Disorders of Consciousness | |
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Classification and external resources | |
Specialty | Psychiatry |
ICD-10 | R40 |
ICD-9-CM | 780.0 |
MeSH | C10.597.606.358 |
Disorders of consciousness are medical conditions that inhibit consciousness. Some define disorders of consciousness as any change from complete self-awareness to inhibited or absent self-awareness and arousal. This category generally includes minimally conscious state and persistent vegetative state, but sometimes also includes the less severe locked-in syndrome and more severe but rare chronic coma.Differential diagnosis of these disorders is an active area of biomedical research. Finally, brain death results in an irreversible disruption of consciousness. While other conditions may cause a moderate deterioration (e.g., dementia and delirium) or transient interruption (e.g., grand mal and petit mal seizures) of consciousness, they are not included in this category.
Patients in such a dramatically altered state of consciousness present unique problems for diagnosis, prognosis and treatment. Assessment of cognitive functions remaining after a traumatic brain injury is difficult. Voluntary movements may be very small, inconsistent and easily exhausted. Quantification of brain activity differentiates patients who sometimes only differ by a brief and small movement of a finger.
Consciousness is a complex and multifaceted concept, divided into two main components: Arousal and Awareness. Arousal is associated with functional brainstem neuron populations projecting to both thalamic and cortical neurons. Therefore, the assessment of reflexes (Using the Glasgow Coma Scale) is important to investigate the functional integrity of the brainstem. Awareness is thought to be related with functional integrity of the cerebral cortex and its subcortical connections. The most important point regarding the classification of disorders of consciousness is, that consciousness cannot be measured objectively by any machine, although many scoring systems have been developed for the quantification of consciousness and neuroimaging techniques are important tools for clinical research, extending our understanding of underlying mechanisms involved. Disorders in consciousness represent immense social and ethical issues because the diagnosis is methodologically complex and needs careful interpretation. Also the ethical framework must be further developed to guide research in these patients.