Hypoglycemia, hypoxia, hyponatremia, hypernatremia, hypercalcemia, hypercarbia, uremia, hyperthyroidism


Stroke, subdural and epidural hematoma, subarachnoid hemorrhage, postictal state, concussion and contusion, meningitis, encephalitis, brain tumor

Drug- or Toxin-Induced:

Lithium intoxication, ethanol, steroids, anticholinergics, sympathomimetics, poisons (eg, mushrooms, carbon monoxide), drugs of abuse including ecstasy (MMDA), gamma hydroxybutyrate (GHB), lysergic acid diethylamide (LSD), phencyclidine (PCP), mescaline


Sepsis, thiamine deficiency, niacin deficiency

substance withdrawal



Manage risk factors including sleep-wake cycle reversal, immobility, visual impairment, hearing impairment, sleep deprivation, and dehydration.


No specific medications have been definitively shown to be effective for delirium prevention, including trials of cholinesterase inhibitors and antipsychotic agents.

identifying sedatives, such as dexmedetomidine, that are less likely to lead to delirium in critically ill patients and on developing protocols for daily awakenings in which infusions of sedative medications are interrupted and the patient is reorientated by the staff.


common etiologies :toxins and metabolic conditions. Observation will usually reveal an altered level of consciousness or a deficit of attention. Attention can be assessed through a simple bedside test of digits forward—pts are asked to repeat successively longer random strings of digits beginning with two digits in a row; a digit span of four digits or less usually indicates an attentional deficit unless hearing or language barriers are present. Delirium is vastly underrecognized, especially in pts presenting with a quiet, hypoactive state and those in the ICU.1. Assess and ensure patient safety. (what are the issues; how to implement?)


Screening tools can aid physicians and nurses in identifying patients with delirium, including the Confusion Assessment Method (CAM)[ the Organic Brain Syndrome Scale; the Delirium Rating Scale; and, in the ICU, the ICU version of the CAM and the Delirium Detection Score. ]

Using the well-validated CAM, a diagnosis of delirium is made if there is (1) an acute onset and fluctuating course and (2) inattention accompanied by either (3) disorganized thinking or (4) an altered level of consciousness. These scales may not identify the full spectrum of patients with delirium, and 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 usually will reveal an altered level of consciousness or a deficit of attention. Other features that are sometimes present include alteration of sleep-wake cycles, thought disturbances such as hallucinations or delusions, autonomic instability, and changes in affect.



Management begins with treatment of the underlying inciting factor (e.g., pts with systemic infections should be given appropriate antibiotics, and electrolyte disturbances judiciously corrected). Relatively simple methods of supportive care can be quite effective, such as frequent reorientation by staff, preservation of sleep-wake cycles, and attempting to mimic the home environment as much as possible. Chemical restraints exacerbate delirium and should be used only when necessary to protect pt or staff from possible injury; antipsychotics at low dose are usually the treatment of choice.

Use of dexmedetomidine was associated with less ICU delirium than midazolam, one of the conventional sedatives.  


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A 76-year-old previously healthy man presents to the emergency department for evaluation of an acute change in mental status. He appears agitated and is pacing the room. He has difficulty focusing his attention and provides an incoherent history. His temperature is 98.4°F, blood pressure is 134/72 mmHg, pulse is 94 bpm, and room-air oxygen saturation is 99%. Laboratory investigations are unremarkable. His wife reports that he has been taking over-the-counter diphenhydramine for an itchy contact dermatitis for the past 2 days. Interference with which neurotransmitter most likely precipitated this change in mental status?






Next Question
You will be able to view all answers at the end of your quiz.

The correct answer is A. You answered C.

The answer is A.(Chap. 34) Delirium is an acute and fluctuating decline in cognition typified by inattention, disorganized thinking, and an altered level of consciousness. The common etiologies of delirium are manifold, and in many patients, the cause is multifactorial. Nearly one-third of cases of delirium are due to medications. Especially in older adults, drugs with anticholinergic properties may precipitate delirium. Deficiency of acetylcholine may play a key role in the pathogenesis of delirium. Diphenhydramine is a sedating antihistamine with substantial anticholinergic activity. Diphenhydramine does not significantly antagonize the activity of serotonin, dopamine, or norepinephrine.


An 82 year-old woman who underwent right knee replacement yesterday develops new symptoms. Right after surgery, she was agitated, awake all night and refused to eat or take postoperative medications. Today she is still agitated and not oriented to time and place. What is the most appropriate management at this point?

A- Restrain in bed and lorazepam administration

B- Restrain in bed and haloperidol administration

C- Sleep enhancement protocol and family support as well as haloperidol administration

D- Diphenhydramine to enhance sleeping

E- Refer to psychiatry department



Delirium in the hospitalized elderly patient can be prevented by implementing all of the following interventions upon admission EXCEPT:

The correct answer is C.

 Medications are not generally considered first line for the prevention of delirium. Other steps such as noise reduction, orientation stimuli, mobilization, assuring access to hearing aids and glasses, a predictable schedule, etc. are preferred. Restraints can increase agitation and lead to an increase in falls, as can the use of bed rails.