Transcript Sensory Disorders

Neurological Disorders
Dr. Kline
FSU-PC
I. Neurological Disorders
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The normal functioning of the CNS can be
affected by a number of disorders, the most
common of which are headaches, tumors,
vascular problems, infections, epilepsy,
head trauma, demyelinating diseases, and
metabolic & nutritional diseases.
A. Vascular Diseases in the brain:
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Minor to total reduction in blood flow to the neurons
deprives the cells of oxygen & glucose, resulting in
interference with cellular metabolism.
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Disruption of cellular metabolism, caused by reduced
blood flow, lasting longer than 10 min. , results in cell
death for neurons in that brain region.
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These disorders account for most common causes of
death & chronic disability in the Western world.
1. Stroke (Cerebral vascular accident)
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Results from severe severe interruption of blood
flow to the brain (usually affecting arteries).
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The onset of a stroke may span days to years,
often with little-to-no warning.
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A stroke produces an infarct (area of dead or
dying tissue resulting from obstruction of blood
vessels normally supplying area).
What factors influence the severity of deficits
resulting from a stroke?
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Location of the blockage
Size of the blood vessels
--prognosis is better if blockage occurred in
small vessels rather than larger vessels.
Relative health of surrounding vessels
Age of patient (younger has better chance of
recovery)
How quickly patient is seen following stroke
2. Cerebral Ischemia- insufficient supply of
blood to brain, are like mini-strokes.
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Decreases in blood flow result of 3 causes:
A. Thrombosis-a plug or clot in a blood vessel that
remains at its point of formation.
B. Embolism -moving (clot, bubble of air, sack of
cells, or fat deposit) from larger vessel into a smaller
vessel.
--often effect middle cerebral artery of left side of
brain which is near speech comprehension for many.
C. Cerebral arteriosclerosis-thickening & hardening
of arteries that reduces blood flow.
3. Migraine Stroke
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People with classic migraines often experience a transient
ischemic attack with some neurological symptoms. These
include:
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Impaired sensory functioning (vision)
Numbness of skin
Difficulties in moving & aphasia (Language Disorder)
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*Account for a significant proportion of strokes in young
people under 40.
 *Occurs more in females than males.
*Cause is unknown (may be vasospasm).
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4. Cerebral Hemorrahage
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Massive bleeding in the brain. Onset is abrupt &
may be quickly fatal. Prognosis often poor.
Causes:
 Hypertension
 Congenital defects of cerebral arteries
 Leukemia & other blood disorders
 Toxic chemicals
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5. Aneurysms
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Vascular dilations resulting from localized
defects in the elasticity of the vessel.
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The vessels distend like a “balloon” until
they are vulnerable to rupture.
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Most common symptom is severe headache,
often present for many months to years.
Treatment for vascular disorders:
Drug therapy (anticoagulants to dissolve clots or
prevent clotting)
 Vasodilators to dilate vessels
 Drugs used to treat hypertension
 Salty solutions to reduce edema in brain
 Surgery to repair damaged vessels; total removal
of aneurysm.
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B. Head Trauma Injuries
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Brain injury from head trauma is most common
form of brain damage in people under 40.
There are two types of Head Trauma Injuries:
 Open-head & closed-head injuries.
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Ways in which Head trauma may damage
the brain:
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1. By directly damaging neurons & support cells (e.g.,
gunshot wound).
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2. By causing blood flow disruption leading to a stroke
(closed-head injury).
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3. By causing bleeding in the brain which causes the
brain to swell.
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4. By making the brain vulnerable to infection (openhead injuries).
1. Open-Head Injuries:
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Results from injury to brain in which the skull is
penetrated either by projectiles (gunshots/missile
wounds) or other moving objects.
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Most people with open-head injuries do not lose
consciousness & produce distinctive symptoms that
may undergo rapid & spontaneous recovery.
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Deficits are specialized & often resemble those of
surgical excisions.
2. Closed-Head Injuries
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Caused by a blow to the head (car accident,
blunt instrument swung at head).
Damage may be three-fold:
 A. Damage at site of blow is called a coup.
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B. The brain may shift & hit the opposite side
of the skull producing an additional bruise
(contusion) known as a countercoup.
Closed-Head Injuries (Contd.)
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C. The brain may suffer additional damage, resulting
from shearing of nerve fibers which produce
microscopic lesions.
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Frontal & temporal areas are most likely to be
damaged in closed-head injuries.
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These injuries are commonly accompanied by loss of
consciousness (from damage to brainstem fibers),
edema (swelling), & hemorrhaging.
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Length of coma often is positively correlated with
severity of damage.
Behavioral impairments resulting from
closed-head injuries:
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1. Discrete impairment of functions mediated by
brain regions that sustained direct impact (coup
& countercoup).
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2. Microscopic lesions caused by shearing of
neurons results in widespread damage.
Mental recovery from Closed-Head Injury:
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Most mental recovery occurs rapidly in the first 6-9
months following injury.
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Memory functions recover more slowly than general
intellectual functions. Depending on length of coma &
amnesia following injury, prognosis may be very good.
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Personality changes may be pronounced; person may
be less likely to recover their personality than they are
to recover general intellectual functioning.
C. Epilepsy
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Results from recurrent seizures (disruptions in neural
firing) of various types that disturb consciousness.
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Seizures may be classified based on potential cause:
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---Symptomatic seizures-caused by infection, trauma,
tumor, toxic chemical, vascular problem, etc.
----Idiopathic seizures- appear spontaneously; with no
apparent cause.
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Symptoms of Epilepsy
1. An aura or warning of a seizure that’s
about to occur.
 E.g., may be an odor, noise, or visual image
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2. Loss of consciousness (ranges from complete
collapse to staring off into space).
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3. Movements (ranging from minor such as
small twitching to large convulsions).
Types of Epilepsy
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1. Focal seizures- seizures occur in a locus
(particular place in brain) & then spread.
E.g., symptoms may start with twitching in one
digit of the hand and quickly spread to the other
fingers & arm.)
2. Complex partial seizures – usually originate
in the temporal lobe (sometimes the frontal
lobe).
Stages of Complex partial seizures
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1. Subjective feelings, forced thoughts, alterations in
mood, dejavu
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2. Automatisms, which are stereotyped repetitive
movements such as lip smacking, chewing, fidgeting.
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3. Postural changes in which person may assume
catatonic postures.
3. Generalized seizures
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Are bilaterally symmetrical without local onset.
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Grand Mal attack is accompanied by loss of
consciousness, stereotyped motor behavior.
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4. Petit mal attack- Brief loss of awareness
during which there is little motor activity such as
blinking, turning the head, rolling the eyes, etc.
Treating Epilepsy
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1. Anticonvulsant drugs are used to treat this.
(E.g., Dilantin, phenobarbital, etc.)
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Mode of action is unknown, may work by
stabilizing weak neural membrane in abnormal
cells.
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2. Surgery to remove focus of epilepsy if known.
D. Brain Tumors
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A mass of cells that grow & have no use.
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Brain tumors grow from glia & other support
cells, not the neurons themselves.
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Tumor growth varies depending on type of
tumor, where its located, & type of cell that it
grows from.
Types of Brain Tumors
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1. Gliomas- tumors that arise from glial cells &
infiltrate the brain. May be benign to malignant.
About 45% of all tumors are gliomas.
 A. Astrocytomas-result from growth of
astrocytes. Usually not malignant & may be
treated fairly easily. Prognosis is good.
 B. Glioblastomas-highly malignant, rapidly
growing.
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2. Meningiomas- attached to meninges. Are
encapsulated on outside of brain. Usually
benign.
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3. Metastatic Tumors- a tumor that results in
the brain from tumor cells carried from the body
elsewhere (breast, liver, lung, etc.).
Treatment for tumors
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Surgery to remove tumors if operable.
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Radiation to reduce or shrink tumors.