A 78-year-old woman with mildAlzheimer disease falls at home and suffers a left hip fracture. She is admitted to the hospital and undergoes a left total hip replacement. Postoperatively she is D5W and treated with meperidine for pain, diphenhydramine for sleep, and prophylactic ranitidine. On the second postoperative day, she pulls out her Foley catheter and her IV. On examination blood pressure is 150/90, pulse rate is 80, and temperature 36.7°C (98°F). Oxygen saturation on room air is 92%. She is markedly confused and appears agitated. She has no focal neurologic findings. Laboratory testing reveals:
What is the best next step in her management?
A. Order CT scan of the brainThis patient has postoperative delirium, characterized by acute onset of confusion and agitation. Frequently the level of consciousness fluctuates. Postoperative delirium is common in the elderly. Males are affected more commonly than females. Delirium occurs more frequently in elderly patients with preexisting dementia, history of alcohol abuse, and memory impairment. Persons with postoperative delirium should receive a careful history that includesmedication review, a focused physical examination, and laboratory testing. Laboratory testing should be directed toward excluding electrolyte disturbance, infection, and hypoxemia. The most common treatable causes of delirium are related to medications and electrolyte disturbances. Medicines with anticholinergic and sedating effects should be avoided. Commonly prescribed drugs with anticholinergic properties include diphenhydramine, tricyclic antidepressants, oxybutynin, and H2 blocking agents. Management of postoperative delirium includes looking for underlying precipitating factors, correcting electrolyte disturbances, discontinuing aggravating medications, removing indwelling devices, avoiding physical or pharmacologic restraints, early mobilization, and the use the orienting stimuli such as clocks and calendars. Postoperative delirium is a serious condition and is associated with increased mortality, prolonged hospital stay, and more frequent nursing home placement after hospitalization. Structural central nervous system disease is an uncommon cause of postoperative delirium, so CT scanning would not be the first test ordered. Pulmonary embolism can cause delirium by causing hypoxia; since this patient’s oxygen saturation is normal, lung scan would not be indicated. Infection can cause postoperative delirium, but this patient’s normal temperature and white blood cell count militate against an infectious cause. Restraints and benzodiazepines often make delirium worse. If pharmaco-therapy is required, haloperidol is usually the first choice.