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Vegetative State

VS

A vegetative state is a condition in which cognitive function is lost and there is a complete absence of responsiveness to stimuli or environmental awareness. However, many bodily functions including heart rate, respiration, blood pressure and others are maintained, due to a functioning brainstem and diencephalon. Autonomic and motor reflexes are also maintained, as is the circadian rhythm of wakefulness and sleep.


Presentation

A patient in a vegetative state will present signs of life that correspond to their level of consciousness. They usually respond to some stimuli and lack any cognitive abilities. Some patients open their eyes in response to feeding or their name. Their eyes may remain in a fixed position, track objects, or have disconjugate eye movements. Some can swallow. Some may follow a circadian rhythm and a sleep-wake cycle. Alternatively, some may experience a constant wakefulness. Other symptoms include the spontaneous production of facial expressions, grunting and moaning, and teeth grinding. These patients usually do not require life support but do require feeding and basic care.

Weight Loss
  • WEIGHT LOSS I’ve been asked about the report that Michael has lost 25% of his pre-accident weight. This is entirely possible, and in fact, probable. A few factors explain this.[formerf1doc.wordpress.com]
Unconscious State
  • Needless to say this is literally just one case study and not an indication the key to waking anyone up from an unconscious state has been found.[newatlas.com]
Hypoxemia
  • The prevalence of VS/AS in hospital settings in Europe is 0.5-2/100.000 population year; one-third traumatic brain damage, 70% following intracranial haemorrhages, tumours, cerebral hypoxemia after cardiac arrest, and end stage of certain progressive[ncbi.nlm.nih.gov]
Red Eye
  • Both patients' medical records registered 36 and 24 episodes of "a red eye," respectively, which in most cases were due to filamentary keratopathy.[ncbi.nlm.nih.gov]
Stupor
  • […] and coma 2016 2017 2018 2019 Non-Billable/Non-Specific Code Type 1 Excludes neonatal coma ( P91.5 ) somnolence, stupor and coma in diabetes ( E08-E13 ) somnolence, stupor and coma in hepatic failure ( K72.- ) somnolence, stupor and coma in hypoglycemia[icd10data.com]
  • […] unconsciousness, insensibility, stupor, oblivion, inertia View synonyms Pronunciation persistent vegetative state[en.oxforddictionaries.com]
  • The Diagnosis of Stupor and Coma 3rd edn (Wiley, New York, 1983). 2. Jennett, B. & Plum, F. Persistent vegetative state after brain damage . Lancet 1 , 734–737 (1972). 3. The Multi-Society Task Force on the Persistent Vegetative State.[nature.com]
  • Posner JB, Saper CB, Schiff N and Plum F: The diagnosis of stupor and coma, 4th ed., 2007.[scholarpedia.org]
Hyperactivity
  • Paroxysmal sympathetic hyperactivity is a relatively common complication early in the course of traumatic brain injury.[ncbi.nlm.nih.gov]
  • OBJECTIVE: To update knowledge of the incidence of paroxysmal sympathetic hyperactivity (PSH, also referred to as dysautonomia), an emergency condition tentatively attributed to sympathetic paroxysms or diencephalic-hypothalamic disarrangement associated[ncbi.nlm.nih.gov]
  • All responsive survivors had spared pupillary light reflex and nociceptive response, and paroxysmal sympathetic hyperactivity.[ncbi.nlm.nih.gov]
Cognitive Deficit
  • We also performed a neuropsychological assessment at the time of the second MRI examination in order to characterize the profile of cognitive deficits. fMRI analysis revealed anatomically appropriate activation to speech in both the first and the second[ncbi.nlm.nih.gov]
  • Although some recovery following 6 months of being vegetative/minimally conscious is not unknown, it is rare, particularly for those with non-traumatic injuries, and the majority of people similarly affected remain with significant cognitive deficits.[ncbi.nlm.nih.gov]
Disconjugate Eye Movement
  • Their eyes may remain in a fixed position, track objects, or have disconjugate eye movements. Some can swallow. Some may follow a circadian rhythm and a sleep-wake cycle. Alternatively, some may experience a constant wakefulness.[symptoma.com]

Workup

In order to diagnose a nonresponsive patient in a vegetative state, the physician must obtain a clinical history and observe the patient when stimulated, for responses to their environment, and while at rest, for spontaneous actions and behaviors. Clinical history can come from previous medical records and accounts from friends and family. Clinical assessment should be repeated several times over the course of a day to account for the patient's sleep/wake cycle. This is also necessary to rule out a state of minimal consciousness. A patient in a state of minimal consciousness will demonstrate inconsistent cognitive activity with purposeful behavior and by following simple commands. This behavior waxes and wanes throughout the day, wherein a patient in a vegetative state will not be able to demonstrate any cognitive activity. There are no recognized tools to quantify cognitive ability or levels of consciousness [7] [8]. Therefore the physical examination must evaluate the patient in several key areas of cognitive function:

  • Response to noxious stimuli (superficial needle prick, sternal rub).
  • Any awareness of their body or their environment.
  • Reproducible or purposeful activity, either spontaneous or in response to an environmental cue.
  • Comprehension of language.

If the patient does not react then they are in a vegetative state.
Other tests should be carried out to determine the etiology of the condition. An MRI or a CT scan of the brain will differentiate a mass lesion from an infarct, or a hemorrhage. MR angiography is more sensitive for cerebral hemorrhage while diffusion-weighted MRI is useful to evaluate ischemic changes. An electroencephalogram (EEG) can detect occult seizure activity or cortical dysfunction. A positron emission tomography (PET) or a Single-photon emission computed tomography (SPECT) scan of the brain can evaluate activity in different parts of the brain and should be part of the workup.

Generalized Periodic Patterns
  • EEG findings included normal, continuous generalized slowing, intermittent generalized slowing, background slowing, background suppression, alpha, generalized periodic pattern, PLEDS, and triphasic waves.[ncbi.nlm.nih.gov]
Triphasic Waves
  • EEG findings included normal, continuous generalized slowing, intermittent generalized slowing, background slowing, background suppression, alpha, generalized periodic pattern, PLEDS, and triphasic waves.[ncbi.nlm.nih.gov]
Gliosis
  • A long-term vegetative state causes the brain to soften and liquefy because of reactive gliosis and autolytic change. The cause of death becomes difficult to diagnose only from the autopsy findings in general.[ncbi.nlm.nih.gov]
Ischemic Changes
  • Neoplasm growth (both benign and malignant) drastically alters the architecture of the brain and may result in ischemic changes, inflammation, or mass effect.[symptoma.com]

Treatment

At this time there is no standard of care for the treatment of a patient in a vegetative state. There is insufficient research to form broad recommendations. The treatment course and specific therapeutic modalities are based on the clinical judgment of the physician and support staff [9] and the cause of the vegetative state. The general consensus is that this condition requires a skilled nursing facility for daily care and to prevent the many conditions associated with chronic inactivity. Nutrition and hydration, often via percutaneous endoscopic gastrostomy (PEG) tube is essential. Other measures include skin care, bladder and bowel care, and oral hygiene. Stress ulcers are a major concern for sedentary patients. Passive flexion and extension of the joints and braces can minimize contracture.

Some medications have demonstrated benefits in cognitive ability in a minimally conscious state. The dopaminergic drug amantadine increases metabolic activity in the brain while the sedative zolpidem improves arousal and cognitive ability in patients with brain injury. These results have not been replicated in patients in vegetative states and further research in this area is required.

Deep brain stimulation (DBS) has been shown to be beneficial to patients in a minimally conscious state. Bilateral thalamic stimulation has demonstrated an improvement in cognitive functioning including object use and verbalization. However, this benefit has not been reflected in patients in a vegetative state. Further research is required to evaluate DBS in the treatment of a vegetative state.

Prognosis

A majority of patients that recover from a vegetative state or a persistent vegetative state are severely disabled. Prognosis of a patient in a vegetative state is mainly dependent on three variables: age, type of brain injury, and time spent in the vegetative state [6]. No one variable appears to carry more weight. Younger patients appear to be more resilient to brain injury. Patients under the age of 35 are more likely to recover from a vegetative state. It is easier for the brain to recover from some types of brain injury than others. Metabolic insults usually carry a better prognosis compared to ischemic damage that may result in neuronal death. Patients suffering from intracranial hemorrhage or head trauma may eventually improve their functioning. The longer a patient stays in a vegetative state the worse their prognosis. The potential for any meaningful recovery after three months in a persistent vegetative state is very low. The most common cause of death for someone in a persistent vegetative state is superadded infection such as pneumonia.

Etiology

A vegetative state does not manifest spontaneously but is the result of an underlying disease. There are three conditions that are most associated with a vegetative state and a variety of other less common conditions.

Main conditions:

  1. Congenital or developmental disorders of the central nervous system may prevent proper brain formation or function.
  2. A traumatic brain injury [5] can lead to hemorrhage, neural injury, or an increase in intracranial pressure.
  3. Degenerative disorders and metabolic disorders that affect neural tissue of the brain can affect neuron function. Neuron death is also possible as metabolites accumulate.

Other conditions:

  1. Direct infection of the central nervous system by bacteria, fungi, or viruses may result in necrosis and inflammation. The fetus and newborns are especially susceptible to infections of this type.
  2. Sepsis and other systemic infections can cause hypoperfusion of the brain.
  3. Acute disseminated encephalomyelitis is an acute demyelinating condition that is often self-limiting but may progress to severely damage the cortical regions of the brain.
  4. Hypertensive episodes may lead to intracranial hemorrhage and an increase in intracranial pressure and mass effect.
  5. Hypoperfusion following a hypotensive episode, cardiac arrest, or uncompensated drop in cardiac output starves the brain of oxygen and nutrients. Even a short hypoxic event can seriously damage the brain, especially the watershed regions.
  6. Neurotoxins such as elevated levels of urea, ammonia, ethanol, lead, silver, or opiates injure the neurons. Prolonged exposure has the potential of permanently damaging the brain.
  7. Seizure activity, or uncoordinated electrical discharges, can damage neurons and rapidly increase metabolic activity in the brain.
  8. Elevated or depressed electrolytes such as sodium, glucose, calcium, or magnesium can prevent proper neuron communication and function. Sufficiently low blood glucose causes seizure activity and loss of consciousness.
  9. Disorders of the endocrine system including thyroid disorders and adrenal insufficiency strongly affect the metabolism of the whole body, including the brain.
  10. Inheritable degenerative conditions including mitochondrial diseases which interfere with neuron metabolism and development.
  11. Acquired metabolic diseases such as Reye syndrome results in cerebral edema and increased intracranial pressure.
  12. Neoplasm growth (both benign and malignant) drastically alters the architecture of the brain and may result in ischemic changes, inflammation, or mass effect.

Epidemiology

It is difficult to gather epidemiological data on vegetative and minimally conscious states due to the wide and varied diagnostic criteria used by clinicians. However, the incidence for vegetative state lasting for at least six months is estimated to be between 5 and 25 events per million population. The prevalence in the United States is between 40 and 168 per million population. There is insufficient data on minimally conscious state to determine incidence or prevalence.

Sex distribution
Age distribution

Pathophysiology

There are several differences that distinguish brain death from a vegetative state. Brain death is an irreversible loss of brain function. On physical examination, there are no cranial reflex responses (pupillary response, corneal reflex, caloric reflex test are all absent). A patient with brain death will never spontaneously open their eyes. There is no spontaneous respiration. On the other hand, a vegetative state is not brain death. A vegetative response is reversible. They maintain spontaneous respiration and reflexes. Their eyes can open spontaneously. Positron emission tomography (PET) can differentiate a brain-dead patient from a vegetative patient. A brain-dead patient will show no neuronal metabolic activity on PET scan (empty skull sign) while a vegetative patient will show some activity. Cortical metabolism in a vegetative state is reduced to 40-50% below normal. This change is reversed in patients who recover from a vegetative state. Additionally, there are differences on electroencephalography (EEG). A brain-dead patient will show no response on EEG to any stimuli including pain, auditory, or temperature. However, a vegetative patient may respond to somatosensory stimuli with cortical activity in the form of evoked potentials that are sensed and recorded by the EEG. This response is quite different when compared to EEG’s from healthy individuals. The defect appears to be in the connections of the somatosensory cortex and the rest of the brain, especially the frontoparietal network. Auditory stimuli, such as the patient’s name, can produce brainstem activity on EEG in the form of endogenous evoked potentials. P300 waves are event-related potentials that reflect a higher process of memory and attention. These waves can be caused by speaking the patient’s name. This unique wave is a sign of brain activity but cannot be used as a diagnostic marker. Patients in a vegetative state that produce a P300 wave may still never recover.

Prevention

A vegetative state is the result of a pathological condition in the brain. Following recommendations for management of high blood pressure, cholesterol, and avoiding smoking can mitigate some risk, especially tumor formation, intracranial hemorrhage, and stroke. Other risk factors, such as head trauma, are almost impossible to plan for or avoid.

Summary

A vegetative state is a chronic disorder of consciousness. Consciousness requires both wakefulness and awareness. A patient in a vegetative state may demonstrate wakefulness by opening their eyes and maintaining reflexes. The reticular activating system functions normally and gives the patient the appearance of alertness. The hypothalamus, medulla oblongata, and spinal column are intact and maintain blood pressure in the peripheral vasculature, cardiac function, breathing and the subtle autonomic signaling required to sustain life. However, patients in a vegetative state do not have awareness of the environmental or of their own body. They rely on healthcare supporters for nourishment, hygiene, and all other basic needs. In a vegetative state the cerebral cortex or the nerve tracks that connect the cortex to the rest of the body are damaged. This prevents cognitive function. The midbrain and pontine areas of the brain may or may not function properly too.

Vegetative states are most often caused by traumatic brain injury and hypoxia. There are several ways to classify the condition. A vegetative state is a loss of cognitive function for less than one month. If the condition lasts longer than one month it is considered a persistent vegetative state. Recovery from a persistent vegetative state is rare but does occur. For instance, there are documented cases where patients recovered from traumatic brain injury; however, recovery is often limited. In a minimally conscious state patients retain some awareness of the environment or themselves. Again, recovery is possible but limited. Patients often transition from minimally conscious state and vegetative state for years after the first insult [1] [2] [3] [4].

Patient Information

A vegetative state is a condition wherein a patient is alive but lacks cognitive ability. This is different from brain death. In brain death, the patient has stopped breathing and reacting to their environment and the condition is irreversible. In a vegetative state the patient is still alive, maintains a sleep and wakefulness pattern, and breathes spontaneously. They may vocalize (cry, laugh, or grunt). They are simply unable to respond to external stimuli, speak, or respond to commands. Patients enter a vegetative state due to injury or illness to the brain such as head trauma or stroke.

How do you treat a vegetative state?
Once a patient enters a vegetative state and is stable the underlying conditions are determined and treatment is attempted. The patient may be sedentary for a long period of time and is at risk for bedsores and infections. Nutrition and other services such as oral care, turning and shifting the patient, and regular skin cleaning must be provided by a skilled nursing facility. Physically therapy prevents joint contractures.

What is the prognosis for a patient in a vegetative state?
The outcome depends entirely on the cause of the vegetative state, the age of the patient, and length of time in the vegetative state. Prognosis is worse for older patients and for patients suffering from the condition for longer than one month. Some patients will slowly return to a normal state, some patients will improve but have a permanent disability, and some patients will not leave the vegetative state at all. Infections are rather common for patients in a vegetative state and can be lethal if not treated aggressively.

References

Article

  1. Bender A, Jox RJ, Grill E, Straube A, Lulé D. Persistent vegetative state and minimally conscious state: a systematic review and meta-analysis of diagnostic procedures. Dtsch Arztebl Int. 2015;112(14):235-42.
  2. Northoff G, Heiss WD. Why is the distinction between neural predispositions, prerequisites, and correlates of the level of consciousness clinically relevant?: Functional brain imaging in coma and vegetative state. Stroke. 2015;46(4):1147-51
  3. Liberati G, Hünefeldt T, Olivetti Belardinelli M. Questioning the dichotomy between vegetative state and minimally conscious state: a review of the statistical evidence. Front Hum Neurosci. 2014;8:865.
  4. Kondziella D, Friberg CK, Frokjaer VG, Fabricius M, Møller K. Preserved consciousness in vegetative and minimal conscious states: systematic review and meta-analysis. J Neurol Neurosurg Psychiatry. 2015 Jul; 2. pii: jnnp-2015-310958
  5. Horsting MW, Franken MD, Meulenbelt J, van Klei WA, de Lange DW. The etiology and outcome of non-traumatic coma in critical care: a systematic review. BMC Anesthesiol. 2015;15:65.
  6. Sandroni C, Cariou A, Cavallaro F, et al.Prognostication in comatose survivors of cardiac arrest: an advisory statement from the European Resuscitation Council and the European Society of Intensive Care Medicine. Resuscitation. 2014;85(12):1779-89.
  7. Peterson A, Cruse D, Naci L, Weijer C, Owen AM. Risk, diagnostic error, and the clinical science of consciousness. Neuroimage Clin. 2015;7:588-97.
  8. Hannawi Y, Lindquist MA, Caffo BS, Sair HI, Stevens RD. Resting brain activity in disorders of consciousness: a systematic review and meta-analysis. Neurology. 2015;84(12):1272-80.
  9. Klingshirn H, Grill E, Bender A, Strobl R, Mittrach R, Braitmayer K, Müller M. Quality of evidence of rehabilitation interventions in long-term care for people with severe disorders of consciousness after brain injury: A systematic review. J Rehabil Med. 2015;47(7):577-85

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Last updated: 2019-07-11 21:45