Causes of brain dysfunction in acute coma: a cohort study of 1027 patients in the emergency department

Abstract

BackgroundComa of unknown etiology (CUE) is a major challenge in emergency medicine. CUE is caused by a wide variety of pathologies that require immediate and targeted treatment. However, there is little empirical data guiding rational and efficient management of CUE. We present a detailed investigation on the causes of CUE in patients presenting to the ED of a university hospital.MethodsOne thousand twenty-seven consecutive ED patients with CUE were enrolled. Applying a retrospective observational study design, we analyzed all clinical, laboratory and imaging findings resulting from a standardized emergency work-up of each patient. Following a predefined protocol, we identified main and accessory coma-explaining pathologies and related these with (i.a.) GCS and in-hospital mortality.ResultsOn admission, 854 of the 1027 patients presented with persistent CUE. Their main diagnoses were classified into acute primary brain lesions (39%), primary brain pathologies without acute lesions (25%) and pathologies that affected the brain secondarily (36%). In-hospital mortality associated with persistent CUE amounted to 25%. 33% of patients with persistent CUE presented with more than one coma-explaining pathology. In 173 of the 1027 patients, CUE had already resolved on admission. However, these patients showed a spectrum of main diagnoses similar to persistent CUE and a significant in-hospital mortality of 5%.ConclusionThe data from our cohort show that the spectrum of conditions underlying CUE is broad and may include a surprisingly high number of coincidences of multiple coma-explaining pathologies. This finding has not been reported so far. Thus, significant pathologies may be masked by initial findings and only appear at the end of the diagnostic work-up. Furthermore, even transient CUE showed a significant mortality, thus rendering GCS cutoffs for selection of high- and low-risk patients questionable. Taken together, our data advocate for a standardized diagnostic work-up that should be triggered by the emergency symptom CUE and not by any suspected diagnosis. This standardized routine should always be completed - even when initial coma-explaining diagnoses may seem evident.

The etiologies of altered level of consciousness in the emergency department

“…Not only neurological, but also systemic critical illnesses should be considered in the management of patients with ALC in the ED. The classifications of the etiologies of ALC in the ED in previous studies varied [1][2][3][4][5][6][7][8]. For example, a previous study included all patients with GCS < 15, Mini-Mental State Examination < 24, disorientation, hallucinations, confusion, or abnormal behavior [1], whereas another study evaluated all patients in the ED with "sudden onset unconsciousness" as the chief complaint [4].…”

“…For example, a previous study included all patients with GCS < 15, Mini-Mental State Examination < 24, disorientation, hallucinations, confusion, or abnormal behavior [1], whereas another study evaluated all patients in the ED with "sudden onset unconsciousness" as the chief complaint [4]. There was a cross-sectional study that evaluated patients with delirium [2], and another study included only comatose patients [5]. Nonetheless, there is a general trend in classification: systemic infections, metabolic causes, and brain disorders per se.…”

“…Völk et al [4] reported that approximately a quarter of all ALC cases in the ED were attributable to cerebrovascular diseases (24%), followed by systemic infections (12%), epileptic seizures (12%), psychiatric disorders (8%), metabolic causes (7%), and intoxications (7%). A recent German study of coma patients in the ED showed that intracranial hemorrhages (22%), epileptic seizures (22%), intoxications (19%), cerebral infarctions (11%), and metabolic causes (6%) were the common causes of coma [5]. In a Turkish study involving 790 patients with ALC in the ED [6], the etiologies were neurological problems (71.6%), trauma (10.4%), metabolic causes (6.1%), cardio-pulmonary disorders (6.2%), systemic infections (3.8%), gynecologic and obstetric causes (0.…”

The accuracy of initial diagnoses in coma: an observational study in 835 patients with non-traumatic disorder of consciousness

“…Fully documented prehospital emergency care reports were available in 835 of 1027 patients from which we could obtain initial diagnoses/ hypotheses. Figure 1 shows the composition of the study cohort and the distribution of final diagnoses [ 15 ].

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“…Accordingly, class II included other primary CNS pathologies without suspicion of acute structural brain damage such as neuro-degenerative diseases or psychiatric disorders (e.g., “pseudo-coma” in dissociative or akinetic states). Class III was reserved for medical disorders, intoxication and rare surgical emergencies that affected the CNS secondarily [ 15 ].…”