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Impaired Consciousness

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Last Updated: 02 July 2021

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Anatomical structures are known to regulate the level of consciousness. Medial view. B. Lateral view. Cortical components of the consciousness system include the medial and lateral fronto-parietal association Cortex, anterior and posterior cingulate, precuneus and retrosplenial Cortex. Subcortical components include the basal forebrain, hypothalamus, thalamus and upper brainstem activating systems. Note that other circuits such as basal ganglia and cerebellum may also participate in attention and other aspects OF consciousness. Behavioral impairment during seizures. Percent correct responses are shown over time before, during and after seizures. Performance on more difficult continuous performance tasks declines rapidly for letters present just before seizure onset and recover quickly after seizures end. Impaired performance on simpler repetitive tapping task task was more transient than on CPT, did not begin until after seizure onset, and was less severely impaired during seizures than on CPT task. The results are based on a total OF 53 seizures in 8 patients. B. EEG signal power changes abruptly at the beginning and end of seizures. Average time-frequency dynamics of spike-wave discharges are shown for EEG channel F7. A total of 54 seizures were analyze. FMRI percent change increases and decreases are show, with a display threshold OF 0. The 5% ictal time period of seizures was Scale to 6. 6s, and preictal, ictal, and postictal time periods temporally align across all seizures. Early fMRI signal increases were seen well before seizure onset in medial orbital frontal, frontal polar, cingulate, lateral parietal, precuneus, and lateral occipital Cortex. After seizure onset, fMRI increases progress to also involve the lateral frontal and temporal cortex. Following the end OF seizures, fMRI increases were seen in the medial occipital Cortex, and lastly in the thalamus. FMRI signal decreases occur later and continue well after seizure end, showing initial strong involvement OF fronto-parietal association Cortex. The data are from a group analysis OF 51 seizures in 8 patients. Positive and negative correlations are shown between the cerebellum and other brain regions. A. Surface rendering. B. Coronal sections. Significant positive correlations with cerebellar blood flow changes were found in the upper brainstem tegmentum and thalamus. Negative correlations were found with bilateral fronto-parietal association Cortex, anterior and posterior cingulate and precuneus. Statistical parametric mapping analysis was across patients with extent threshold, k = 125 voxels, and height threshold, P = 0. 01. Under normal conditions, upper brainstem-diencephalic activating systems interact with the Cerebral Cortex to maintain normal consciousness. B. Focal seizure involving mesial temporal lobe. If seizures remain confine, then simple-partial seizure will occur without impairment of consciousness. Intracranial EEG recordings show fast polyspike activity in the temporal lobe. C. Spread OF seizure activity from temporal lobe to midline subcortical structures. Propagation often occurs to contralateral mesial temporal as well. D. Inhibition OF subcortical activating systems leads to depressed activity in the bilateral fronto-parietal association Cortex, and to loss OF consciousness. Intracranial EEG recordings from the fronto-parietal association Cortex show slow wave activity resembling deep sleep.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions

Vegetative state

A vegetative state that lasts for more than 1 month is considered a persistent vegetative state. Most people with persistent vegetative state do not recover any mental function or ability to interact with the environment in a meaningful way. However, few people with persistent vegetative state improve enough that diagnosis is change to a minimally conscious state. In people in minimally conscious state, awareness is severely but not completely impaired. When any recovery occur, cause was usually brain damage due to head injury, not a disorder that results in the brain being deprived of oxygen. Also, recovery is often very limited. For example, people may reach for any and all objects or may utter the same word over and over. Rarely, people in persistent vegetative state due to head injury continue to slowly improve over months to years. The vegetative state occurs when cerebrum is severely damage, but the reticular activating system is still functional. A Reticular activating system controls whether a person is awake. It is a system of nerve cells and fibers located deep within the upper part of the brain stem. Most people in vegetative state have lost all capacity for awareness, think, and conscious behavior. However, in few people, functional magnetic resonance imaging and electroencephalography have detected evidence of some brain activity suggesting possible awareness. In these people, cause was usually head injury, not a disorder that result in the brain being deprived of oxygen. When people were asked to imagine moving part of their body, these tests show appropriate brain activity for such action. However, these tests cannot determine how much awareness these people have. Awareness that can be detected only by these tests is called covert consciousness. Any recovery from vegetative state is unlikely after 1 month if the cause was anything other than head injury. If the cause was head injury, recovery is unlikely after 12 months. However, few people improve over period of months or years. Rarely, improvement occurs late. After 5 years, about 3% of people recover ability to communicate and understand, but few can live independently, and none can function normally.


Treatment and care

Treatment can't ensure recovery from a state of impaired consciousness. Instead, supportive treatment is used to give the best chance of natural improvement. Providing nutrition through feeding tube makes sure person is move regularly so they don't develop pressure ulcers gently exercising their joints to prevent them becoming tight, keeping their skin clean, managing their bowel and bladder, keeping their teeth and mouth clean, offering opportunities for periods of meaningful activity-such as listening to music or watching television, being show pictures or hearing family members talking


Recovery

Many patients emerge spontaneously from VS / UWS within a few weeks. Some people improve gradually, whereas others stay in a state of impaired consciousness for years. Many people never recover consciousness. Chances of recovery depend on the extent of injury to the brain and age, with younger patients having a better chance of recovery than older patients. Generally, adults have about 50 percent chance and children 60 percent chance of recovering consciousness from VS / UWS within the first 6 months in case of traumatic brain injury. For non-traumatic injuries such as strokes, recovery rate falls within the first year. After this period, the chance that VS / UWS patient will regain consciousness is very low and, of those patients who do recover consciousness, most experience significant disability. The longer patient is in VS / UWS, the more severe resulting disabilities are likely to be. Some patients who have entered vegetative State go on to regain a degree of awareness. The likelihood of significant functional improvement for VS / UWS patients diminishes over time. There are only isolated cases of people recovering consciousness after several years. Few people who do regain consciousness after this time often have severe disabilities caused by damage to their brain.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions

Minimally conscious state

Minimally conscious State is a condition of severely altered consciousness that is distinguished from vegetative state by the presence of minimal but clearly discernible behavioral evidence of self or environmental awareness. There is increasing evidence from neurobehavioral and neuroimaging studies that important differences in clinical presentation, neuropathology and functional outcome exist between MCS and VS. This chapter describes characteristic features of MCS, discusses specialized assessment techniques required for accurate diagnosis, outlines potential pathophysiologic mechanisms underlying MCS, describes effectiveness of existing treatment interventions, identifies key issues in clinical practice and offer New directions for further scientific inquiry.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions

Treatment and care

Treatment cant ensure recovery from a state of impaired consciousness, however supportive treatment is used to give the best chance of natural improvement. This can involve: providing nutrition through feeding tubes, making sure person move regularly so they do not develop pressure ulcers, gently exercising their joints to prevent them becoming tight, keeping their skin clean, managing their bowel and bladder-for example, using a catheter to drain bladder, keeping their teeth and mouth clean efforts should be make to establish functional communication and environmental interaction when possible. Offering opportunities for periods of meaningful activity-such as listening to music or watching television, being shown pictures or hearing family members talking visual-showing photos of friends and family, or favourite film hearing-talking or playing favourite song, smell-putting flowers in the room or spraying favourite perfume touch-holding their hand or stroking their skin with different fabrics in all circumstances, patient should be treat with dignity, and caregivers should be cognisant of patients potential for understanding and perception of pain. In early MCS, prevention of complications and maintenance of bodily integrity should be emphasise because of the likelihood of further improvement. While not empirically validate, families have reported benefits from Arousal regimes, such as those implemented by Dr Ted Freeman. Therapy involves family members taking Coma patient through a regimen of controlled auditory, visual and physical stimulation for up to six hours day every day. A person with experience in neurologic assessment of patients with impaired consciousness should be primarily responsible for establishing diagnosis and prognosis and for coordinating clinical management. An Additional opinion of a physician or other professional with particular expertise in evaluation, diagnosis, and prognosis of patients in MCS is recommended when assessment will impact critical management decisions.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions

Withdrawing nutritional support

If a person is in a state of impaired consciousness for a long time, usually at least 12 months, it may be recommended that nutritional support is withdraw. This is because: there is almost no chance of recovery by this point. Prolonging life would have no benefit to individual concerned prolonging treatment would offer only false hope and cause unnecessary emotional distress to friends and family of person concerned medical team will discuss issue with family members, and will give them time to consider all implications. If the court agrees with the decision, nutritional support will be withdrawn and the person will die peacefully within a few days or weeks.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions

Consciousness and the brain

There are two main schools of thought on defining consciousness. In one approach, certain aspects of consciousness call qualia are considered inaccessible to third-person investigation, and can only be described through first-person experience 5 6. Note that in this approach by definition, some aspects of consciousness cannot be explained based on external observations, and are therefore outside the domain of scientific research. In another approach, no priority limits are set on potential domain of scientific investigation, and the best explanation for first-person experience is included as possible subject of empiric study 7 8. According to this second approach, all aspects of consciousness may be better understood through scientific investigation, though of course much work remains to be done Regardless of which of these alternatives is prefer, most philosophers and scientists agree that the term consciousness applies to a broad collection of processes of which qualia are just one part. From a neurological perspective, most or all of these processes are implemented through specific brain networks. Plum and Posner introduce a classic distinction between brain systems that regulate level of consciousness and those that provide content of consciousness 9 10. Content of consciousness can be viewed as substrateit is what we are conscious of, and includes all of hierarchically organized sensory and motor systems, memory, and emotions / drives. Brain networks serving content of consciousness are the subject of most research in neuroscience. The level of consciousness determines whether we are awake, attentive and aware of the content of consciousness. In analogy to sensory, motor and other cortical-subcortical brain systems, we can refer to specialized structures involved in regulating level of consciousness as consciousness system 11 12.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions

Types of decreased consciousness

A special problem of critically ill patients is sudden onset of altered consciousness that persists longer than is typical for most seizures, but may be due to the reversible cause of stupor-Coma. Differential diagnosis of alteration of consciousness in acute inpatient setting is somewhat narrower if symptoms are transient. Thorough clinical evaluation is necessary, with special emphasis on neurologic etiologies, review of laboratory values, and vital signs. 8 Table 3 summarizes some of the more common etiologies. Strokes and TIAs occur in critically ill patients, triggered by prothrombotic states, inflammation, infections, cardiac arrhythmias, paradoxical emboli, and various other causes. Rarely, decreased level of consciousness is only a manifestation of TIA, but if deficits are transient, diminished responsiveness might be only sign note and report by intensive care unit staff. Nonconvulsive status epilepticus is increasingly recognized as cause of altered consciousness in critically ill. In one series, 19% of all ICU patients with unexplained Coma had subclinical seizures on continuous EEG monitoring. 9 While NCSE may present as waxing-waning twilight state with intermittent automatisms, all too often the level of responsiveness is invariant over hours, and automatisms are absent. 10 EEG is absolutely necessary in order to exclude NCSE. While routine EEG is long enough to detect recurring partial electrographic seizures or spike-wave discharges of NCSE, longer EEG recording is necessary to exclude acute repetitive seizures as condition that also can cause persisting but reversible stupor. In the absence of NCSE and acute repetitive seizures, EEG data measure severity of organic encephalopathies of all types. Critically ill patients often have had prior events of brief unconsciousness, and contacting lay and professional witnesses of these events is as important as in outpatient and ED evaluations. General factors at play include acute hepatic or renal failure, infections, and fever. Hypertensive encephalopathy can be quite transient. 11 Postoperative patients in stupor-Coma have detailed records of intraoperative blood pressure monitoring, but periods of hypotension during transfers between postanesthesia units and ICUs may be poorly document. There is often alteration of drug absorption, distribution with changes in intravascular volumes and protein binding, drug metabolism and elimination, and drug-drug interactions. 12 thorough review of drugs is needed An important and common phenomenon of alteration of alertness in the ICU, often fluctuating, is Delirium. Recent data have established a high prevalence of Delirium in the ICU, up to 80% in high-risk medical ICU patients. 13 Delirium is an independent predictor of increased mortality and worse outcome. Recognize risk factors for Delirium in ICU include sepsis, fever, exposure to sedatives and opiates, disruption of sleep, preexisting dementia, older age, and acute sensory deprivation.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions

Summary

Evaluating transient impairment of consciousness is critical to diagnosing epileptic seizures, syncope, parasomnias, organic encephalopathies, and psychogenic nonepileptic seizures. Effective evaluation of episodic unconscious events demands interactive interviewing of patients and witnesses of events, with judgment as to historians' observational abilities. When generalizing tonic-clonic seizures have been witnessed by medical staff or other reliable observers, search for concomitant nonconvulsive events and for comorbid illnesses often elucidate diagnoses unsuspected by referring physician. Consultation for stupor-coma should not miss potentially reversible acute severe encephalopathy, particularly when reversibility requires timely therapy. Perspicacious analyses of complex cognitive-motor phenomena support judicious application of diagnostic procedures, including brief or prolong EEG and video-EEG, EKG tilt-table testing, EKG loop monitoring, and brain imaging. Transient alteration of consciousness is a major clinical challenge for neurology. Evaluating transient impairment of consciousness is critical to diagnosing epileptic seizures, syncope, parasomnias, organic encephalopathies, and psychogenic nonepileptic seizures. Primary care physicians, general hospitalists, and emergency physicians struggle with these diagnoses in all but their most straightforward presentations, and typically baffle when faced with the coexistence of multiple causes of episodic alteration of consciousness within 1 patient. Consulting a neurologist is best equip among physicians to direct diagnostic process in determining causes of transiently impaired consciousness, whether these are amenable to neurologic therapeutics or are best treated by a cardiologist, psychiatrist, or neurosurgeon. A neurologist must enter patient care arena with extensive knowledge of causes of transiently impaired consciousness, which this review presume. Consciousness is often considered by its form and its content, and with many limitations, both form and content are objectively evaluated based on an individual's behavior. The patient's subjective appreciation of impaired consciousness is in itself likely to be impaired, but sometimes provides useful clues to the cause of impairment. This review aims to assist general neurologists in honing strategies and techniques to maximize recovery of information from patients and witnesses of impaired consciousness events, and to push beyond wishful mindsets of patient, family members, and even referring physicians, who may bias their information toward diagnoses that are unlikely to recur, are easily treat, or are nonpsychiatric. Increase sensitivity and specificity of prolonged electrophysiologic tests are associated with greater cost and relative inconvenience, and this review also aims to assist consulting neurologist in mastering indications and applications of results for each test.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions

Patients and methods

Eye Abnormalities: Pupils may be dilate, pinpoint, or unequal. One or both pupils may be put in midposition. Eye movement may be dysconjugate or absent or involve unusual patterns. Homonymous hemianopia may be present. Other abnormalities include absence of blinking in response to visual threat, as well as loss of oculocephalic reflex, oculovestibular reflex, and corneal reflexes. Diagnosis and initial stabilization should occur simultaneously. Temperature is a measure to check for hypothermia or hyperthermia; if either is present, treatment is started immediately. Glucose levels must be measured at bedside to identify low levels, which should also be corrected immediately. If trauma is involve, neck is immobilize until clinical history, physical examination, or imaging tests exclude unstable injury and damage to the cervical spine. Medical identification bracelets or contents of a wallet or purse may provide clues to the cause. Relatives, paramedics, police officers, and any witnesses should be questioned about the circumstances and environment in which the patient was find; containers that may have held food, alcohol, drugs, or poisons should be examined and saved for identification and possible chemical analysis. The Glasgow Coma Scale was developed to assess patients with head trauma. For head trauma, score assigned by Scale is valuable prognostically. For Coma or impaired Consciousness of any cause, Scale is Use because it is a relatively reliable, objective measure of severity of unresponsiveness and can be used serially for monitoring. Scale assign Points based on Responses to stimuli. Pupillary Responses and extraocular movements provide information about brain stem function. One or both pupils usually become fixed early in Coma due to structural lesions, but pupillary Responses are often preserve until very late when Coma is due to diffuse metabolic disorders, although Responses may be sluggish. If one pupil is dilate, other causes of anisocoria should be consider; they include past ocular trauma, certain headaches, and use of scopolamine patch. If nystagmus away from irrigated ear also occur, patient is conscious and psychogenic unresponsiveness is likely. In conscious patients, 1 mL of ice water is often enough to induce ocular deviation and nystagmus. Thus, if psychogenic unresponsiveness is suspect, small amount of water should be used because cold caloric testing can induce severe vertigo, nausea, and vomiting in Conscious patients. If the cause is not immediately apparent, noncontrast Head CT should be done as soon as possible to check for masses, hemorrhage, edema, evidence of bone trauma, and hydrocephalus. Initially, noncontrast CT rather than contrast CT is preferred to rule out brain hemorrhage. MRI can be done instead if immediately available, but it is not as quick as newer-generation CT scanners and may not be as sensitive for traumatic bone injuries. MRI or contrast CT can then be used if noncontrast CT is not diagnostic; it may detect isodense subdural hematomas, multiple metastases, sagittal sinus thrombosis, herpes encephalitis, or other causes missed by noncontrast CT.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions

Results

Diagnosing impaired consciousness is always a challenge. In many situations in the emergency room, doctors have to save time by doing other examinations firstfor example, for hypoglycaemic coma, drug poisoning, and hepatic encaephalopathy. As doctors are not prepared to risk missing abnormality, the use of computed tomography to screen patients with impaired consciousness for brain lesion has become routine. Compute tomography of cranium visualises brain lesions, but it does not identify extrinsic or metabolic brain dysfunctions, which affect more than half of patients with impaired consciousness. 2 previous studies suggest that vital signsblood pressure and pulse rateare useful diagnostic tools in patients with impaired consciousness. Patients with acute stroke and those with increased intracranial pressure often have hypertension. 3 4 Cushing response is a well recognised clinical manifestation of increased intracranial pressure. 5 Hypotension and tachycardia, on the other hand, are usual in states of depressed consciousnessfor. Example, intoxication, endocrine diseases, and sepsisbecause of metabolic brain dysfunction. 6 we examine whether vital signs could be used to distinguish between patients with impaired consciousness who are likely to have intracranial lesion from those who are not.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions

Discussion

Nowadays, there is scarce information available regarding incidence and risk factors of IC at Stroke onset in LHI, relationship between IC at Stroke onset and Stroke-related complications and clinical outcomes in LHI patients has not been systematically examine. In the present study, we find that IC occurs in 1 out of every 3 LHI patients at Stroke onset. Independent risk factors of IC at Stroke onset were initial Stroke severity assessed by baseline NIHSS score and atrial fibrillation, while dyslipidemia appeared to protect against IC at Stroke onset. IC at Stroke onset was associated with a higher frequency of Stroke-related complications, especially brain edema and pneumonia. LHI patients with IC at Stroke onset had higher rates of In-Hospital death, 3-month mortality, and 3-month unfavorable outcome. However, after adjusting for age, baseline NIHSS score and other confounders, IC at Stroke onset was not an independent predictor of clinical outcome in LHI patients. Although sudden impairment of consciousness at Stroke onset in LHI patients is common in clinical practice, incidence and risk factors of IC at Stroke onset in LHI patients are poorly understood. Previous studies of IC after Stroke usually assess consciousness states at time of hospital admission or after hospitalization. Data from various Stroke research suggests that about 14. 4-53. 8% of large supratentorial infarction patients experience IC on admission when admitted to Hospital within 6-48 h from onset 15 17 25 26 27 28. In published cohort of 564 placebo-treated patients with major anterior circulation infarction, IC was present in 409 patients during 24-h time period 29. Another cohort of 208 LHI patients based on Lausanne Stroke Registry reported that 55% of cases experienced IC within 24 h after admission 30. Here we provide evidence that IC at Stroke onset is common in LHI patients, occurring in more than one thirds of LHI patients in our cohort. Differences in incidence of IC between our study and others could be easily explained by heterogeneity in time between Stroke onset and Hospital admission. Because different pre-Hospital care, disease courses and Stroke-related complications could contribute to different consciousness states at time of admission. It is worth noting that the time interval between Stroke onset and Hospital arrival in our study seems to be very long, median prehospital delay is 24 versus 26 h in the two groups respectively. This might be explained by that the current study was a hospital-base study conducted in a large Hospital that covering over 4 million local residents in western China, so some patients were transferred from smaller hospitals for advanced treatment. Furthermore, more than one fourth of LHI patients come from rural areas in our study, and many patients lack knowledge of the importance of seeking immediate medical service after the onset of Stroke. In the present study, we find that LHI patients with IC at Stroke onset show a higher rate of atrial fibrillation, and the most common Stroke etiology in the IC group was Cardio-embolism.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions

Sources

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions

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