Unit 3 Pathophysiology - Chapter 17 Alterations in cognitive systems, cerebral hemodynamics, and motor fx Flashcards
3 systems that support cognitive
- attentional system
- memory and language system
- affective or emotive system
Full consciousness
- awareness of self + environment, including abiliy to respond to external stimuli w/ different resposnes
two components
1) arousal (state of awakeness)
2) awareness (content of thought)
Level of consciousness can range from..?
Alert/oriented to confusion and coma
Altered breathing pattern and level of coma?
- Level of hemispheric and brain dysfunction
Pupillary changes
- level of brainstem fx
- drug action
- response to hypoxia and ischemia (dilate)
Abnormal eye movements
- nystagmus (repetitive, uncontrolled movements)
- divergent gaze
- d/t alterations in brain stem
Loss of cortical inhibition and decreased consciousness
- abnormal flexor and extensor movements
Brain death
- irreversible total brain damage
- unable to maintain cardiac + respiratory + other vital fx
Cerebral death
- irreversible coma is death of cerebral hemispheres exclusive of brainstem and cerebellum (little brain; feature of hindbrain, under temporal and occiptal lobes of cerebral cortex)
Can arousal return in a vegetative state?
Yes, arousal can return with a minimally conscious state
* content of thought (awareness) is absent or markedly reduced
Locked-in syndrome (ventral pontine syndrome)
- level of arousal and awareness (content of thought) intact
- BUT efferent pathways disrupted w/ complete paralysis
- rare disorder of nervous system; able to communicate with blinking eye movements (usually retain upper eye lid control and vertical eye movement d/t sparing of mid-brain tectum)
Akinetic mutism
- neurobehavioral state
- severe loss of motivation to move or inability to voluntarily start motor response, or BOTH
Deficit in selective attention
- Brain stem
- parietal lobe structures
- pulvinar nucleus of thalamus (visual attention fx center)
- neglect syndrome – individual cannot focus on selective stimuli and as a result NEGLECTS those stimuli
Amnesia - retrograde, anterograde, or global
- retrograde (loss of past memories)
- anterograde (retention of old memories but inability to form new ones)
- global (combination of both)
Frontal areas of brain
- vigilance, detection, and working memory (temporary information storage)
- Vigilance deficit — person cannot maintain search & scanning activities
- Detection deficit — person is unmotivated and unable to use feedback
Data processing deficit
- issue w/ recognizing and processing sensory information
1) Agnosia - defect of recognitio and can be tactile, visual or auditory; caused by sensory or interpretive area of cerebral cortex
2) Aphasia - impariment of comprehension (sensory) or production of language (expressive or motor)
3) Acute confusional states – described as defects in attention and coherence of thoughts + actions (e.g hyperactive delirium – r/t ANS)
Types of aphasia
1) expressive aphasia – loss ability to produce spoken or written langauge with slow or difficult speech (broca’s area in frontal cortex, left side back, left hemisphere [responsible for langauge and speech]) — expressive
2) receptive aphasia – disturbance in understanding all language, such as verbal and reading comprehension (wernicke’s area in posterior segement of temporal lobe, left side/hemisphere) — sensory
3) transcortial aphasia - motor, sensory, or mixed (functional repetition skills) – broca or lesion outside language areas on left hemisphere)
4) Global aphasia - anterior and posterior speech area, with expressive and receptive aphasia
5) Anomic aphasia - inability to name objects, people, or qualities
Dementia
- acquired impairment of intellectual function, memory, and language w/ alteration in behavior
- d/t trauma, vascular disease, infection, progressive neurodegeneration
Alzheimer’s disease
- progressive cognitive deterioration and is characterized by beta-amyloid deposits (triggers a complex cascade of events ending in neuronal cell death, loss of neuronal synapses, and progressive neurotransmitter deficits; all of these effects contribute to the clinical symptoms of dementia) and neurofibrillary tangles in the cerebral cortex and subcortical gray matter
- other pathophysiology: 1) sustain immune response + inflammation, glucose metabolism derangement, and prion-like self-replicating properties r/t deposits and tau tangles
- cholinesterase inhibitors can sometimes temporarily improve cognitive fx
- Two epsilon-4 alleles (increased risk), epsilon-2 allele (may be decreased risk)
- HTN, diabetes, dyslipidemia and smoking can increase risk
SX
* loss of short term memory – eg, asking repetitive questions, frequently misplacing objects or forgetting appointments
* Impaired reasoning, difficulty handling complex tasks, and poor judgment (eg, being unable to manage bank account, making poor financial decisions)
* Language dysfunction (eg, difficulty thinking of common words, errors speaking and/or writing)
* Visuospatial dysfunction (eg, inability to recognize faces or common objects)
* Behavior disorders (eg, wandering, agitation, yelling, persecutory ideation) are common.
Vascular dementia
Vascular cognitive impairment and dementia is the 2nd most common cause of dementia among older people. It is more common among men and usually begins after age 70. It occurs more often in people who have vascular risk factors (eg, hypertension, diabetes mellitus, hyperlipidemia, smoking) and in those who have had several strokes. Many people have both vascular dementia and Alzheimer disease.
Subcortical ischemic vascular cognitive impairment and dementia is caused mainly by small vessel disease. Subcortical lacunar lesions may develop, as may white matter lesions, which are mainly subcortical. Subcortical ischemic vascular cognitive impairment and dementia may include
- Multiple lacunar infarction: Multiple lacunar infarcts occur deep within hemispheric white and gray matter.
- Binswanger dementia: This variant is associated with severe, poorly controlled hypertension and systemic vascular disease. It causes diffuse and irregular loss of axons and myelin with widespread gliosis, tissue death due to an infarction, or loss of blood supply to the white matter of the brain.
Multi-infarct dementia affects medium-sized blood vessels, leading to large cortical infarcts.
Post-stroke dementia is immediate and/or delayed irreversible cognitive decline that begins within 6 months after stroke.
Mixed dementia is characterized by both vascular cognitive impairment, dementia, and other coexisting pathology (eg Alzheimer disease, dementia with Lewy bodies).
sx:
* memory loss, impaired executive function, difficulty initiating actions or tasks, slowed thinking, personality and mood changes, language deficits
* vascular cognitive impairment and dementia tends to cause memory loss later and to affect executive function earlier
As the disease progresses, focal neurologic deficits often develop:
- Exaggeration of deep tendon reflexes
- Extensor plantar response
- Gait abnormalities
- Weakness of an extremity
- Hemiplegias
- Pseudobulbar palsy (unable to control facial movements) with pathologic laughing and crying
- Other signs of extrapyramidal dysfunction
- Aphasias
Dementia vs delirium
Dementia should not be confused with delirium, although cognition is disordered in both. The following helps distinguish them:
- Dementia affects mainly memory, is typically caused by anatomic changes in the brain, has slower onset, and is generally irreversible.
- Delirium affects mainly attention, is typically caused by acute illness or drug toxicity (sometimes life threatening), and is often reversible.
Frontotemporal dementia (FTD)
About half of FTDs are inherited; most mutations involve chromosome 17q21-22 and result in abnormalities of the microtubule-binding tau protein; thus, FTDs are generally considered tauopathies.
Pick disease is a term used to describe pathologic changes in FTD, including severe atrophy, neuronal loss, gliosis, and presence of abnormal neurons (Pick cells) containing inclusions (Pick bodies)
- affects personality, behavior, and usually language function (syntax and fluency) more and memory less than does Alzheimer disease
- abstract thinking and attention are impaired
- diffculty sequencing, visuopatial and construction tasks less affected
- orientation is preserved, but info retrieval of info may be impaired
depending on which part of brain - frontal release signs
- some develop motor neuron disease w/ muscle atrophy, weakness, fasciculations (twitching of individual muscle), bulbar symptoms (eg, dysphagia, dysphonia, difficulty chewing), dysphonia, difficulty chewing, aspiration pneumonia and early death
Generalized-onset seizures
- both hemispheres
- awareness is usually impaired and conscious is usually lost
1) Generalized-onset motor seizures (motor activity is usually bilateral from the onset) [invovle changes in muscle activity, which can be limb stiffening, jerking, and loss of muscle control or convulsions]
* tonic-clonic seizures // formerly grand mal (Abrupt loss of consciousness, body stiffening (tonic) and then shaking (clonic); may begin with sudden cry, sometimes loss of bladder control or biting of tongue; usually lasts about two minutes, followed by a period of confusion, agitation, and fatigue; headaches and soreness are common afterwards)
* clonic seizures (sustained rhythmic jerking occurs in the limbs on both sides of the body and often in head, neck, face, and trunk. Clonic seizures usually occur in infants and should be distinguished from jitteriness or shuddering attacks. Clonic seizures are much less common than tonic-clonic seizures.)
* tonic seizures (stiffening of body muscles with falling; loss of consciousness; can occur in sleep; more common in infants and children)
* atonic seizures (sudden, brief loss of muscle tone with falling (drop attacks); usually no loss of consciousness
* myoclonic seizures (sudden brief shocklike jerks or twitches of the arms and/or legs; may drop things; no impairment of consciousness; frequently occurs shortly after awakening; not preceded by stiffening)
* myoclonic-tonic-clonic (myoclonic jerking [brief bursts] followed by tonic and clonic movements)
* myoclonic-atonic (myoclonic jerking following by atonia)
* epileptic spasms (infantile spasm) – Spasms begin with a sudden, rapid, tonic contraction of the trunk and limbs, sometimes for several seconds. Spasms range from subtle head nodding to contraction of the whole body. They involve flexion, extension, or, more often, both (mixed). The spasms usually occur in clusters, often several dozen, in close succession and occur typically after children wake up and occasionally when falling asleep. Sometimes, at first, they are mistaken for startles. [developmental may be present before onset of infantile spasm]
2) Generalized-onset nonmotor seizures (may include motor activity) [behavior arrest or mvmt stops and person just stares]
* Typical absence seizures (petit mal seizure formerly) – consist of 10-30 sec loss of consciousness w/ eyelid fluttering; axial muscle (tail, trunk and eyeballs) may or may not be lost; do not fall or convulse instead abruptly stop activity and then resume abruptly with not postictal sx or knowledge that seizure occurred
Occasional eyelid fluttering or nodding of the head or other “automatic” hand or mouth movements (
* Atypical absence seizures (part of Lennox-Gastaut syndrome - form of severe epilepsy)
a) differ from typical absence seizure as follow:
They last longer.
Jerking or automatic movements are more pronounced.
Loss of awareness is less complete.
* Myoclonic absence seizures, the arms and shoulders jerk rhythmically (3 times/second), causing progressive lifting of the arms. Typically, these seizures last 10 to 60 seconds. Impairment of awareness may not be obvious. Myoclonic absence seizures are caused by various genetic disorders; sometimes the cause is unknown.
* Eyelid myoclonia consists of myoclonic jerks of the eyelids and upward deviation of the eyes, often precipitated by closing the eyes or by light. Eyelid myoclonia can occur in motor as well as nonmotor seizures.
A postictal state often follows generalized-onset seizures; it is characterized by deep sleep, headache, confusion, and muscle soreness; this state lasts from minutes to hours. Sometimes the postictal state includes Todd paralysis (a transient neurologic deficit, usually weakness, of the limb contralateral to the seizure focus).
Focal-onset seizure
- aura is common
- Focal-onset seizures originate in networks in one hemisphere and may originate in subcortical structures. They may be discretely localized or more widely distributed.
Classified as:
* Focal aware seizures (formerly, simple partial seizures) – Recall, responsiveness, and consciousness are intact
1) Jacksonian seizure: begin in one hand then march up one arm
Jacksonian seizures are partial seizures that begin in one part of the body such as the side of the face, the toes on one foot, or the fingers on one hand. The jerking movements then spread to other muscles on the same side of the body.
2) fencing posture - begin with an arm raising and the heard turning toward raised arm
* Focal impaired-awareness seizures (formerly, complex partial seizures) // complex partial seizure [if awareness is imparied during any part of the seizure] – loss of consciousness or awareness; vague or dreamlike state // retain some awareness of environment
1. Oral automatisms (involuntary chewing or lip smacking)
1. Limb automatisms (eg, automatic purposeless movements of the hands)
1. Utterance of unintelligible sounds without understanding what they say
1. Resistance to assistance
1. Tonic or dystonic posturing of the extremity contralateral to the seizure focus
1. Head and eye deviation, usually in a direction contralateral to the seizure focus
1. Bicycling or pedaling movements of the legs if the seizure emanates from the medial frontal or orbitofrontal head regions
Motor: (usually w/ no loss of consciousness + inovles only one side or limb)
* Automatisms (coordinated, purposeless, repetitive motor activity)
* Atonic (focal loss of muscle tone)
* Clonic (focal rhythmic jerking)
* Epileptic spasms (focal flexion or extension of arms and flexion of trunk)
* Hyperkinetic (causing pedaling or thrashing)
* Myoclonic (irregular, brief focal jerking)
* Tonic (sustained focal stiffening of one limb or one side of the body)
Nonmotor:
* Autonomic dysfunction (autonomic effects such as gastrointestinal (GI) sensations, a sense of heat or cold, flushing, sexual arousal, piloerection, and palpitations)
* Behavior arrest (cessation of movement and unresponsiveness as the main feature of the entire seizure)
* Cognitive dysfunction (impairment of language or other cognitive domains or positive features such as déjà vu, hallucinations, illusions, or perceptual distortions)
* Emotional dysfunction (manifesting with emotional changes, such as anxiety, fear, joy, other emotions, or affective signs without subjective emotions)
* Sensory dysfunction (causing somatosensory, olfactory, visual, auditory, gustatory, or vestibular sensations or a sense of heat or cold)
can evolve into generalized-onset tonic-clonic seizure (focal-to-bilateral tonic-clonic seizure)
Lennox-Gastaut syndrome
Epileptic syndrome with onset in early childhood, 1 to 5 years of age; includes various generalized seizures (tonic-clonic, atonic [drop attacks], akinetic, absence, and myoclonic); EEG has characteristic “slow spike and wave” pattern; results in intellectual disability and delayed psychomotor developments
Juvenile myoclonic epilepsy
Generalized epilepsy syndrome with onset in adolescence; multifocal myoclonus; seizures often occur early in morning, aggravated by lack of sleep or after excessive alcohol intake; occasional generalized convulsions; requires long-term medication treatment
Status Epilepticus
Continuing or recurring seizure activity in which recovery from seizure activity is incomplete; unrelenting seizure activity can last 30 min or more; other forms can evolve into status epilepticus; medical emergency that requires immediate intervention
