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97 terms

Unit 4 Pathophys

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In what space does the cerebrospinal fluid circulate around the brain and spinal cord?
The subarachnoid space
Where are the language centers located in the brain?
Left hemisphere
What is the corticospinal tract?
A pyramidal tract for efferent impulses
What is the function of the limbic system?
Determines emotional responses
What/where is the limbic system?
Many nuclei & connecting fibers in the cerebral hemispheres that encircle the superior part of the brain stem.
How should CSF look? (What are the normal physical characteristics?)
Clear and colorless
How would damage to the auditory association area in the left hemisphere be manifested in an individual?
Inability to understand what is heard
What is a "vegetative state"?
Is the brainstem still functioning?
Loss of awareness and intellectual function, but continued brainstem function
What constitutes the criteria for "brain death"?
No activity on EEG, absence of all reflexes, no spontaneous respirations
Define aphasia
The inability to comprehend or express language appropriately
List early signs of increasing intracranial pressure.
Papilledema
Why does vomiting occur with increased intracranial pressure?
Pressure on the emetic center in the medulla
What change is seen in blood pressure in increased intracranial pressure?
Increasing pulse pressure
Describe the herniation that results from increased intracranial pressure.
Displacement of brain tissue downward toward the spinal cord
Why does a brain tumor cause a headache?
Stretches the meninges and blood vessel walls
Define papilledema.
Increased pressure of CSF at the optic disc
What effects do you see in the body because of a growing brain abcess?
Systemic vasoconstriction and slower heart rate
If intracranial pressure increases with a intracerebral hemorrhage, the pupil of the eye (ipsilateral to the lesion) becomes dilated and unresponsive to light. Why?
Pressure on the parasympathetic fibers in cranial nerve III
What are characteristics of malignant brain tumors? Do they usually metastasize outside the CNS?
Occupy space in the brain causing increase ICP and increased pressure on surrounding tissue. They can be treated but rarely removed due to inaccessible locations within the brain.
Primary brain tumors are invasive but rarely metastasize outside the CNS
What signs and symptoms would you expect from a tumor in the left frontal lobe?
Weakness in the right side of the face
Why are focal or generalized seizures an early indicator of a tumor?
Surrounding inflammation stimulates neurons to discharge uncontrollably
Why are TIAs an early warning sign of?
They often warn of potential cerebrovascular accidents
Where would you guess was the source of an embolus causing a CVA?
Common carotid artery
Collateral circulation is more likely when a CVA results from what circumstance or condition in the brain?
Development of an atheroma
Regarding stroke, what is the most common cause?
an atheroma with thrombus.
What effect would result from cerebral infarction due to obstruction in the right cerebral artery?
Contralateral weakness in the leg, impaired spatial relationships
Following CVA, why might some neurologic function return?
Presence of collateral circulation, reduced inflammation in the area, and development of alternative neuronal pathways
Which type of CVA has the poorest prognosis?
hemorrhagic CVA
What factors predispose an individual to having a CVA?
Hypertension, diabetes mellitus, smoking cigarettes, and history of coronary artery disease
What are the typical early signs of a ruptured cerebral aneurysm?
Severe headache, nuchal rigidity, and photophobia
What is a berry aneurysm?
They usually develop at points of bifurcation in the circle of Willis, they are usually asymptomatic for many years, and after rupture, blood appears in the subarachnoid space
In bacterial meningitis, where do swelling and purulent exudates form?
The pia, arachnoid, and surface of the entire brain
List signs of acute bacterial meningitis.
Severe headache, nuchal rigidity, and photophobia
How are viruses in many types of encephalitis spread?
Bites of mosquitoes and ticks
Describe pathophysiology of a tetanus infection.
It is caused by an anaerobic, spore-forming bacillus, the exotoxin causes strong skeletal muscle spasms, and death may result from respiratory failure
Describe pathophysiology of Guillain-Barre syndrome.
Inflammation and demyelination of peripheral nerves leading to ascending paralysis
What damage occurs with a depressed skull fracture?
A section of the skull bone is displaced below the level of the skull, causing pressure on the brain
Following a head injury, what is the most likely cause of secondary damage to the brain?
hematoma or infection
What is an epidural hematoma?
Located between the dura and the skull
Define otorrhea.
CSF leaking from the ear
Why may secondary damage occur shortly after a spinal cord injury?
Unstable fractures or dislocations of vertebrae, catecholamine release in the area, decreased blood pressure
What is the expected effect during the period of spinal shock following a spinal injury at C5?
Possible periods of apnea
Following an injury at L2 to L3, what would indicate recovery from spinal shock?
Spastic paraplegia
Define nuchal rigidity.
Stiff hyperextended neck associated with irritation of spinal nerve roots.
What are the signs of autonomic dysreflexia in a person with cervical spinal injury?
Sudden marked increase in blood pressure with bradycardia
Expressive aphasia results from damage to what area of the brain?
Left frontal lobe (Broca's area)
What is the usual result of damage to the right occipital lobe?
Loss of left visual field
What is the causative organism of meningitis in children?
N. meningitides
At what level of the spinal column is a lumbar puncture usually performed?
Usually performed at L3 - 4
What signs are indicative of post-polio syndrome?
Progressive fatigue and weakness
Describe the pathophysiology of Reye's syndrome
Precipitated by a combination of viral infection and administration of ASA. Cerebral edema develops. Liver damage is common.
Which type of fracture typically occurs at the base of the skull?
basilar
Why do seizures commonly occur with head injuries?
Presence of blood irritates neurons
When can an accurate assessment of the extent of permanent spinal cord damage usually be completed?
Approximately 10 days to 2 weeks following injury if no complications arise
What causes CSF accumulation in noncommunicating hydrocephalus?
An obstruction is present in the aqueduct of Sylvius or other channel
What are typical signs of hydrocephalus in the neonate?
Enlarged head with bulging fontanels, irritability and feeding difficulties, eyes are turned downward with sclerae showing above the pupils
What is the cause of myelomeningocele?
Herniation of the meninges, CSF, and spinal cord or nerves through the vertebral defect
How is the presence of spina bifida diagnosed prenatally?
Prenatally by ultrasound or detection of AFP in maternal blood or amniotic fluid
What characteristic do all individuals with cerebral palsy have?
A form of motor disability
What causes cerebral palsy?
Nonprogressive brain damage to the fetus or neonate
What is the major cause of brain damage in cerebral palsy?
hypoxia
The ataxic form of cerebral palsy results from damage to what area of the brain?
The cerebellum
What are generalized seizures? Do they involve one or both cerebral hemispheres?
The uncontrollable discharge of neurons in both hemispheres
What recording is used to diagnosis and classify seizures?
Electroencephalogram
What are the events (in order) that follow the aura during a tonic-clonic seizure?
Loss of consciousness then the tonic stage
What does the clonic stage of a seizure consist of?
Alternating contractions and relaxation of skeletal muscles
What is a psychomotor seizure?
A seizure consisting of bizarre or inappropriate activity
Define status epilepticus.
Seizures are recurrent or continuous without full recovery between episodes, severe hypoxia and acidosis develop, and if the condition persists, there may be additional brain damage
Which type of seizure commonly occurs in children?
Generalized absence
What things might precipitate a seizure?
Hypoglycemia, brain abscess, high fever in young children
Describe the pathophysiology of multiple sclerosis?
Progressive, random degeneration of peripheral nerves
What are common early signs of multiple sclerosis?
Tremors, weakness in the legs, visual problems
Describe the pathophysiology of Parkinson's Disease.
Degeneration of the basal nuclei with a deficit of dopamine
What are common early manifestations of Parkinson's Disease?
tremors at rest in the hands and difficulty initiating voluntary movements
Where is progressive degeneration occurring with amyotrophic lateral sclerosis?
Upper and lower motor neurons
Describe the pathophysiology of ALS (Amyotrophic lateral sclerosis AKA "Lou Gehrig's Disease")
Affects both upper and lower motor neurons in the brainstem and spinal cord. No indication of inflammation around the nerves.
Loss of upper motor neurons leads to spastic paralysis and hyperreflexia
Damage to lower motor neurons results in flaccid paralysis with decreased muscle tone and reflexes.
Loss of neurons occurs in a diffuse and asymmetrical pattern but proceeds without remission
What are some early typical signs of ALS?
Weakness and muscle atrophy in upper extremities
Describe the pathophysiology of myasthenia gravis?
It is an autoimmune disorder in which the cholinergic receptors at the neuromuscular junctions are damaged. Cause is unknown.
Describe the pathophysiology of Huntington's Disease.
Progressive atrophy of the brain occurs, with degeneration of neurons, particularly in the basal ganglia and the frontal cortex.
Ventricles are dilated
Depletion of GABA (gamma-aminobutyric acid)—major inhibitory neurotransmitter in basal nuclei and substantia nigra
Inherited disorder that does not manifest until midlife.
What are signs and symptoms of Huntington's Disease?
Presents with choreiform movements in the upper body and decreased ability to concentrate
What physical changes in the brain occur in Alzheimer's Disease?
Cortical atrophy with plaques and neurofibrillary tangles, impairing conduction
What are early signs of Alzheimer's Disease?
Behavioral changes, inability to reason
Describe the pathophysiology of schizophrenia.
Hallucinations, delusions, and disorganized thought processes, short attention span
Which neurologic disorders involve biochemical abnormalities involving neurotransmitters in the brain?
Bipolar disorder, schizophrenia, Huntington's Disease
What causes a herniated intervertebral disc at the L4 to L5 level?
A protrusion of the nucleus pulposus through the annulus fibrosis
What would be the initial effect of a herniated intervertebral disc at L4 to L5 level?
Lower back pain radiating down the leg
What is the typical change in blood pressure with increased intracranial pressure?
a. Increased diastolic pressure
b. Decreasing systolic pressure
c. Systolic and diastolic pressures decreasing proportionately
d. Increasing pulse pressure
d. Increasing pulse pressure
How does the heart rate change as intracranial pressure increases?
a. Rate decreases
b. Rate increases
c. No change in rate
b. Rate increases
What is the expected effect during the period of spinal shock following a spinal injury at C5?
a. Spastic paralysis below the level of the injury
b. Urinary incontinence
c. Possible periods of apnea
d. Normal blood pressure
b. Urinary incontinence
Which statement best describes herniation resulting from increased intracranial pressure:
a. Movement of brain tissue into ventricles
b. Movement of brain stem upwards
c. Pushing of excess CSF and blood down around the spinal cord
d. Displacement of brain tissue downward toward the spinal cord
d. Displacement of brain tissue downward toward the spinal cord
Which of the following does not apply to Reye's syndrome?
a. No permanent damage in the body
b. Precipitated by a combination of viral infection and administration of ASA
c. Cerebral edema develops
d. Liver damage is common
a. No permanent damage in the body
What are common late manifestations of Parkinson's Disease?
difficulty chewing and swallowing, urinary retention, orthostatic hypotension
Regarding stroke, when may warning signs begin to appear?
warning signs may appear with partial obstruction of the artery
Regarding stroke, when do increased neurologic deficits develop?
increasing neurologic deficits usually develop during the first few days
TIA
Transient Ischemic Attack - "mini-stroke" - caused by temporary blockage due to a clot. Last under 5 minutes, leaving no lasting brain damage. Serious warning of the possibility of a real stroke.
What typical signs and symptoms do individuals with schizophrenia demonstrate?
disorganized thoughts, impaired communication; positive: delusions, bizarre behavior; negative: flat emotions, decreased speech
What physical changes occur in the brain of a person with schizophrenia?
reduced gray matter in the temporal lobes, enlarged third and lateral ventricles, abnormal cells in the hippocampus, excessive dopamine secretion, & decreased blood flow to the frontal lobes.