Approach to the Patient: Delirium As the diagnosis of delirium is clinical and made at the bedside, a careful history and physical examination is necessary when evaluating patients with possible confusional states. Screening tools can aid physicians and nurses in identifying patients with delirium, including the Confusion Assessment Method (CAM) (Table 26-1); the Organic Brain Syndrome Scale; the Delirium Rating Scale; and, in the ICU, the Delirium Detection Score and the ICU version of the CAM. These scales are based on criteria from the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders (DSM) or the World Health Organization's. | Chapter 026. Confusion and Delirium Part 3 Approach to the Patient Delirium As the diagnosis of delirium is clinical and made at the bedside a careful history and physical examination is necessary when evaluating patients with possible confusional states. Screening tools can aid physicians and nurses in identifying patients with delirium including the Confusion Assessment Method CAM Table 26-1 the Organic Brain Syndrome Scale the Delirium Rating Scale and in the ICU the Delirium Detection Score and the ICU version of the CAM. These scales are based on criteria from the American Psychiatric Association s Diagnostic and Statistical Manual of Mental Disorders DSM or the World Health Organization s International Classification of Diseases ICD . Unfortunately these scales themselves do not identify the full spectrum of patients with delirium. All patients who are acutely confused should be presumed delirious regardless of their presentation due to the wide variety of possible clinical features. A course that fluctuates over hours or days and may worsen at night termed sundowning is typical but not essential for the diagnosis. Observation of the patient will usually reveal an altered level of consciousness or a deficit of attention. Other hallmark features that may be present in the delirious patient include alteration of sleep-wake cycles thought disturbances such as hallucinations or delusions autonomic instability and changes in affect Table 26-1 The Confusion Assessment Method CAM Diagnostic Algorithm The diagnosis of delirium requires the presence of features 1 and 2 and of either 3 or 4a Feature 1 Acute onset and fluctuating course This feature is satisfied by positive responses to these questions Is there evidence of an acute change in mental status from the patient s baseline Did the abnormal behavior fluctuate during the day that is tend to come and go or did it increase and decrease in severity Feature 2 Inattention This feature is satisfied by a positive .