Understanding diagnosis and assessment

Delirium is a life-threatening medical emergency, particularly for older adults. It often goes unrecognized by health care providers. Early recognition and treatment of delirium are essential. If left untreated, delirium can result in permanent disability or even death.

Mental confusion is not a normal part of aging. Rather, it is an indication that something is wrong in the brain. When mental status is assessed during a delirium, the results may be misinterpreted as dementia. 

It is therefore essential to get collateral background history on the older person, including previous functional and cognitive status.

Be sure to listen to family and caregivers as they can provide valuable information regarding abnormal sudden change in the patient’s character. 


The Diagnostic and Statistical Manual IV (DSM IV-TR, 2000) criteria diagnose the core features of delirium:

  1. Disturbance of consciousness (reduced clarity of awareness of the environment with reduced ability to focus sustain or shift attention)
  2. A change in cognition (memory deficit, disorientation, language disturbance); or development of a perceptual disturbance (not part of a pre-existing condition such as dementia)
  3. Acute onset (hours to days) and fluctuating during the course of the day
  4. Evidence from the personal history, physical examination or laboratory findings that the disturbance is caused by the direct physiological consequences of a general medical condition.


Meagher, O’Hanlon and O’Mahoney (1996) describe three forms of delirium:

  1. Hyperactive delirium, which is easily recognized and occurs in approximately 30% of cases.  Persons present with repetitive behaviours such as plucking at sheets, picking, wandering, or perceptual disturbances such as illusions or hallucinations.
  2. Hypoactive delirium, which is easily missed and occurs in about 25% of cases. Persons appear quiet and withdrawn and may be misdiagnosed with depression.
  3. mixed pattern of hypoactive and hyperactive symptoms that fluctuate, and includes lucid periods.  This presentation occurs in about 45% of people with delirium.


Delirium often has a multifactorial etiology. Very vulnerable persons may develop a delirium with more minor insults.

  • increasing age
  • dementia
  • sensory impairments.


Precipitating factors for delirium include

  • medications (including substance withdrawal),
  • severe acute illness,
  • surgery,
  • infections,
  • metabolic abnormalities (including dehydration and electrolyte abnormalities),
  • hypoxemia,
  • severe pain,
  • problems with elimination.


Factors that can make delirium worse include

  • Physical restraints
  • Inappropriate caregiver approach (e.g., trying to reason with patient)
  • Too much caffeine
  • Uncontrolled pain
  • Lack of sleep


Effective therapy for the delirious older person is considered the detection and treatment of predisposing and precipitating factors. The search for the factors contributing to the development of delirium is based on a medical history, physical examination, and laboratory investigations. Not finding a specific cause does not indicate that a delirium is not present – many cases have no definite found cause.

In order to rule out medical problems that may be causing or contributing to the delirium, laboratory testing for persons with a suspected delirium should include: complete blood count, electrolyte panel, metabolic panel, thyroid function tests, urinalysis, electrocardiogram, and chest x-ray (CCSMH, 2006).

The treatment of delirium is the treatment of the underlying problem.  Sedating medication, such as antipsychotics, should only be used if the patient is otherwise unmanageable – these do not shorten the course of the delirium, and may prolong it.  For the most part benzodiazepines should be avoided as they will only worsen the delirium and lengthen its course.



Delirium can be prevented, through prevention of hospital-associated complications, avoidance of overuse of medications, and attention to the basics of nursing care such as nutrition, hydration, elimination, sleep, sensory input and good pain control.

Visit the Hospital Elder Life Program (HELP) for more information on how delirium can be prevented.


 A handy reminder: 

Dr. Kenneth Rockwood, MD, FRCPC, FRCP, remind us of the “delirium chant”:




Metabolic abnormalities


Heart problems

Some combination

Something else

 Dr Rockwood says: “The list is necessarily exhaustive and focuses on what is most common. The chant allows people to proceed without thinking, which is how a lot of medicine needs to work when the volumes are high. It repeats meds 3 times because that is most common, and to remind people that meds can be rx, OTC, or alcohol.”


 Sample Case studies




American Psychiatric Association. (2000). Diagnostic and statistical manual of mental disorders (4th ed., text rev.).Washington,DC: Author.

Canadian Coalition for Seniors’ Mental Health. (2006). National Guidelines for Seniors’ Mental Health: The Assessment and Treatment of Delirium.Toronto,ON: Canadian Coalition for Seniors’ Mental Health

Meagher, DJ, O’Hanlon, D, O’Mahoney. (1996). The use of environmental strategy andpsychotropic medication in the management of delirium. British Journal of Psychiatry, 168 (4), 512-515