Diagnostic Approach to the Patient with Altered Mental Status

Abstract

Acute encephalopathy is a common presenting symptom in the emergency room and complicates many hospital and intensive care unit admissions. The evaluation of patients with encephalopathy poses several challenges: limited history and examination due to the patient's mental status, broad differential diagnosis of systemic and neurologic etiologies, low yield of neurodiagnostic testing due to the high base rate of systemic causes, and the importance of identifying less common neurologic causes of encephalopathy that can be life-threatening if not identified and treated. This article discusses the differential diagnosis of acute encephalopathy, presents an approach to the history and examination in a patient with encephalopathy, reviews the literature on the yield of neurodiagnostic testing in this population, and provides a diagnostic framework for the evaluation of patients with altered mental status.

Keywords

altered mental status - encephalopathy - delirium

Publication History

Article published online:
01 October 2024

• References

• 1 Ropper AH, Samuels MA, Klein JP. et al. Adams and Victor's Principles of Neurology. 12th ed. McGraw Hill;; 2023. . Accessed September 3, 2024 at: https://accessmedicine-mhmedical-com.ucsf.idm.oclc.org/book.aspx?bookid=3313
• 2 Naughton BJ, Moran MB, Kadah H, Heman-Ackah Y, Longano J. Delirium and other cognitive impairment in older adults in an emergency department. Ann Emerg Med 1995; 25 (06) 751-755
• 3 Wofford JL, Loehr LR, Schwartz E. Acute cognitive impairment in elderly ED patients: etiologies and outcomes. Am J Emerg Med 1996; 14 (07) 649-653
• 4 Kanich W, Brady WJ, Huff JS. et al. Altered mental status: evaluation and etiology in the ED. Am J Emerg Med 2002; 20 (07) 613-617
• 5 Fong TG, Jones RN, Marcantonio ER. et al. Adverse outcomes after hospitalization and delirium in persons with Alzheimer disease. Ann Intern Med 2012; 156 (12) 848-856 , W296
• 6 Racine AM, Touroutoglou A, Abrantes T. et al; SAGES Study Group. Older patients with Alzheimer's disease-related cortical atrophy who develop post-operative delirium may be at increased risk of long-term cognitive decline after surgery. J Alzheimers Dis 2020; 75 (01) 187-199
• 7 Fong TG, Jones RN, Shi P. et al. Delirium accelerates cognitive decline in Alzheimer disease. Neurology 2009; 72 (18) 1570-1575
• 8 Saczynski JS, Marcantonio ER, Quach L. et al. Cognitive trajectories after postoperative delirium. N Engl J Med 2012; 367 (01) 30-39
• 9 Völk S, Koedel U, Pfister H-W. et al. Impaired consciousness in the emergency department. Eur Neurol 2018; 80 (3-4): 179-186
• 10 Gerlier C, Forster M, Fels A, Zins M, Chatellier G, Ganansia O. Head computed tomography for elderly patients with acute altered mental status in the emergency setting: value for decision-making and predictors of abnormal findings. Clin Exp Emerg Med 2022; 9 (04) 333-344
• 11 Hufschmidt A, Shabarin V. Diagnostic yield of cerebral imaging in patients with acute confusion. Acta Neurol Scand 2008; 118 (04) 245-250
• 12 Ormseth CH, LaHue SC, Oldham MA, Josephson SA, Whitaker E, Douglas VC. Predisposing and precipitating factors associated with delirium: a systematic review. JAMA Netw Open 2023; 6 (01) e2249950
• 13 Kim KT, Kwon DH, Jeon JC, Kim IC, Park JA, Seo JG. A multicenter study of altered level of consciousness in the emergency room. Intern Emerg Med 2022; 17 (08) 2329-2337
• 14 Kim KT, Jeon JC, Jung C-G, Park JA, Seo JG, Kwon DH. Etiologies of altered level of consciousness in the emergency room. Sci Rep 2022; 12 (01) 4972
• 15 Forsberg S, Höjer J, Ludwigs U, Nyström H. Metabolic vs structural coma in the ED – an observational study. Am J Emerg Med 2012; 30 (09) 1986-1990
• 16 Aslaner MA, Boz M, Çelik A. et al. Etiologies and delirium rates of elderly ED patients with acutely altered mental status: a multicenter prospective study. Am J Emerg Med 2017; 35 (01) 71-76
• 17 Schmidt WU, Ploner CJ, Lutz M, Möckel M, Lindner T, Braun M. Causes of brain dysfunction in acute coma: a cohort study of 1027 patients in the emergency department. Scand J Trauma Resusc Emerg Med 2019; 27 (01) 101
• 18 Caplan LR, Kelly M, Kase CS. et al. Infarcts of the inferior division of the right middle cerebral artery: mirror image of Wernicke's aphasia. Neurology 1986; 36 (08) 1015-1020
• 19 Hier DB, Mondlock J, Caplan LR. Recovery of behavioral abnormalities after right hemisphere stroke. Neurology 1983; 33 (03) 345-350
• 20 Mori E, Yamadori A. Acute confusional state and acute agitated delirium. Occurrence after infarction in the right middle cerebral artery territory. Arch Neurol 1987; 44 (11) 1139-1143
• 21 Mesulam MM, Waxman SG, Geschwind N, Sabin TD. Acute confusional states with right middle cerebral artery infarctions. J Neurol Neurosurg Psychiatry 1976; 39 (01) 84-89
• 22 Nagaratnam N, Bou-Haidar P, Leung H. Confused and disturbed behavior in the elderly following silent frontal lobe infarction. Am J Alzheimers Dis Other Demen 2003; 18 (06) 333-339
• 23 Schmahmann JD. Vascular syndromes of the thalamus. Stroke 2003; 34 (09) 2264-2278
• 24 Arauz A, Patiño-Rodríguez HM, Vargas-González JC. et al. Clinical spectrum of artery of Percheron infarct: clinical-radiological correlations. J Stroke Cerebrovasc Dis 2014; 23 (05) 1083-1088
• 25 Lazzaro NA, Wright B, Castillo M. et al. Artery of Percheron infarction: imaging patterns and clinical spectrum. AJNR Am J Neuroradiol 2010; 31 (07) 1283-1289
• 26 Castaigne P, Lhermitte F, Buge A, Escourolle R, Hauw JJ, Lyon-Caen O. Paramedian thalamic and midbrain infarct: clinical and neuropathological study. Ann Neurol 1981; 10 (02) 127-148
• 27 Bogousslavsky J, Regli F, Assal G. The syndrome of unilateral tuberothalamic artery territory infarction. Stroke 1986; 17 (03) 434-441
• 28 Bogousslavsky J, Regli F, Uske A. Thalamic infarcts: clinical syndromes, etiology, and prognosis. Neurology 1988; 38 (06) 837-848
• 29 Suzuki T, Iwakuma A, Tanaka Y. et al. Changes in personality and emotion following bilateral infarction of the posterior cerebral arteries. Jpn J Psychiatry Neurol 1992; 46 (04) 897-903
• 30 Verslegers W, De Deyn PP, Saerens J. et al. Slow progressive bilateral posterior artery infarction presenting as agitated delirium, complicated with Anton's syndrome. Eur Neurol 1991; 31 (04) 216-219
• 31 Medina JL, Rubino FA, Ross E. Agitated delirium caused by infarctions of the hippocampal formation and fusiform and lingual gyri. Neurology 1974; 24: 1181-1183
• 32 Horenstein S, Chamberlin W, Conomy J. Infarction of the fusiform and calcarine regions: agitated delirium and hemianopia. Trans Am Neurol Assoc 1967; 92: 85-89
• 33 Glees P, Griffith HB. Bilateral destruction of the hippocampus (cornu ammonis) in a case of dementia. Monatsschr Psychiatr Neurol 1952; 123 (4-5): 193-204
• 34 Medina JL, Chokroverty S, Rubino FA. Syndrome of agitated delirium and visual impairment: a manifestation of medial temporo-occipital infarction. J Neurol Neurosurg Psychiatry 1977; 40 (09) 861-864
• 35 Benke T. Peduncular hallucinosis: a syndrome of impaired reality monitoring. J Neurol 2006; 253 (12) 1561-1571
• 36 Browndyke JN, Tomalin LE, Erus G. et al. Infarct-related structural disconnection and delirium in surgical aortic valve replacement patients. Ann Clin Transl Neurol 2023
• 37 Simaan N, Fahoum L, Filioglo A. et al. Characteristics of multiple acute concomitant cerebral infarcts involving different arterial territories. J Clin Med 2023; 12 (12) 3973
• 38 Bendszus M, Stoll G. Silent cerebral ischaemia: hidden fingerprints of invasive medical procedures. Lancet Neurol 2006; 5 (04) 364-372
• 39 Messé SR, Acker MA, Kasner SE. et al; Determining Neurologic Outcomes from Valve Operations (DeNOVO) Investigators. Stroke after aortic valve surgery: results from a prospective cohort. Circulation 2014; 129 (22) 2253-2261
• 40 Samim M, Hendrikse J, van der Worp HB. et al. Silent ischemic brain lesions after transcatheter aortic valve replacement: lesion distribution and predictors. Clin Res Cardiol 2015; 104 (05) 430-438
• 41 Sun X, Lindsay J, Monsein LH, Hill PC, Corso PJ. Silent brain injury after cardiac surgery: a review: cognitive dysfunction and magnetic resonance imaging diffusion-weighted imaging findings. J Am Coll Cardiol 2012; 60 (09) 791-797
• 42 Meller SM, Baumbach A, Brickman AM, Lansky AJ. Clinical implications for diffusion-weighted MRI brain lesions associated with transcatheter aortic valve replacement. Catheter Cardiovasc Interv 2014; 83 (03) 502-508
• 43 Chen C-H, Peterson MD, Mazer CD. et al. Acute infarcts on brain MRI following aortic arch repair with circulatory arrest: insights from the ACE CardioLink-3 randomized trial. Stroke 2023; 54 (01) 67-77
• 44 Levesque M, Iorio-Morin C, Bocti C, Vézina C, Deacon C. Nonepileptic, stereotypical, and intermittent symptoms (NESIS) in patients with subdural hematoma: proposal for a new clinical entity with therapeutic and prognostic implications. Neurosurgery 2020; 87 (01) 96-103
• 45 Pai A, Hegde A, Nair R, Menon G. Adult primary intraventricular hemorrhage: clinical characteristics and outcomes. J Neurosci Rural Pract 2020; 11 (04) 623-628
• 46 Guo R, Ma L, Shrestha BK, Yu Z, Li H, You C. A retrospective clinical study of 98 adult idiopathic primary intraventricular hemorrhage cases. Medicine (Baltimore) 2016; 95 (42) e5089
• 47 Arboix A, García-Eroles L, Vicens A, Oliveres M, Massons J. Spontaneous primary intraventricular hemorrhage: clinical features and early outcome. ISRN Neurol 2012; 2012: 498303
• 48 Geocadin RG. Posterior reversible encephalopathy syndrome. N Engl J Med 2023; 388 (23) 2171-2178
• 49 Roth C, Ferbert A. Posterior reversible encephalopathy syndrome: long-term follow-up. J Neurol Neurosurg Psychiatry 2010; 81 (07) 773-777
• 50 Sutter R, Rüegg S, Kaplan PW. Epidemiology, diagnosis, and management of nonconvulsive status epilepticus: opening Pandora's box. Neurol Clin Pract 2012; 2 (04) 275-286
• 51 Kaplan PW. Behavioral manifestations of nonconvulsive status epilepticus. Epilepsy Behav 2002; 3 (02) 122-139
• 52 Claassen J, Taccone FS, Horn P, Holtkamp M, Stocchetti N, Oddo M. Neurointensive Care Section of the European Society of Intensive Care Medicine. Recommendations on the use of EEG monitoring in critically ill patients: consensus statement from the neurointensive care section of the ESICM. Intensive Care Med 2013; 39 (08) 1337-1351
• 53 Maganti R, Gerber P, Drees C, Chung S. Nonconvulsive status epilepticus. Epilepsy Behav 2008; 12 (04) 572-586
• 54 Jordan KG. Nonconvulsive status epilepticus in acute brain injury. J Clin Neurophysiol 1999; 16 (04) 332-340 , discussion 353
• 55 Theodore WH. The postictal state: effects of age and underlying brain dysfunction. Epilepsy Behav 2010; 19 (02) 118-120
• 56 Fagan KJ, Lee SI. Prolonged confusion following convulsions due to generalized nonconvulsive status epilepticus. Neurology 1990; 40 (11) 1689-1694
• 57 Michael BD, Solomon T. Seizures and encephalitis: clinical features, management, and potential pathophysiologic mechanisms. Epilepsia 2012; 53 (Suppl. 04) 63-71
• 58 Granerod J, Ambrose HE, Davies NW. et al; UK Health Protection Agency (HPA) Aetiology of Encephalitis Study Group. Causes of encephalitis and differences in their clinical presentations in England: a multicentre, population-based prospective study. Lancet Infect Dis 2010; 10 (12) 835-844
• 59 Chan KH, Cheung RTF, Fong CY, Tsang KL, Mak W, Ho SL. Clinical relevance of hydrocephalus as a presenting feature of tuberculous meningitis. QJM 2003; 96 (09) 643-648
• 60 Raut T, Garg RK, Jain A. et al. Hydrocephalus in tuberculous meningitis: Incidence, its predictive factors and impact on the prognosis. J Infect 2013; 66 (04) 330-337
• 61 Baldwin KJ, Zunt JR. Evaluation and treatment of chronic meningitis. Neurohospitalist 2014; 4 (04) 185-195
• 62 Chow FC, Marra CM, Cho TA. Cerebrovascular disease in central nervous system infections. Semin Neurol 2011; 31 (03) 286-306
• 63 Uy CE, Binks S, Irani SR. Autoimmune encephalitis: clinical spectrum and management. Pract Neurol 2021; 21 (05) 412-423
• 64 Maas AI, Stocchetti N, Bullock R. Moderate and severe traumatic brain injury in adults. Lancet Neurol 2008; 7 (08) 728-741
• 65 Velmahos GC, Jindal A, Chan LS. et al. “Insignificant” mechanism of injury: not to be taken lightly. J Am Coll Surg 2001; 192 (02) 147-152
• 66 Foster SM, Muller A, Jones P. et al. External signs of trauma: a poor predictor of injury in found down and ground level falls. Am J Surg 2020; 220 (05) 1300-1303
• 67 Dobbs MR. Toxic encephalopathy. Semin Neurol 2011; 31 (02) 184-193
• 68 Mirijello A, Sestito L, Antonelli M, Gasbarrini A, Addolorato G. Identification and management of acute alcohol intoxication. Eur J Intern Med 2023; 108: 1-8
• 69 Griffin III CE, Kaye AM, Bueno FR, Kaye AD. Benzodiazepine pharmacology and central nervous system-mediated effects. Ochsner J 2013; 13 (02) 214-223
• 70 Day E, Daly C. Clinical management of the alcohol withdrawal syndrome. Addiction 2022; 117 (03) 804-814
• 71 Soyka M. Treatment of benzodiazepine dependence. N Engl J Med 2017; 376 (12) 1147-1157
• 72 Boyer EW. Management of opioid analgesic overdose. N Engl J Med 2012; 367 (02) 146-155
• 73 Kosten TR, Baxter LE. Review article: effective management of opioid withdrawal symptoms: a gateway to opioid dependence treatment. Am J Addict 2019; 28 (02) 55-62
• 74 Panenka WJ, Procyshyn RM, Lecomte T. et al. Methamphetamine use: a comprehensive review of molecular, preclinical and clinical findings. Drug Alcohol Depend 2013; 129 (03) 167-179
• 75 Zimmerman JL. Cocaine intoxication. Crit Care Clin 2012; 28 (04) 517-526
• 76 Li MJ, Shoptaw SJ. Clinical management of psychostimulant withdrawal: review of the evidence. Addiction 2023; 118 (04) 750-762
• 77 Shprecher D, Mehta L. The syndrome of delayed post-hypoxic leukoencephalopathy. NeuroRehabilitation 2010; 26 (01) 65-72
• 78 Bhattacharyya S, Darby RR, Raibagkar P, Gonzalez Castro LN, Berkowitz AL. Antibiotic-associated encephalopathy. Neurology 2016; 86 (10) 963-971
• 79 Payne LE, Gagnon DJ, Riker RR. et al. Cefepime-induced neurotoxicity: a systematic review. Crit Care 2017; 21 (01) 276
• 80 Kuriyama A, Jackson JL, Doi A, Kamiya T. Metronidazole-induced central nervous system toxicity: a systematic review. Clin Neuropharmacol 2011; 34 (06) 241-247
• 81 Moorthy N, Raghavendra N, Venkatarathnamma PN. Levofloxacin-induced acute psychosis. Indian J Psychiatry 2008; 50 (01) 57-58
• 82 De Bock M, Sienaert P. Corticosteroids and mania: a systematic review. World J Biol Psychiatry 2024; 25 (03) 161-174
• 83 Sonneville R, de Montmollin E, Poujade J. et al. Potentially modifiable factors contributing to sepsis-associated encephalopathy. Intensive Care Med 2017; 43 (08) 1075-1084
• 84 Sonneville R, Benghanem S, Jeantin L. et al. The spectrum of sepsis-associated encephalopathy: a clinical perspective. Crit Care 2023; 27 (01) 386
• 85 Chen J, Shi X, Diao M. et al. A retrospective study of sepsis-associated encephalopathy: epidemiology, clinical features and adverse outcomes. BMC Emerg Med 2020; 20 (01) 77
• 86 Krinitski D, Kasina R, Klöppel S, Lenouvel E. Associations of delirium with urinary tract infections and asymptomatic bacteriuria in adults aged 65 and older: a systematic review and meta-analysis. J Am Geriatr Soc 2021; 69 (11) 3312-3323
• 87 Gofton TE, Young GB. Sepsis-associated encephalopathy. Nat Rev Neurol 2012; 8 (10) 557-566
• 88 Young GB, Bolton CF, Austin TW, Archibald YM, Gonder J, Wells GA. The encephalopathy associated with septic illness. Clin Invest Med 1990; 13 (06) 297-304
• 89 Bolton CF, Young GB, Zochodne DW. The neurological complications of sepsis. Ann Neurol 1993; 33 (01) 94-100
• 90 Riggs JE. Neurologic manifestations of electrolyte disturbances. Neurol Clin 2002; 20 (01) 227-239 , vii
• 91 Arieff AI, Ayus JC. Pathogenesis of hyponatremic encephalopathy. Current concepts. Chest 1993; 103 (02) 607-610
• 92 Achinger SG, Ayus JC. Treatment of hyponatremic encephalopathy in the critically ill. Crit Care Med 2017; 45 (10) 1762-1771
• 93 Arieff AI, Guisado R. Effects on the central nervous system of hypernatremic and hyponatremic states. Kidney Int 1976; 10 (01) 104-116
• 94 Adrogué HJ, Madias NE. Hypernatremia. N Engl J Med 2000; 342 (20) 1493-1499
• 95 Adrogué HJ, Madias NE. Hyponatremia. N Engl J Med 2000; 342 (21) 1581-1589
• 96 Amanzadeh J, Reilly Jr RF. Hypophosphatemia: an evidence-based approach to its clinical consequences and management. Nat Clin Pract Nephrol 2006; 2 (03) 136-148
• 97 Nagata N. Hypophosphatemia and encephalopathy in alcoholics. Intern Med 1998; 37 (11) 911-912
• 98 Yang SL, Wang CH, Feng YK. Neurologic and psychiatric manifestations in hypoparathyroidism. Clinical analysis of 71 cases. Chin Med J (Engl) 1984; 97 (04) 267-272
• 99 Fonseca OA, Calverley JR. Neurological manifestations of hypoparathyroidism. Arch Intern Med 1967; 120 (02) 202-206
• 100 Marx SJ. Hyperparathyroid and hypoparathyroid disorders. N Engl J Med 2000; 343 (25) 1863-1875
• 101 Langley WF, Mann D. Central nervous system magnesium deficiency. Arch Intern Med 1991; 151 (03) 593-596
• 102 Malouf R, Brust JCM. Hypoglycemia: causes, neurological manifestations, and outcome. Ann Neurol 1985; 17 (05) 421-430
• 103 Sima AAF. Encephalopathies: the emerging diabetic complications. Acta Diabetol 2010; 47 (04) 279-293
• 104 MacCario M, Messis CP, Vastola EF. Focal seizures as a manifestation of hyperglycemia without ketoacidosis: a report of seven cases with review of the literature. Neurology 1965; 15: 195-206
• 105 Maccario M. Neurological dysfunction associated with nonketotic hyperglycemia. Arch Neurol 1968; 19 (05) 525-534
• 106 Fried LF, Palevsky PM. Hyponatremia and hypernatremia. Med Clin North Am 1997; 81: 585-609
• 107 Vanholder R, Pletinck A, Schepers E, Glorieux G. Biochemical and clinical impact of organic uremic retention solutes: a comprehensive update. Toxins (Basel) 2018; 10 (01) 33
• 108 Rosner MH, Husain-Syed F, Reis T, Ronco C, Vanholder R. Uremic encephalopathy. Kidney Int 2022; 101 (02) 227-241
• 109 De Deyn PP, Vanholder R, Eloot S, Glorieux G. Guanidino compounds as uremic (neuro)toxins. Semin Dial 2009; 22 (04) 340-345
• 110 Seifter JL, Samuels MA. Uremic encephalopathy and other brain disorders associated with renal failure. Semin Neurol 2011; 31 (02) 139-143
• 111 Johnson WJ, Hagge WW, Wagoner RD, Dinapoli RP, Rosevear JW. Effects of urea loading in patients with far-advanced renal failure. Mayo Clin Proc 1972; 47 (01) 21-29
• 112 Eknoyan G, Beck GJ, Cheung AK. et al; Hemodialysis (HEMO) Study Group. Effect of dialysis dose and membrane flux in maintenance hemodialysis. N Engl J Med 2002; 347 (25) 2010-2019
• 113 Wijdicks EFM. Hepatic encephalopathy. N Engl J Med 2016; 375 (17) 1660-1670
• 114 Butterworth RF. Pathogenesis of hepatic encephalopathy and brain edema in acute liver failure. J Clin Exp Hepatol 2015; 5 (Suppl. 01) S96-S103
• 115 Sherlock S, Summerskill WHJ, White LP, Phear EA. Portal-systemic encephalopathy; neurological complications of liver disease. Lancet 1954; 267 (6836) 454-457
• 116 Kappus MR, Bajaj JS. Covert hepatic encephalopathy: not as minimal as you might think. Clin Gastroenterol Hepatol 2012; 10 (11) 1208-1219
• 117 Ong JP, Aggarwal A, Krieger D. et al. Correlation between ammonia levels and the severity of hepatic encephalopathy. Am J Med 2003; 114 (03) 188-193
• 118 Ge PS, Runyon BA. Serum ammonia level for the evaluation of hepatic encephalopathy. JAMA 2014; 312 (06) 643-644
• 119 Klijn CJ, Kappelle LJ. Haemodynamic stroke: clinical features, prognosis, and management. Lancet Neurol 2010; 9 (10) 1008-1017
• 120 Finnerty Jr FA. Hypertensive encephalopathy. Am J Med 1972; 52 (05) 672-678
• 121 Pak M, Hara M, Miura S. et al. Delirium is associated with high mortality in older adult patients with acute decompensated heart failure. BMC Geriatr 2020; 20 (01) 524
• 122 Uthamalingam S, Gurm GS, Daley M, Flynn J, Capodilupo R. Usefulness of acute delirium as a predictor of adverse outcomes in patients >65 years of age with acute decompensated heart failure. Am J Cardiol 2011; 108 (03) 402-408
• 123 Caplan LR. Cardiac encephalopathy. Curr Treat Options Cardiovasc Med 2004; 6 (03) 217-222
• 124 Caplan LR. Cardiac encephalopathy and congestive heart failure: a hypothesis about the relationship. Neurology 2006; 66 (01) 99-101
• 125 Kilburn KH. Neurologic manifestations of respiratory failure. Arch Intern Med 1965; 116: 409-415
• 126 Wijdicks EFM. Historical appreciation of brain vulnerability from pure hypoxemia. Neurocrit Care 2023; 39 (02) 522-526
• 127 Sekhon MS, Ainslie PN, Griesdale DE. Clinical pathophysiology of hypoxic ischemic brain injury after cardiac arrest: a “two-hit” model. Crit Care 2017; 21 (01) 90
• 128 Thelmo Jr FL, Tzarnas S, Rosal NR, Kramer M, Walters L. Cystocerebral syndrome: an updated review and a new proposed mechanism for an often forgotten cause of delirium. Cureus 2020; 12 (10) e11034
• 129 Blackburn T, Dunn M. Cystocerebral syndrome. Acute urinary retention presenting as confusion in elderly patients. Arch Intern Med 1990; 150 (12) 2577-2578
• 130 Leonard R, Tinetti ME, Allore HG, Drickamer MA. Potentially modifiable resident characteristics that are associated with physical or verbal aggression among nursing home residents with dementia. Arch Intern Med 2006; 166 (12) 1295-1300
• 131 Harper CG, Giles M, Finlay-Jones R. Clinical signs in the Wernicke-Korsakoff complex: a retrospective analysis of 131 cases diagnosed at necropsy. J Neurol Neurosurg Psychiatry 1986; 49 (04) 341-345
• 132 Caine D, Halliday GM, Kril JJ, Harper CG. Operational criteria for the classification of chronic alcoholics: identification of Wernicke's encephalopathy. J Neurol Neurosurg Psychiatry 1997; 62 (01) 51-60
• 133 Weathers AL, Lewis SL. Rare and unusual ... or are they? Less commonly diagnosed encephalopathies associated with systemic disease. Semin Neurol 2009; 29 (02) 136-153
• 134 Donnino MW, Vega J, Miller J, Walsh M. Myths and misconceptions of Wernicke's encephalopathy: what every emergency physician should know. Ann Emerg Med 2007; 50 (06) 715-721
• 135 Bleggi-Torres LF, de Medeiros BC, Werner B. et al. Neuropathological findings after bone marrow transplantation: an autopsy study of 180 cases. Bone Marrow Transplant 2000; 25 (03) 301-307
• 136 Thomson AD, Cook CCH, Touquet R, Henry JA. Royal College of Physicians, London. The Royal College of Physicians report on alcohol: guidelines for managing Wernicke's encephalopathy in the accident and Emergency Department. Alcohol Alcohol 2002; 37 (06) 513-521
• 137 Casaletto JJ. Is salt, vitamin, or endocrinopathy causing this encephalopathy? A review of endocrine and metabolic causes of altered level of consciousness. Emerg Med Clin North Am 2010; 28 (03) 633-662
• 138 Brownlie BE, Rae AM, Walshe JW, Wells JE. Psychoses associated with thyrotoxicosis - ‘thyrotoxic psychosis.’ A report of 18 cases, with statistical analysis of incidence. Eur J Endocrinol 2000; 142 (05) 438-444
• 139 McDermott MT. Hyperthyroidism. Ann Intern Med 2020; 172 (07) ITC49-ITC64
• 140 Feldman AZ, Shrestha RT, Hennessey JV. Neuropsychiatric manifestations of thyroid disease. Endocrinol Metab Clin North Am 2013; 42 (03) 453-476
• 141 Burmeister LA. Coma in thyroid storm: review of aggregated English-language case reports. J Endocr Soc 2019; 3 (07) 1261-1274
• 142 Angell TE, Lechner MG, Nguyen CT, Salvato VL, Nicoloff JT, LoPresti JS. Clinical features and hospital outcomes in thyroid storm: a retrospective cohort study. J Clin Endocrinol Metab 2015; 100 (02) 451-459
• 143 Kwaku MP, Burman KD. Myxedema coma. J Intensive Care Med 2007; 22 (04) 224-231
• 144 Devdhar M, Ousman YH, Burman KD. Hypothyroidism. Endocrinol Metab Clin North Am 2007; 36 (03) 595-615 , v
• 145 Sonino N, Fava GA. Psychiatric disorders associated with Cushing's syndrome. Epidemiology, pathophysiology and treatment. CNS Drugs 2001; 15 (05) 361-373
• 146 Brown EG, Douglas VC. Moving beyond metabolic encephalopathy: an update on delirium prevention, workup, and management. Semin Neurol 2015; 35 (06) 646-655
• 147 Ely EW, Inouye SK, Bernard GR. et al. Delirium in mechanically ventilated patients: validity and reliability of the confusion assessment method for the intensive care unit (CAM-ICU). JAMA 2001; 286 (21) 2703-2710
• 148 McNicoll L, Pisani MA, Zhang Y, Ely EW, Siegel MD, Inouye SK. Delirium in the intensive care unit: occurrence and clinical course in older patients. J Am Geriatr Soc 2003; 51 (05) 591-598
• 149 Brown EG, Josephson SA, Anderson N, Reid M, Lee M, Douglas VC. Evaluation of a multicomponent pathway to address inpatient delirium on a neurosciences ward. BMC Health Serv Res 2018; 18 (01) 106
• 150 LaHue SC, Maselli J, Rogers S. et al. Outcomes following implementation of a hospital-wide, multicomponent delirium care pathway. J Hosp Med 2021; 16 (07) 397-403
• 151 Inouye SK, Bogardus Jr ST, Charpentier PA. et al. A multicomponent intervention to prevent delirium in hospitalized older patients. N Engl J Med 1999; 340 (09) 669-676
• 152 Stevens RD, Bhardwaj A. Approach to the comatose patient. Crit Care Med 2006; 34 (01) 31-41
• 153 Cadena RS, Sarwal A. Emergency neurological life support: approach to the patient with coma. Neurocrit Care 2017; 27 (Suppl. 01) 74-81
• 154 Easter JS, Haukoos JS, Meehan WP, Novack V, Edlow JA. Will neuroimaging reveal a severe intracranial injury in this adult with minor head trauma? The rational clinical examination systematic review. JAMA 2015; 314 (24) 2672-2681
• 155 van den Berge JH, Schouten HJ, Boomstra S, van Drunen Littel S, Braakman R. Interobserver agreement in assessment of ocular signs in coma. J Neurol Neurosurg Psychiatry 1979; 42 (12) 1163-1168
• 156 van den Berge JH, Braakman R, Schouten HJ. Interobserver agreement in assessment of vestibulo-ocular responses. J Neurol Neurosurg Psychiatry 1987; 50 (08) 1045-1047
• 157 Sullivan SJ, Hammond-Tooke GD, Schneiders AG, Gray AR, McCrory P. The diagnostic accuracy of selected neurological tests. J Clin Neurosci 2012; 19 (03) 423-427
• 158 Miller TM, Johnston SC. Should the Babinski sign be part of the routine neurologic examination?. Neurology 2005; 65 (08) 1165-1168
• 159 Stein SC, Spettell C, Young G, Ross SE. Limitations of neurological assessment in mild head injury. Brain Inj 1993; 7 (05) 425-430
• 160 Schmidt WU, Lutz M, Ploner CJ, Braun M. The diagnostic value of the neurological examination in coma of unknown etiology. J Neurol 2021; 268 (10) 3826-3834
• 161 O'Regan NA, Ryan DJ, Boland E. et al. Attention! A good bedside test for delirium?. J Neurol Neurosurg Psychiatry 2014; 85 (10) 1122-1131
• 162 Pompei P, Foreman M, Cassel CK, Alessi C, Cox D. Detecting delirium among hospitalized older patients. Arch Intern Med 1995; 155 (03) 301-307
• 163 O'Keeffe ST, Gosney MA. Assessing attentiveness in older hospital patients: global assessment versus tests of attention. J Am Geriatr Soc 1997; 45 (04) 470-473
• 164 Rosselli M, Tappen R, Williams C, Salvatierra J. The relation of education and gender on the attention items of the mini-mental state examination in Spanish speaking Hispanic elders. Arch Clin Neuropsychol 2006; 21 (07) 677-686
• 165 Gerakios F, Yarnall AJ, Bate G. et al. Delirium is more common and associated with worse outcomes in Parkinson's disease compared to older adult controls: results of two prospective longitudinal cohort studies. Age Ageing 2024; 53 (03) afae046
• 166 Sutter R, Ristic A, Rüegg S, Fuhr P. Myoclonus in the critically ill: diagnosis, management, and clinical impact. Clin Neurophysiol 2016; 127 (01) 67-80
• 167 Suri R, Rodriguez-Porcel F, Donohue K. et al. Post-stroke movement disorders: the clinical, neuroanatomic, and demographic portrait of 284 published cases. J Stroke Cerebrovasc Dis 2018; 27 (09) 2388-2397
• 168 Gupta N, Pandey S. Post-thalamic stroke movement disorders: a systematic review. Eur Neurol 2018; 79 (5-6): 303-314
• 169 Kim JS. Asterixis after unilateral stroke: lesion location of 30 patients. Neurology 2001; 56 (04) 533-536
• 170 Shahrizaila N, Yuki N. Bickerstaff brainstem encephalitis and Fisher syndrome: anti-GQ1b antibody syndrome. J Neurol Neurosurg Psychiatry 2013; 84 (05) 576-583
• 171 Smith TJ, Johnson CR, Koshy R. et al. Thiamine deficiency disorders: a clinical perspective. Ann N Y Acad Sci 2021; 1498 (01) 9-28
• 172 Mathew L, Vale A, Adcock JE. Arsenical peripheral neuropathy. Pract Neurol 2010; 10 (01) 34-38
• 173 Bissell DM, Anderson KE, Herbert L. Porphyria. N Engl J Med 2017; 377: 862-872
• 174 Heath PD, Booth L, Leigh PN, Turner AM. Legionella brain stem encephalopathy and peripheral neuropathy without preceding pneumonia. J Neurol Neurosurg Psychiatry 1986; 49 (02) 216-218
• 175 Bodner RA, Lynch T, Lewis L, Kahn D. Serotonin syndrome. Neurology 1995; 45 (02) 219-223
• 176 Lim BL, Lim GH, Heng WJ, Seow E. Clinical predictors of abnormal computed tomography findings in patients with altered mental status. Singapore Med J 2009; 50 (09) 885-888
• 177 Leong LB, Wei Jian KH, Vasu A, Seow E. Identifying risk factors for an abnormal computed tomographic scan of the head among patients with altered mental status in the Emergency Department. Eur J Emerg Med 2010; 17 (04) 219-223
• 178 Naughton BJ, Moran M, Ghaly Y, Michalakes C. Computed tomography scanning and delirium in elder patients. Acad Emerg Med 1997; 4 (12) 1107-1110
• 179 Thacker PJ, Sethi M, Sternlieb J, Schneider D, Naglak M, Patel RR. Rapid response: to scan or not to scan? The utility of noncontrast CT head for altered mental status. J Patient Saf 2021; 17 (08) e1125-e1129
• 180 Lai MMY, Wong Tin Niam DM. Intracranial cause of delirium: computed tomography yield and predictive factors. Intern Med J 2012; 42 (04) 422-427
• 181 Hijazi Z, Lange P, Watson R, Maier AB. The use of cerebral imaging for investigating delirium aetiology. Eur J Intern Med 2018; 52: 35-39
• 182 Hardy JE, Brennan N. Computerized tomography of the brain for elderly patients presenting to the emergency department with acute confusion. Emerg Med Australas 2008; 20 (05) 420-424
• 183 Benbadis SR, Sila CA, Cristea RL. Mental status changes and stroke. J Stroke Cerebrovasc Dis 1994; 4 (04) 216-219
• 184 Theisen-Toupal J, Breu AC, Mattison MLP, Arnaout R. Diagnostic yield of head computed tomography for the hospitalized medical patient with delirium. J Hosp Med 2014; 9 (08) 497-501
• 185 Brown G, Warren M, Williams JE, Adam EJ, Coles JA. Cranial computed tomography of elderly patients: an evaluation of its use in acute neurological presentations. Age Ageing 1993; 22 (04) 240-243
• 186 Balachandran JS, Jaleel M, Jain M. et al. Head CT is of limited diagnostic value in critically ill patients who remain unresponsive after discontinuation of sedation. BMC Anesthesiol 2009; 9: 3
• 187 Rafanan AL, Kakulavar P, Perl II J, Andrefsky JC, Nelson DR, Arroliga AC. Head computed tomography in medical intensive care unit patients: clinical indications. Crit Care Med 2000; 28 (05) 1306-1309
• 188 Salerno D, Marik PE, Daskalakis C, Kolm P, Leone F. The role of head computer tomographic scans on the management of MICU patients with neurological dysfunction. J Intensive Care Med 2009; 24 (06) 372-375
• 189 Khan S, Guerra C, Khandji A, Bauer RM, Claassen J, Wunsch H. Frequency of acute changes found on head computed tomographies in critically ill patients: a retrospective cohort study. J Crit Care 2014; 29 (05) 884.e7-884.e12
• 190 Pristavu C, Martin A, Irina Ristescu A. et al. Analysis of emergency head computed tomography in critically ill oncological patients. Radiol Oncol 2021; 55 (02) 172-178
• 191 Vijayakrishnan R, Ramasubramanian A, Dhand S. Utility of head CT scan for acute inpatient delirium. Hosp Top 2015; 93 (01) 9-12
• 192 Sutter R, Kaplan PW. What to see when you are looking at confusion: a review of the neuroimaging of acute encephalopathy. J Neurol Neurosurg Psychiatry 2015; 86 (04) 446-459
• 193 Morandi A, Gunther ML, Vasilevskis EE. et al. Neuroimaging in delirious intensive care unit patients: a preliminary case series report. Psychiatry (Edgmont) 2010; 7: 28-33
• 194 Polito A, Eischwald F, Maho A-LL. et al. Pattern of brain injury in the acute setting of human septic shock. Crit Care 2013; 17 (05) R204
• 195 Zehtabchi S, Abdel Baki SG, Grant AC. Electroencephalographic findings in consecutive emergency department patients with altered mental status: a preliminary report. Eur J Emerg Med 2013; 20 (02) 126-129
• 196 Zehtabchi S, Abdel Baki SG, Omurtag A. et al. Prevalence of non-convulsive seizure and other electroencephalographic abnormalities in ED patients with altered mental status. Am J Emerg Med 2013; 31 (11) 1578-1582
• 197 Bautista RED, Godwin S, Caro D. Incorporating abbreviated EEGs in the initial workup of patients who present to the emergency room with mental status changes of unknown etiology. J Clin Neurophysiol 2007; 24 (01) 16-21
• 198 Billakota S, Sinha SR. Utility of continuous EEG monitoring in noncritically ill hospitalized patients. J Clin Neurophysiol 2016; 33 (05) 421-425
• 199 Naeije G, Gaspard N, Depondt C, Pepersack T, Legros B. Acute confusional state of unknown cause in the elderly: a study with continuous EEG monitoring. Epilepsy Behav 2012; 23 (03) 330-334
• 200 Gilmore EJ, Gaspard N, Choi HA. et al. Acute brain failure in severe sepsis: a prospective study in the medical intensive care unit utilizing continuous EEG monitoring. Intensive Care Med 2015; 41 (04) 686-694
• 201 Claassen J, Mayer SA, Kowalski RG, Emerson RG, Hirsch LJ. Detection of electrographic seizures with continuous EEG monitoring in critically ill patients. Neurology 2004; 62 (10) 1743-1748
• 202 Kurtz P, Gaspard N, Wahl AS. et al. Continuous electroencephalography in a surgical intensive care unit. Intensive Care Med 2014; 40 (02) 228-234
• 203 Oddo M, Carrera E, Claassen J, Mayer SA, Hirsch LJ. Continuous electroencephalography in the medical intensive care unit. Crit Care Med 2009; 37 (06) 2051-2056
• 204 Betjemann JP, Nguyen I, Santos-Sanchez C, Douglas VC, Josephson SA. Diagnostic yield of electroencephalography in a general inpatient population. Mayo Clin Proc 2013; 88 (04) 326-331
• 205 Kamel H, Betjemann JP, Navi BB. et al. Diagnostic yield of electroencephalography in the medical and surgical intensive care unit. Neurocrit Care 2013; 19 (03) 336-341
• 206 Husain AM, Horn GJ, Jacobson MP. Non-convulsive status epilepticus: usefulness of clinical features in selecting patients for urgent EEG. J Neurol Neurosurg Psychiatry 2003; 74 (02) 189-191
• 207 Khan RB, Yerremsetty PK, Lindstrom D, McGill LJ. Emergency EEG and factors associated with nonconvulsive status epilepticus. J Natl Med Assoc 2001; 93 (10) 359-362
• 208 Garrido E, Adeli A, Echeverria-Villalobos M, Fiorda J, Hannawi Y. Prevalence of electrographic seizures in hospitalized patients with altered mental status with no significant seizure risk factors who underwent continuous EEG monitoring: a retrospective study. Cureus 2024; 16 (03) e55903
• 209 Laccheo I, Sonmezturk H, Bhatt AB. et al. Non-convulsive status epilepticus and non-convulsive seizures in neurological ICU patients. Neurocrit Care 2015; 22 (02) 202-211
• 210 Towne AR, Waterhouse EJ, Boggs JG. et al. Prevalence of nonconvulsive status epilepticus in comatose patients. Neurology 2000; 54 (02) 340-345
• 211 Kapadia FN, Shukla U, Gursahani R. Utility of electroencephalogram in altered states of consciousness in intensive care unit patients. Indian J Crit Care Med 2005; 9: 19-21
• 212 Sutter R, Kaplan PW. Clinical and electroencephalographic correlates of acute encephalopathy. J Clin Neurophysiol 2013; 30 (05) 443-453
• 213 Struck AF, Ustun B, Ruiz AR. et al. Association of an electroencephalography-based risk score with seizure probability in hospitalized patients. JAMA Neurol 2017; 74 (12) 1419-1424
• 214 Herman ST, Abend NS, Bleck TP. et al; Critical Care Continuous EEG Task Force of the American Clinical Neurophysiology Society. Consensus statement on continuous EEG in critically ill adults and children, part I: indications. J Clin Neurophysiol 2015; 32 (02) 87-95
• 215 Warshaw G, Tanzer F. The effectiveness of lumbar puncture in the evaluation of delirium and fever in the hospitalized elderly. Arch Fam Med 1993; 2 (03) 293-297
• 216 Shah K, Richard K, Edlow JA. Utility of lumbar puncture in the afebrile vs. febrile elderly patient with altered mental status: a pilot study. J Emerg Med 2007; 32 (01) 15-18
• 217 Nothem ME, Salazar AG, Nanchal RS, Bergl PA. Diagnostic yield of combined lumbar puncture and brain MRI in critically ill patients with unexplained acute encephalopathy: a retrospective cohort study. Crit Care Explor 2023; 5 (07) e0936
• 218 Jackson Jr WL, Shorr AF. The yield of lumbar puncture to exclude nosocomial meningitis as aetiology for mental status changes in the medical intensive care unit. Anaesth Intensive Care 2006; 34 (01) 21-24
• 219 Adelson-Mitty J, Fink MP, Lisbon A. The value of lumbar puncture in the evaluation of critically ill, non-immunosuppressed, surgical patients: a retrospective analysis of 70 cases. Intensive Care Med 1997; 23 (07) 749-752
• 220 Khasawneh FA, Smalligan RD, Mohamad TN, Moughrabieh MK, Soubani AO. Lumbar puncture for suspected meningitis after intensive care unit admission is likely to change management. Hosp Pract 2011; 39 (01) 141-145
• 221 Metersky ML, Williams A, Rafanan AL. Retrospective analysis: are fever and altered mental status indications for lumbar puncture in a hospitalized patient who has not undergone neurosurgery?. Clin Infect Dis 1997; 25 (02) 285-288