10 - Central Nervous System Flashcards
What diseases result when:
- loss of neurons?
- abnormal function of neurons?
- abnormal excitation of neurons?
- Alzheimer’s
- Parkinson’s
- Epilepsy
What is intracranial pressure (ICP) characterized by? What are 3 causes? Symptoms?
Characterized by pressure of CSF, can result in brain herniation if not relieved
Causes:
- brain parenchyma tumor, cerebral edema
- CSF outflow obstruction
- hemorrhaging, hematoma
Symptoms: headache, nauseua, vision change, loss of consciousness, death
What’s the diff btwn epidural and subdural hematoma, subarachnoid and intracerebral hemorrhage?
Epidural:
- arterial hemorrhage btwn skull and dura
- usually due to trauma, symptoms not immediate
Subdural:
- venous hemorrhage btwn dura and arachnoid
- due to cerebral atrophy, symptoms have slower onset than epidural
Subarachnoid:
- hemorrhage btwn arachnoid and pia
- usually due to trauma, rupture of aneurysms (Berry aneurysm)
Intracerebral:
- hemorrhage into substances of brain from intracerebral vessels
- usually due to trauma, stroke, and tumor
What is global ischemia characterized by and the two major patterns of injury?
General reduction of oxyen supply leads to stroke
-
Multiple small foci or ischemic necrosis:
- results in multi-infarct dementia (progressive mental deterioriation) -
Hypoperfusion from cardiac failure:
- pump failure => cardiogenic shock
- loss of fluid => hypovolemic shock
- loss of peripheral vascular tone => hypotonic shock
What’s the difference btwn global and focal ischemia?
Global: generalized ischemic necrosis
Focal: more localized and more fixable
Characterization of hemorrhagic strokes and 4 causes
Characterized by stroke resulting from blood vessel rupture
Causes:
1. HTN
2. cerebral amyloid angiopathy
3. cerebral arteriovenous malformation
4. intracranial aneurysm
What is a major cerebrovascular disease
Stroke
What are the 4 classifications of CNS trauma?
- Concussion: head trauma leading to altered consciousness
- Contusion: bruising of soft tissue
- Laceration: tearing of soft tissue
- Spinal cord injury: hyperextension, hyperflexion, can result in ligament rupture and possible loss of feeling
Difference btwn coup and contrecoup injury?
Coup = contusion at site of impact
Contrecoup = contusion at opposite site of impact
Difference btwn hyperflexion and hyperextension?
Hyperflexion = head goes forward
Hyperextension = head goes backwards
What are the 3 causes of CNS infections?
- hematogenous/vascular spread
- direct extension from adjacent structures (e.g. fractures)
- ascending neural route
what are the 4 main CNS infections
- Myelitis: inflammation of spinal cord parenchyma
- Encephalitis: inflammation of brain parenchyma (virus)
- Meningitis: inflammation of meninges
- Cerebral abscess: localized pus-forming infection by bacteria
Three main classifications of meningitis?
-
Acute pyogenic (bacterial)
- Group B strep
- N. meningitidis
- S. pneumoniae - Aseptic (viral)
-
Chronic
- TB, fungal, lyme, syphilis
How do the following cause CNS infections: virus, prions, protozoa, fungi
Virus:
- usually encephalitis
- other examples: herpes, HIV, AIDS, measles, rubella
Prions:
- small particles with no RNA/DNA but only infects nervous system
- most common = Creutzfeldt-Jakob disease (CID)
- example: bovine spongiform encephalopathy in cows
Protozoa:
- toxoplasmosis as opportunistic during AIDS
Fungi:
- causes infection in immunocompromised
What is the most common disease caused by prions?
Creutzfeldt-Jakob disease (CJD)
What is multiple sclerosis characterized by? What does its pathology involve? Symptoms?
- autoimmune demyelinating disease characterized by chronic relapsing and remitting course
- pathology involves white matter and leads to plaques
- affects both sensory and motor pathways (limb weakness, loss of sensation with tingling, blurred vision)
What are the two metabolic disorders? What are they deficient in and what accumulates?
Tay-Sachs Disease
- deficiency in hexosaminidase A
- accumulation of gangliosides in neurons leading to toxicity
Niemann-Pick Disease
- deficiency in sphingomyelinase
- accumulation of sphinomyelin in neurons leading to toxicity
What are the three nutritional deficiency diseases and what do they cause?
1. Thiamine (Vit B1) Deficiency
- Wernicke encephalopathy (disturbance of ocular function)
- Korsakoff syndrome (amnesia)
2. Vitamin B12 Deficiency
- causes uncoordinated movement, sensorimotor peripheral neuropathy
3. Nicotinic acid (Vit B3) Deficiency
- causes dermatitis, diarrhea, and delirium
What are the indirect (2) and direct (3) effects of chronic alcoholism?
Indirect:
- nutritional and metabolic disturbances
- repeated head trauma
Direct:
- Cerebellar atrophy = uncoordinated movement
- Cortical atrophy = mental deterioration
- myelopathy and sensory-motor neuropathy = sensory deficiency, tremor, muscle fatigue
Main characteristics of Alzheimer’s (3)
- atrophy of brain (frontal and occipital cortical gyri) due to loss of neurons
- form of dementia with insidious impairment of intellectual function and progressive disorientation/memory loss
- histological changes include neurofibrillary tangles and neuritic plaques
Main characteristics of Parkinson’s (3)
- subcortical neurodegenerative disease due to decreased dopaminergic neurons in substantia nigra
- TRAP symptoms: Tremor, Rigidity, Akinesia, Postural instability
- Palor of substantia nigra, loss of melanin-rich neurons (remaining have Lewy bodies)
Main characteristics of Huntington’s (3)
- Autosomal dominant, atrophy of basal ganglia and frontal cortex
- Mutation in HTT gene causing CAG expansions
- Characterized by involuntary, gyrating movements and progressive dementia
Main characteristics of Amyotrophic Lateral Sclerosis (ALS) (3)
- aka Lou Gehrig’s disease
- progressive, fatal motor neuron disease due to loss of motor neurons in spinal cord
- motor weakness and progressive wasting of muscles leading to muscle loss and death (paralysis of resp mscles)
What are the two primary CNS neoplasms?
Glioma & Meningioma
Characteristics of glioma. Which type is most prominent?
- Tumors arising from glial cells:
- astrocytoma
- oligodendroglioma
- ependymoma - Astrocytic tumors: astrocytoma and glioblastoma
- glioblastoma is highly aggressive with poor prognosis
Characterizations of meningioma (2)?
- neoplasm arising from meninges, normally benign but can be fatal depending on location
- good prognosis
