Diagnostic yield of head computed tomography for the hospitalized medical patient with delirium

Abstract

BACKGROUND Delirium is common in hospitalized patients and warrants early diagnosis and treatment. Often the evaluation of delirium includes head computed tomography imaging. However, in hospitalized medical patients, the yield of head computed tomography is unknown. OBJECTIVE To determine the diagnostic yield of head computed tomography when evaluating a hospitalized medical patient with delirium in the absence of a recent fall, head trauma, or new neurologic deficit. DESIGN AND SETTING Retrospective medical record review at a large academic medical center in Boston, Massachusetts. PARTICIPANTS We reviewed all medical records for head computed tomography scans performed from January 2010 through November 2012 in patients on the general medicine or medical subspecialties units. MAIN OUTCOMES A “positive” head computed tomography was defined as an intracranial process that could explain delirium. An “equivocal” head computed tomography was defined as the presence of a finding of unclear significance in relation to delirium. RESULTS There were 398 patients hospitalized for >24 hours who underwent head computed tomography for delirium. Two hundred twenty head computed tomography studies met eligibility criteria, with 6 (2.7%) positive and 4 (1.8%) equivocal results. All positive and equivocal findings resulted in change in management. CONCLUSIONS The diagnostic yield of head computed tomography in determining the cause of delirium in hospitalized patients is low. Due to the low rate of positive findings, head imaging is unnecessary in the majority of cases of delirium. However, there may be a subset of high‐risk individuals in which head imaging is indicated. Journal of Hospital Medicine 2014;9:497–501. © 2014 Society of Hospital Medicine

The use of cerebral imaging for investigating delirium aetiology

“…The rate of positive findings in CT brain scanning is comparable to previous literature in hospitalized patients with delirium, although this figure varied (3-45%) in previous studies depending on the patient population and outcome definition [6,[8][9][10][11][12][13]. This study included all patients with delirium, whereas some studies only included delirium patients with falls, head trauma and neurological deficits [8] or excluded patients with head trauma [11]. Also, this study's outcome definition excluded chronic pathology (such as chronic small vessel ischaemia) whereas some previous studies incorporated all abnormal findings on CT brain and therefore had a relatively high rate of abnormal findings, 45% in one study [12].…”

“…The yield of pathological findings on CT brain ranges between 3 and 45% for hospitalized patients with delirium, with studies having varying definitions of positive imaging results [6,[8][9][10][11][12][13]. The use of cerebral magnetic resonance imaging (MRI) as diagnostic tool in delirium has not yet been compared to CT brain.…”

ACR Appropriateness Criteria® Acute Mental Status Change, Delirium, and New Onset Psychosis

“…CT Head. The reported detection of treatment-altering findings on head CT is very low in elderly patients with new onset delirium unless one of the following risk factors is present: focal neurologic deficit, history of recent falls or head injury, anticoagulation therapy, signs of elevated intracranial pressure, or significant deterioration of consciousness [8,[38][39][40]. Acute pathology that resulted in a change of management was detected in a small proportion of patients on head CT, including ischemic and hemorrhagic stroke, subdural hematoma, SAH, encephalitis or meningitis, and cerebral tumors.…”

“…Acute pathology that resulted in a change of management was detected in a small proportion of patients on head CT, including ischemic and hemorrhagic stroke, subdural hematoma, SAH, encephalitis or meningitis, and cerebral tumors. Therefore, the low diagnostic yield of CT in this setting must be weighed against the risk of possible, preventable morbidity [8,11], acknowledging that patients may not have clinical signs on examination that predict a focal pathology [41]. There is no relevant literature regarding the use of contrast-enhanced head CT in the evaluation of delirium.…”

“…Early detection and accurate diagnosis are extremely important as mortality in patients may be twice as high if the diagnosis of delirium is missed [7]. Up to 10% to 31% of patients may have delirium at admission, and it may develop in up to 56% of admitted patients [8], particularly following surgery or in the intensive care unit [8]. Delirium is not explained by a pre-existing neurocognitive disorder, does not occur in a state of severely reduced arousal, such as a coma, and is thought to be directly precipitated by one or more underlying causes, including another medical condition, intoxication, toxin exposure, or withdrawal [9].…”