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Neurological System Disorders
Quiz - definitions done
56
Nursing
Undergraduate 1
11/14/2012

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Cards

Term

Increased Intracranial Pressure

(IICP)

Definition

may result from anything that takes up volume in the brain

 

eg. tumuor, edema, excess CSF or hemorrhage

Term
4 Stages of Intracranial Hypertension
Definition

Stage 1: Vasoconstriction and external compression of the venous system occur in order to decrease the ICP (may be asymptomatic)

 

Stage 2: when continuing swelling exceeds this compensatory mechanism, oxygenation is compromised (confusion, drowsiness), and systemic vasoconstriction occurs to increase systemic blood presure in order to overcome decreased flow in the brain

 

Stage 3: with continued swelling, when ICP begins to equal arterial pressure, cerebral perfusion pressure falls, and hypoxia and hypercapnia of brain tissue occur (rapid deterioration: small sluggish pupils); all compensatory mechanisms have been used and dramatic rise in ICP over a very short period of time

 

Stage 4: brain tissue shifts (herniates) from the compartment of greater pressure to a compartment of lesser pressure; this increases pressure in the lower compartment and impairing its blood supply; therefore, ICP increased to where it equals systolic arterial pressure at w/c point cerebral blood flow ceases

Term
Cerebral Edema
Definition

- an increase in the fluid content of brain tissue

- occurs after trauma, infection, hemorrhage, tumour

- distorts blood v., displaces brain tis, causes herniation

 

- caused by:

- increased permblty of BBB

- toxins cause failure of transport mechanism of cells so more Na+ inside cell and more H20 inside cell: occurs in gray matter

- obstruction of circulation of CSF in ventricles so fluid leaks into surrounding brain tissue

Term
Hydrocephalus
Definition

- excess fluid in ventricles, subarachnoid space, or both

 

- caused by:

- too high production of CSF eg. tumour in choroid plexus

- obstructed flow thru ventricles eg. aqueduct stenosis

- too low reabsorption of CSF eg. interference w/ arachnoid villi


- develops over time but can occur rapidly as a result of brain injury

Term
3 characteristics of neuromotor dysfunction
Definition

1. alterations in muscle tone

- can result in a spectrum fr. flaccidity (hypotonia) to rigidity (hypertonia)

- dystonia - sustained invol. twisting movement of the hand and foot


2. alterations in movement

- paresis

- paralysis

- hyperkinesia


3. alterations in complex motor performance

- includes 3 types:

- disorders of posture: decorticate, decerebrate

- disorders of gait: spastic gait

- disorders of expression: hypermimesis, dyspraxia/apraxia


Term
Hypotonia
Definition
flaccidity
Term
Hypertonia
Definition
rigidity
Term
Dystonia
Definition
sustained involuntary twisting movement of the hand and foot
Term
Paresis
Definition
partial paralysis = weakness
Term
Paralysis
Definition

- loss of motor neuron fxn so that a muscle gr. is unable to overcome gravity

 

- occur in both upper (brain/spinal cord) and lower (cranial/spinal nerves) motor neurons

- for upper: hemiparesis/hemiplagia, paraparesis/paraplagia, quadriparesis/quadriplegia

Term
Hyperkinesia
Definition

- excessive movements eg. tremors, tics

 

- due to physical or chemical causes eg. insufficient dopamine

Term
Decorticate
Definition

- upper extremities flexed at the elbows and held close to the body and lower extremities are externally rotated and extended

 

- may occur w/ cerebral hemisphere damage

Term
Decerebrate
Definition

- increased tone in extensor muscles and trunk muscles, w/ clenched jaw and extended neck so head in neutral position, all four limbs rigidly extended

 

- occurs w/ brain stem lesions

Term
Spastic Gait
Definition

- a shuffling gait w/ leg extended and held stiff

Term
Hypermimesis
Definition
- inappropriate laughter or crying
Term
Dyspraxia/apraxia
Definition

- inability performing tasks that require learned motor skills (speaking, writing, using tools, following instructions)

 

- problem is w/ use of muscles, not w/ comprehension

Term
Closed brain trauma
Definition

- dura remains intact

- may result in both focal brain injuries (one area) or diffuse axonal injuries (more than one area)

Term
Open brain trauma
Definition

- break in the dura

- resulting in exposure of the cranial contents to the environment

Term
Contusions
Definition

- bruises in brain tissue

- blood leaking fr. injured blood vessels

 

- edema occurs around/in damaged area as well as infarction, necrosis, hemorrhage

- effects peak 18-36 hr after injury

- sequence of events:

- immediate loss of consciousness

- loss of reflexes

- brief period of no respiration

- brachycardia

- decrease in BP

- vital signs may stabilize in a few sec.

- reflexes and consciousness return

- residual effects may persis

 

- eg. extradural (epidural) hematomas, subdural hematomas, intracerebral hematomas

 

Term
Coup injury
Definition

- impact against the object, causing direct trauma to brain at point of impact

Term
Contrecoup injury
Definition

- impact w/in skull, causing impact injury at area opposite to object, and shearing forces through the brain

 

- fr. head bouncing off object of initial impact

Term
Extradural (epidural) hematomas
Definition

- injury causes bleeding bet. the dura mater and the skull due to arterial bleeding

Term
Subdural hematomas
Definition

- bleeding bet. the dura mater and the brain

- acute caused by traumatic injury develop rapidly, commonly w/in hrs

- chronic (due to accompanying cond.) develop over weeks to months

Term
Intracerebral hematomas
Definition

- bleeding w/in the brain

- penetrating injury or shearing forces traumatize small blood v.

- may be delayed, appearing 3-10 days after injury

Term
Penetrating brain trauma
Definition

- projectiles and debris fr. scalp and skull injury/fracture penetrate dura mater

Term

3 Mechanisms produce brain damage

Definition

1. Primary

a. focal brain injury: contusions - coup, contrecoup

- ex of contusions:

- extradural hematomas

- subdural hematomas

- intracerebral hematomas

- penetrating brain trauma


b. diffuse brain injury: diffuse axonal injury (DAI) - concussion

- categories:

- mild concussion

- classic cerebral concussion

- mild DAI

- moderate DAI

- severe DAI


2. Secondary - indirect result of primary trauma

- mechanisms:

- cerebral edema

- IICP

- decreased cerebral perfusion pressure

- ischemia

- brain herniation

- brain damage occurs hrs. to days after primary trauma


3. Tertiary



Term
Focal brain injury
Definition

- specific, grossly observable brain lesions that occur in a precise location

Term
Diffuse brain injury
Definition

- concussion, result of shaking, rotational and twisting movements

- involves widespread area of the brain, w/ damage to axonal fibers - can be observed only with microscope

 

- reduces the speed of informational processing

Term
Mild concussion
Definition

- no loss of consciousness but CSF pressure increases

- confusion lasts for several mins, retrograde amnesia

Term
Classic cerebral concussion
Definition

- loss of consciousness for up to 6 hr. 

- confused state lasts for several hrs., headache, nausea, retrograde amnesia

Term
Mild DAI
Definition

- 6-24 hr coma

- may display decerebrate or decorticate w/ extended periods of stupor/restlessness

Term
Moderate DAI
Definition

- >24hr coma

- may display above posturing w/ unconsciousness lasting days or weeks

- on awakening, permanent deficit in memory, reasoning, language, etc.

Term
Severe DAI
Definition

- emerge fr. coma in the first 3 months after injury

- initial injury eventually results in compromised coordinated movements, verbal and written communication skills, inability to learn and reason

Term
Cerebrovascular disorders
Definition

- abnormality of the brain caused by a pathologic process in the blood v. 

- vessel wall lesions

- occlusion of the v. lumen by thrombus or embolus

- rupture of the v.

- alteration in blood quality eg. increased blood viscosity

 

- result can be either ischemia w/w/o infrctn/hmorrhage

- leads to cerebrovascular accident or stroke

 

- risk factors: arterial hypertension, smoking, diabetes, insulin resistance, polycythemia

Term
Thrombotic Stroke
Definition

- occlusions formed by thrombi developing in arteries supplying the brain

- develop as a result of atherosclerosis, after plaque ruptures and a clot is formed

- piece of thrombus detaches and lodges in vessel upstream, causing acute ischemia

Term

Transient ischemic attack

(TIA)

Definition

- a brief episode of neurologic dysfunction caused by a focal disturbance of brain w/ symptoms lasting less than 1 hr, no evidence of infarction and complete clinical recovery

 

- result of platelet clumps or vessel narrowing w/ spasm, causing an intermittent blockage of circulation

 

- no treatment, high risk of repeat occurrence and eventual stroke

Term
Embolic Stroke
Definition

- involves fragments that break fr. a thrombus formed outside the brain

- may plug lumen of small vessel entirely or may shatter

- a second stroke usually follows b/c the source of emboli continues to exist

Term
Hemorrhagic stroke
Definition

- a mass of blood forms and grows to displace adjacent brain tissue

- associated w/ increased systolic and diastolic pressures over several years

- causes include hypertension, ruptured aneurysms, trauma

Term
Intracranial aneurysm
Definition

- size vary fr. 2mm-2/3cm, classified on the basis of shape

- asymptomatic; first indication is an acute subarachnoid hemorrhage and/or intracerebral hemorrhage

- rupture thru thin areas, causing hemorrhage, producing local changes in cerebral cortex

- produces painful headache or unconsciousness or both

Term
Multiple Sclerosis
Definition

- acquired autoimmune inflammatory disorder

- involves destruction of axonal myelin in the CNS

 

- onset usually bet. 20-40 yrs/more common in women

- symptoms include paresthesias of the face, trunk or limbs, weakness, visual disturbances

Term

Alzheimer Disease


Definition

- most common causes of severe cognitive dysfunction in older persons and the leading cause of dementia

- cause is unknown

- plaques form bet. neurons and protein containing tangles form inside neurons, damaging and killing neurons, disrupting nerve impulse transmission

- forgetfulness, emotional upset/illness, memory loss, behavioral changes

- no cure

Term
Types of Stroke
Definition

1. Thrombotic stroke - occlusions by thrombi in arteries supplying the brain

2. Embolic stroke - fragments that break fr. a thrombus formed outside the brain

3. Hemorrhagic stroke - mass of blood forms and grows to displace adjacent brain tissue

Term
Alterations in arousal
Definition

1. Structure: infections, neoplasms, trauma, etc.

 

2. Metabolism: hypoxia, drugs, electrolytes disturbances

 

3. Psychogenic: uncommon, through psychiatric disorder

Term
Glasgow coma scale
Definition

- a method used for assessing level of consciousness in person w/ brain injury

- numbered scores given to responses of eye opening, verbal utterances, and motor responses

Term

Evaluation of arousal

- to determine the extent of brain dysfunction

Definition

1. level of consciousness

2. patterns of breathing

3. pupillary changes

4. oculomotor responses

5. motor responses

Term

Persistent vegetative state

(PVS)

Definition

- complete unawareness of self or the surrounding environment

- sleep-wake cycles are present, brain stem reflexes are intact but bowel and bladder incontinence

Term
Locked-in syndrome
Definition

- complete paralysis of vol. muscles except the eye movements

- fully consciousness w/ intact cognitive fxn but can't communicate thru speech or body movements

Term
Outcomes of alterations in arousal
Definition

1. brain death - no recovery

2. cerebral death - irreversible coma

3. PVS - unawareness of self and environment

4. minimally conscious state - follow simple commands

5. locked-in syndrome - paralysis of vol. muscles

Term
Alterations in awareness
Definition

- include all cognitive fxns

- caused by destruction of tissue caused by hypoxia/ischemia or compression, or effects of toxins/chemicals

- involved:

- selective attention

- memory

- executive attention deficits

Term
Seizure
Definition

- sudden temporary change in motor, sensory, autonomic or psychic clinical manifestations and a temporary altered level of arousal - convulsions (jerky movements)

- results fr. a sudden, explosive, disorderly discharge of cerebral neurons

- caused by cerebral lesions, biochemical disorder, cerebral trauma and epilepsy

Term
Agnosia
Definition

- inability to recognize the form/nature of objects

- affects one sense

- caused by any damage to a specific part of the brain

Term
Dysphasia
Definition

- inability to understand or use of symbols (written/verbal)

- caused by dysfuxn in left cerebral hemisphere

 

Term
Aphasia
Definition
- inability to communicate
Term
Acute confusional states
Definition

- inability to concentrate on incoming sensory info.; highly distractible

- caused by drug intoxication, nervous system disease, trauma, surgery, etc.

Term
Dementia
Definition

- progressive failure of cerebral functions such as orienting, memory, language, judgment and decision-making

- accompanied by behavioral alterations

- caused by neuron degeneration, atherosclerosis, trauma, infection

Term
3 injury states in cerebral blood flow
Definition

1. inadequate cerebral perfusion

2. normal cerebral perfusion w/an elevated intracranial pressure

3. excessive cerebral blood volume

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