Comparison between Dementia and Delirium


Dementia and delirium are two common neurological conditions with varying similarities and differences. Dementia is a neurodegenerative condition with a slow onset ( Fong,  Davis, Growdon, Albuquerque, & Inouye, 2015). Delirium is an acute mental status change ( Fong et al., 2015). An inexperienced  practitioner may have some difficulties in differentiating between the two conditions as certain similarities can present with either condition. Delirium and dementia are two separate mental conditions; however, both can be attributed with impaired memory and judgement, confusion, disorientation, variable degrees of paranoia and hallucinations (Lippmann & Perugula, 2016).

In reviewing specific presentations that differ between dementia and delirium. A consideration of delirium can be suspected if the patient presents with sudden cognitive confusion, while on the contrary a consideration for dementia can be established if the incidence has occurred slowly overtime ( Lippmann & Pergula, 2016).  Delirium duration is variable, whereas dementia duration is chronic and progressive ( Lippmann & Pergula, 2016). Both conditions affect cognition in some aspect. Deciding upon the length of the presenting condition can give the provider a better understating if the condition is dementia or delirium.

Both dementia and delirium tend to affect the elderly more often ( Lippmann & Pergula, 2016). In delirium certain medical complaints are seen such as;  infections, depression, diabetes, substance abuse or exposure to certain poisons or medications( Lippmann & Pergula, 2016). Medical conditions seen with dementia are issues related to a stroke, hypertension, Parkinson’s disease and dispositions to delirium ( Lippmann & Pergula, 2016).

The attention span typically seen in dementia is normal unless the dementia staging is advanced (

Fong et al., 2015

). Delirium attention  is minimized regarding focus, sustainability or shift in attention ( Fong et al., 2015). In delirium the  patient’s speech can be incoherent, disorganized and distractible ( Fong et al ., 2015). In dementia, the speech can be methodical, but may develop anomia or aphasia ( Fong et al., 2015).


Alzheimer dementia is evident with amyloid plaques and neurofibrillary tangles ( Buttaro, Trybulski, Polgar-Bailey, & Sandburg-Cook, 2017).  Alzheimer dementia is clinically associated with atrophy in the cerebral cortex  and is most noticeable in the frontal, temporal, and parietal lobes (Buttaro et al., 2017).  Catecholaminergic, serotonergic, and cholinergic transmission is affected in dementia; along with a reduction of the enzyme found in cholinergic neurons called choline acetyltransferase (Buttaro et al., 2017).

The exact cause of delirium has not accurately been identified. However, there are many possible causes for the physiological occurrence in developing delirium. One cause is in relation to inadequate cerebral metabolism, reported by areas of slowing on an electroencephalogram (Buttaro et al., 2017). Another physiological occurrence is in relation to central abnormalities, where an imbalance occurs between central cholinergic, cytokine activation and adrenergic metabolism ( Buttaro et al., 2017). Furthermore, changes in inhibitory tone and connectivity can  occur, due to a stress reaction from high levels of corticosteroids (Buttaro et al., 2017). Essentially delirium can be classified as reversible and an impairment of  either cerebral oxidative metabolism or neurotransmitter dysfunctions ( Lippmann & Pergula, 2016). And dementia is ultimately due to altered brain function from exogenous insult or an intrinsic course ( Lippmann & Pergula, 2016).


In both cases of dementia and delirium, a thorough and detailed health history is indicated , preferably from the patient. However, if the patient is unable to communicate,  a thorough health history can be obtained from a guardian, caretaker, or close relative ( Buttaro et al., 2017). A full neurological exam should also be included in suspected dementia or delirium ( Downing, Caprio,  & Lyness, 2013). The provider should also review a medication reconciliation for dementia and delirium  including all over the counter and prescriptive medications, along with questions pertaining to alcohol or substance use ( Buttaro et al., 2017). Specific assessments in relation to  suspected delirium involve close observation of the patient’s ability to ambulate , level of consciousness, speech, appearance and their overall interaction during the exam (Buttaro et al., 2017). Specific assessments in relation to dementia involve neurologic sings, blood pressure, cardiac assessment , cognition, mood, function and overall behavior  (Buttaro et al., 2017). The U.S. Preventative Task Force (2014) stated that nearly 29% to 76% of patients in the primary setting are underdiagnosed with dementia. Clinically the assessments for both diseases are similar in nature, however determining the exact cause of a delirium case can take strong clinical knowledge and skills that will lead to the diagnosis.


There are assessment tools that can be utilized in both dementia and delirium. In the case of delirium, the confusion assessment method (CAM)  can be utilized and is known as the most widely used tool in screening for delirium ( Downing et al., 2013). CAM is a brief assessment tool  to diagnose and monitor delirium onset, inattention, disorganized thinking, and altered level of consciousness (Downing et al., 2013). The assessment tools recommended for dementia is the Folstein Mini-Mental State Exam (MMSE) and the Montreal Cognitive Assessment (MoCA) ( Downing et al., 2013). The MoCA entails more cognitive domains than the MMSE ( Downing et al., 2013).

Cognitively simple tests that depend on focusing attention versus testing memory is useful in deciphering delirium from dementia (Morandi et al., 2016). Based upon assessment tool results will depend on the clinical need for further neurological testing and referrals. In addition, to a thorough health and physical history a computed tomography (CT) or magnetic resonance imaging (MRI) of the head can be ordered in either case  to rule out various conditions such as mass or vascular lesions, or infections (Buttaro et al.,2017). Blood work and diagnostic testing is not listed as current first line examinations for dementia, however they can be initiated  after a positive assessment screening to diagnose the dementia subtype (U.S. Preventative Task Force [USPSTF], 2014). Specifically, for dementia labs can  include  a vitamin B12,  folate  and a metabolic screen (Buttaro et al., 2017). Additional labs that can be ordered for delirium include drug and alcohol levels and a urine culture and sensitivity (Buttaro et al., 2017).


There is no curative treatment for dementia, however there are medications than can slow the progression. The FDA has four approved medications in the treatment of moderate dementia ( Downing et al., 2017). One classification is cholinesterase inhibitors: Donepezil, Rivastigmine, and Galantamine ( Downing et al., 2017). The other classification is an N-methyl-D-aspartate receptor noncompetitive antagonist: Memantine ( Downing et al., 2017). According to Downing ( 2013)  nonpharmacological treatment is geared towards reduction in patient harm and caregiver stress through patient safety measures, functionality and quality of life.

Delirium usually resolves on its own; However, it may take some time to fully resolve ( Downing et al., 2013). Delirium has an abrupt onset, but it can take weeks for complete resolution of symptoms ( Downing et al., 2013). According to Downing ( 2013) treatment necessitates environmental changes along with behavioral support. Patients recovering from delirium should also be monitored closely and provided frequent reorientation reminders (Buttaro et al.,2017). Minimal medication management can be utilized cautiously with symptom control towards agitation, restlessness, and hallucinations with antipsychotics such as; risperidone, quetiapine, and olanzapine (Buttaro et al., 2017).

Providers should be educated and aware that in 2005, the US Food and Drug Administration issued black box warnings in the use of antipsychotics in dementia, related to the risks of cardiovascular events and death ( Downing et al., 2013). Understanding and recognizing the clinical differences between dementia and delirium is imperative in providing patients and their families with the proper medical treatment, education, advice and referrals that are needed.


  • Buttaro, T., Trybulski, J., Polgar-Bailey, P., & Sandburg-Cook, J. (2017).

    Primary care: A collaborative practice

    (5th ed.). Retrieved from
  • Downing, L. J., Caprio, T. V., & Lyness, J. M. (2013). Geriatric psychiatry review: Differential diagnosis and treatment of the 3 D’s – delirium, dementia, and depression.

    Current Psychiatry Reports



    (6), 365. Retrieved from
  • Fong, T. G., Davis, D., Growdon, M. E., Albuquerque, A., & Inouye, S. K. (2015). The interface between delirium and dementia in elderly adults.

    The Lancet. Neurology



    (8), 823-832. Retrieved from
  • Lippmann, S., & Perugula, M. L. (2016). Delirium or dementia?.

    Innovations in clinical neuroscience



    (9-10), 56-57. Retrieved from
  • Morandi, A., Davis, D., Bellelli, G., Arora, R. C., Caplan, G. A., Kamholz, B…Rudolph, J. L. (2016). The diagnosis of delirium superimposed on dementia: An emerging challenge.

    Journal of the American Medical Directors Association



    (1), 12-18. Retrieved from
  • U.S. Preventative Task Force (USPSTF). (2014).

    Cognitive Impairment in Older Adults



    Retrieved from