosis?
Degenerative disorder of the upper and lower motor neurons of the corticospinal tract.
What is the pathogenesis of Spongiform Encephalopathy?
Prion protein is normally expressed in CNS neurons in an alpha-helical configuration. Disease arises with conversion to a Beta-pleated conformation. This pathological protein is not degradable and converts normal protein into pathologic form.
Resulting in damage to neurons and glial cells with intracellular vacuoles.
What is an epidural hematoma?
Collection of blood between the dura and skull
Classically due to fracture of the temporal bone and rupture of the middle meningeal artery
What is a tonsillar herniation?
Involves displacement of the cerebellar tonsils into the foramen magnum - compression of the brainstem leads to cardiopulmonary arrest
What are the CSF findings associated with Fungal meningitis?
Lymphocytes with decreased CSF glucose
What are the early signs of ALS?
Atrophy and weakness of hands.
What vessels are most commonly affected in lacunar strokes?
Lenticulostriate vessels
Involvement of the internal capsule leads to mainly motor stroke
Involvement of the thalamus leads to mainly sensory stroke
What are the clinical features of Huntington Disease?
Presents with chorea that can progress to dementia and depression
What is Spongiform Encephalopathy?
Degenerative disease due to prion protein
What are the clinical features of Parkinsons?
Tremor
Rigidity
Akinesia
Postural instability
What is a subdural hematoma?
Collection of blood underneath the dura and covers the surface of the brain
What is an uncal hernation?
Displacement of the temporal lobe uncus under the tentorium cerebelli
Compression fo CNIII leads to down and out dilated pupil
Compression of PCA leads to infarction
What is a subarachnoid hemorrhage?
Bleeding into the subarachnoid space
What are the genetics associated with Huntington Disease?
Autosomal Dominant Disorder characterized by expanded trinucleotide repeats (CAG) in the huntingtin gene
Further expansion of repeats during anticipation
What is Huntington Disease?
Degeneration of GABAergic neurons in the caudate nucleus of the basal ganglia.
What is Alzheimers Diseases and what are the clinical features?
Degenerative disease of the cortex (grey matter) and the most common cause of dementia
Clinical Features:
- Slow onset of memory loss; beings with short term and progresses to long term
- Loss of learned motor skills and language
- Changes in behavior and personalite
- Patients become mute and bedridden
- Focal neuro deficits are not seen in early disease
What happens in mild global ischemia?
Transient confusion with prompt recovery
What are the characteristics of Pick Disease?
Frontotemporal dementia
Degenerative disease of the frontal and temporal cortex
Spares parietal and occiptal lobes
Characterized by round aggregates of tau protein (pick bodies) in neurons of the cortex
Behavioral and language symptoms arise early
Lacunar strokes occur?
Secondary to hyaline arteriolosclerosis (complication of HTN)
What is Parkinsons Diseases?
Degenerative loss of dopaminergic neurons in the substantia nigra of the basal ganglia (pars compacta)
Rare cases of MPTP exposure
What is a subfalcine herniation?
Displacement of the cingulate gyrus under the falx cerebri
Compression of the ACA leads to infarction
What are the characteristics of Normal Pressure Hydrocephalus?
Increased CSF resulting in dilated ventricles
Can cause dementia in adults
Presents as triad of urinary incontinence, gait instabilitym and dementia (wet, wacky, and wobbly)
LP improves symptoms
What is adrenoleukodystrophy?
Due to impaired addition of CoEnzyme A to long chain fatty acids
Accumulation of fatty acids damages adrenal glands and white matter of brain
What are the characteristics of Central pontine Myelinolysis?
Focal demyelination of the PONS
Due to rapid intravenous correction of hyponatremia
Occurs in malnourished patients
Presenting with locked in syndrome - only able to move eyes
What are the genetics associated with AD?
Most cases are sporadic
Risk increases with age
E4 allele of apolipoprotein E (APOE) is associated with increased risk
E2 allele is associated with decreased risk
What is CJD and what are the clinical characteristics?
Most common spongiform encephalopathy.
Usually sporadic, but can arise due to exposure to prion-infected tissue via HGH or corneal transplant.
Presents as rapidly progressive dementia associated with ataxia and startle myoclonus
Periodic sharp wave (spike wave complexes) on EEG and death within a year.
