[Coma in the emergency room]

Coma of unknown origin (CUO) is a frequent unspecific emergency symptom associated with a high mortality. A fast diagnostic work-up is essential given the wide spectrum of underlying diagnoses that are made up of approximately 50% primary central nervous system (CNS) pathologies and approximately 50% extracerebral, almost exclusively internal medical causes. Despite the high mortality associated with this symptom, there are currently no generally accepted management guidelines for adult patients presenting with CUO. We propose an interdisciplinary standard operating procedure (SOP) for patients with acute CUO as has been established in our maximum care hospital. The SOP is triggered by simple triage criteria that are sufficient to identify CUO patients before arrival in hospital. The in-hospital response team is led by a neurologist. Collaboration with nursing staff, internal medicine, anesthesiology, neurosurgery and trauma surgery is organized along structured pathways that include standardized laboratory tests, including cerebrospinal fluid (CSF), toxicology, computed tomography (CT) and CT angiography imaging (CTA). Our data suggest that neurologists and internists need to be placed at the beginning of the diagnostic work-up. Imaging should not just be carried out depending on the clinical syndrome because sensitivity, specificity and inter-rater reliability of the latter are not sufficient and because in many cases, multiple pathologies can be detected that could each explain CUO alone. Clinical examination, imaging and laboratory testing should be regarded as components of an integrative diagnostic approach and the final aetiological classification should only be made after the diagnostic work-up is complete.