Disorders of Neural Function

Meningitis

Inflammation of the meninges and subarachnoid space; CSF may also become infected

Caused by: bacteria(more severe)- group B strep, Neisseria, Streptococcus pneumoniae, Haemophilus influenzae, and Viruses: enterovirus, West Nile virus, HIV, herpes

• infection or irritant tirggers inflammation leading to swelling or meninges and increased intracranial pressure(ICP)

Meningitis

• risk factors

younger than 25, living in community setting(dorms), pregnancy(listeria), working with animals, immunodeficiciency

Meningitis can be

• viral, bacterial

• viral- self limiting

• bacteria- life-threatening(rapid, severe)

Meningitis

• manifestations

• complications

• mimics flu symptoms: fever, chills, LOC, N/V, photophobia(light sensitivity), severe headache, nuchal rigidity(stiff neck), bulging fontanelles(infants), poor feeding or irritability in children, tachypnea, tachycardia, rash

• permanent neurologic damage(hearing loss, blindness, speech difficulties, learning disabilities, behavior problems), seizures, paralysis adrenal gland failure(caused by the Neisseria bacteria), cerebral edema, shock, death

Encephalitis

MORE SEVERE THAN MENINGITIS

Inflammation of the brain and spinal cord, usually from an infection

Caused by bacteria: lyme disease, TB, syphilis and viral(coxsackievirus, echovirus, poliovirus, adenovirus, herpes, cytomegalovirus, eastern equine, west nile, st loius, measles and mumps

• infection triggers inflammatory response—> vasodilation, increased capillary permeability, leukocyte infiltration(increased WBC)

Encephalitis may be

primary(direct viral infection of the brain or spinal cord)

secondary(travels from elsewhere in the body)

• Most cases are mild and self-limiting, but can be severe and life-threatening

• Vulnerable groups: immunocompromised, young children, O.A., high-incidence area

Encephalitis

• manifestations

• complications

Most cases are mild and go undetected

• Symptoms are similar to meningitis but with a more gradual onset: flu symptoms, headache, bulging fontanels, neck rigidity, photophobia, diplopia, seizures, ataxia, weakness, LOC, paralysis, tremors, rash

  • confusion, hallucinations, personality changes, paresthesia, abnormal deep tendon reflexes

• nerve cell degeneration, cerebral edema, cerebral hemorrhage, and brain damage

Zika Virus Disease

Caused by a flavivirus

• outbreaks in Africa, the Americas, Asia, and the Pacific

• Brazil: 2015 - large outbreak —> neurologic complications

Transmission: mosquito(primary), foreign travel, sexual transmission(virus lives longest in semen)

• other sources: mother to fetus, blood transfusion

• Zika can cause Guillain-Barre syndrome(persons own immune system is attacking their own nerves—>paralysis and weakness)

BABIES BORN WITH SMALL HEADS

• higher risk of miscarriage and contracture

Increased Cranial Pressure(ICP)

Results from increased pressure in the cranial cavity(3 components: brain tissue, CSF, blood)

Caused by traumatic brain injury, tumor, hydrocephalus, cerebral edema, and hemorrhage

• Monro-Kellie hypothesis: increase in volume of one component must be compensated for by a decrease in volume of another(1 volume increases, another decreases); usually shifts are in CSF and blood because brain tissue does not move easily

2 other compensatory mechanisms for ICP:

Autoregulation: the blood vessels will dilate to increase blood flow and constrict if ICP increases

Cushing’s reflex: the hypothalamus increases sympathetic stimulation when the mean arterial pressure drops below the ICP —→

• CUSHING’S TRIAD(IMPORTANT): increased blood pressure, bradycardia, and Cheyne-Stokes respirations(deep, fast breathing—→periods of apnea)

Herniation

Feared complication of increased ICP

• Refers to displacement of brain tissue(if CSF and blood flow can’t accomodate)

• push downward on brainstem

Manifestations of Increased ICP

Common: decreasing LOC, vomiting(projectile); from pressure on medulla, Cushing’s triad, fixed and dilated pupils, posturing(decorticate: towards the core, decerebrate: away from the core)

Infants: separated sutures and bulging fontanelle

Older children and adults: behavior changes, severe headache, lethargy, neurologic deficits, and seizures

Hematoma

Collection of blood in the tissue that develops from ruptured blood vessels

• Hematomas can develop immediately or slowly because of a traumatic brain injury(TBI) or surgery(some kind of trauma)

Epidural Hematoma

Bleeding between the dura and skull(EPI-DUR), usually caused by an arterial tear

• An arterial tear is larger and more severe than a venous rupture

Manifestations: neurologic dysfunction that develops within a few hours of injury

• symptom pattern: brief LOC—→short period of alertness—>LOC again

Subdural Hematoma

Between the dura and the arachnoid, usually caused by a small venous tear

• develops slowly; manifestations are present within 24 hours of an injury

• progresses rapidly and has a high mortality

  • ICP increases over a period of about a week after the injury

Chronic subdural hematomas: elderly adults associated with brain atrophy: manifestations develop slowly after injury because of slow leak

Intracerebral Hematomas

Bleeding within the brain tissue

• caused by

  • contusion or shearing injury

  • HTN

  • CVA(strokes)

  • aneurysms, or vascular abnormalities

Subarachnoid Hemorrhage

Bleeding in the space between the arachnoid and pia

Primary clinical presentation:

⚬ Severe headache with a sudden onset that is worse near the back of the head

Hematoma complications

Bleeding—→localized pressure on tissue—>increased ICP

• blood may coagulate and form a solid mass

• Fluid from the hemolysis exerts osmotic pressure, drawing more fluid into the capsule —→ edema increases the mass size, applying more pressure and increasing ICP

• bleeding can trigger vasospasm and ischemia

• Can result in herniation of brain tissue

Spinal Cord Injury

• results from

• caused by

Result from direct injury to the spinal cord or indirectly from damage to surrounding bones, tissues, or blood vessels

• direct damage if cord is pulled, pressed sideways, or compressed

Caused by motor vehicle accidents, falls, violence, sports injuries, and weakening vertebral structures(RA and osteoarthritis)

What can occur inside or outside the spinal cord after a spinal injury?

Hemorrhage(bleeding), fluid accumulation, and edema(occurs inside or outside spinal cord, but within spinal canal)

Spinal Shock:

• most common in which demographic

Temporary suppression of neurologic function because of spinal cord compression; neurologic function gradually returns

• caucasians and males; average age has increased from 29 to 43

Spinal Cord Injury: Complications

• loss of neurologic function

• varying degrees of paralysis

• Cauda equina syndrome(medical emergency): injury to the nerve roots in the area of the cauda equina —→ can cause bladder and bowel dysfunction, pain/altered sensation in legs, loss of sexual sensation, saddle numbness(pelvis)

Another spinal cord injury complication:

• autonomic hyperreflexia

Massive sympathetic response that can cause headaches, hypertension(HYPERTENSIVE CRISIS), seizures, stroke, and death

• associated with injuries above T6

noxious stimuli triggers cascade(look at diagram)

Spinal Cord Injury: Manifestations

Manifestations are usually below the level of injury

• Cervical injuries: C4 and up

  • upper and lower extremities; breathing difficulties, loss of bowel and bladder control; paresthesia; spasticity; pain; weakness; paralysis; BP instable; temperature fluctuations; diaphoresis

• Thoracic: trunk and lower extremities

  • similar manifestations as cervical, but no breathing difficulties here

• Lumbar sacral injuries

  • lower extremeties impacted; bowel and bladder dysfunction, may need to walk in a wheelchair or brace

Another Spinal Cord injury complication: Neurogenic shock: (compare to autonomic hyperreflexia)

An abnormal vasomotor response secondary to disruption of sympathetic impulses

⚬ Hemodynamic impact (DECREASED HR & BP)

Respiratory failure,

Effects of immobility(constipation, pulmonary infection, UTI, thrombus, impaired skin integrity, contractures)

bowel and bladder dysfunction

sexual dysfunction

chronic pain

death

• Autonomic hyperreflexia can happen at any time after injury; neurogenic shock happens more acutely

Side by side diagram

Vascular Neurological Disorders: Transient Ischemic Attack (TIA)

• what is it

• what is it caused by

• what does it mimic

• TIAs are a warning sign for what

A TEMPORARY episode of cerebral ischemia that results in symptoms of neurologic deficits (“mini stroke”)

Causes: cerebral artery occlusion(e.g., thrombus, embolus, or plaque); cerebral artery narrowing(e.g., atherosclerosis or spasms), or cerebral artery injury (e.g., inflammation or hypertension)

• neurologic deficits mimic a CVA(stroke) except these deficits resolve within 24 hours(usually 1-2 hours)

• may occur single or in a series

TIA can be a warning sign for a stroke, but not all CVAs are preceded by a TIA

• 1/3 who have a TIA eventually have a stroke

• half of these CVAs occur within 1 year of TIA

TIA Risk Factors

Smoking, DM, bad diet, hypercholesterolemia, older age, oral contraceptive, excessive alcohol, and illicit drug use

TIA Manifestations

• begin suddenly and last shortly

• same as for a stroke(reflect the location of ischemia)

• Permanent brain damage, injury from falls, and CVA

BEFAST

B: loss of Balance, headache, dizziness

E: blurred vision

F: facial drooping

A: arm or leg weakness

S: speech difficulty

T: time to call for an ambulance immediately

Muscle weakness or paralysis(face, arm, or leg unilateral), ataxia, changes in sensation: agnosia-inability to recognize or identify sensory stimuli, aphasia(speaking), dysphagia(swallowing), dysgraphia(writing), diplopia, nystagmus, vision loss, difficulty reading, change in LOC, confusion, personality/mood changes, vertigo, incontinence

Vascular Neurological Disorders: Cerebrovascular Accident (CVA)

• what is it

  • what does it interrupt

• caused by

stroke, or brain attack

• interruption of cerebral blood supply

• ischemic damage is permanent

Causes: ⚬ Total vessel occlusion (e.g., thrombus, embolus, or plaque) or cerebral vessel rupture (e.g., cerebral aneurysm, arteriovenous malformation, or hypertension)

Two major types of CVA

ischemic strokes: most common

hemorrhagic strokes: most fatal

CVA

• complications

• most common in

• risk factors(similar to TIA)

• neurologic deficits and death

• Most common in African Americans and people living in the Southeast region

Additional risk factors: ⚬ Physical inactivity, stress, obesity, hypertension, smoking, dyslipidemia, diabetes mellitus, atherosclerosis, oral contraceptive usage, excessive alcohol consumption, illicit drug use, and advancing age

CVA Manifestations

Similar to those of TIA, except they do not resolve

• may improve with time and therapy, but they can remain —→complications

Additional manifestations: headaches with hemorrhagic strokes because of increased ICP

Vascular Neurological Disorders: Cerebral Aneurysm

• what is it it

• causes(similar to CVA and TIA)

A localized outpouching of a cerebral artery due to weakening of the artery wall

• can put pressure on surrounding tissue; as well as leak or rupture; causing or CVA or death

Common causes:⚬ Congenital defects, hypertension, diabetes mellitus, dyslipidemia, connective tissue diseases (e.g., Marfan syndrome), traumatic brain injuries, arteriovenous malformations, cigarette smoking, illicit drug use, and brain tumor

Cerebral Aneurysm

• most frequent type

• where does it occur

• when does it cause symptoms

• Manifestations:

Most are berry or saccular

Most frequently occur in multiples on the circle of Willis

Usually asymptomatic until they grow large or rupture

• vision issues(diplopia and vision loss), headache, eye pain, and neck pain

• Sudden, severe headache is an indication that the aneurysm has ruptured; may resemble symptoms of increased ICP and CVA

Headache disorders

• Another name for headache; where does pain occur

• characterized by

• where can the headaches occur

• what kind of pain

• onset of pain

• cephalalgia: refers to pain in any region of the head

• recurrent headaches

• one or both sides, one area, radiate across the head, or have a vise-like quality

• sharp, throbbing, or dull

• develops gradually or suddenly, last hours to days

Primary headache disorders

• caused by

• examples

• No apparent underlying cause

• migraines, tension type headaches(TTH), trigeminal autonomic cephalagias(TACs)

• genetic and environmental factors(chemical activity, nerves, blood vessels, muscles of the brain, head, and neck)

Secondary headache disorders:

• causes

• Red flag symptoms

Less common

• underlying causes: tumors, infections, hemorrhage, aneurysm, cerebral arteriovenous malformation, acute sinusitis, otitis media, concussion, dehydration, dental problems/infections, glaucoma, hangovers, carbon monoxide poisoning, monosodium glutamate ingestion, altered CSF pressure or volume, and skull deformities.

  • if you fix the cause, then the headache goes away

Red flag symptoms: thunderclap headache; new-onset headaches; persistent morning headache with nausea; headaches that get worse over time; headaches associated with postural changes; and aura symptoms that last longer than an hour(indication that headache is coming on-could be visual like seeing dots, neck pain, impaired balance)

Seizure

• What is it

• primary causes

• secondary causes

transient physical or behavior alteration that results from an abnormal electrical activity in the brain

• Primary Causes: ⚬ Altered membrane ion channels ⚬ Altered extracellular electrolytes ⚬ Imbalanced excitatory and inhibitory neurotransmitters

Secondary Causes :⚬ Trauma, hypoglycemia, electrolyte disorders, acidosis, infection, fever, chemical ingestion(e.g., medications, illicit drugs, and alcohol),cerebral ischemia or hypoxia

Epilepsy

• what is it

• characterized by

• complications

• seizure disorder resulting from spontaneous firing of abnormal neurons;

• characterized by recurrent seizures; there is no underlying or correctable cause

Complications: Brain damage • Traumatic brain injury • Aspiration• Mood disorders • STATUS EPILEPTICUS: seizure activity lasting longer than 5 minutes or subsequent seizure(s) that occur before the individual has fully regained consciousness within this timeframe

The two different kinds of seizures

• postictal period

Focal and Generalized

• not all can be easily defined as either focal or generalized

• some begin as focal and spread to the entire brain

• some people may have both types of seizures with no clear pattern

Postictal period: just after the seizure, the individual will be confused, fatigued, and fall into a deep sleep

Focal Seizure

also called partial seizure

• occurs in just one part of the brain

• manifestations vary depend on part of brain being affected

Frontal lobe: movement, emotions, memory, language, social/sexual behavior, and personality

Temporal lobe: hearing, speech, memory, emotions

Parietal lobe: bodily sensations

Occipital lobe: processing vision

Brain stem: breathing, hr, temperature

Cerebellum: balance and coordination

Generalized Seizure

Abnormal neuronal activity on both sides of the brain • May cause loss of consciousness, falls, or massive muscle spasms

• many different types…

Absence seizure(previuosly called petit mal seizure)

individual may appear to be staring into space and/or have jerking or twitching muscles

• often missed

Tonic seizure

causes stiffening of muscles of the body, generally those in the back and extremities

Clonic seizure

causes repeated jerking movements of muscles on both sides of the body

Tonic–clonic seizure (previously called grand mal seizure):

causes stiffening of the body and repeated jerks of the arms and/or legs as well as loss of consciousness

Myoclonic seizure

causes jerks or twitches of the upper body, arms, or legs

• like when you fall asleep and suddenly jerk awake

Atonic seizure:

causes a loss of muscle tone; will fall down or may drop his or her head involuntarily•

Chronic Degenerative Disorders: mulitple sclerosis

• what is it

• how does damage occur

Debilitating autoimmune condition: progressive and irreversible demyelination of brain, spinal cord, and cranial nerves

• Damage occurs in diffuse patches throughout the nervous system and slows or stops nerve impulses

• Progression of the damage varies

Who is MS most common in?

• what age do symptoms onset

• what are complications

• characterized by

• may progress without…

Most common in women, caucasians, and those living in temperate climates

• symptoms onset between age 20 and 40

• complications: epilepsy, paralysis(legs), and depression

  • varying depending on degree of damage to nerves

• characterized by remissions and exacerbations; which may last for days to months

  • may progress without remission

Multiple Sclerosis Manifestations

• really think about those slowing nerve impulses

• MS more conitive manifestations

Sensory: Vision issues (e.g.,diplopia and vision loss);Slurred speech; Paresthesia; Hearing loss

• Fatigue; Dizziness

• Decreased attention span, poor judgment, and memory loss

• Difficulty reasoning and solving problems

• Dysphagia

• Problems moving arms or legs

• Weakness and/or tremor in one or more arms or legs

• Ataxia; Unsteady gait; Muscle spasms

• Constipation and stool leakage

• Urinary frequency, urgency, hesitancy, or incontinence

• Sexual dysfunction

Amyotrophic Lateral Sclerosis

• aka

• damage to what

• What is not affected

nerves lose their ability to…

• increases risk for what?

• Lou Gehrigs disease

• damage to upper motor neurons of cerebral cortex and lower motor neurons of brain stem

• Sensory neurons, cognitive function,and cranial nerves III, IV, and VI arenot affected

• Nerves lose their ability to trigger rmuscle movement, resulting in muscle weakness, disability, paralysis, and eventually death (usually within 3years of onset of symptoms)

• • May also increase the risk for dementia

Amyotrophic Lateral Sclerosis

• causes

• Upper motor neurons

• Lower motor neurons

• manifestations

no definitive cause; genes and environment

• ALS people lack the enzyme that protects cells from free radical damage

• excess glutamate(toxic to nerves)

• A.I. response

Upper motor neurons—→spastic paralysis and hyperreflexia

Lower motor neurons—→ flaccid paralysis

Manifestations: foot drop, lower extremity/upper extremity/hand weakness and clumsiness, walking difficulty, twitching in upper extremities and tongue, choking, unbalanced

ALS and MS similar manifestations

walking difficulty, weakness in legs/arms, slurred speech, dysphagia, muscle cramps

Chronic Degenerative Disorders: Parkinson’s disease

• what is it

• what does it result in; when 80% of…

• when do tremors decrease

• cause

• more common in who?

Progressive condition involving the destruction of the substantia nigra in the brain

• Results in a lack of dopamine

When 80% of the dopamine-producing cells are destroyed, movement issues typically include tremors of the hands and head develop

• tremors may decrease when the body part is moved intentionally

• cause: unknown

• more common in men and those living in rural area

Parkinson’s Disease Manifestations

REMEMBER THESE: slowing or stopping automatic movements(blinking), masklike appearance, difficulty initiating or continuing movement(walking or getting out of a chair)movement, loss of fine hand movements(writing, eating), shuffling/unsteady gait, slowed movements

constipation, urinary hesitancy or urgency, dysphagia, drooling, anosmia(loss of sense of smell), myalgia

Parkinson’s Disease Manifestations: Tremors

• where do they occur/when

• eventually tremors happen where in the body

• when are they worse

• example

occur in limbs at rest or while held out, go away during purposeful movement

• eventually seen in the head, lips, tongue, feet

• may be worse when tired, excited, stress

• example: finger-thumb rubbing(pill-rolling - tremor)

Huntingtons Disease

Autosomal dominant; chromosome 4 (increased chance of getting the disease the further it gets passed down genetically)

• genetically programmed degeneration of neurons

• atrophy of the brain(basal ganglia and frontal cortex)

Most cases appear at age 30-40

• 10-30 years to live

Huntingtons Manifestations

initially insidious

• family members may report unusual behaviors: mood swings, irritable, depressed, angry, antisocial, hallucinations, paranoia, psychosis * commonly mistaken for psychiatric disorder

Early signs: trouble driving, learning new things, answering questions, remembering facts

Myasthenia Gravis

• pathway

• muscles involved

A.I. condition

• acetylcholine receptors are destroyed by IgG autoantibodies—→disrupts normal connection between the nerve and muscle at the neuromuscular junction

Weakness of voluntary muscles due to decreased nerve stimulation

• muscle weakness increases during activity and improves after rest

muscles of Eye, eyelid movement, facial expression, talking, chewing, and swallowing

• muscles that control breathing, neck, limb movement

MA triggered by

• myasthenic crisis

• factors that worsen and cause myasthenic crisis

unclear

• thymus abnormalities, hyperthyroidism, A.I disorders

Myasthenic crisis: life-threatening: muscles too weak to breathe

• fatigue, illness, stress, heat, alcohol, meds(beta blockers, calcium channel blockers, quinine, antibiotics)

MG manifestations

difficulty climbing stairs, lifting objects, or rising from seated position

• dysarthia(motor speech)

• eye, vision issues

• drooping head

• facial paralysis

• fatigue, hoarseness, changing voice

• breathing difficulty

• dysphagia

Dementia

• what is it

  • what skills does it impair

• issues with what

group of conditions in which cortical function is decreased

• impairing cognitive skills and motor coordination

• Issues with memory; short memory losses and confusion about historical events

Behavior and personality changes interfere with relationships, work, and ADLs

Types of dementia

• dementia is an umbrella term

⚬ Alzheimer’s disease

⚬ Vascular dementia

⚬ Dementia with Lewy bodies

⚬ Frontotemporal dementia

⚬ Creutzfeldt-Jakob disease

⚬ AIDS dementia complex

Alzheimers

• most common form of…

• what happens to brain tissue

• associated with what three pathologic characteristics

Most common form of dementia

• brain tissue degenerates and atrophies causing a steady decline in memory and mental abilities

1. amyloid plaques mix with proteins, neuron remnants, and nerve cell pieces

2. Neurofibrillary tangles: abnormal collections of a protein called tau that clumps together

3. Connections between neurons responsible for memory and learning are lost: neurons cant survive if connection to other neurons are lost

Alzheimers

• what kind of aging

• higher rates in who

• additional risk factors

• complications

• abnormal aging, risk increases with age

• rates higher in women, and those with less education

• Additional risk factors: fx, HTN, hypercholesterolemia, DM, TBI

• prevalence + mortality rates on the rise

• complications: infection(pneumonia, UTI), fall injuries, malnutrition, dehydrations, ulcers

Alzheimer’s manifestations

insidious onset

• 10-20 years

• Memory loss, problems with abstract thinking, difficulty finding the right word to express thoughts or even follow conversations, difficulty reading and writing, disorientation (even in familiar surroundings), loss of judgment, difficulty performing familiar tasks, personality changes, hallucinations, and incontinence of bowel or bladder

Brain tumors

may be malignant or benign

• can be life threatening due to increased ICP and difficulty assessing

• may be primary, but most are secondary(breast, colon, kidney, lung, melanoma, sarcoma)

brain tumor cont

Primary tumors are thought to arise from genetic mutations

• Risk factors for primary tumors: ⚬ Advancing age; exposure to radiation and occupational chemicals

• Prevalence and mortality rates are highest among Caucasians and males

• Complications: ⚬ Neurologic deficits ⚬ Seizures , Personality changes ⚬ Death

Brain Tumor Manifestations

• Vary depending on size and location

• new onset or change in headaches

• headaches increasing in frequency and severity

• unexplained N/V

• vision problems

• gradual loss of sensation and movement

  • balance difficulties, speech difficulties, hearing problems, hormone(endocrine) disorders