nervous system Flashcards
function of the nervous system
responsible for body’s ability to both interact with environment and to regulate/control the body and internal organs, muscles, glands
alterations in cognitive systems, arousal and awareness
any state not fully conscious.
Consciousness is arousal (state of awakeness) and awareness (content of thought.
Arousal-mediated by reticular activating system (RAS), regulating aspects of attention and information process, and maintains consciousness
Cognitive cerebral functions require a functioning RAS.
Awareness encompasses all cognitive functions and is mediated by attentional systems, memory systems, language systems, and executive systems. Selective attention (orienting) is ability to select specific information to process from all available competing environmental and internal stimuli
Memory deficits, image processing difficulties, poor vigilance, poor detection of threats, poor short term memory
alterations in cognitive systems, data processing deficits
problems associated with recognizing and processing sensory information
Agnosia- defect of pattern recognition, failure to recognize form and nature of objects. Can be tactile, visual, auditory, generally only one sense is affected. Sometimes objects cant be named by touching it, but able to name it by looking at it
Aphasias - impairment of comprehension or production of language, impaired written or verbal communication. Also called dysphasia. Can be expressive, receptive, mixed (repeats words spoken to them), mute,
Acute confusional state - transient disorders of awareness, either sudden or gradual onset, delirium
alterations in cognitive systems, seizures
manifestation of disease, not a specific disease entity. Sudden, transient disruption in brain electrical function, caused by abnormal excessive discharges of cortical neurons.
Any disorder altering neuronal environment can cause seizures. Metabolic congenital, genetic predisposition, perinatal, postnatall, myoclonic syndromes, brain tumor, vascular disease, drug/ETOH abuse, hypoglycemia, fatigue, lack of sleep, stress, fever, water intoxication, constipation, antipsychotics, respiratory alkalosis - hyperventilation, blinking lights, poorly adjusted television screen, loud noises, certain music, odors, being startled, increased risk for women before or during menses
alterations in cerebral dynamics, ICP
ICP - normal is 5-15 mmHg. Increased ICP happens with increased intercranial content. Blood, edema, tumors, excess CSF. Must reduce volume of other cranial contents. Stages 1-4, with progressing levels of LOC loss.
1 - vasoconstriction and external compression of venous system occur to compensate, so ICP may not change much as body compensates.
2 - ICP continues to increased, exceeding ability to compensate. Compromises neuronal oxygenation, arterial vasoconstriction occurs to elevate systemic BP to overcome ICP. Can include confusion, restlessness, drowsiness, slight pupillary and breathing changes
3 - ICP approaches arterial pressure, brain tissues experience hypoxia and hypercapnia, condition rapidly deteriorates. Includes decreased arousal, central neurogenic hyperventilation, widened pulse pressure, bradycardia, small and sluggish pupils
4 - brain tissue shifts (herniates) from greater pressure to compartment of lesser pressure. Blood supply is compromised, causing further ischemia and hypoxia. Small hemorrhages may develop, hydrocephalus may develop,
alteration in cognitive systems, motor function, muscle tone
movements are complex patterns of activity controlled by cerebral cortex, pyramidal system, extrapyramidal system, and muscle motor units. Dysfunction in any area can cause motor dysfunction. Normal muscle tone involves slight resistance to passive movement. resistance is smooth, constant, even.
Hypo or hypertonia
Flaccidity
Spasticity
Paratonia-resistance to passive movement
Dystonia-involuntary twisting or abnormal posture or repetitive movements
Rigidity
Plastic or lead pipe-increased muscular tone independent the degree of force in passive movement
Myotonia-impaired ability to relax after contraction
alterations in motor function, muscle movement
Dopamine has role in several movement disorders, too much or too little
Hyperkinesia, includes tremors
disorders of the nervous system
Central-TBi, spinal cord injury, degenerative disorders of the spine, CVD, primary headaches, infection and inflammation of the meninges, demyelinating disorders
PNS - radiculopathies-alterations in spinal nerve root functions as they emerge from or enter the vertebral canal neuropathies-alterations in the nerves themselves, may be injured axons
Neuromuscular junction disorders
normal conduction thru the junction fails to function EX botulism with paralysis, myasthenia gravis
tumors of CNS
malignant or not. Metastatic from systemic cancer are 10 times more common than primary brain tumors. Primary spinal cord tumors are also rare, as metastatic tumors from other sites perforate to spine from other tumors or structurs
Dopamine
precursor of both epinephrine or norepinephrine. Epinephrine induces general vasodilation because of the predominance of beta-adrenergic receptors in the muscle vasculature
Disorders of the nervous system and neuromuscular junction adults
· TBI – injury to brain from external force, most common are falls, then unintentional blunt trauma and MVA, males have highest incidence in every age group. Classified as primary or secondary. Primary is direct impact or injury. Secondary is indirect consequence of primary injury and includes systemic responses
· Spinal cord injury
· Degenerative disorders of the spine
· Cerebrovascular disorders
· Primary headache syndromes-can be associated with tumors, meningitis, CVD. Migraine is headache lasting 4-72 hours, head pain + n/v, photophobia and phonophobia. More common in women, 25-55 age.
· Infection and inflammation of the CNS-meningitis, inflammation of brain/spinal cord,
· Demyelinating disorders
peripheral nervous system disorders
Radiculopathies-alterations in spinal nerve root functions as they emerge from or enter the vertebral canal
· Neuropathies – alterations in the nerves themselves, may be injured axons
neuromuscular junction disorders (motor end plate
Normal conduction thru the junction fails to function. Ex – botulism with paralysis, myasthenia gravis (chronic autoimmune disease)
tumors of the CNS
Malignant or non-malignant. Metastatic from systemic cancer are 10 times more common than primary brain tumors.
· Primary spinal cord tumors are rare, metastatic tumors perforate to spine from other tumors or structures
dopamine is precursor of….
both epinephrine and norepinephrine. Epinephrine induces general vasodilation because of the predominance of beta-adrenergic receptors in the muscle vasculature.
anterior horn
associated with skeletal muscle innervation and movement
dorsal root ganglia
carries sensory information from body to spinal cord
posterior horn
receives sensory information from body
substantia gelatinosa
directly involved in pain transmission, located at tip of posterior horn of spinal cord
disorders and alterations of nervous system in children
can arise any time before birth, through adolescence, and symptoms are often different in children than adults, even with similar disorders. Both genetics and environment shape the development of the nervous system. Neuro exam at birth detects mostly reflex responses that require an intact spinal cord and brainstem.
name nervous system disorders in children
Structural malformations-neural tube defects (most common anomaly and include anencephaly, spina bifida, myelomeningocele, craniosynostosis, lissencephaly, microcephaly), craniosynostosis, malformations of brain development
· Alterations in function-static encephalopathies, acute encephalopathies
· CVD in children-perinatal stroke, childhood stroke
· Epilepsy and seizure disorders
· Childhood tumors-brain-most common solid tumor and cause of cancer death in children, arise from brain tissue and do not metastasize, retinoblastoma-tumor of the retina and extends into vitreous humor,
· Cerebral palsy, disorder of movement, caused by injury or abnormal development in the immature brain up to 1 year of age
· Metabolic disorders lead to diffuse brain dysfunction-phenylketonuria (PKU) is inability to convert phenylalanine to tyrosine and brain damage occurs before metabolites can be detected in the urine
· Defects in amino acid, lipid, and more rarely carbohydrate metabolism. May not manifest until childhood or adulthood. Early dx and tx is vital to avoid severe neurological problems. Newborn screening is recommended for 35 genetic and metabolic conditions, and helps identify problems before symptoms develop.
· Drug induced encephalopathies-accidental ingestion, therapeutic overdose, intentional overdose, ingestion of environmental toxins
· Meningitis-infection of meninges, viral/bacterial/fungal often preceded by URI, or GI infection
· Encephalitis-inflammation of the brain. Can be present along with meningitis
· HIV-results in developmental delays and impaired brain growth, CDC has classification for findings
anatomy of central nervous system
brain and spinal cord.Brain-integrated circuit of millions of neurons, receives 15-20% of cardiac output.
Spinal cord-transmits long motor and sensory tracts originating in the brain and synapse with cell bodies in gray matter before exiting to the body. Somatic and autonomic reflexes, motor pattern control centers, sensory and motor modulation. Starts at medulla oblongata and ends at conus medullaris
somatic nervous system
voluntary movements, transmits sensory information
autonomic nervous system
regulates involuntary bodily functions like heart rate and digestion, no conscious control. Always motor and never sensory.
3 parts of Autonomic nervous system
Sympathetic nervous system-fight, flight, fawn, freeze. Secrets norepinephrine. Adrenergic fibers. Catabolic system.
· Parasympathetic nervous system-network of nerves that relaxes your body after periods of stress or danger, also running life-sustaining processes when relaxed. Sitting on the toilet, eating a sandwich, reading a book
· Enteric nervous system - network of neurons in the GI tract that regulates digestion independently of the brain and spinal cord. Controls peristalsis, secretion of enzymes, etc
ganglion
collection of somas in the PNS
afferent
afferent arrives, is sensory, is posterior in the spinal cord, usually found in PNS
efferent
efferent exits, sending signals. Is motor and anterior in the brain
nerve cells
neurons and glial cells. Neurons transmit electrical signals. Glial cells support neurons.Neurons-sensory, motor, interneurons. Have a cell body (soma), axon (carries signals away from cell body), dendrites (receive signals from other cells).
· Glial cells – neuroglia, non-neuronal cells that support and protect neurons. Most abundant cells in CNS. Schwann cells are glial cells that produce myelin in the PNS, along with oligodendrocytes. Glial cells support, protect, maintain homeostasis, communication, regulate inflammation, form the blood-brain barrier, acts as scaffold for neural development, aids, prevents, and helps recover from neural injury. Types are oligodendrocytes, schwann, astrocytes, microglia, ependymal, satellite, enteric.
cranial nerves
12 paired nerves originating from the brain, extending to various parts of the head, face, and neck. They are numbered according to order of origin from the brain.
Oh Oh Oh, To Touch And Feel Very Good Velvet, Ah Heaven
Some Say Marry Money, But My Brother Says Big Brains Matter Most mnemonic to remember function
mnemonic to remember cranial nervesI O lfactory S for sensory
II O ptic S for sensory
III O culomotor M for motor
IV T rochlear M for motor
V T rigeminal B for both
VI A bducens M for motor
VII F acial B for both
VIII V estibular S for sensory
XI G lossopharyngeal B for both
X V agus B for both
XI A ccessory M for motor
XII H ypoglossal M for motor
cranial nerves function and name
Olfactory – smell
Optic – vision, pupil reactivity to light and accommodation
Oculomotor – most extraocular movements, elevation of eyelid, pupil reactivity from external stimulus
Trochlear – ocular movement down and outwardly
Trigeminal – sensation to face and mouth, sensory aspects of corneal reflex
Abducens – turns eye laterally
Facial – majority of facial movement, motor aspect of corneal reflex, taste
Vestibulocochlear – hearing and balance
Glossophargyngeal – taste, gag reflex (sensory component)
Vagus – gag reflex (motor)
Accessory - shoulder movement
Hypoglossal – tongue movement and articulation of speech
bells palsy
facial cranial nerve, number 7. Inflammation, infection leads to compression and nerve damage. Results in facial asymmetry, may cause dysarthria, oral incompetence, difficulty expressing emotions nonverbally, resulting in social isolation and emotional distress. Patients present with weakness and numbness, usually preceded 1-2 days prior by dull ache behind or within the ipsilateral ear. Most are concerned with stroke, if facial asymmetry is present.
Glascow Coma Scale
evaluates person’s LOC and assesses severity of traumatic brain injury by evaluating eye-opening, verbal, and motor responses. Esp useful in TBI
The score is the sum of the scores as well as the individual elements. For example, a score of 10 might be expressed as GCS10 = E3V4M3.
Best eye response (4)
No eye opening
Eye opening to pain
Eye opening to sound
Eyes open spontaneously
Best verbal response (5)
No verbal response
Incomprehensible sounds
Inappropriate words
Confused
Orientated
Best motor response (6)
No motor response.
Abnormal extension to pain
Abnormal flexion to pain
Withdrawal from pain
Localizing pain
Obeys commands
different types of sensory receptors
Nociceptors (Pain)
· Mechanoreceptors (touch, pressure, mechanical)
· Photochemical (light on retina)
· Chemoreceptors (flavors, odors, oxygen levels, osmolarity of body fluids, CO2 levels in blood)
· Thermoreceptors (heat and cold)
· Proprioception (sensing location of body parts)
· Audition and balance (sound and positional movement)
Process of nerve injury and regeneration – mature neurons do not divide, CNS injuries can cause permanent loss of damaged neurons. PNS nerves can repair themselves, thru…
local (when axon is severed, cut ends retract and axolemma covers cut ends, diminishing escape of axoplasm. Macrophages and Schwann cells phagocytize damaged tissue.
· Antegrade (Wallerian) occurs in distal axon, swelling appears on axon terminal, degenerates and loses contact with postsynaptic membrane within 7 days, macrophages and Schwann cells phagocytize remnants of axon terminal, Schwann cells proliferate and form column of Schwann cells enclosed by basal lamina
· Retrograde changes-occur proximal end of injured axon, are similar to retrograde changes but only back to next node of Ranvier. 7-14 days later, new sprouts project from proximal segment guided by schwann cells and enter sustaining substrate of schwann cells for axonal regrowth. Slow, about 1 mm per day and only in myelinated fibers in PNS
name different neurotransmitters
released at specific synapses, transmit signals between neurons, localized effect, acts on neurons nearby, have short effect
· Norepinephrine – brain, spinal cord, ANS synapses. CNS -sleep wake cycles, mood. PNS – sympathetic nerve transmission
· Acetylcholine - brain, spinal cord, neuromuscular junction of skeletal muscle, ANS synapses, decrease is associated with Alzheimer’s
· Dopamine – brain, ANS synapses, Parkinsons happens due to destruction of dopamine-secreting neurons
· Histamine – posterior hypothalamus, arousal, attention
· Serotonin – brain, spinal cord. Mood, anxiety, sleep induction. Elevated in schizophrenia
· GABA – calming
different modulators
influence activity of neurons, can be released more widely, including extracellular fluid, affects are longer and over larger area, can last minutes to hours, modulate activity of other neurotransmitters, influencing release, sensitivity, or overall effect, can affect behavior and physiology of organism
· Endorphins – pain and stress, reduce pain and promote feelings of well-being
· Serotonin-mood, sleep, appetite
· Dopamine – reward, motivation, movement
· Norepinephrine-increases alertness and arousal
· Histamine-allergic reactions and inflammation
· GABA – calming neurotransmitter
alzheimer’s
known genetic component, as certain known genetic mutations increase Alzheimer’s risk. Specific mutations lead to early onset, and other mutations are late onset. Amyloid plaques are extracellular and contain beta-amyloid, which comes from a normal membrane protein called amyloid precursor protein. Functions typically lost first are learning, memory, thinking, planning.
neurofibrillary tangles
intracellular, tangled strands of abnormal tau protein that interfere with normal intracellular transport of nutrients and promote neural cell death
diffuse axonal injuries
DAI occurs with all brain injuries and affects neurons in widespread areas of the brain. May result in altered or loss of consciousness
Brain function of different divisions
most brain functions are from integration of multiple different inputs from different parts
· Prefrontal-goal-oriented behavior, ability to concentrate, short term or recall memory, elaboration of thought and inhibition on limbic area
· Brodmann-premotor, involved in programming motor movements, frontal eye fields
· Broca- speech, language processing,
· Parietal lobe- somatic sensory input
· Occipital lobe- primary visual cortex, visual association
· Temporal lobe-Wernicke’s area, sensory speech area, reception and interpretation of speech, memory consolidation and smell
· Insula – sensory and emotional information, routes information to other areas of the brain
· Corpus callosum – myelinated fibers that connect the two hemispheres, coordinates activities between the two
· Limbic system-amygdala, hippopcampus, fornix, hypothalamus, related autonomic nuclei, mediates emotion and long-term memory thru connections in prefrontal cortex, primitive behavioral responses, visceral reaction to emotion, motivation, mood, feed behaviors, biologic rhythms, sense of smell
· Diencephalon – vital functions, visceral activities, closely associated with limbic system
· Hypothalamus – in diencephalon, maintains constant internal environment, implements behavioral patterns, controls autonomic nervous system function, regulates body temperature, endocrine function, adjusts emotional expression, works thru endocrine system and neural pathways. Visceral and somatic responses, affectual responses, hormone synthesis, sympathetic and parasympathetic activity, temperature regulation, feeding responses, physical expression of emotions, sexual behavior, pleasure-punishment centers, level of arousal or wakefulness
· Substantia nigra in midbrain synthesizes dopamine
· Cerebellum – reflexive, involuntary fine-tuning of motor control, maintaining balance and control of posture
Function of spinal cord
transmit long motor and sensory tracts that originate in the brain and then synapse with cell bodies in gray matter of spinal cord before exiting to the body. Also somatic and autonomic reflexes, motor pattern control centers, sensory and motor modulation.
aging of nervous system
decreased brain weight and size
· fibrosis, thickening of meninges
· narrowing of gyri and widening of sulci
· increase in size of ventricles
· decrease in number of neurons
· decrease in myelin
· lipofuscin deposition (pigment resulting from cellular autodigestion)
· decreased dendritic processes and synaptic connections
· activation of microglial function
· increased neuroinflammation
· loss of protective brain mechanisms
· formation of intracellular tangles
· imbalance in amount and distribution of neurotransmitters
· atrophy of epithelial cells and thickening of basement membrane
· decline in melatonin level
· arterial atherosclerosis, which may cause infarcts and scars
· increased permeability of blood brain barrier
· decreased vascular density
· decreased tendon reflexes
· skeletal muscle atrophy
· progressive deficit in taste and smell
· decreased vibratory sense
· decrease in accommodation and color vision
· decrease in neuromuscular control, change in gait and posture
· sleep disturbances
· memory impairments
· cognitive alterations associated with chronic disease
patho of myastenia gravis
immune system mistakenly produces antibodies that attack acetylcholine receptors, blocking or destroying them. So less acetylcholine is available to stimulate muscle contraction, reduces strength of muscle contractions, leading to weakness. Affects eye muscles, facial and limb muscles. Weakness worsens with muscle use and improves with rest.
theories of pain
· specificity – pain is distinct sensation with specialized receptors, that transmit to pain center in brain, so pain is independent sensation with own dedicated sensory system
· pattern – not specific sensation, but pattern of nerve impulses generated by intense stimulation of nonspecific receptors, use same receptors as other things like heat and cold but frequency of discharge during pain is higher and more intense, resulting in pain
· gate control-modulated in spinal cord before reaching brain. A gate in spinal cord can be closed or opened, allowing or blocking pain signals from reaching brain. Gate is controlled by balance of activity in different nerve fibers. Non-painful stimuli can close the gate, reduce pain. Brain can send signals down spinal cord to modulate pain intensity.
clinical descriptions of pain
nociceptive – includes somatic (fracture, thermal, traumatic injury), visceral (bowel obstruction, endometriosis, gastritis) referred (ureteral distention localizes to testicle, angina localizes to arm, neck, back)
· neuropathic or nonnociceptive – central pain (lesion/dysfunction of brain or spinal cord), peripheral pain (lesion or dysfunction of peripheral nervous system
· neurogenic pain – neuralgia (pain in distribution of nerve), constant-either sympathetically independent or dependent
· temporal (time related) acute or chronic
· regional pain – particular region of body like abdomen, chest, headache, etc
· etiologic pain – caused by disease process like cancer, dentist, inflammation, ischemic, vascular, postoperative
five categories of pain
nociceptive-damage to body tissues, sharp, aching, throbbing
· neuropathic-damage or dysfunction of nervous system, shooting, burning, electrical, nociplastic, radicular, psychogenic
· nociplastic pain – altered nociception in absence of damage of tissue or nervous system, sensations vary widely, examples are fibromyalgia, IBS, chronic low back pain
· radicular pain – compressed or inflamed spinal cord, often radiates, example sciatica
· psychogenic pain – mental or emotional factors, challenging to diagnose and manage
common chronic pain conditions
persistent low back pain
· myofascial pain- muscle spasm, tenderness, stiffness
· chronic postoperative pain – from disruption or cutting of sensory nerves
· cancer pain
· deafferentation pain – damage to peripheral nerve
· hyperesthesias – increased sensitivity and decreased pain threshold to tactical/painful stimuli, diffuse, modified by fatigue and emotion, mixed with other sensations
· hemiagnosia – loss of ability to identify source of pain on one side of body, can produce discomfort, anxiety, moaning, agitation, distress, but no attempt to withdraw, associated with stroke
· phantom limb pain
· complex regional pain syndrome-chronic pain after limb injury, surgery, fractures, autonomic and neuroinflammatory features and pain out of proportion to expected pain
pathogenesis and benefits of fever
exogenous and endogenous pyrogens activate immune cells, to release cytokines (interleukin-1, tumor necrosis factor-alpha, and IL 6, circulate to hypothalamus, and raise body’s temperature set point. Body may increase heat production thru shivering, increased metabolism, and decrease heat loss
Benefits of fever include enhancing activity of immune cells, helping them to combat pathogens. Inhibits pathogen growth that may thrive at normal body temps. Increases vulnerability of rapidly dividing pathogens to destruction, acting in concert with other stressors. Can improve survival during infection. Fever boosts production of cytokines. Fever is considered adaptive mechanism for controlling infection. Higher body temps decrease serum levels of iron, zinc, copper, all of which are needed for bacterial replication. Body switches from burning glucose to metabolism based on lipolysis and proteolysis, depriving bacteria of a food source. Also causes lysosomal breakdown and autodestruction of cells, preventing viral replication in infected cells. Fever should only be suppressed if it is high enough to produce serious side effects, and more studies are needed on this. Febrile seizures occur with temps above 100.4, although most kids usually have temps much higher before seizing.
common sleep disorders
dyssomnias (disorders of initiating and maintaining sleep and disorders of excessive sleepiness, parasomnias (disorders that primarily do not cause a complaint of insomnia or excessive sleepiness)
· dyssomnias include insomnia, restless leg syndrome, OSA, hypersomnia, narcolepsy, circadian rhythm sleep disorders
· parasomnias include three types of arousal disorders such as confusional arousal, sleepwalking, night terrors, rearranging furniture, eating food, violent behavior, bruxism, sleep enuresis, sleep-wake transition disorders such as head banging, sleep talking, nocturnal leg cramps, sleep paralysis, nightmares, sleep apnea, SIDS. More common in children and may be familial.
Pediatric sleep patterns, differences between adults and older adults
· newborns sleep 16-18 hours a day on irregular schedule related to culture and parental/family influences. Sleep cycle is 50-60 minutes long, enter REM immediately on falling asleep, have well developed sleep-wake cycling.
· Older adults sleep less, total sleep time is decreased, takes longer to initiate and maintain sleep. Tend to go to sleep earlier in evening and awaken more frequently during the night and earlier in the morning. Less able than younger individual to tolerate sleep deprivation, and good sleep quality in middle age promote better cognitive function and memory in older age
changes to olfaction and taste with aging
decline in taste buds
· less saliva production
· nerve degeneration, reduces taste signaling to the brain
· reduced flavor perception
· nerve endings in nose responsible for smell degenerate, diminishing olfaction
· reduced mucus production means smells don’t stay in the nose long enough to smell them
· olfactory epithelium changes, shrink and change with age
· weakened olfaction reduces ability to taste, as many flavors are perceived thru taste and smell together
· safety concerns increase with reduced smell and taste
different mechanisms of heat loss and heat regulation
older adults have lower body temps than younger people
· poor responses to environmental temperature extremes due to slowed blood circulation, structural and functional changes in skin
· overall decrease in heat producing activities
· presence of heart and lung diseases
· cold stress in older adults decreases coronary perfusion
· delayed and decreased shivering response
· slowed metabolic rate
· decreased vasoconstrictor and vasodilator responses
· diminished or absent sweating
· decreased amount of brown fat
· desynchronization of circadian rhythm
· undernutrition
· decreased perception of heat and cold
disorders of heat regulation
hyperthermia-body temp increase without hypothalamic set point increase
· can cause nerve damage, coagulation of cell proteins, death
· 105.8, nerve damage can produce convulsions in adults
· Death results at 109.4
· Therapeutic hyperthermia destroys pathologic microorganisms or tumor cells
· Heat cramps occur in abdomen and extremities and follow prolonged sweating and sodium loss, accompanied by fever, rapid pulse rate, increased BP. Tx is dilute salt solutions
· Heat exhaustion is prolonged high core or environmental temps, which cause profound vasodilation and profuse sweating, leading to dehydration, decreased plasma volumes, hypotension, decreased cardiac output, tachycardia. Weakness, dizziness, confusion, nausea, fainting.
· Heat stroke possibly lethal, result of overstressed thermoregulatory center. Can be caused by exertion, overexposure to environmental heat, or impaired physiologic mechanisms for heat loss. High core temp, rapid pulse rate, confusion, agitation, coma. Compilations are cerebral edema, degeneration of CNS, swollen dendrites, renal tubular necrosis, hepatic failure with delirium, coma, eventually death
· Malignant hyperthermia-lethal hypermetabolic complication of rare inherited muscle disorder that may be trigger by inhaled anesthetics and depolarizing muscle relaxants. The syndrome involves either increased myoplasmic calcium release or decreased calcium uptake. This allows intracellular calcium levels to rise, producing sustained, uncoordinated muscle contractions; muscle cell hypermetabolism; increased muscle work; increased oxygen consumption; and a raised level of lactic acid production. Acidosis develops and body temperature rises (body temperature may rise 1°C [1.8°F] every 5 minutes) with resulting tachycardia and cardiac dysrhythmias, hypotension, decreased cardiac output, and cardiac arrest. The syndrome is caused by a defect in the ryanodine receptor. Signs resemble those of coma: unconsciousness, absent reflexes, fixed pupils, apnea, and occasionally a flat electroencephalogram. Oliguria and anuria are common. It is most common in children and adolescents. Treatment includes withdrawal of the provoking agents, body cooling therapy, and drugs that antagonize the ryanodine receptor.
different levels of altered consciousness
Lethargy-severe drowsiness, can be aroused by moderate stimuli, but falls back quickly to sleep
· Obtundation-similar but worse than lethargy, reduced alertness, slowed responses to stimulation, increased periods of sleep
· Stupor-only vigorous and repeated stimuli can arouse person, then quickly lapses back into unresponsiveness when left undisturbed
· Coma-unarousable unresponsiveness, unresponsive to all stimuli
· Confusion-state of disorientation or uncertainty about surroundings
· Delirium-state of acute confusion, often with mild disorientation, restlessness, possible hallucinations
· Syncope -brief loss of consciousness, often referred to as fainting
different patterns of breathing
Eupnea-normal
· Tachypnea-rapid
· Bradypnea-slow
· Irregular-cheyne stokes
criteria of brain death
Completion of all appropriate diagnostic and therapeutic procedures with no possibility of brain function recovery.
· Unresponsive coma, no motor or reflex movements
· No spontaneous respirations, apnea
· No brainstem functions-ocular responses to head turning or caloric stimulation, dilated, fixed pupils, no gag or corneal reflex
· Persistence of these signs for appropriate observation period
· irreversible cessation of function of entire brain, including brainstem and cerebellum.
· When there is no evidence of brain function for an extended period.
· A flat or isoelectric EEG for 6-12 hours in person who is not hypothermic and has no depressant drugs in the system.
acute confusional states can be caused by
drug intoxication, alcohol of drug withdrawal, metabolic disorders-hypoglycemia, thyroid storm, brain trauma or surgery, post anesthesia, febrile illness, heat stroke, electrolyte imbalance, dehydration, heart, kidney, liver failure
delirium
difficulty concentrating, focusing attention, restlessness, irritability, insomnia, tremulousness, poor appetite. Unpleasant or terrifying dreams, hallucinations, delusions. Fully developed delirium is completely inattentive, and perceptions are grossly altered, with extensive misperception and misinterpretation. Conversation is incoherent. Person appears distressed and often perplexed. Frank tremor and high levels of restless movement are common. May be violent, cannot sleep, may be flushed, has dilated pupils, rapid pulse rate, elevated temp, profuse sweating.
causes of dementia
· Infection-encephalitis, meningitis, neurosyphilis
· Chronic SDH
· Nutritional deficiencies
· Alcohol and sedative chronic intoxication
· Thyroid abnormalities
· Chronic hepatic encephalopathy
· Cerebral vasculitis
· Sarcoidosis
· Frontal and temporal lobe tumors
· Pseudodementia of depression
· Medical side effects
· Anticholinergics
· Antihypertensives
· Antihistamines
· Alzheimers, dementia with Lewy bodies, frontotemporal dementia, pick disease, huntingtons, parkinsons
· Vascular dementia
· Multi-infarct
· Strategic single infarct
· Binswanger disease-diffuse white matter disease
· Amyloid angiopathy
· Creutzfeldt-jakob
· Postencephalitic dementia
· HIV dementia
neuro dysfunction in children
wide range of conditions affecting brain, spinal cord, nerves, impacting various functions like movement, cognition, communication. Epilepsy, cerebral palsy, autism, developmental delays, migraines, headaches, neuromuscular disorders, brain tumors, stroke, encephalitis, meningitis, functional neurological disorders
