The CNS Flashcards
What is the etiology of meningitis in adults?
Streptococcus pneumoniae
Neisseria meningitidis
What is postural instability?
an impairment of postural reflexes that cause a feeling of imbalance and a tendency to fall
What is the risk factor for myelomeningocele?
folate deficiency during the first several weeks of gestation
What are gliomas?
primary brain tumors that display histological features of glial cells; they generally effect the cerebral hemispheres
What is large artery, low flow TIA associated with?
tightly stenotic atherosclerotic lesions
What is an epidural hematoma?
occurs after blunt trauma and results from disruption of the middle meningeal artery and vein
What are the two parts of the central nervous system (CNS)?
The brain
Spinal Cord
What is loss of brain structural integrity mediated by?
release of various proteases, particularly the matrix metalloproteases (MMP)
Why does a patient with meningitis get a stiff neck?
flexion of spine leads to stretching of meninges
traction on the inflamed meninges is painful, resulting in limited range of motion through the cervical spine
What does tau cause?
inflammatory response
What is Chronic Traumatic Encephalopathy (CTE)?
a dementing illness that develops after repeated head trauma
What are the causes of intracranial hemorrhage?
hypertension/vascular wall injury
structural lesions
tumors
What causes periventricular leukomalacia?
decreased oxygen/blood flow in teh periventricular region of the brain
Damage to the glial cells
What is aseptic meningitis caused by?
viruses
What happens when cerebral blood flow is 25 mL/100gm/min?
onset of anaerobic glycolysis
Tissue acidosis
What are the leptomeninges?
pia and arachnoid mater
What is the function of the spinal cord?
conducts signals to and from the brain
controls reflexes
What are the consequences of hydrocephalus in children and adults?
expansion of the ventricles and increased ICP
What is multiple sclerosis (MS)?
a heterogenous disorder with variable clinical and pathologic features; DEMYELINATION DISORDER; starts as autoimmune disorder
What cerebrosvacular disease classes can cause Transient Ischemic Attack (TIA) or Ischemic stroke?
process occurs in the vessels
Process originates remotely
Process results from inadequate cerebral blood flow
What is Bacterial Meningitis?
infection of the arachnoid mater and the CSF in both the subarachnoid space and cerebral ventricles
What are the cardinal clinical symptoms of Alzheimers?
MEMORY IMPAIRMENT
executive function and judgement/problem soloving
behavioral and psychological symptoms
What does a myelomeningocele cause?
damage to the spinal cord and nerves
physical and intellectual disabilities
What causes the loss of brain structural integrity of brain tissue and blood vessels?
cerebral ischemia and infarction
What is the etiology of cerebral palsy?
prenatal factors and peri/postnatal factors
Prematurity
What is meningoencephalitis?
inflammation of the meninges and brain parenchyma
What happens when cerebral blood flow is 11 mL/100 g/min?
membrane failure and cell death
What is the presymptomatic period of Alzheimers Disease?
between onset of biochemical changes in the brain and the development of clinical symptoms of AD
due to genetic mutations in APP, PSEN1 and PSEN2
What is the pathophysiology of Traumatic Vascular Injury?
injured cerebral microvasculature causing MICROTHROMBI and NEURONAL DEATH
BBB disruption, edema and FOCAL ISCHEMIA
Bridging veins being stretched in elderly
Brain contusion on the opposite side of brain impact are?
Contrecoup
What initiates most activities of the nervous system?
sensory experiences exciting sensory receptors
What causes vasogenic edema?
BBB disruption and increased vascular permeability
What is the risk factors for meningiomas?
prior radiation therapy to the head and neck; increased incidence with age
What is the pathogenesis of MS?
1) inflammatory immune mediated disorder with autoreactive lymphocytes
2) microglia form complex with activated T cells causing destruction of the myelin and oligodendrocytes
3)
What causes sporadic onset of Alzheimers Disease?
APOE epsilon 4 mutation which inhibits the clearance of amyloid beta protein
What is cerebral autoregulation?
cerebral flow is maitained at a relatively constant level regardless of moderate variations in perfusion pressure
What two stroke types have athersclerotic risk factors?
Ischemic Thrombotic and Ischemic Embolic
What happens to the penumbra of the brain when blood flow is decreased to it?
has potential to recover because it is only undergoing apoptosis because some ATP is available
What is meningitis?
inflammation of the leptomeninges within the subarachnoid space
What are the steps of Wallerian Degeneration?
1) swelling in distal axon
2) neurofilaments hypertrophy
3) myelin sheath shrinks and disintegrates
4) axon degenerates and disappears
What GCS score is considered mild TBI?
13-15
What is the most important role of the nervous system?
control various bodily activities
What is a concussion/Acute Mild TBI?
GCS between 13-15 measured at approximately 30 minutes after the injury; altered mental state with or without LOC
What is the cause of Dismyelination?
genetics; abnormally produced myelin
What GCS score is considered moderate TBI?
9-12
What happens when autoregulation fails?
cerebral vasodilation and cerebral edema
The magnitude and distribution of a traumatic brain lesion depends on what three things?
the shape of the object causing the trauma
the force of impact
whether the head is in motion at the time of injury
What are the three mechanisms of TIA?
large artery, low Blood flow TIA
Embolic TIA
Lacunar or small penetrating vessel TIA
What is the pathogenesis of Meningitis?
1) Cytokine production
2) increased BBB permeability
Altered cerebral blood flow
increased ROS
3) neuronal damage, increased ICP, and cerebral edema
4) Clinical presentation of meningitis
What causes cytotoxic edema?
hypoxia/ischemia
What is Clinically Isolated Syndromes (CIS) of MS?
first attack of disease; patient hasn’t had any other symptoms and there are no lesions
How does DAI develop?
tissue shearing at interface of grey and white matter
What is the most common type of TBI?
Diffuse Brain Injury (DBI)
What are the most common tumors of the brain?
Gliomas
What is Parkinson’s Disease?
progressive neurodegenerative disorder in which dopamine is lacking
What is the function of the Cerebellum?
muscle tone, posture, and balance
What is the etiology of CTE?
repeated concussions
What occurs at the proximal end of the severed axon?
similar degeneration occurs but only back to the next node of ranvier
What is periventricular leukomalacia (PVL)?
necrosis of the white matter near the lateral ventricles that occurs most often in premature infants
What causes hydrocephalus?
reduced flow or decreased resorption of CSF
What are the clinical features of Metastatic brain tumors?
headache the will worsen due to Increased ICP
Seizures
What is periventricular white matter?
the white matter adjacent to the ventricles
What causes brain stem neurologic abnormalities?
Chiari malformation
What types of cerebral palsy would occur if children with prematurity survive?
Periventricular Leukomalacia (PVL)
Intraventricular Hemorrhage
Bronchopulmonary Dysplasia
What areas of the brain have sensory areas?
All levels of Spinal Cord Medulla Pons Mesencephalon Cerebellum Thalamus Areas of Cerebral Cortex
What are upper motor neuron symptoms of ALS?
weakness with slowness
hyperreflexia
spasticity
The consequences of CNS trauma depend on what two things?
the location of the lesion
limited repair
What is associated with severe cognitive dysfunction?
Presence of placques and tangles
What is the function of the astrocyte foot in the BBB?
allows small and lipophilic molecules (like alcohol) to cross
Allows water uptake
Contributes to brain swelling
What are the two major types of Cerebral Edema?
Vasogenic and Cytotoxic
What are the four main disease patterns of MS?
Clinically Isolated Syndromes (CIS) Relapsing Remitting (RR) Secondary Progressive (SP) Primary Progressive (PP)
What does Wallerian degeneration cause?
scar formation
What are the motor functions of the nervous system?
Contraction of SKELETAL and SMOOTH (organs) Muscle
Secretion of chemical substances by exocrine and endocrine glands
How does sensory information enter the CNS?
by peripheral nerves
Why does a patient with meningitis have fever?
cytokines affect the thermoregulatory neurons of the hypothalamus
invading pathogens produce pyrogens that can reset the hypothalamic thermal set point
How do astrocytes react to acute nerve injury?
cellular swelling
What is the etiology of meningiomas?
abnormal chromosome 22
What is caused by severe global cerebral ischemia?
BRAIN DEATH including irreversible cortical injury and brainstem damage
What are the three major levels of CNS Function?
Spinal Cord Level
Subcortical/Lower Brain Level
Higher Brain/Cortical Level
What is traumatic brain injury (TBI)?
a heterogenous disease determined by the Glasgow Goma Scale
What are the areas of CNS affected by MS called?
placques or lesions
What is a myelomeningocele?
cleft in the vertebral column with a corresponding defect in the skin so that the meninges and spinal cord are exposed
What are neurons?
The brains immune cells; protect brain from injury and disease
What is ischemia?
Decrease in blood flow to the brain
What is the pathophysiology of Bacterial Meningitis and what is it called?
1) pathogen penetration
2) NF-kB activation
3) leukocyte transmigration that occur at the BBB
Mechanistic TRIAD
What is cerebrovascular disease?
pathophysiological process involving the blood vessels of the brain
What is the pathophysiology of a concussion/Acute Mild TBI?
direct external contact forces or from the brain being slapped against intracranial surfaces with acceleration/deceleration trauma
What grade are primary tumors?
Grade 1 or 2
What is the function of the cerebral cortex?
performs associative activities such as thinking, learning, and remembering
What is lacunar/small penetrating vessel TIA induced by?
stenosis
What causes hypoxia?
low a low partial pressure of oxygen
Impaired oxygen carrying capacity
Toxins that interfere with oxygen use
In what area of the severed axon does Wallerian degeneration occur?
the distal axon
What causes Diffuse Brain Injury (DBI)?
impact, acceleration, and deceleration forces
What grades are malignant or high grade tumors?
Grade 3 or 4
What is herniation?
the displacement of brain tissue past dural folds or through openings in the skull
What is Focal Cerebral Ischemia?
reductino or complete blockage of blood flow to a LOCALIZED area of the brain; cerebral arterial occlusion leads first to focal ischemia and then to infarction
What is Amyotrophic Lateral Sclerosis (ALS)?
persistently progressive neurodegenerative disorder causing:
Muscle weakness
disability
Eventually death
What are the clinical outcomes of global cerebral ischemia?
transient confusional state to irreversible damage to CNS tissue
What is TIA?
a TRANSIENT episode of neurologic dysfunction caused by focal brain, spinal cord, or retinal ischemia WITHOUT ACUTE INFARCTION
What is the pathogenesis of Alzheimer’s Disease?
amyloid precursor protein (APP) is cleaved by beta-secretases and gamma secretases
PSEN1 and 2 mutations cause production of amyloid beta
Tau is hyperphosphorylated and aggregates
Why does a patient with meningitis have nausea and vomiting?
increased ICP stimulates the vomiting center