Module 12 Neurocognitive Flashcards
Medical Imaging
- Skull & spine x-ray
- CT
- Angiography
- MRI
Electrophysiological Studies
- EEG
- EMG
- Nerve conduction
- Evoked potential
Cerebrospinal Fluid (CSF) Studies
- Cell count
- Biochem
- Microbio
- Cytology
Molecular Genetics & Cytogenetics
- Inherited disorders
- Tumours
Biochemical Analysis
- Metabolic disorders
Frontal Lobe
- Thinking
- Feelings/emotion
- Speech
Temporal Lobe
- Hearing
- Memory
Parietal Lobe
- Sensation
- Speech
Brainstem
- Eye & facial movement
- Breathing
- Heartbeat
Cerebellum
- Balance
- Coordination
Unique CNS Tissues
- Neurons
- Astrocytes
- Oligodendroglia
- Ependyma
- Microglia
- Choroid plexus
- Leptomeninges
CNS Tissues Found Elsewhere
- Dura (connective)
- Blood vessels
- Pericytes
- Smooth muscle
- Phagocytes (macrophages)
Neurons
- Initiate & transmit impulses
- Synapses (point of connection)
Astrocytes
- Scaffolding
- Insulate nerve fibres
- Growth & nutrition of neurons
- Maintain CNS environment (BBB)
- Repair of injuries
Oligodendrocytes
- Maintain myelin
- Conduction velocity of nerve fibers
Microglia
- Defensive (immunologic) responses
Neuronal Degeneration
- Atrophy
- Damage
- Necrosis
Axonal Degeneration
- Axonal swellings/loss
Glial Reaction
- Astrocytic hyperplasia
- Proliferation
- Astrocytosis/gliosis
Demyelination
- Damage to myelin/oligodendrocytes
Vascular Changes
- Vasculitis & vasospasm (ischemia)
- Vasogenic edema (BBB breakdown)
Cerebral Edema
- Vasogenic (breakdown of BBB)
- Accumulation of extracellular fluid (tumour, abscess, cytotoxic)
- Intracellular swellings of neurons/glia (hypoxia, ischemia)
Migration of Systemic Inflammatory Cells
- Neutrophils, lymphocytes, macrophages
- To CNS
Neoplastic Components
- Gliomas
- Metastases
Infectious Components
- Bacterial
- Fungal
- Viral
- Prion
- Worm
- Parasites
Vascular Components
- Cerebral infarcts
- Hemorrhages
- Ischemia
- Perinatal
Traumatic Components
- Brain/spinal injuries
Neurodegenerative Components
- Dementias, Alzheimer’s
- Movement disorders, Parkinson’s
Demyelinanting Components
- Multiple sclerosis
- Leukodystrophies, adrenoleukodystrophy
Intrinsic Tumour
- Intra-axial
- Gliomas (astrocytic, oligodendroglia)
- 3 tiered diagnosis (histology, molecular alterations, WHO grade)
Extrinsic Tumour
- Extra-axial
- Meningiomas, schwannomas
- Secondary metastases (lung, breast, melanoma)
Primary Tumour (Adults)
- Astrocytoma (includes glioblastoma)
- Oligodendrogliomas
- 90% supratentorial
Primary Tumour (Children)
- Astrocytoma
- Ependymomas
- Medulloblastomas
- 90% infratentorial
Histological Primary Tumour Features
- Suggest higher grade & poor prognosis
- Increasing cellularity
- Mitoses
- Nuclear pleomorphism
- Endothelial proliferation
- Necrosis
Primary Tumour Molecular Features
- IDH mutation (better prognosis)
- Chromosomal
Meningiomas
- Derived from meninges
- Based on dura
- Middle to old age
- Cured by resection
- Various histological patterns
Metastatic Tumours
- Difficult to asses prevalence
- Most common CNS neoplasm in adults
- Lung, breast, melanoma, renal cell carcinoma, colorectal
- Commonly located in cerebral hemispheres (grey/white matter junction)
- Less commonly seen in cerebellum & brainstem
Meningitis Types
- Bacterial (neutrophils)
- Viruses (lymphocytes)
- Fungi (immunocompromised, cryptococcus, candida)
- Cloudy leptomeninges
Bacterial Meningitis
- Many pathogens
- Fever
- Neck stiffness
- Headache
- Confusion
- Cloudy CSF
Cloudy Leptomeninges
- Purulent exudate in subarachnoid space
- Abundant polymorphs in leptomeningeal spaces
- May extend to vessels, ventricular wall, brain
Encephalitis
- Headache
- Fever
- Seizure
- Loss of consciousness
- Viruses most common (HSV, HIV, CMV)
Cerebral Abscesses (Direct Spread)
- (50% of cases)
- Middle ear, paranasal sinus, dental infections
- Mixed flora
- Streptococcus milleri
Cerebral Abscesses Hematogenous Spread
- (25% of cases)
- Bronchiectasis
- Congenital heart disease
- Bacterial endocarditis
- Mixed flora
- Streptococcus viridians
- Trauma & iatrogenic
Cerebrovascular Disorder
- Stroke
- Symptoms lasting 24+ hours
- Leading to death
- No apparent cause (vascular origin)
- Ischemic (infractions)
- Hemorrhagic (non-traumatic)
Cerebral Infarct
- Localized area of tissue necrosis
- Supplied by vascular pattern
- Neurons, glia, vessels
- Causes occlusion
Occlusion Consequences
- Narrowing of arteries
- Cerebral, vertebral, internal carotid
- Middle cerebral artery distribution most common
Vascular Occlusion Causes
- Thrombosis
- Atherosclerosis
- Vasculitis
Vascular Occlusion Clinical Manifestations
- Dependent on size & location of infract
- Transient ischemic attack (TIA)
- Symptoms subside in 24hrs
- Stroke
- Neurological defects (24+ hrs)
Intracerebral Hemorrhage
- Hypertension (Primarily)
- Leukemia
- Blood disorders
- Tumours
- Vascular malformation
- Aneurysms
- Amyloid angiopathy
- Vasculitis
- Immune mediated
- Sepsis
- Medications
- Anticoagulants
- Drug abuse
Subarachnoid Hemorrhage
- Developmental
- Berry aneurysm
- Vasculitis
- Immune mediated (nonseptic)
- Inflammatory aneurysm (mycotic)
- Septic vasculitis
- Amyloid angiopathy
- Arteriovenous malformation (AVM)
Hypertension Hemorrhage
- Hypertensive arteriosclerotic changes
- Wall weakening of arterioles/micro vessels
- Results in rupture
- Treatment of hypertension to reduce incidence
- Rupture into ventricles/brain swelling (Fatal)
Hypertension Hemorrhage Sites
- Basal ganglia
- Thalamus regions
- Pons
- Cerebellum
Cerebral Amyloid Angiopathy
- Deposition of amyloid (beta)
- Weakens vessel wall (subarachnoid & cortical)
- Leads to rupture
- Intracerebral & subarachnoid hemorrhages
- Elderly (Alzheimer’s)
Berrys (Saccular) Aneurysm
- Developmental defect
- Weakening of arterial wall
- Anterior communicating artery most common site
Manifestation of Berry Aneurysm
- Local pressure
- Isolated 3rd cranial nerve palsy
- Rupture/hemorrhage
- Subarachnoid, intracerebral, intraventricular
Duret’s Hemorrhage
- Brain swelling
- With uncal/tonsillar herniaition
- Secondary brain hemorrhage
Infarction
- Compression necrosis/vasospasm
- Constriction of vessel walls after subarachnoid hemorrhage
Hydrocephalus
- Blood clots
- Ventricles & subarachnoid space
Head Injury
- Leading cause of death in people under 45
- Impact/blunt force
- Focal, diffuse pattern
Skull Fracture
- Radiate/pass impact site
- Not always associated with brain damage
- Force required
Skull Fracture Patterns
- Linear, single line
- Comminuted, multiple lines
- Compound, communicates with cranial cavity
- Depressed, margins pushed into cranial cavity
- Hinge, across base of skull
Traumatic Intracranial Hemorrhage
- Bleeding inside cranium
Traumatic Intracranial Hemorrhage Sites
- Outside dura (epidural)
- Under dura (subdural)
- Under arachnoid (subarachnoid)
- In brain (intracerebral)
- Cerebral ventricles (intraventricular)
Epidural Hematoma
- Result of fracture to squamous temporal bone
- Damage to middle meningeal artery/vein
- Lucid interval association
Subdural Hemorrhage
- Acute
- Associated with other brain trauma
- Fall/blow to head
- Various tears
Brain Contusion
- Hallmark of brain damage in head injury
- Bruise to surface
- Overlying pia matter intact
Topography
- Involve gyri crest
- Contact with protuberance within skull
Coup Contusion
- Occur under site of impact
- Result of blowC
Contre-Coup Contusion
- Opposite (at distance) from impact site
- Result of fall
- Occipital impact most obvious
Alzheimer’s
- Cortical degeneration
- 50-70% of dementia cases
- Slow progression
- Motor & sensory systems in tact
Alzheimer’s Gross Pathology
- Atrophy
- Frontal & temporal emphasis
Alzheimer’s Mirco Pathology
- Neuronal loss in cerebral cortex
- Gliosis (astrocytes proliferation & hypertrophy)
- Amyloid deposits
- Neurofibrillary tangles
- Neuritic plaques
Alzheimer’s Stages
- Thal (A)
- Braak (B)
- CERAD ©
- National institute on aging (NIA-AA)
Parkinson’s
- Movement disorder
- Slow progression
- Unknown causes
- No cure
Parkinson’s Symptoms
- Resting tremor (shaking)
- Generalized slowness (bradykinesia)
- Stiffness of limbs (rigidity)
- Gait/balance (postural dysfunction & frequent falls)
Parkinson’s Neurochemistry
- Loss of dopamine (DA)
- Imbalance of neurotrans in basal ganglia
- Dopamine replacement relives symptoms
Parkinson’s Pathology
- Loss of pigments in substantia nigra (midbrain)
- Eosinophilic inclusions in cytoplasm (Lewy Bodies)
- Increased astrocytes (gliosis)
Lewy Bodies
- Cortical degeneration
- Cerebral cortex dementia association
- Mutation of alpha synuclein gene PD early onset
Primary Demyelination
- Damage/breakdown of myelin
- Sparing of axons
- MS
Secondary Demyelination
- Myelin breakdown
- Injured/dying axons
- Neurodegenerative diseases
Primary Demyelination Incidence
- Common in temperate latitudes
- 20-40 yrs onset
- Female more common
Primary Demyelination Etiology
- Genetic predisposition
- Environmental
Primary Demyelination Pathogenesis
- Autoimmune reaction against oligodendroglia
- CNS myelin with T-lymphocyte sensation
Primary Demyelination Clinical Manifestations
- Relapsing
- Intermittent chronic course
- Unilateral limb weakness
- Paresthesia
- Optic neuritis
- Charcot’s tirad (nystagmus, tremor, dysarthria)
- Impaired intelligence
- CSF increased IgG
Macro Pathology of MS
- Scattered
- Grey
- Sharply defined plaques (demyelinated areas)
- White matter, brain stem, spinal cord, optic nerve
Micro Pathology of MS
- Early active lesions
- Perivenous demyelination
- Perivascular lymphocytes (T-cells)
- Oligodendroglia loss
- Areas coalesce visible MS plaques with inflammation
- Chronic lesions show gliosis
- Axon preservation