Thalamic proton magnetic resonance spectroscopy in vegetative state induced by traumatic brain injury.
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OBJECTIVES: To determine whether proton magnetic resonance spectroscopy (MRS), a newer radiographic technology, would be useful in the evaluation of the thalamus of patients in vegetative states resulting from traumatic brain injury. METHODS: 14 victims of severe traumatic brain injury who were in the vegetative state and whose magnetic resonance images of the thalamus were normal underwent bilateral thalamic proton (MRS) studies. The N-acetyl aspartate to creatine (NAA:Cr) and choline to creatine (Cho:Cr) ratios were obtained for each patient. The proton thalamic MRS findings of patients who were in a persistent vegetative state (n = 8) and in patients who had regained awareness after being in the vegetative state (n = 6) were compared with proton thalamic MRS findings in five healthy volunteers. RESULTS: While conventional magnetic resonance imaging suggested that each patient had a normal thalamus, proton MRS indicated that the thalamus of each patient in the series was damaged. The NAA:Cr ratio was significantly lower in the thalami of both the patients who remained in a persistent vegetative state for the duration of the study and in those who regained awareness after being in the vegetative state (p < 0.001). In addition, NAA:Cr ratios were lower in the group of patients who remained in a persistent vegetative state than in the group of patients who regained awareness after being in the vegetative state (p < 0.001). CONCLUSIONS: Results suggest that the NAA:Cr ratio within the thalamus is significant and that thalamic MRS may be helpful when attempting to determine the degree of severity of neuronal and axonal injury in patients in the vegetative state. (+info)
Consent and end of life decisions.
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This paper discusses the role of consent in decision making generally and its role in end of life decisions in particular. It outlines a conception of autonomy which explains and justifies the role of consent in decision making and criticises some misapplications of the idea of consent, particular the role of fictitious or "proxy" consents. Where the inevitable outcome of a decision must be that a human individual will die and where that individual is a person who can consent, then that decision is ethical if and only if the individual consents. In very rare and extreme cases such a decision will be ethical in the absence of consent where it would be massively cruel not to end life in order to prevent suffering which is in no other way preventable. Where, however, the human individual is not a person, as is the case with abortion, the death of infants like Mary (one of the conjoined twins in a case discussed in the paper), or in the very rare and extreme cases of those who have ceased to be persons like Tony Bland, such decisions are governed by the ethics of ending the lives of non-persons. (+info)
Proton magnetic resonance spectroscopy improves outcome prediction in perinatal CNS insults.
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OBJECTIVE: Prediction of neurologic outcome is difficult in neonates with acute nervous system injury. Previous studies using proton magnetic resonance spectroscopy ((1)H-MRS) have been used to predict short-term neurologic outcome in neonates with a variety of neurologic insults. We were interested in determining the effectiveness of combining clinical evaluation and spectroscopy obtained at the time of injury in predicting neurologic outcome at 24 months. STUDY DESIGN: We studied 33 neonates with acute central nervous system injury, 5.8+/-3.7 days of injury, owing to hypoxic-ischemic encephalopathy. Neonates were assessed using clinical variables (initial arterial pH, initial blood glucose, Sarnat score, electroencephalography) and spectroscopy (NAA/Cho, NAA/Cre, Cho/Cre, and lactate). Neonates were divided into two outcome groups: good/moderate and poor. Differences between the groups were assessed using chi(2) and t-test analyses. We analyzed the best predictors of outcome using discriminant analysis and calculated sensitivity, specificity, positive, and negative predictive values for each variable independently and in combination. RESULTS: There were significant differences between the good/moderate and poor outcome for the Sarnat score, EEG, lactate, and NAA/Cho. Spectroscopy combined with clinical variables improved sensitivity, but not specificity for predicting outcome. The presence of lactate had the best individual predictive value. Combination of the clinical with the MRS variables had the highest predictive value. CONCLUSION: Proton magnetic resonance spectroscopy done early after injury improves the ability to predict neurologic outcome at 24 months of age. (+info)
Awakenings from persistent vegetative state: report of three cases with parkinsonism and brain stem lesions on MRI.
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Three patients with a persistent vegetative state after severe head injury are reported. They recovered from a prolonged disturbance of consciousness after the administration of levodopa. These patients all had parkinsonian features. On magnetic resonance imaging, the distribution of lesions implied a diffuse axonal injury involving the substantia nigra or ventral tegmental area. The existence of patients whose dopaminergic systems may have been selectively damaged by a severe head injury should be recognised because such individuals may respond to levodopa treatment. (+info)
Proceeding with clinical trials of animal to human organ transplantation: a way out of the dilemma.
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The transplantation of porcine organs to humans could in the future be a solution to the worldwide organ shortage, but is to date still highly experimental. Further research on the potential effects of crossing the species barrier is essential before clinical application is acceptable. However, many crucial questions on efficacy and safety will ultimately only be answered by well designed and controlled solid organ xenotransplantation trials on humans. This paper is concerned with the question under which conditions, given the risks involved and the ethical issues raised, such clinical trials should be resumed. An alternative means of overcoming the safety and ethical issues is suggested: willed body donation for scientific research in the case of permanent vegetative status. This paper argues that conducting trials on such bodies with prior consent is preferable to the use of human subjects without lack of brain function. (+info)
Ethics roundtable debate: withdrawal of tube feeding in a patient with persistent vegetative state where the patients wishes are unclear and there is family dissension.
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The decision to withdraw or withhold life supporting treatment in moribund patients is difficult under any circumstances. When the patient becomes incompetent to clarify their wishes regarding continued maintenance in long-term facilities, surrogates sometimes cannot agree, further clouding the issue. We examine a case where the State's interests come into play, forcing a controversial resolution. (+info)
Continuing care settings cater for some of the most disabled individuals. Their care can often present major ethical dilemmas; teams involved in such care require a broad range of skills. We illustrate this with a challenging case history and discuss specific dilemmas, including investigation and treatment in the absence of specific consent and advance directives. We suggest that continuing care should be recognised as a valuable component of training in geriatric medicine. (+info)
Differential responses in three thalamic nuclei in moderately disabled, severely disabled and vegetative patients after blunt head injury.
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In vivo imaging techniques have indicated for many years that there is loss of white matter after human traumatic brain injury (TBI) and that the loss is inversely related to cognitive outcome. However, correlated, quantitative evidence for loss of neurons from either the cerebral cortex or the diencephalon is largely lacking. There is some evidence in models of TBI that neuronal loss occurs within the thalamus, but no systematic studies of such loss have been undertaken in the thalamus of humans after blunt head injury. We have undertaken a stereological analysis of changes in numbers of neurons within the dorsomedial, ventral posterior and lateral posterior thalamic nuclei in patients assessed by the Glasgow Outcome Scale as moderately disabled (n = 9), severely disabled (n = 12) and vegetative (n = 10) head-injured patients who survived between 6 h and 3 years, and controls (n = 9). In histological sections at the level of the lateral geniculate body, the cross-sectional area of each nucleus and the number and the mean size of neurons within each nucleus was quantified. A statistically significant loss of cross-sectional area and number of neurons occurred in the dorsomedial nucleus in moderately disabled, and both the dorsomedial and ventral posterior thalamic nuclei in severely disabled and vegetative head-injured patients. However, there was no change in neuronal cell size. In the lateral posterior nucleus, despite a reduction in mean cell size, there was not a significant change in either nuclear area or number of neurons in cases of moderately disabled, severely disabled or vegetative patients. We posit, although detailed neuropsychological outcome for the patients included within this study was not available, that neuronal loss in the dorsomedial thalamus in moderately and severely disabled and vegetative patients may be the structural basis for the clinical assessment in the Glasgow Outcome Scale. In severely disabled and vegetative patients, loss of neurons from the ventral posterior thalamic nucleus may also reflect loss of response to afferent stimuli. (+info)