Development of a risk score to guide brain imaging in older patients admitted with falls and confusion

Abstract

Objectives: CT scanning of the brain is commonly performed in older people admitted to hospital with a fall, but the yield of positive findings is low. We used audit data to develop a risk-stratification score to guide more efficient use of CT scanning. Methods: 12 potential predictors of positive CT findings were derived from a literature review. Case notes of consecutive patients presenting with falls and confusion who had undergone brain imaging were reviewed as part of an ongoing audit. Correlation of each factor with positive CT findings was undertaken and a final risk score was developed. Receiver-operating characteristic analysis was undertaken, an optimum cut-off identified, and positive and negative predictive values were calculated. Results: 66 patients with a mean age of 74.8 years were included. 13 of the 66 (20%) brain imaging studies revealed a new pathology. Previous history of falls, atrial fibrillation, head or face trauma, focal neurological signs, warfarin use and a Glasgow coma score of ,14 were significant univariate positive predictors. Antecedent dementia was included as a negative predictor. The final weighted score (range -1 to 8 points) gave an area under the curve of 0.83 (95% confidence interval 0.70 to 0.96, p,0.001). When using a cut-off of 3 points, sensitivity for significant new pathology on brain imaging was 83%, specificity was 89%, positive predictive value was 63% and negative predictive value was 96%. Conclusion: A simple weighted risk score may be able to guide the need for brain imaging in older people presenting to hospital with falls. The score requires validation in a larger, prospectively collected cohort. Patients who fall and present to medical admissions units with confusion pose a diagnostic problem because of their inability to give a coherent history. A pre-existing diagnosis of dementia often further hampers the clinical assessment; because of these reasons, older people with falls and confusion often under go CT of the head. The diagnostic yield of these investigations is often low. A study of 294 patients with acute confusion found a diagnostic yield of only 14% if clinical suspicion was the sole reason for referral [1]. A large number of these investigations could therefore, in theory, be avoided, enabling better use of resources, reducing healthcare costs and minimising patient exposure to unnecessary radiation. To better target the use of brain imaging in this patient group, a risk scoring system is required. Such scoring systems have been developed for use in general [2] and paediatric patients [3] presenting with head trauma, but old age is usually included as part of the indication for scanning. As such, existing risk scoring systems may lack discrimination when used in older patients. Pre-existing falls risk scoring systems that are widely used, such as the Tinetti score [4], are mainly designed to calculate risk of falls rather than to help preselect patients that might have significant intracranial pathology as a cause (or result) of their fall.We the...

Head computed tomography for elderly patients with acute altered mental status in the emergency setting: value for decision-making and predictors of abnormal findings

“…With the increasing use of CT imaging in EDs, our analysis suggests a scope for future intervention studies to evaluate the accuracy of clinical prediction rules for identifying intracranial lesions in elderly patient with isolated AMS. Previously, the utility of head CT for evaluating AMS in emergency medicine has mainly been studied through reviews of nonselected cohorts, including patients who have a high risk of cerebral lesions because of neurological signs, [27][28][29][30][31][32] traumatic brain injuries, 33,34 unusual headaches, 35 or the use of antiplatelet or anticoagulant treatments. 32,36 Few studies have specifically examined elderly patients undergoing head CT in EDs for isolated AMS, but that situation accounted for 14% to 30% of head CT requests.…”