altered mental status ( ams ) is a symptom complex that continually poses a great challenge in the emergency department ( ed ) . the purpose of the study is to provide insight into the clinical , demographical features as well as the outcome of patients presenting to our ed through to their entire length of stay in the hospital . we aim to provide clinicians with the necessary information regarding the epidemiology of this symptom complex in an urban ed . this will guide future allocation of resources in the most cost - effective manner in the management of patients with ams . a prospective observational study was conducted on all patients presenting to the ed with altered mental state ( ams ) from december 2006 to october 2007 at tan tock seng hospital ( ttsh ) , singapore . ttsh is an urban ed with an annual census of 154,000 in 2007 and receives patients from all regions in the country . a pilot study using retrospective data in our department together with review of the literature [ 24 ] formed the basis of an ams data collection form that was prospectively completed by the ed doctors for all recruited patients . ams was defined as a state of drowsiness , unresponsiveness , sudden behavioural change , disorientation or confusion , agitation or hallucination . all patients above 18  years of age who presented with ams at triage in the ed were included in the study . patients referred from another healthcare facility for whom their referring physicians had already worked out the cause for ams were excluded from the study . similarly , patients who had sustained major trauma from motor vehicle crashes or falls from heights were excluded . the management and the utilisation of specific investigations like computer tomographic ( ct ) scans were based on the discretion of the attending doctors . demographic , clinical , radiological and laboratory data of each patient throughout the stay in the hospital from entry into the ed till discharge or demise were collected . ed electronic notes , ams forms , inpatient medical records , radiology films and reports were reviewed . all tests were conducted at the 5% level of significance , with odds ratios ( or ) and corresponding 95% confidence intervals ( ci ) reported where applicable . from december 2006 to october 2007 , 967 patients with ams were recruited into our study . ams patients presented most commonly ( 67% ) within the first 24 h of onset of symptom with drowsiness as the most common presenting complaint ( 51% ) . table  1demographics of study population ( n  =  967)variablestotalgendermales459 ( 48%)ethnicitychinese747 ( 77%)malay106 ( 11%)indian86 ( 9%)others28 ( 3%)age range ( in years)65 and above581 ( 60%)type of amsdrowsiness331 ( 51%)sudden behavioural change180 ( 27%)unresponsiveness248 ( 37%)disorientated / confused199 ( 30%)agitation51 ( 8%)hallucination41 ( 6%)duration of amsacute ( 24 h)647 ( 67%)subacute ( less than 7  days)215 ( 22%)chronic ( more than 7  days)105 ( 11%)concurrent medicationsbenzodiazepine55 ( 6%)tricyclic anti - depressant8 ( 1%)ssris54 ( 6%)anti - psychotics66 ( 7%)anti - coagulant34 ( 4%)anti - platelet121 ( 13%)alcohol53 ( 6% ) demographics of study population ( n  =  967 ) the frequency of ams increases with age in a non - gaussian manner with a mode of 75  years and mean of 66.5  years ( sd of 18.1 ) . after the initial screening investigations of an electrocardiogram and capillary blood sugar , the subsequent management was based on the discretion of the attending emergency physician or inpatient specialists . of note , 674 patients ( 70% ) received ct scan of the brain , of which 394 ( 58% ) were performed at the ed and the rest at the ward level . of all ct scans performed , 246 ( 36% ) were reported to be abnormal ; 135 were found to have ischaemic stroke , 106 to have haemorrhagic stroke and 5 to have tumours . all patients were admitted to either the medical , neurology or neurosurgical units based on the attending ep s provisional diagnosis . the various definitive causes of ams upon discharge or demise are demonstrated in table  2 . n  =  392 ) and > 65 ( n  =  600)*cause of death1864 years65  years and aboveneurological11.7%22.7%infectious4.3%14.0%metabolic4.3%7.8%toxicological6.0%2.2%cardiac1.5%5.9%organ specific impairment5.0%1.7%psychiatric1.1%1.7%trauma1.0%1.4%miscellaneous3.2%4.7%*n  >  967 as some patients were assessed to have more than one cause of ams causes of ams in patients aged 1664 ( n  =  392 ) and > 65 ( n  =  600 ) * * n  >  967 as some patients were assessed to have more than one cause of ams in the younger age group of 1664  years , the various ams causes were more evenly distributed with neurological , psychiatric and toxicological aetiologies as relatively more common . in the older age group of > 65  years , neurological , infectious and metabolic aetiologies were more common . in the latter group of patients , the sources of infection include urinary tract infection ( 36% ) , pneumonia ( 22% ) and sepsis ( 27% ) . the mean hospital length of stay was 11.6  days ( median 7  days ; range 1137  days ) . patients with abnormal ct results stayed longer than those whose results were normal ( median of 9  days ; range 1137  days compared with median of 6  days ; range 1114  days ; p  =  0.001 ) . overall , 106 ( 11% ) patients died during hospitalisation ; 36 ( 33.9% ) and 39 ( 36.8% ) deaths were attributed to ischaemic stroke and haemorrhagic stroke , respectively . we investigated the causes of mortality between the younger ( 1864  years ) and older ( > 65  years ) subgroups . the majority of younger patients died from haemorrhagic stroke , while in older patients , mortality is distributed amongst ischaemic stroke ( 38% ) , haemorrhagic stroke ( 30% ) and others ( chiefly infection ; 20% ) . old ( n  =  30 ; 28%)65  years and above ( n  =  76 ; 72%)p valuetrauma1 ( 3.3%)5 ( 6.6%)0.673cardiac1 ( 3.3%)4 ( 5.3%)1.000others*5 ( 16.7%)15 ( 19.7%)0.790ischaemic stroke7 ( 23.3%)29 ( 38.2%)0.176haemorrhagic stroke16 ( 53.3%)23 ( 30.3%)0.043*others include infective causes or combination of infective and cva ; trauma includes relatively minor mechanisms like falls distribution of causes of mortality between two age subgroups * others include infective causes or combination of infective and cva ; trauma includes relatively minor mechanisms like falls table  4 illustrates the outcomes of the survivors . the majority of patients were discharged to primary care ( 76% ) or the hospital s outpatient clinics ( 12% ) . a small minority of patients were transferred to step - down care comprising of nursing homes ( 2.4% ) and rehabilitation hospitals ( 3.8% ) . table  4distribution of outcomes of surviving ams patients ( n  =  861)outcomenumberdischarge to primary care651discharge to nursing home21transfer to rehabilitation hospital33discharge to hospital outpatient clinic107discharged against medical advice26missing data*23*missing data includes those with incomplete data or those whose disposition was not available at time of conclusion of study distribution of outcomes of surviving ams patients ( n  =  861 ) * missing data includes those with incomplete data or those whose disposition was not available at time of conclusion of study . acute onset of ams within 24 h is the most common reason for seeking consultation at the ed . among the various aetiologies , neurological causes are the most common , and our findings agree with what had been reported by kanich et al . . futhermore , this has important downstream implications for triaging and cost - effective use of investigations , especially ct scan of the brain [ 6 , 7 ] . we have demonstrated that ams is a symptom complex that carries a high admission rate , a long length of stay and significant mortality rate ( 11% in our study , and this agrees with what is reported by zeynep kekec et al . ) . our study has also demonstrated that the causes of ams vary amongst the different age groups . although it is not as common as other complaints like chest pain , it is one that challenges the physician s judgment , and time is required in the evaluation of such patients . ams will continue to be a diagnostic challenge for eps worldwide as the world s population ages . appropriate management of ams in geriatric patients in the ed requires substantial staff time , training , resources and commitment . in addition , ep s satisfaction in management of this group of patients who require prolonged clinician time will also be affected in this high - stress environment . ams is and will be a growing symptom complex that prompts caregivers to consult the public healthcare system particularly in the context of a rapidly aging population in many countries . the common and important causes of ams require timely diagnosis , intervention and are largely amenable to treatment . ams remains a symptom that carries a significant degree of morbidity and mortality , especially in elderly patients with neurological aetiologies . future research should be targeted to exploring cost - effective ways to triage , investigate and manage this symptom complex .
aimspatients with altered mental status ( ams ) present commonly to the emergency department ( ed ) . 
 the aim of this prospective study is to identify the various clinical features of this diverse group of patients and trace their outcomes 
 . this will allow clinicians to be aware of the natural history of the symptom complex and the difficulties in managing them.methodsin this prospective observational study , we recruited patients aged 18 and above diagnosed with ams at tan tock seng hospital ed from december 2006 to october 2007 . 
 this is an urban ed . 
 demographic , clinical , radiology , laboratory data , final diagnosis and length of stay were collected from their entry into the ed till discharge or demise using the ed s and inpatient electronic records.resultsfrom december 2006 to october 2007 , 967 patients with a mean age of 66.5  years diagnosed with ams were recruited into our study . 
 the total number of ct scans done during the study period was 674 , of which 246 ( 37% ) were abnormal and 428 ( 63% ) were normal . 
 the mean hospital length of stay was 11.6  days . 
 patients with abnormal ct results stayed longer than those whose results were normal ( median of 9  days versus median of 6  days ) . 
 the three most common causes of ams in our study population were of neurological ( 34.4% ) , infectious ( 18.3% ) and metabolic ( 12% ) aetiologies . 
 overall , 106 ( 11% ) patients died during hospitalisation ; 36 ( 33.9% ) and 39 ( 36.8% ) deaths were attributed to ischaemic stroke and haemorrhagic stroke , respectively.conclusionsams remains a symptom complex that carries a significant length of hospital stay and mortality . 
 the most common causes of ams are those that require timely intervention and are highly treatable 
 . this study will provide insight into proper allocation of resources to manage this group of patients , from triaging to investigations and treatment at the ed and inpatient levels .