Neuro Anaphy

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B. PATHOPHYSIOLOGY

1.) Anatomy and Physiology

FUNDAMENTALS OF NERVOUS SYSTEM CONDUCTION

Within the brain and nervous system are specialized cells, known as neurons. The

neurons are responsible for delivering chemical messages to other cells to achieve some

response. This is the basis of how our nervous system works. Within the brain, there are

approximately 100 billion neurons. Neurons are typically classified by the direction that they

send information. Sensory, or afferent, neurons send impulses from sensory receptors in the

periphery or some organ to the central nervous system. Motor, or efferent, neurons send impulses

away from the central nervous system to muscles or glands.

Neurons have specialized extensions called dendrites and axons. Dendrites bring

information to the cell body (soma) and axons take information away from the cell body. Some

neuronal axons are myelinated (have a fatty substance coating them that speeds impulse

transmission) and some are not. Nodes of Ranvier are short unmyelinated segments of an axon.


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Neurotransmitters then cross the synapse where they may be accepted by the next

neurons receptor site. The action that follows activation of a receptor site may be either

depolarization (excitatory in nature) or hyperpolarization (inhibitory in nature). If the neuron is

depolarized, its response is excitatory. If the neuron is hyperpolarized, the response is inhibitory.

There are three major categories of substances that act as neurotransmitters. They are

amino acids, peptides, and monoamines, plus acetylcholine. The major neurotransmitters of the

brain are glutamic acid and GABA. The peripheral nervous system has only two

neurotransmitters. They are acetylcholine and norepinephrine. Neurotransmitters vary greatly in

the response they enact upon particular cells or receptor sites. Acetylcholine, for example, can be

excitatory or inhibitory depending upon which receptor site it binds to. The following is a list of

several known and well-studied neurotransmitters.

Neurotransmitter Function

Acetylcholine Mostly excitatory

Dopamine Excitatory and inhibitory

Epinephrine Excitatory

Norepinephrine Excitatory

Serotonin Excitatory

Glutamate Excitatory

Glycine Mostly inhibitory

g-Aminobutiric acid (GABA) Inhibitory


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The meninges cover the brain and spinal cord and protect them as well. There are three

meningeal layers. They are the dura mater, arachnoid mater, and pia mater.

Courtesy of the National Cancer Institute,2004www.nci.gov

Dura Mater

The dura mater is the outer, tough layer of the meninges. It lines the inside of the skull.

The dura mater also separates specific portions of the brain. The falx cerebri is a portion of the

dura mater that separates the right and left hemispheres of the brain. The tentorium cerebelli is a

portion of the dura mater that separates the cerebrum from the cerebellum (AACN, 1998).

Arachnoid Mater

The arachnoid mater is the middle layer of meninges.It is a web-like structure that allows the passage of blood vessels and through it. Between the

arachnoid mater and the pia mater, is the subarachnoid space. Cerebral spinal fluid (CSF) flows
http://www.nci.gov/http://www.nci.gov/


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subarachnoid space, as discussed earlier is the space below the arachnoid, between the arachnoid

and the pia mater (AACN, 1998).

THE BRAIN

The brain in an adult is one of the bodys largest organs. It weighs about three pounds

and is divided into four major parts: the cerebrum, diencephalon, brain stem, and cerebellum

(Tortora, 1989).

Cerebrum

The cerebrum is the largest portion of the brain. It covers the diencephalon. The surface

of the cerebrum is composed of gray matter and is known as the cerebral cortex. During

embryonic development the gray matter grows in increased proportion to the underlying white

matter. This increased growth rate causes the gray matter to fold into itself and create

convolutions known as gyri.

The deep grooves between the folds are known as fissures. The shallow grooves between

the fold are known as sulci. The most noticeable fissure is the one that nearly separates the right

and left hemispheres of the brain the longitudinal fissure. The hemispheres remain connected

by the corpus collosum, a transverse bundle of nerve fibers. Additionally, between the

hemispheres is an extension of the dura mater known as the falx cerebri.

Each cerebral hemisphere is subdivided into lobes. The central sulcus separates the

frontal from the parietal lobe The frontal and the temporal lobes are separated by the lateral


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The precentral gyrus, is located immediately anterior to the central sulcus and is the

major motor area of the brain. The post central gyrus is located immediately posterior to the

central sulcus and is the major motor area of the brain.

White Matter -The white matter that is underneath the cerebral cortex and consists of

three different types of nerve fibers. Association fibers transmit impulses between gyri in

the same hemisphere. Commisural fibers transmit nerve impulses from gyri on one

hemisphere with the corresponding gyri in the opposite hemisphere. Finally, protection

fibers transport nerve impulses from parts of the cerebrum to other parts of the brain and

spinal cord (Tortora, 1989).

Limbic System - The limbic (border) system is composed of certain components of the

cerebrum and the diencephalons. The components of this system are the limbic lobe, the

hippocampus, amygdaloid nucleus, the mamillary bodies of the hypothalamus, and the

anterior nucleus of the thalamus. Basically, the limbic system encircles the brainstem and

functions in the emotional aspects of behavior that are essential to our survival. It also

plays a role in memory, although the exact mechanism is not understood fully. The limbic

system is also thought to play some part in how we sense pleasure, pain, anger, rage, fear,

sadness and sexual feelings. Because of its role in these core emotions, it is also known as

the visceral or emotional brain (Tortora, 1989).


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Parietal Lobe - The parietal lobe is located behind the central sulcus. It is concerned with

perception of stimuli related to touch, pressure, temperature, and pain. The parietal lobescan be divided into two functional regions, involving sensation and perception. The

overall role of the parietal lobe is to integrate sensory information to form a single

perception (cognition) (Kandel, Schwartz and Jessel, 1991).

Temporal Lobe - The temporal lobe is located below the lateral fissure. It is concerned

with sensory perception and recognition of auditory stimuli (hearing) and memory

(hippocampus) (Read, 1981; Tortora, 1989). Individuals with temporal lobes lesions have

difficulty placing words or pictures into categories. The temporal lobes are highly

associated with memory skills and language. Temporal lobe damage may result in

impaired memory, difficulty recognizing words or speaking, and recall of non-verbal

stimuli such as music or drawings (Tortora, 1989).

Occipital Lobe - The occipital lobe is located at the back of the brain, behind the parietal

lobe and temporal lobe. It is concerned with many aspects of vision. Lesions or damage

to the occipital lobe typically results in visual changes, even producing visual

hallucinations.


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system. The hypothalamus is also known as the master gland of the endocrine system,

for this reason. It produces and releases hormones that stimulate the pituitary gland. This

connection or relationship with the pituitary gland is referred to as the hypothalamic-

pituitary axis. The three major hormones that stimulate the hypothalamus are growth

hormone releasing hormone (GRH), thyrotropic releasing hormone (TRH), and

corticotropin releasing hormone (CRH) (AACN, 1998). These hormones travel to the

pituitary via the hypothalamic pituitary stalk. Once in the pituitary, they act to produce or

release other hormones from the pituitary gland. The hypothalamus is also responsible for

the mind over body phenomenon. When strong emotions are produced by the cerebral

cortex, nerve impulses travel down through the hypothalamus to the body. Likewise,

continued psychological stress traveling upward through the hypothalamus may produce

long-term, very, real, systemic illnesses. The hypothalamus also plays a role in feelings

such as rage and aggression and regulates body temperature, hunger, thirst, sleep and

wake cycles.

Brain Stem

The brain stem consists of the medulla oblongata, pons, and mid-brain, or

mesencephalon.


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Pons - Pons means bridge. The pons is the bridge that connects the spinal cord with the

brain and certain parts of the brain with each other. These connections occur via fibersthat run in two major directions. The transverse fibers connect with the cerebellum. The

longitudinal fibers connect the spinal cord or medulla with the upper parts of the brain

stem.

Mid-Brain - The mid-brain, or mesencephalon, extends from the pons to the lower

portion of the diencephalons. The cerebral aqueducts travels through the mid-brain and

connects the third and fourth ventricles. Within the midbrain, there are nerve fibers that

convey nerve impulses from the cerebral cortex to the pons and spinal cord. The mid-

brain also has some reflex centers that control eye, head, and neck movements. The mid-

brain is also the origin of cranial nerves II and IV (Tortora, 1989).

The Reticular Activating System - The reticular activating system is so named because it

resembles the reticular system of a leaf. It is a network of neurons located in the central

core of the brainstem that serves to monitor the state of the body in functions such as

arousal, sleep, and muscle tone. The reticular activating system is the attention center in

the brain. The reticular activating system is connected at its base to the spinal cord where

it receives information projected directly from the ascending sensory tracts. The brain

stem reticular formation runs all the way up to the midbrain. As a result, the reticular

activating system serves as a point of union for signals from the outside world to our


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Cerebrospinal Fluid

The cerebral spinal fluid, or CSF, protects and cushions the brain from injury. The CSF

acts as a shock absorber from injuries that would normally send the brain crashing up against the

inside of the skull. By nature of its circulatory abilities, it also delivers nutrients filtered from the

blood to the brain and spinal cord and removes wastes and toxic substances produced by the

brain and spinal cord (Tortora, 1989).

It circulates in the subarachnoid space, around the brain, the spinal cord and the ventricles

of the brain. The ventricles, like the hearts ventricles are spaces. In the brain, there are two

lateral ventricles located in each hemisphere of the brain, just under the corpus collosum. There

is a third ventricle just in between and below the thalamus. Finally, there is a fourth ventricle,

just below the brain stem and beside the cerebellum. All four ventricles may circulate CSF

between them by way of foramen (narrow oval openings), aqueducts (canal-like passages), and

apertures (openings) (Tortora, 1989).


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unites the anterior and posterior blood supply to the brain. This is a unique mechanism of

cerebral circulation that allows the brain to have a backup system if one source of blood is

interrupted.

The cerebral arteries arise from the Circle of Willis and supply specific areas of the brain.

The posterior cerebral artery (PCA) supplies blood to the occipital lobe, midbrain, thalamus, and

part of the temporal lobes.

The middle cerebral artery (MCA) supplies blood to parts of the frontal, parietal and

temporal lobes. The anterior cerebral artery (ACA) supplies blood to different areas of the

frontal parietal and temporal lobes (AACN 1998)


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components of cranial nerves transmit nerve impulses from the brain to target tissue outside of

the brain. Sensory components transmit nerve impulses from sensory organs to the brain.

A summary of the functions of the cranial nerves is listed in the table below.

Cranial Nerve Major Functions

Cranial Nerve I: Olfactory Sensory Smell

Cranial Nerve II: Optic Sensory Vision

Cranial Nerve III: Oculomotor Sensory and Motor

Primarily Motor

Eyelid and eyeball

movementCranial Nerve IV: Trochlear Sensory and Motor

Primarily Motor

Innervates superior

oblique

Turns eye downwardand laterally

Cranial Nerve V: Trigeminal Sensory and Motor ChewingFace and mouth touch

and pain

Cranial Nerve VI: Abducens Sensory and Motor Primarily Motor

Turns eye laterallyProprioception

Cranial Nerve VII: Facial Sensory and Motor Controls most facialexpressions

Secretion of tears and

saliva and Taste

Cranial Nerve VIII: Vestibulocochlear

(auditory)

Sensory Hearing

Equilibrium sensationCranial Nerve IX: Glossopharyngeal Sensory and Motor Taste

Senses carotid blood

pressure


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proprioception

Spinal Cord

The spinal cord is the primary structure that connects the brain and peripheral nervous

system. It is protected by the vertebrae of the spinal column. The spinal cord is located in the

vertebral foramen and is made up of 31 segments: 8 cervical, 12 thoracic, 5 lumbar, 5 sacral and

1 coccygeal vertebrae. While a pair of the spinal nerves exit from each segment of the spinal

cord, the spinal cord itself extends down to only the last of the thoracic vertebrae. The spinalnerves that branch from the spinal cord from the lumbar and sacral levels must run in the

vertebral canal for a distance before they exit the vertebral column. This collection of nerves in

the vertebral canal is called the cauda equina (horses tail).


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Reflexes are rapid, involuntary responses to stimuli which are mediated over simple

nerve pathways called reflex arcs. Involuntary reflexes are very fast, traveling in milliseconds.

The fastest impulses can reach 320 miles per hour (Sherwood, 1997). Reflexes can be

categorized as either autonomic or somatic. Autonomic reflexes are not subject to conscious

control, are mediated by the autonomic division of the nervous system, and usually involve the

activation of smooth muscle, cardiac muscle, and glands. Somatic reflexes involve stimulation of

skeletal muscles by the somatic division of the nervous system.

When peripheral reflexes are intact, a sensory stimulus travels to the spinal cord. That

stimulus is then converted to a motor stimulus within the spinal cord. The motor stimulus travels

back to the site of sensory input and usually causes muscle contraction. An example is the knee-

jerk reflex or placing your hand on a hot stove. The sensory stimulus does not need to travel all

the way to the brain to be interpreted and then back to the site of potential injury (Sherwood


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PERIPHERAL NERVOUS SYSTEM

The peripheral nervous system is subdivided into the somatic nervous system and the

autonomic nervous system. The somatic nervous system consists of the twelve pairs of cranial

nerves and thirty-one pairs of spinal nerves.

Somatic Nervous System

The somatic nervous system is typically under voluntary control. The somatic nervous

system includes all nerves controlling the muscular system and external sensory receptors. The

somatic nervous system has both motor and sensory divisions. Motor fibers are efferent fibers

which innervate skeletal muscle. They are present in spinal nerves and cranial nerves III, IV, VI

and XII and terminate at the skeletal muscles. Sensory fibers are afferent fibers that relay

sensations such as touch, pain and temperature from the skeletal muscles via peripheral, spinal,

and cranial nerves V, VII, IX and X to the central nervous system (Tortora, 1989).

Autonomic Nervous System

In contrast, the autonomic nervous system is not voluntary. It is also a good thing it is

not. If it was voluntary, we would have to think about every heart beat we had, the amount of

blood we delivered to specific tissues, the dilation of our pupils, and how much digestive

motility our gastrointestinal tract needed. In other words, the autonomic nervous system

regulates the activities of the internal organs (Sherwood, 1997).

The autonomic nervous system has two main parts, the sympathetic and the

parasympathetic systems These two opposite systems often operate in opposition to each


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muscles (Tortora, 1989). Sympathetic stimulation also dilates the pupils, dilates the trachea and

bronchi, stimulates the conversion of glycogen into glucose, inhibits peristalsis in the

gastrointestinal tract, and inhibits contraction of the bladder and rectum. The overall effect of

sympathetic activation is to increase cardiac output, systemic vascular resistance (both arteries

and veins), and increase arterial blood pressure. Enhanced sympathetic activity is particularly

important during exercise, emotional stress, and during hemorrhagic shock (AACN, 1998;

Sherwood, 1997).

Parasympathetic Nervous System

When the parasympathetic system is activated, it works to decrease heart rate,

contractility, and conduction velocity of the myocardial tissue via the vagus nerve, cranial nerve

X. Parasympathetic nerves mainly innervate salivary glands, gastrointestinal glands, and genital

erectile tissue where they cause vasodilation (Tortora, 1989).

The parasympathetic system returns the body functions to normal after they have been

altered by sympathetic stimulation. In times of danger, the sympathetic system prepares the body

for aggressive activity. The parasympathetic system reverses these changes when the danger is

over. Parasympathetic stimulation causes slowing down of the heartbeat, lowering of blood

pressure, constriction of the pupils, increased blood flow to the skin and viscera, and decreased

peristalsis of the gastrointestinal tract (AACN, 1998; Sherwood, 1997).

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injures part of the brain, it leaves a scar, and this scar can then trigger abnormal electrical activity

that can start a seizure.

Dr. Sacco said that bleeding (hemorrhagic) strokes are more likely to produce seizures

than ischemic strokes. That accounts for many of the seizures that hit 26 percent of stroke

survivors in the first 30 days, making seizure risk the greatest during that period.

Focusing on Treatment

Although research has led to a greater understanding of how to treat seizures, no cure has

been found. Physicians focus on controlling seizures with medicine while keeping side effects to

a minimum.

Once a seizure occurs, getting help quickly is essential. Promptly treating seizures seems

to lower the risk of having more seizures, Dr. Sacco said, and increases the chance of becoming

seizure-free. Medications may be less successful once seizures and their consequences become

established.

The longer you go seizure-free on medicine, the lower your risk and the more

reasonable it may be to take you off medicine.

If you have seizures early in the period of a stroke, yes, you are still at risk for long-term

seizures. However, suppose that you have them early, get treated and remain seizure-free. You

may be over the acute period and be able to come off the drugs


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disease, stroke, brain tumors and Alzheimers disease. Of these, stroke is the most frequent

cause.

If you are a stroke survivor and havent had seizures yet, having another stroke is going

to increase your risk of seizures, Dr. Sacco said. Effective lifestyle changes to reduce the risk of

seizures are the same as those to reduce the risk of recurrent stroke. Controlling weight and

blood pressure, increasing physical activity and eating nutritious food will help.

Out of Control

With most seizures, the effects last only a few seconds or minutes, and normal physical

and mental functions are restored. But a condition called status epilepticus, in which a person has

an abnormally long seizure or does not regain consciousness between seizures, is life-

threatening. A seizure lasting longer than five minutes, for practical purposes, should be treated

as a status epilepticus condition. Immediate medical help is necessary.

Status epilepticus has been known to cause further injury (to the brain), especially if its

occurring around the time of the stroke, Dr. Sacco said. Status epilepticus in anybody will

increase the risk of mortality.

Drug Interaction

Stroke survivors who take blood thinners such as warfarin must be carefully watched by

their doctors. Warfarin, an anticoagulant, fights the formation of blood clots, which could cause

another stroke. Because it affects the liver, warfarin magnifies the detrimental effect that anti-

seizure medicines have on the liver For the same reason Dr Sacco recommends that alcohol


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All drugs have risks, and you dont want to use a drug if you dont need it. Not every

stroke patient has a seizure.

Epilepsy is the commonest neurologic disorder with therapeutic indications. Prevalence

of epilepsy is 0.5-1%.

Seizure is a clinical manifestation where you have a neuron which fires excessively, so

there is hyper-excitability of a neuron coupled with hyper synchronization. Hyper

synchronization means that a hyper-excitable neuron will lead to excessive excitability of a large

group of surrounding neurons and you end with millions of neurons in the brain firing

excessively leading to the clinical manifestations of the seizure.

The phenotype of the seizure depends on the site it occurs at. If the seizure comes from

the limbic system you will end up with temporal lobe or emotional disturbances. If it occurs in

the rolandic area you will have motor seizure. If it starts in both sides of the brain you will end

up with generalized seizure.

Seizure is a sudden time limited involuntary alteration of behavior with or without loss of

consciousness accompanied by an abnormal electrical discharge. Epilepsy is a disorder of the

CNS whose symptoms are seizures.

Seizures are a symptom of epilepsy. Seizures ("fits," convulsions) are episodes of

disturbed brain function that cause changes in attention or behavior. They are caused by

abnormally excited electrical signals in the brain.

A single seizure may be related to a temporary medical problem (such as brain or tumor


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cases, partial seizures can spread to wide regions of the brain. They are likely to develop

from specific injuries, but in most cases the exact origins are unknown (idiopathic ).

Generalized seizures. These seizures typically occur in both sides of the brain. Many

forms of these seizures are genetically based. There is usually normal neurologic

function.

PARTIAL SEIZURES (ALSO CALLED FOCAL SEIZURES)

These seizures are subcategorized as "simple" or "complex partial."

Simple Partial Seizures. A person with a simple partial seizure (sometimes known as

Jacksonian epilepsy) does not lose consciousness, but may experience confusion, jerking

movements, tingling, or odd mental and emotional events. Such events may include deja

vu, mild hallucinations, or extreme responses to smell and taste. After the seizure, the

patient usually has temporary weakness in certain muscles. These seizures typically last

about 90 seconds.

Complex Partial Seizures. Slightly over half of seizures in adults are complex partial

type. About 80% of these seizures originate in the temporal lobe, the part of the brain

located close to the ear. Disturbances there can result in loss of judgment, involuntary or

uncontrolled behavior, or even loss of consciousness. Patients may lose consciousness

briefly and appear to others as motionless with a vacant stare. Emotions can be

exaggerated; some patients even appear to be drunk. After a few seconds, a patient may

begin to perform repetitive movements such as chewing or smacking of lips Episodes


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Tonic-Clonic (Grand Mal) Seizures. The first stage of a grand mal seizure is called the

tonic phase, in which the muscles suddenly contract, causing the patient to fall and lie stiffly for

about 10 - 30 seconds. Some people experience a premonition or aura before a grand mal seizure.

Most, however, lose consciousness without warning. If the throat or larynx is affected, there may

be a high-pitched musical sound (stridor) when the patient inhales. Spasms occur for about 30

seconds to 1 minute. Then the seizure enters the second phase, called the clonic phase. The

muscles begin to alternate between relaxation and rigidity. After this phase, the patient may lose

bowel or urinary control. The seizure usually lasts a total of 2 - 3 minutes, after which the patient

remains unconscious for a while and then awakens to confusion and extreme fatigue. A severe

throbbing headache similar to migraine may also follow the tonic-clonic phases.

Absence (Petit Mal) Seizures. Absence or petit mal seizures are brief losses of

consciousness that occur for 3 - 30 seconds. Physical movement and loss of attention may stop

for only a moment. Such seizures may pass unnoticed by others. Young children may simply

appear to be staring or walking distractedly. Petit mal may be confused with simple or complex

partial seizures, or even with attention deficit disorder. In petit mal, however, a person may

experience attacks as often as 50 - 100 times a day.

Myoclonic. Myoclonic seizures are a series of brief jerky contractions of specific muscle

groups, such as the face or trunk.

Atonic (Akinetic) Seizures. A person who has an atonic (or akinetic) seizure loses muscle

tone Sometimes it may affect only one part of the body so that for instance the jaw slackens


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could be tied to the condition. For most people, genes are only part of the cause, perhaps

by making a person more susceptible to environmental conditions that trigger seizures.

Head trauma sustained during a car accident or other traumatic injury can cause

epilepsy.

Medical disorders. Events like strokes or heart attacks that result in damage to the brain

also can cause epilepsy. Stroke is responsible for up to one-half of epilepsy cases in those

over age 35.

Dementia is a leading cause of epilepsy among older adults.

Diseases such as meningitis, AIDS and viral encephalitis can cause epilepsy.

Prenatal injury. Before birth, babies are susceptible to brain damage caused by an

infection in the mother, poor nutrition or oxygen deficiencies. This can lead to cerebral

palsy in the child. About 20 percent of seizures in children are associated with cerebral

palsy or other neurological abnormalities.

Developmental disorders. Epilepsy can sometimes be associated with other

developmental disorders, such as autism and Down syndrome.


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Seizures occur whenever there is a scar in the brain, said Ralph L. Sacco, M.D.,

professor of neurology and epidemiology at Columbia University Medical Center. When stroke

injures part of the brain it leaves a scar and this scar can then trigger abnormal electrical activity


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Seizures are one of the most common complications of stroke. Overall, 5%-15% of stroke

patients will experience seizure within 2 years of stroke. The reported risk factors for and

incidence of seizures after stroke vary widely, likely secondary to differences in study design,

study populations, and use of antiepileptic drugs (AEDs). In previous studies, the main risk

factors for poststroke seizures include stroke subtype, location and severity. Poststroke seizures

rates are highest in those with intraparenchymal hemorrhage and large supratentorial ischemic

strokes, and lowest after transient ischemic attacks, lacunar infarcts, and brainstem strokes.

Although frequently encountered in clinical practice, there are few evidence-based guidelines for

therapy of poststroke seizures. Poststroke seizures are classified as early or late according to

their temporal proximity to the stroke. Early seizures, also termed acute symptomatic seizures,

occur within the first week following stroke. These early seizures are likely provoked by the

metabolic and physiologic derangements associated with acute infarction or hemorrhage. Late

seizures are thought to result from epileptogenesis, changes in neurons that result in permanent

hyperexcitability. (Herman, Susan T. MD.2011. Bech Israel Deaconess Medical Center, Harvard

Medical School. Boston, MA)

The following factors increase your chance of developing some seizure disorders:

Previous brain injury-seizure disorder usually develops within one year of injury

Previous brain infection

Brain tumor


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Chemical abnormalities (decreased or excess blood sodium or glucose, low blood

calcium)

Liver or Kidney Failure

Severe, untreated High Blood Pressure

Chronic diseases (eg, Systemic Lupus Erythematosus , Polyarteritis Nodosa ,

Porphyria , Sickle Cell Anemia , Whipple's Disease )

Syphilis

If you already have a seizure disorder, the following factors can increase your chance of

having a seizure:

Sleep deprivation

Alcohol

Hormonal changes (such as those that occur at points during the menstrual cycle)

Stress

Flashing lights, especially strobe lights

Use of certain medicines

Missing doses of anti-epileptic medicines


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3) Schematic Diagram

NERVOUS SYSTEM

ETIOLOGY PREDISPOSINGFACTORS

- an electrical disturbance - idiopathic(genetic,in the nerve cells in one developmental

defects)section of the brain, causing - acquired

(hypoxemia,them to emit abnormal, vascular

insufficiency,recurring, uncontrolled, fever (childhood),

head injury,electrical discharges hypertension,

CNS infections,metabolic and toxic

conditions,brain tumor, drug and

alcoholwithdrawal, and

allergies)

CELLULAR/ METABOLIC CHANGES GROSS ANATOMICAL PHYSICAL CHANGES

PHYSIOLOGIC MANIFESTATION

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- when the integrity of the neuronal cell - involuntary movements may spread - epigastricsensations, pallor,membrane is altered, the cell begins firing centrally and involve the entire limb, including sweating,flushing, goose fleshwith increased frequency and amplitude. one side of the face and lower extremities. (piloerection),

pupillary dilation,When the intensity discharges reaches the the client also may exhibit changes in posture tachycardia,and tachypnea.threshold, the neuronal firing spreads to or spoken utterancesadjacent neurons, ultimately resulting toseizure. Inhibitory neurons in epilepsy haveslow neuronal firing in the cortex, anteriorthalamus, and basal ganglia. Once theinhibitory processes develop or theepileptogenic neurons are exhausted, theseizure stops then later events depress the

CNS activity and impair consciousness

SIGNS AND SYMPTOMS LABORATORY FINDINGSTONIC PHASE:

- fall, loss of consciousness, yell or tonic cry, - MRI may detect lesions in thebrain, focal abnormalities,extension of arms, legs, and/or face, fingers and cerebral degenerative changesand jaw clenched. AUTONOMIC SYMPTOMS - EEG may allow diagnosis of thetype and location of theinclude increase in blood pressure, heart rate occurring seizure.and bladder pressure, flushing, sweating, - SPECT may identify the epileptogeniczone so that the

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increased salivation and bronchial secretion, area in the brain giving rise toseizures can be removedand apnea surgically.CLONIC PHASE:

- muscles relax completely, then muscle tonereturns which causes rhythmic jerking of headand body.POST-ICTAL PHASE:

- biting of the tongue, cheek or lip, andurinary incontinence are common

SEIZURE

COMPLICATIONS

- Hypoxic brain damage and mental retardation may follow repeated seizures- Depression and anxiety may develop. Long-term social isolation may also occur

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Neuro Anaphy