Chapter 11 Nervous System

Ascending Fibers

- Also known as Afferent tracks - carry sensory information in the form of action potentials from the periphery back to the brain. CONTAIN VARIETY OF TRACTS THAT COMMUNICATE SPECIFIC SENSORY INPUT: - anterior spinothalamic tracts: permit sensations of light touch, pressure, tickling, itching - lateral spinothalamic tracts: allow sensations of pain and temperature - spinocerebellar tracts: est. body's position in relation to cerebellum - corticospinal tracts: coordinates movements, esp. hands - vestibulospinal tracts: involuntary movements - reticulospinal tracts: involuntary movements

Descending Fibers

- Also known as Efferent tracks - Carry motor impulses in the form of action potentials from the brain to the PNS

Spinal Cord

- Exits the skull through the large opening in skull - foramen magnum and extends through vertebral canal to L2 - At L2 it transitions into individual nerve roots - caudal equine - Consists of 31 pairs of spinal nerves that branch off at regular intervals - Central portion is an H-shaped area of gray matter, which contains nerve cell bodies. - White matter consisting of nerve fiber tracts, or pathways, surrounds the gray matter.

Spina bifida occulta

Mildest and most common form - results in small gap in 1/more vertebrae - spinal nerves and meninges don't usually protrude through opening. - usually no s/s & no neurologic deficits - defect may not be evident other than a dimple, birthmark, or tuft of hair over site.

Cranial Nerves

12 pairs of cranial nerves branch directly from base of brain - some carry sensory fibers, others only carry motor fibers, few carry both. - each nerve travels from brain through the foramen to it destination Brain accomplishes variety of physiologically vital functions & cognitive activities in part through set of nerves

Transient Ishemic Attack (TIA)

A temporary episode of cerebral ischemia that results in symptoms of neurologic deficits - a.k.a. ministrokes cuz the neuro deficits mimic CVA or stoke but they resolve with in 24 hrs (1-2 most cases) - may occur alone or in series - warning sign that a CVA may be impending, however NOT all CVAs are preceded by a TIA - 1:3 eventually have stroke - 1/2 of this will happen within one ear of TIA Ischemia can occur cuz of cerebral artery occlusion (thrombus, embolus, plaque), cerebral artery narrowing (atherosclerosis), or cerebral artery injury (inflammation of HTN). RISK FACTORS: migraines, smoking, DM, advancing age, inadequate nutrition, hypercholesterolemia , oral contraceptive, excessive alcohol, drugs Complications: permanent brain damage, injury from falls, and CVA S/S: begin suddenly & last for short period. Same as stroke. Reflect location of ischemia. Muscle weakness/paralysis of face, arm, leg, unilateral paresthesia, aphasia, receptive aphasia

Generalized Seizures

Abnormal neuronal activity on both sides of the brain May cause loss of consciousness, falls or massive muscle spasms. Absence seizure (petit mal) - staring into space Tonic seizure - causes stiffening of muscles of the body, generally those in the back & extremities. Clonic seizure - causes repeated jerking movements of muscles on both sides of the body. Myoclonic seizure - causes jerks or twitches of upper body, arms or legs Atonic seizure - causes loss of normal muscle tone, will fall down or may drop his or her head involuntarily Tonic-clonic seizure - (grand mal) causes stiffening of the body and reappeared jerks of the arms and or legs as well as loss of consciousness Postictal period - just after the seizure, the individual may be confused, fatigued and fall into a deep sleep

Neurogenic Shock

An abnormal vasomotor response secondary to disruption of sympathetic impulses.

Lobes classification

Areas with in and across lobes are classified as: - motor: stimulates muscle activity - sensory: receives sensory information - association : integrates information & starts coordinated responses

Neuron Anatomy

Axon - projection that transmit impulses away from the cell body Dendrites - projections that transmit impulses toward cell body Terminal boutons - tiny bulges at end of axon that communicates with neurons, muscle fibers, or glands Myelin sheath - surrounds some axons and increases rate of impulse transmission Schwann cells - produce the myelin sheath Nodes of Ranvier - separate the Schwann cells White matter - bundles of myelinated nerves Synapse - gap between the neurons

TIA Manifestations

Begin suddenly & last for short period. Same as stroke. Reflect location of ischemia. Muscle weakness/paralysis of face, arm, leg, unilateral paresthesia, aphasia, receptive aphasia Dysphagia, dysgraphia, difficulty reading, vision issues, changes in sensation and in levels of consciousness, personality , mood or emotional changes, confusion, agnosia, ataxia , vertigo, incontinence

Central Nervous System

Brain - housed and protected by skull - contains billions of neurons, types of neural cells Spinal cord - housed and protected by vertebral column Meninges - membrane that encases CNS Cerebrospinal Fluid - plasma-like liquid that fills the space between the arachnoid and the Pia mater layers to provide additional cushion and support. Ventricles - interconnected, hollow areas of the brain where CSF is produced, fills, and flows Types of Neural Cells - neuroglia cells provide support - neuralgia cells: + scaffold neural tissue + isolate and protect neuron cell membranes + regulate interstitial fluid + defend neuron agains pathogens + assist with neural repair.

Spinal Cord Injuries Manifestations

Cervical Injuries - can affect both upper & lower ext. & include breathing difficulties, loss of normal B/B control, paresthesia, sensory changes, spasticity, pain, weakness, paralysis, BP instability, temp fluctuations, diaphoresis. Thoracic Injuries - affect lower extremities, S/S same as cervical Lumbar Sacral Injuries - affect lower extremities in varying degree, S/S similar to cervical injury with exception of breathing difficulties.

Hydrocephalus

Common condition of excess CSF accumulation within the skull, which dilates the ventricles and compresses the brain and blood vessels - may be present at birth or develop later in life - Fatal if left untreated Causes: CSF flow disruption: noncommunicating or an obstructive hydrocephalus CSF not properly absorbed by bloodstream: communicating hydrocephalus Risk Factor: prematurity, pregnancy complications, congenital defects, nervous system tumors, CNS infections, cerebral hemorrhage, severe head injury S/S: infants - unusually large head, rapid increase in head size, bulging fontanel, projectile vomiting, lethargy, irritability, high pitched cry, feeding difficulties, seizures, eyes gaze downward, developmental delay DX: H&P, T, MRI, Xray, prenatal U.S. TX: surgical repair of blockage, shunt placement, ABT Tx, endoscopic 3rd ventriculostomy, life long F/U exams, multidisciplinary team management

Medulla

Conduction pathway for ascending and descending nerve tracts that coordinate: Heart rate, Peripheral Vascular resistance, breathing, swallowing, vomiting, coughing, and sneezing

Brain Stem

Connects brain to spinal cord - crucial for many body functions - injury cans result in death Collaborates with hypothalamus to regulate vital activities Main thoroughfare for information traveling to and from brain. 10 fo 12 cranial nerves exit from here. Contains: pons, midbrain, medulla

Pons

Contains nerves that regulate sleep and breathing

Diencephalon

Contains: - Thalamus : receives and relays most of sensory input, affects moods, initiate body movement - Sub thalamus: participates in motor activities - Epithalamus: functions are unclear - Hypothalamus : most inferior portion, regulates many bodily functions

Autonomic Nervous System

Controls smooth muscles. - Resp. for fight-or-flight response - Not under conscious control affects heart rate, BP, intestinal motility. - Has 2 subdivisions: Sympathetic & Parasympathetic

Multiple Sclerosis

Debilitating autoimmune condition that involves a progressive and irreversible demyelination of brain, SC, and cranial nerves

Temporal lobe

Essential for Hearing and Memory

Frontal lobe

Facilitates voluntary motor activity Plays role in personality traits

Neurons Functions

Fundamental unit of nervous system - generate and transmit bioelectrical impulses - don't have ability to divide - can't be replaced when old or injured - not all cell death = loss of function - undamaged neurons in brain will assume fxn of damaged neurons - Severed peripheral nerves can regenerate to a point of reestablish connections while severed brain and spinal cord cannot be repaired - severed SC nerves result in paralysis and loss of sensation below area of damage - require constant oxygen and glucose supply

Synapse

Gap between neurons Presynaptic terminal - terminal bouton or some similar structure Synaptic cleft - space between neurons Postsynaptic cell membrane - opposite end to the presynaptic terminal

Neural Impulses

Generated by small ionic changes Action potential - ability to create this charge Resting potential - charge at rest The plasma side of the neuron membrane has a slight charge at rest because of the Na ions concentrated on the outside of the cell At each synaptic transmission, small burst of neurotransmitters is released and then either destroyed by enzymes or reabsorbed by the postsynaptic membrane to be recycled for the next transmission Some neurotransmitters inhibit action potential

Dementia

Group of conditions in which cortical fxn is decreased, impairing cognitive skills and motor coordination. Issue with memory are common - include short term memory loss as well as confusion about historical events. - behavioral and personality changes interfere with relationships, work, and ADLs Causes: vascular disease, infections, toxins, genetic conditions Types: Alzheimers, Creutzfeldt-Jakob disease, and AIDS dementia complex.

Cerebral Palsy

Group of non progressive D/O that appear in infancy or early childhood & permanently affect motor movement & muscle coordination. - usually damage to cerebellum during prenatal period but can occur any time during 1st 3 yrs of life, when brain is developing. - other cerebral fining may be affected - can also occur cuz of brain abnormalities Contributing factors: prematurity, low birth wt., breech births, multiple fetuses, hypoxia, maternal or fetal hypoglycemia, cerebral hemorrhage, neuro inf. head injury, maternal inf. during pregnancy, maternal exposure to toxin in pregnancy, severe jaundice. S/S: may/may not be evident at birth. Vary in severity. May affect entire body or one area. , one side or both sides of body. Complications: balance and coordination issues, contractures, malnutrition, communication and speech delays, learning of cognition difficulties, seizures, visual issues, urinary incontinence, chronic pain. TX: muscle relaxers, botox, anti seizure meds, pain management, PT OT ST, ortho devices and braces. surgery,

Zika Virus Disease

Growing worldwide health concern, a condition that is caused by flavivirus. Brazil: in 2015 large outbreak of Zika virus disease with more neuro complications Transmission: mosquito, foreign travel, sexual transmission, lab exposure - other sources: mother to fetus, blood transfusion S/S: mild, self-limiting illness that incubates 3-12 days Flulike symptoms, rash, conjunctivitis, muscle pain, HA Complications: rare but severe - with maternal-fetal transmission: microcephaly, miscarriage Zika virus can cause Guillain-Barre Syndrome TX: supportive, rest, hydration, analgesics, antipyretics Prevention: protective clothing, minimize outdoor exposure, using insect repellant, condom, abstinence

Spinal Cord Injury Treatment

Immediate: - immobilization of spine - corticosteroids agent to reduce swelling - spinal traction - surgical repair of vertebral fxs or surgical removal fo fluid compressing the SC (decompression laminectomy) - Resp management - Bed Rest Long term: - PT, OT, ST - Mobility assistive devices - Electronic devices ( brain computer interface) - Long term resp management - Meticulous skin care - B/B training or management - Antispasmodic agents, botox injections to tx muscle spasms - Pain management - Nutritional support - prompt tx of infections

Spinal Nerves

In the PNS each one of these comprises 2 types of nerves : - sensory nerves - motor nerves

Encephalitis

Inflammation of the brain and SC, usually resulting from an infection. Causes: Virus and bacterial - infection triggers the inflammatory responses that caused vasodilation, increased capillary permeability, leukocyte infiltration - inflammatory process can cause nerve cell degeneration and diffuse brain destruction - May be Primary ( direct viral inf. of Brain & SC) or Secondary ( rest of body) . Most cases mild and self-limiting, but can be severe & life-threatening Complications: cerebral edema, cerebral hemorrhage, brain damage - result from meningeal irritation and neuro damage - similar to meningitis but with more gradual onset - most cases mild and go undetected S/S: flulike symptoms, HA, neck rigidity, confusion, hallucinations, personality changes, diplopia, seizures, muscle weakness, paresthesia/paralysis, loss of consciousness, tremors, abnormal deep tendon reflexes, rash, bulging fontanel TX: usually self limiting, requiring not treatment , rest, adequate nutrition, liquids, resp. support, reorientation and emotional support, analgesics, antipyretics, antiviral agents, Abt Tx, Corticosteroids, anti seizure , PT, ST, OT Prevention: vaccinations, wearing protective clothing, mosquito repellant, eliminating water sources

Meningitis

Inflammation of the meninges, usually from bacterial/viral infection - CSF may also become affected. - Infection or irritant triggers the inflammatory process, leading to swelling of the meninges and increased ICP. Causes: bacterial (Neisseria meningitides, Streptococcus pneumonia, H. influenza) , viruses, tumors, allergens Risk Factors: <25 yrs age, living in community setting, pregnancy, working with animals, immunodeficiency - can be self-limiting (viral) or life-threatening (acute bacterial) Complications: perm neuro damage, seizures, hearing loss, blindness, speech difficulties, learning disabilities, behavior problems, paralysis, renal failure, adrenal gland failure, shock, death. S/S: fever, chills, mental status change, N/V, photophobia, severe HA, stiff neck, agitation, bulging fontanel, decreased consciousness, opisthotonos, DX: throats cultures, lumbar puncture CSF, TX: Abt if bacterial, hydration, manage fever, vaccinations

Cerebrum

Largest of regions - Controls higher thought process - Right and Left hemisphere, each contain subdivisions called Lobes - frontal - parietal - occipital - temporal Surrounded by cerebral cortex: thin layer of gray matter White matter - lies beneath gray matter - contains bundles of axons that transmit impulses from the cerebral cortex to the SC, enhancing communication & coordination of activities Gyri - folds that increase surface area Sulci - grooves between gyro

Autonomic hyperreflexia

Massive sympathetic response that can cause HA, HTN, Tachycardia, seizures, stroke, and death: most commonly associated with injuries above T6 Spinal Cord Injuries

Brain Tumor

May be malignant or benign - can be life threatening d/t increased ICP and difficulty assessing. May be primary, but most are secondary tumors - primary tumors thought to arise from genetic mutations - Risk factors for primary tumors: advanced age, exposure to radiation and occupational chemicals Caucasians and males more prone Complications: neuro deficits, seizures, personality changes, death. S/S: vary depending on size and location: - new onset or change in pattern of HA - HA of increasing frequency & severity - unexplained N/V - Vision problems - gradual loss of sensation or movement in an extremity - balance and speech difficulties. - confusion - hearing problems - hormonal (endocrine) d/o DX: H&P, head MRI, Bx TX: depends on size and location Surgery, radiation (internal or external), chemo (Temodar), targeted drug therapies (Avastin) Rehab: PT, OT, ST

Alzheimer's disease

Most common form of dementia. - brain tissue degenerates and atrophies, causing steady decline in memory and mental abilities - Exact etiology unknown, but associated with 3 pathologic characteristics 1. amyloid plaques mix with collection of additional proteins, neuron remnant, and other nerve cell pieces 2. Neurofibrillary tangles: abnormal collections of a protein called tau that clumps togethers 3. Connections between neurons responsible for memory and learning are lost, neurons can't survive when their connections are lost. - not part of normal aging, but risk increases with age - rates higher in women and may be higher in those persons with less education Additional Risk Factors: family hx, HTN, high cholesterol, DM, Hx of traumatic brain injury - prevalence and mortality rates are on the rise. Complications: infections( pneumonia, UTIs), injuries R/T fall, malnutrition, dehydration, decubitus ulcers S/S: insidious onset, course may extend 10-20 years, memory loss, problems with abstract thinking, can't think of right word to use, difficulty reading and writing, disorientation, loss of judgment, can't perform familiar tasks, personality changes, incontinence of B/B TX: no cure. Meds to manage symptoms and maximize functioning - cholinesterase inhibitors

Spina Bifida

Most common neural tube birth defect in US - posterior spinner processed on the vertebrae fail to fuse, permits the meninges and SC to herniate - vary from mild to debilitating - Common site: lumbar area - Occurs in 3 forms, each vary in severity - spina bifida occulta, meningocele, myelomeningocele Cause: exact reason unknown, thought to be genetic/environmental - most common in Caucasian and Hispanics Risk Factors: family hx, folate deficiency, certain med (anti seizure agents), DM. Pre-pregnancy obesity, increased body temp (saunas, hot tubs) Complications: physical and neurological impairments, hydrocephalus, meningitis, learning problems. S/S: depend on severity and types DX: H&P, amniocentesis, US, xrays TX: may not be required, surgery (in utero or out), C-Section, management team.

Reticular Formation functions

Most of the many nerve fibers pass through branches that terminate here. - Acts as a gatekeeper receiving all incoming and outgoing information - Sends impulses to cerebral cortex through specialized nerve fibers that make up the reticular activation system - This along with reticular activation system are responsible for alertness during the day and can prevent sleeping at night.

Peripheral Nervous System

Nerves: bundles of nerve fibers; each fiber is a part of the neuron FXN: transport messages to and from CNS 31 spinal nerve pairs: 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, 1 coccygeal Ganglia - collections of nerve cell bodies outside the CNS Spinal nerves - arise from several small nerves called rootlets along dorsal and ventral surfaces of S.C. - 6-8 rootlets combine to form each dorsal root & ventral root, which come together to form = spinal nerve.

Occipital lobe

Process visual information

Parkinson's disease

Progressive condition involving the destruction of the substantial nigra in the brain. Results in lack of dopamine - when about 80% of dopamine producing cells are destroyed, movements issues that typically include tremors of hands and head develop. Tremors may disappear or decrease when body part is moved on purpose Pill rolling Cause unknown S/S: rigid or stiff muscles, slowed, quieter speech with monotone voice, stooped position, anxiety, stress, tension, confusion, dementia, depression, syncope, hallucination, memory loss, seborrhea DX: neuro assessment, other tests to R/O other conditions TX: NO CURE medications, deep brain stimulation, PT and OT, coping strategies, support, proper nutrition, adequate rest

Meningocele

Rarest form that involves the same bony defect as in spina bifida occulta, but meninges protrude through vertebral opening. - meninges and CSF form sac on the surface of the back - Transillumination can confirm absence of nerve tissue in sac - SC develops normally - neuro impairment not usually present - membranes can be surgically removed with little or no damage to nerve pathways - Infection/rupture of sac can lead to neuro impairment

Parietal Lobe

Receives and interprets sensory input with exception of smell, hearing and vision.

Nervous System

Receives and reacts to environmental stimuli on a physiologic and cognitive level - 3 main components: -Brain, Spinal Cord, and Nerves CNS= Brain and Spinal Cord PNS= nerves

Cerebral Vascular Accident Treatment

Requires prompt tx to minimize brain damage Should be delivered within 3 hours of symptoms onset. Determine if CVA is ischemic or hemorrhagic in origin before tx. - Ischemic stroke: thrombolytic agents, ASA, angioplasty, carotid endarterectomy - Hemorrhagic stroke: surgical repair of aneurysms or Arteriovenous malformations as well as blood removal Corticosteroids and antyhypertensives can be given with either types

Sympathetic Nervous System (SNS)

Resp. Fight-or-Flight - response initiated when person startled, augmented by secretion of the adrenal medulla - stimulates the adrenergic receptors

Parasympathetic Nervous System

Resp. for rest and digest response - stimulates the cholinergic receptors

Spinal Cord Injuries

Result from direct injury to the SC or indirectly from damage to surrounding bones, tissues, or blood vessels. Causes: MVA, falls, violence, sport injuries, weakening vertebral structures. - direct damage can occur if SC is pulled, pressed sideways, or compressed. This damage ma occur if the head, neck, or back twists abnormally during an accident or injury Spinal Shock: temporary suppression of neurologic fxn cuz of SC compression, neurologic fxn gradually returns. These injuries result in loss of neurologic functioning, can result in death. Complications: Resp. failure, effects of immobility, changes in B/B pattern, sexual dysfunction, chronic pain, death. DX: H&P, Spinal CT and MRI, Spinal Xray, Spinal myelogram

Brain Injury

Result of sudden and violent blow or jolt to head (called closed injury) or a penetrating head wound (open injury) that disrupts the normal brain functioning. - Injury can cause brain, damage nerve fibers, and cause hemorrhage Causes: falls, MVA, penetration of an object, assaults Varies from mild to severe Persons at highest risk: kids 0-4 & 15-19 yrs old, > 65 y/o, certain military personnel, Af-Amer ( highest death rate), individuals with hx of substance abuse Complications: can occur from one significant event or multiple mild events, changes in thinking, sensation, language, or emotions, seizures, Alzheimers disease, Parkinsons, memory decline, depression, death. S/S; may be vague & develop slowly, sudden or severe. outward appearance of head not indication of injury severity. Fluid draining from nose, mouth, ears. Fx of skull or face, bruising, swelling at injury site, scalp wound, impaired healing, smell, taste, speech or vision. poor short term memory. Concussions. DX: H&P, Glasgow coma scale, Head CT and MRI, ICP monitoring TX: rest, analgesics, cold compress, osmotic diuretics, anti seizure agents, sedatives, surgery, rehab

Plexus

Several nerves intersecting to form an organized collaboration: Branch into the peripheral nerves. Four occur in body: - Cervical @ C1 - C4 - Brachial @ C5 - T1 - Lumbar @ L1 - L4 - Sacral @ L4 - S4

Midbrain

Smallest region of Brain - acts as relay station for auditory and visual information - controls visual and auditory system - eye movement

Electrical Impulses: Steps

Step 1: protein gates open, Na flows into cells = increasing charge (aka Depolarization) Step 2: Rapid outflow of + charged K+ ions immediately following depolarization to return to resting potential Step 3: Impulses travel down the nerve, triggering release for neurotransmitter from presynaptic terminal Step 4: Neurotransmitters cross the synaptic cleft, only in one direction, to stimulate electrical reaction in nearby neurons Step 5: This electrical reaction passes through those neurons to the next synapse, where process is repeated.

Cerebral Vascular Accident (CVA)

Stroke/brain attack, refers to an interruption of central blood supply - ischemic damage is permanent Causes: total vessel occlusion (thrombus, embolus, plaque) or cerebral vessel rupture (cerebral aneurysm) MAJOR TYPES OF CVA: - Ischemic strokes (most common) - Hemorrhagic strokes ( most fatal) Complications: neurologic deficit and death Risk Factors: most common in Af. Amer , living in southeast region. Physical inactivity, obesity, HTN, smoking, high cholesterol, DM, atherosclerosis, birth control use, too much alcohol use, drugs S/S: CVA symptoms don't resolve, similar to TIA. DX: H&P, Head CT and MRI, Carotid US, Cerebral arteriogram, serum clotting studies, CBC, blood chem. .

Cerebellum

The "little brain" at the rear of the brainstem; functions include processing sensory input and coordinating movement output and balance Basal ganglia: - lies deep in cerebellum, diencephalon, midbrain - plays pivotal role in coordination, motor movement, and posture Limbic System: - includes portion of cerebrum and diencephalon - works in conjunction with hypothalamus to influence: - instinctive behavior - emotions - motivation - mood, pain and pleasure

AIDS Dementia Complex

The HIV invades the brain tissue - may be exacerbated by opportunistic infections and tumors associated with AIDS Causes: M.R. and delayed motor development in congenital HIV Staging system to describe progression: from 0 (normal) to 4 ( nearly vegetative ) S/S: encephalitis, behavioral changes, and gradual decline in cognitive function. Also a progressive slowing of motor function with loss of dexterity and coordination DX: H&P, neuro assessment, mental status eval, Head CT and MRI, Bx TX: aggressive antiviral therapy CAN BE FATAL IF UNTREATED

Focal Seizure

a.k.a Partial seizure Occurs in one part of the brain and varies depending on the area of the brain affected. Simple focal seizure: individual remains conscious but experiences unusual feelings or sensations that can take many forms. Complex focal seizure: individual has changes in or loss of consciousness, producing a dreamlike experience, may display strange, repetitious behaviors called automatisms. - Usually lasts few seconds - Some people experience Yaris - Seizure characteristics tend to be similar with every seizure - Can easily be confused with other d/o.

Myelomeningocele

a.k.a. open Spina Bifida: MOST severest form - spinal canal remains open along several vertebrae - meninges, S.C., spinal nerves, & CSF protrude through large opening at birth and form sac infants back - skin covers sac in some cases - tissues & nerves exposed in most cases, making infant vulnerable to life threatening infections Complications: neuro impairment (paralysis) B/B problems, seizures, other medical complications

Sensory Nerves

a.k.a: Afferent Nerves fxn: carry impulses from Body to Brain Dermatone: area of the skin innervate by a given pair of spinal sensory nerves

Motor Nerves

a.k.a: Efferent Nerves fxn: carry impulses from Brain to corresponding muscle receptor = muscle contraction & movement.

Interneurons

connect sensory and motor neurons in spinal cord

Meninges

membranes that cover the brain and spinal cord - Duramater : outer and toughest layer - Arachnoid layer: middle layer, spider web-like vascular system - Pia Mater: innermost layer

Seizure Disorder

transient physical or behavior alteration that results from an abnormal electrical activity in the brain Causes; altered membrane ion channels, altered extracellular electrolytes, imbalanced excitatory and inhibitory neurotransmitters . Can occur secondary to trauma, low BS, electrolyte D/O, acidosis, infection, tumors or chemical ingestion Epilepsy: seizure D/O resulting from spontaneous firing of abnormal neurons, characterized by recurrent seizures for which there is no underlying or correctable cause. Complications: brain damage, traumatic brain injury, aspiration, mood d/o, status epilepticus Two broad categories: focal & generalized not all can be easily defined as one or the other some start as focal then spread to entire brain some have both types but not clear pattern DX: H&P, Head CT and MRI, Head PET, Electroencephalogram Tx: Seizure; safety Epilepsy : anti seizure agents, surgical resection or transaction, avoid triggers