Altered Level of Consciousness

Abstract

An altered level of consciousness usually indicates a serious and potential life-threatening disease and therefore requires an immediate diagnostic and therapeutic procedure including cerebral imaging. The first clinical step includes an understanding of preexisting diseases and the circumstances of the acute disorder as well as a careful neurological examination. Laboratory testing and – if suspected – a toxicological screening should be performed immediately to Identify biochemical abnormalities e.g., hypoglycemia. If disease of the central nervous system as the cause of the decreased level of consciousness is suspected cerebral imaging is required. CT scanning of the head reveals traumatic brain injury as well as hemorrhagic and ischemic stroke. CT-angiography may show an acute occlusion of a major cerebral artery or an aneurysm as a cause of subarachnoid hemorrhage. If an intervention is planned, digital substraction angiography is the gold standard of cerebral arterial imaging and offers the opportunity to remove an arterial thrombus in patients with ischemic stroke or to occlude an aneurysm in patients with subarachnoid hemorrhage. However, some central nervous system diseases like infratentorial stroke or cerebral sinus thrombosis can better be visualized by MRI. Because a decreased level of consciousness can be caused by a wide range of diseases, an interdisciplinary approach of neurologists, neurosurgeons and radiologists is required for immediate and potentially life-saving therapy.