Chapter 26 Flashcards
Neurological disorders are associated with
abnormality of or injury to the brain
A neurologist asks about
the history of the patient and their family history
A neurologist observes
behaviors while taking the history to assess mental status, motor control, and speech abnormalities
Neurologist can perform basic
cognitive tests, such as memory and attention
The function of all 12 cranial nerves can be assessed in
about 2 minutes
Follow-up testing can use
EEG, CT, or MRI scans
Incidence of TBI is difficult to determine because
many go unreported
Males between the ages
of 15 and 30 are at higher risk of TBI from sports injuries and car accidents
following TBI
There is a long-term decrease in glucose metabolism
Open Head Injuries
Traumatic brain injuries where the skull is penetrated by an object
Closed Head Injuries
A blow to the head that does not penetrate the skull
Coup
damage to the brain at the site of the blow caused by the brain impacting with the skull
Contrecoup
damage to the brain at the side of the brain opposite the site of the blow, caused by the brain rebounding from the initial injury and impacting the skull
Shearing
the twisting or breaking of nerve fibers caused by the rapid movement of the brain inside the skull
Hematoma
mass of blood trapped in the skull
Edema
swelling that can result in pressure on the delicate nervous tissue
Effects of Closed Head Injury
Coma, impact functions located at the site of the coup or contrecoup injuries, Injuries can also result from the widespread trauma throughout the brain and are associated with loss of complex cognitive functions and efficiency
patients with closed head injuries report
difficulty concentrating, Personality and social behaviors are also impacted, Behavioral changes from head injuries may make patients more susceptible to further head injuries
Behavioral Assessment of Head Injury
Neuroimaging can provide some information about TBI, but behavioral assessments are most valuable
2 kinds of behavioral effects result from closed head injuries
- discrete impairments 2. more generalized impairments
generalized impairments
minute lesions and lacerations scattered throughout the brain, loss of complex cognitive functions, including reductions in mental speed, concentration, and overall cognitive efficiency
Discrete Impairment’s
damage to the frontal and temporal lobes, the areas most susceptible to closed head injuries
Glasgow Coma Scale
used to quantify unconsciousness and recovery of consciousness using three scales
3 scales of the Glasgow Coma Scale
eye opening, motor response, verbal response
Glasgow Coma Scale 8 or less - 9-12 - 13+
8 or less associated with severe head injury, 9-12 indicates moderate head injury, 13+ indicate mild head injury, but these individuals still experience consequences related to their injury
recovery from TBI
can occur over 2 to 3 years, but most recovery occurs within the first 6 to 9 months
Memory recovers
more slowly than other cognitive functions
If the damage involves the brainstem
the prognosis for recovery is not as good
Most head injuries are
preventable, such as using safer practices and better equipment in sports and education in the workplace
Assessment of symptoms using
smartphones and wearable technology is helping assess severity for auto accidents and combat injuries
Primary brain injuries, immediate on impact
coup, countercoup, fiber shearing or stretching, macro/microscopic lesions, Primary brain injuries, immediate on impact
Secondary injuries
Intracranial hemorrhage and edema, Ischemic or bleed-induced damage, Increased intracranial pressure or distortion, Effects of multiple injuries and hypoxia
Injurious effects, delayed
Degeneration of gray and white matter, Hydrocephalus
Epilepsy
is a brain disorder caused by seizure
Seizure
spontaneous, abnormal discharges of brain neurons as a result of scarring from injury, infections, or tumors.
Epilepsy is diagnosed after
at least one seizure, but typically after multiple seizures
Seizures occur in about
1 in 20 individuals during their lifetime
Symptomatic seizures are
associated with a known cause, such as infection, trauma, fever, or other disorder
Idiopathic seizures are
spontaneous and without any known or obvious cause
genetics and seizures
There is likely a genetic predisposition to seizures; influenced by numerous genes
Aura
a subjective sensation, perception, or motor experience associated with seizure onset
consciousness and seizures
Loss of consciousness, ranging from staring into space to complete loss
Movement
many seizures include full body movements or repetitive behaviors
Precipitating factors in susceptible individuals
drugs, emotional stress, fever, hormonal changes, hyperventilation, sensory stimuli, sleep, sleep deprivation, trauma
Classifying Seizures
EEG typically confirms the diagnosis of epilepsy
t/f not everyone with an abnormal EEG has seizures
True
Focal seizures
seizures begin in one location in the brain and the electrical activity spreads to involve other brain regions
focal aware seizures
the person is conscious throughout the seizure
focal impaired awareness seizure, or complex partial seizure
the person is generally aware that a seizure is beginning, performs automatic behaviors, has a fixed posture, and loses conscious awareness of the condition
Automatic behaviors
onreflexive actions performed without conscious volition associated with focal impaired awareness seizures
Generalized seizures
Seizure activity occurs in both hemispheres without a clear focus
Generalized seizures typically cycle through a number of stages (3)
tonic stage, clonic stage, postseizure, a postictal depression
Tonic stage
body stiffens and breathing stops
Clonic stage
rhythmic shaking occurs
postseizure, a postictal depression
during which the patient loses affect and is confused
Grand mal
also known as a generalized tonic-clonic seizure
Akinetic seizures
ordinarily seen only in children, child collapses suddenly, seizures are often of very short duration, and the child may get up after only a few seconds
Myoclonic spasm
massive seizures that basically consist of sudden flexion or extension of the body and often begin with a cry
Dissociative seizures
are seizures or attacks that feature many of the characteristics associated with focal seizures but that are accompanied by no discernable change in EEG or any other brain-scan measure
Incidence of dissociative seizures is about
2 to 3 per 10,000 people
epileptic seizures self-
terminate
when a seizure does not stop
GABA agonists or glutamate antagonists can be administered to end the seizure
Drugs are used to
inhibit the development of seizures or their propagation
drugs used to prevent seizures
GABA agonists, Sodium-channel blockers,
Most common drugs are
anesthetics and anticonvulsants
Drugs are not effective for
30% to 40% of the population, who rely on deep brain stimulation or surgery to remove the brain regions where seizures start
Tumors
Mass of new tissue that grows independent of surrounding cells and does not have a physiological purpose
Brain tumors originate from
glia or other supporting cells, as the neurons do not grow and divide
Benign tumors generally
do not reoccur after removal
malignant tumors
are progressive
Encapsulated tumors
are localized in a distinct location, but put pressure on surrounding tissue
Infiltrating tumors
interact with surrounding cells and either destroy them or interfere with their function
Meningioma
encapsulating tumor
Glioblastoma
Infliltrating tumor
Glioblastoma
Infiltrating tumor
Glioma
Any brain tumor that arises from glial cells and infiltrate the surrounding brain
Glioma accounts for
45% of brain tumors
Meningioma
An encapsulated brain tumor that grows from the meninges
Meningioma are
Benign and encapsulated
Meningioma cause symptoms by
by compressing adjacent brain tissue
Metastatic tumor
Tumor cells from elsewhere in the body start to grow in the brain
prognosis of metastatic tumor
multiple tumors that have a poor prognosis and are difficult to treat
factors of Headache
stress, neurological diseases such as tumors, or migraines
pain of headaches occurs in
dura mater, the arteries and veins of the brain, and the cranial and cervical nerves
headache Pain results from
pressure, displacement, or inflammation
Migraine impacts
5% to 20% of the population at some point in their lives
Migraines are often
Often unilateral and preceded by an aura or mood disturbance
Classic migraines
Start with an aura, thought to be caused by vasoconstriction of the cerebral arteries that results in loss of blood flow to the occipital cortex, Depolarization spreads to surrounding neurons, Headache is associated with blood flow returning to normal
Common migraines are not associated
with an aura
Cluster headaches are
unilateral and recur for days or weeks before disappearing
Muscle-contraction headaches
results from persistent contraction of the muscles of the scalp and neck due to stress
hemiplegic migraine
A migraine that leads to paralysis of one side of the body
ophthalmologic migraine
A migraine that affects vision
Nonmigrainous vascular headaches
associated with dilation of the arteries and can be caused by fever, eating disorders, high altitude, food, or chemicals
Infections
Pathogenic microorganisms that invade the brain and evoke reactions by the tissue to their presence and to the toxins they generate
treating migraines
ergotamine compounds, which block vasodilation-producing serotonin receptors on blood vessels, are often given in conjunction with caffeine
Infections kill neural cells via several processes
interference, disturbing processes, altering neuronal characteristics, pus, edema
Interference of infection
Interfering with the neuronal blood supply to produce thrombosis, hemorrhaging of capillaries, or even complete choking off of larger blood vessels.
Disturbing processes of infections
Disturbing glucose or oxygen metabolism in brain cells severely enough to kill them.
Altering characteristics of infections
Altering the characteristics of neural-cell membranes, thus changing the neurons’ electrical properties or interfering with their basic enzymatic processes, producing an array of abnormal conditions.
pus and infections
it changes the composition of the extracellular fluids surrounding a neuron, thus altering neuronal function, and its presence increases pressure on the brain, disturbing normal functioning
edema and infections
leads to compression of the brain tissues, resulting in dysfunction.
4 Types of CNS Infection
Viral infections, Bacterial infections, Mycotic infections, Parasitic infections
viral infections
A virus has an RNA or a DNA genome and invades host cells to replicate
vectors for viral infections
mosquitos for West Nile virus and Zika virus
Bacterial infections
Bacteria replicate by cell division
Bacterial meninges
the meninges are infected by the bacteria and become inflamed
Brain abscesses
are pockets of pus produced by bacteria that destroy the cells in the area
Mycotic infections
Fungal infections of the brain by yeasts, molds, and mushrooms
Is the brain resistant to mycotic infections
Normally, the brain is resistant to such infections, but can be susceptible following cancer or tuberculosis
Parasitic infections
Parasites are living organisms that live inside another organism
Malaria
a parasite transmitted by mosquitos; infects the capillaries of the brain and results in local hemorrhages
Toxoplasma gondii
causes toxoplasmosis and is transmitted from rats through domestic cats to humans who clean up after the cats
Treating CNS Infections
Many treatments involve managing symptoms more than removing the infectious agent, particularly for viruses
bacterial infections are treated well with
antibiotics
Apraxia damaged area
neocortex
Apraxia
neurological disorder characterized by the inability to perform learned (familiar) movements on command, even though the command is understood and there is a willingness to perform the movement
Ataxia damaged area
cerebellar damage
Ataxia
Failure of muscular coordination or irregularity of muscular action
Athetosis damaged area
abnormal function of the extrapyramidal system.
Athetosis
Ceaseless slow, sinuous, writhing movements, especially in the hands
Catalepsy damaged area
due to dopamine loss.
A feature of Parkinson disease, due to dopamine loss
Catalepsy
Cataplexy
Complete loss of movement and posture during which muscle tone is absent but consciousness is spared
Chorea
Literally, “to dance”; refers to a wide variety of ceaseless, jerky movements that appear well coordinated but that are performed involuntarily
Hemiplegia damaged area
contralateral motor cortex
hemiplegia
Complete or partial paralysis to one half of the body
Palsy
Usually refers to persisting movement disorders due to brain damage acquired perinatally
Paralysis
Complete loss of movement (more commonly) or sensation in a part of the body
Paralysis damaged region
permanent after damage to motor neurons; temporary after damage to motor cortex
Paraplegia
Paralysis or paresis of the lower torso and legs following spinal-cord damage.
Spasticity
Increased tone in certain muscle groups that maintain posture against the force of gravity. If the limb is moved against the rigidity, resistance will initially increase and then tone will suddenly melt .
Spasticity damaged area
damage to the extrapyramidal motor fibers.
(clasp-knife reflex)
Muscle resistance will initially increase and then tone will suddenly melt
Tardive dyskinesia
Slow, persistent movements, particularly of the mouth and tongue. Usually follows long-term treatment with antipsychotic drugs.
Myasthenia Gravis
This is a severe muscle weakness characterized by muscle fatigue after little activity or exercise
Myasthenia Gravis most common in
females than males and age of onset is typically in the 30s
first muscles to show weakness in Myasthenia Gravis
Muscles innervated by the cranial nerves are the first to show symptoms, with initial symptoms including drooping eyelids and difficulty chewing and swallowing
when do symptoms of Myasthenia Gravis occur?
Symptoms initially occur at the end of day and are relieved by sleep
Myasthenia Gravis cause
Acetylcholine receptors at the neuromuscular junction are destroyed by the immune system
Multiple Sclerosis
Myelin is attacked and destroyed in the motor and sensory tracts
Means of attach in MS
could be bacteria, viruses, or antibodies
Is myelin loss caused by MS universal
not universal, but occurs in patches throughout the nervous system
How is MS spotted
Disease tends to show symptoms, then the symptoms go away for a while, then they come back
MS is more common in
in females than males (3:2) and more common in the northern hemisphere
innervation in quadra/paraplegia
Initially, all innervation is lost, including reflexes and even thermoregulation, but some reflexes return over time
Brown–Séquard syndrome
occurs if just one side of the spinal cord is damaged, impacting only some of the ascending and descending pathways
Hemiplegia
Loss of voluntary movements on one side of the body and changes to some reflexes
Hemiplegia damage
damage to the cortex and basal ganglia contralateral to the side of motor impairment
Cases of hemiplegia
can occur in infants but mostly in older adults with high blood pressure
Babinski sign in intact individuals
they will flex their toes downward after a stimulus to the bottom of the foot
Babinski sign in intact individuals with hemiplegia
Individuals with hemiplegia extend their toes
Hyperkinetic–dystonic syndromes
increase motor activity
Hyperkinetic–dystonic syndromes (2)
huntingtons disease, Tourette’s
Hypokinetic–rigid syndrome
decreases movement
Hypokinetic–rigid syndrome (1)
Parkinsons disease
Huntington Disease
Behaviors include writhing and twisting movements (choreas), Results in intellectual deterioration and personality changes
Huntington’s age of onset
typically 30 to 50 years old
Huntington impairments
Impairments of recent memory, slowed information processing, and emotional changes such as depression and anxiety
Huntington cause
Caused by a mutation in the huntingtin gene, a dominant gene, which results in a defective protein that accumulates in the basal ganglia
Huntingtons physical characteristics of the brain
The cortex of patients shows shrinkage and thinning, particularly the basal ganglia
Role of the Basal Ganglia
Basal ganglia contain multiple pathways to influence movement
Indirect pathway of basil ganglia
inhibitory for voluntary movement
Basil ganglia and huntingtons disease
Huntington disease is associated with a decrease in activity in the indirect pathway due to cell loss in the putamen and globus pallidus, resulting in a decrease in inhibition of movement
Huntingtons disease impaired tests
Performance is also impaired on tests of frontal-lobe function
Tourette Syndrome stage I
Initially the symptoms are tics of the face, limbs, or body
Tourette Syndrome stage II
the tics are accompanied by inarticulate cries
Tourette Syndrome stage
echolalia and coprolalia are added to the tics and cries
echolalia
repeating what others have said, as well as repeating actions
coprolalia
The utterance of obscene or lewd words
Tourette syndrome does run in families, so is assumed to have
a genetic component
Tourette’s age of onset
between ages 2 and 15
physical brain makeup in individuals with Tourette’s
have a larger putamen and smaller thalamus
In addition to the tics, patients have visuospatial difficulties
on tests and in the real world
Parkinsons disease
Symptoms include tremor, muscular rigidity, involuntary movement, and postural disturbance; these can occur in different parts of the body
Parkinsons positive symptoms
describe abnormal behaviors that have been gained
Parkinsons negative symptoms
or normal behaviors that have been lost
Positive symptoms of Parkinsons
Tremors , Muscular rigidity, Involuntary movements,
Negative symptoms of Parkinsons
Postural disorders, Righting disorders, Locomotive disorders, Speech disturbances, Akinesia
Tremors
Alternating movements of the limbs when they are at rest stop during voluntary movements or during sleep
Muscular rigidity
Simultaneously increased muscle tone in both extensor and flexor muscles is particularly evident when the limbs are moved passively at a joint
Involuntary movements sometimes referred to as Akathesia or cruel restlessness
These movements may consist of continual changes in posture, sometimes to relieve tremor and sometimes to relieve stiffness but often for no apparent reason
Postural disorders
An inability to maintain or difficulty in maintaining a body part (head, limbs, and so forth) in its normal position in relation to other body parts is referred to as a disorder of fixation
Disorders of equilibrium
consist of difficulties in standing or even sitting unsupported
Righting disorders
Patients have difficulty standing from a supine position
Locomotive disorders
difficulty initiating stepping
Festination
take faster and faster steps and end up running forward.
Speech disturbances
almost complete absence of tone (prosody) in the speaker’s voice
Akinesia
poverty or slowness of movement may manifest in a blank facial expression or lack of blinking, swinging the arms when walking, spontaneous speech, or typical fidgeting movements
cause of Parkinsons
cause is unknown, or idiopathic
Postencephalitic form of Parkinsons
due to damage to cells of the substantia nigra following encephalitis
Drug-induced Parkinson disease
can result from drugs used to treat schizophrenia, and is reversible
Recreational drugs, such as a synthetic form of heroin, can cause
permanent damage to dopamine cells, resulting in Parkinsons
Parkinson disease is observed when dopamine levels
are reduced by more than 90% below normal levels
There may be a genetic influence to Parkinsonism, but
most cases are likely not genetic
is there a cure for Parkinsons?
no
Pharmaceutical treatment therapy of Parkinsons
includes l-dopa, which will cross the blood–brain barrier and be converted to dopamine to supplement what has been lost
Monoamine oxidase inhibitory and tricyclic antidepressants enhance
dopamine neurotransmission
Anticholinergic drugs are used to block the
acetylcholine signaling that increases when dopamine decreases
Newer treatments for parkinsons include
DBS, stem cells to replace lost dopamine neurons
Cerebral Vascular Disorders
Damage to the blood vessels can reduce or eliminate blood flow to a region
Cerebral Vascular Disorders damge
most often occurs in the arteries, due to the higher blood pressure
Cerebral vascular accident (stroke)
sudden appearance of neurological symptoms as a result of blood supply being interrupted
infarct
is the region of the brain that is directly impacted by the stroke and is characterized by dead and dying cells
Types of Cerebral Vascular Disorders
Cerebral ischemia
Migraine stroke
Cerebral hemorrhage
Cerebral hemorrhage
Blood vessel fails, resulting in bleeding into the brain
Cerebral hemorrhage causes
high blood pressure, trauma, or toxic chemicals
Migraine stroke
Blood flow is interrupted by a constriction of the blood vessel
Migraine stroke causes
Cause of the vascular spasm is not known
Cerebral ischemia
Blood vessel is blocked, preventing enough blood from reaching the brain
thrombosis
a clot in the vessel that has remained where it was formed
Embolism
a clot or other plug that formed in a larger vessel and got stuck in a smaller vessel
cerebral arteriosclerosis
arteries thicken and harden, restricting blood flow
Angiomas
Abnormal blood vessels that divert the normal flow of blood Result in abnormalities in the pattern and amount of blood flow
Aneurysms
The walls of blood vessels are normally elastic to withstand the blood pressure, An aneurysm is a region where that elasticity is defective, leading to the vessel walls ballooning out and weakening the structure of the vessel
Treating Cerebral Vascular Disorders
Ideal treatment is to restore blood supply, but this is not always possible
drugs to prevent cell death
Drugs to block excitation and calcium channels can be effective to block cell death
how to handle and aneurism
Surgery to support an aneurysm or remove blood that is putting pressure on surrounding tissue may be effective
