Carole Bullock

June 09, 2011

June 9, 2011 (Dallas, Texas) — Delirium is an extremely common condition that may occur in up to 30% of patients older than 65 years, and the prevalence is increasing.

A new study illustrating the growing burden of this condition was reported by Neil Winawer, MD, associate professor of medicine, Emory University School of Medicine, and director, hospital medicine, Grady Memorial Hospital, Atlanta, Georgia, who gave an overview here at Hospital Medicine 2011: Society of Hospital Medicine (SHM) Annual Meeting.

In his presentation, "So You Say You Don't Remember: Inpatient Delirium Evaluation and Management," Dr. Winawer addressed diagnostic and management strategies for delirium and provided some startling statistics.

"Mortality at 1 month is 14% and is 22% at 6 months, which is twice as high as in patients without delirium," he reported, "and [delirium] increases hospital length of stay."

What separates those who develop delirium from those who maintain an intact sensorium? According to Dr. Winawer, delirium results from a combination of a patient's underlying susceptibility and the magnitude of the precipitating event. For example, patients with preexisting cognitive impairment such as severe dementia or cerebrovascular disease require only a minimal insult (eg, urinary tract infection, dehydration, etc) to experience an altered level of consciousness, whereas those with normal cognitive functioning require a more noxious insult, such as a severe illness or major surgery.

"Hospitalized patients with delirium may wander, fall, or pull out indwelling catheters. Delirium can manifest as inattention, disorganized thinking and altered level of consciousness, disorientation, memory impairment, perceptual disturbance, abnormal psychomotor activity, or altered sleep–wake cycle," he said in an interview with Medscape Medical News.

The management of delirium focuses on identifying and treating the underlying illness. If no etiology is readily identified, then the delirium itself is treated with supportive therapy.

The diagnostic work-up includes taking a history and performing a physical exam, assessing potential sites of infection, and compiling neurologic findings. Laboratory testing should include checking for drug withdrawal/toxicity; assessing volume status of serum electrolytes, creatinine, glucose, and calcium levels; and performing a urinalysis and a complete blood count.

A diagnostic tool Dr. Winawer recommends is the Confusion Assessment Method, which includes 4 aspects of confusion/delirium: acute onset and fluctuating course, inattention, disorganized thinking, and altered level of consciousness. Diagnosis of delirium by the Confusion Assessment Method requires the presence of both features 1 and 2 and either feature 3 or feature 4.

"This was identified as the best bedside instrument...compared with the gold standard of a [Diagnostic and Statistical Manual of Mental Disorders]-based diagnosis by a psychiatrist, neurologist, or geriatrician," Dr. Winawer said, citing a recent study showing that the Confusion Assessment Method had a sensitivity of 86% and a specificity of 93%.

Keys to effective management of delirium include early mobilization, physical therapy, maximization of nutrition/fluid status, and avoiding polypharmacy.

Dr. Winawer pointed out that drug therapy in the treatment of delirium is not extensively studied.

"The [most commonly studied] agent has been Haldol (haloperidol, Ortho-McNeil-Janssen Pharmaceuticals), 0.5 mg - 1.0 mg, which is effective in controlling psychotic features and agitation and has a low risk for sedation and hypotension," he noted.

Other agents for management of delirium that he made note of include the atypical antipsychotics risperidone, olanzapine, quetiapine, and ziprasidone, which have "fewer extrapyramidal side effects. In the intensive care unit, however, there is less data supporting the use of antipsychotics. The [Modifying the INcidence of Delirium (MIND)] Study included 101 mechanically ventilated patients. It was an investigation of the use of Haldol vs ziprasidone vs placebo, finding 'no difference in delirium-free days, ventilator-free days, hospital [length of stay] or mortality,' " Dr. Winawer said.

Benzodiazepines are the drug of choice for alcohol/sedative drug withdrawal, but they should be used with caution in patients at high risk for respiratory depression, such as patients with chronic obstructive pulmonary disease or pneumonia, he cautioned.

According to Dr. Winawer, neuroimaging is also a hot topic for those working up delirium. In a study of 279 computed tomography head scans performed in patients older than 70 years with delirium, 42 patients had an acute central nervous system disorder (15%), and of those patients, 40 had new focal neurologic findings and/or significant changes in their level of consciousness (unable to speak, open eyes, or follow simple commands).

"If a patient is awake, able to follow simple commands, and has no focal neurologic findings, then [computed tomography] scanning is not emergently indicated," he said.

"It's also important to work with family and caregivers to make sure they understand what can be done to help the patient," he added.

Hospital Medicine 2011: Society of Hospital Medicine (SHM) Annual Meeting: Practice Management Session 2. Presented May 11, 2011.