Acute confusion (Delirium)



Confusion has been defined as a state of altered consciousness in which patients are bewildered and misinterpret the world around them.


Primary and secondary confusion

Primary confusion is caused by a direct pathology in the central nervous system, eg. CNS injury,  dementia

Dementia is a chronic brain syndrome

Leads to chronic confusion

Causes - Alzheimer's disease, Pick`s disease, Creutzfeldt-Jakob Disease,  HIV dementia.

Typically the onset of primary conditions is insidious

Acute, secondary confusion may complicate primary

Secondary confusion is caused by something else


Clinical features

Alterations cognition, general behaviour, motor activity and features of psychotic or neurotic conditions

Thinking becomes disorganised

Memory disturbance.

Alteration in the sleep - wake cycle


Severity of confusion may fluctuate during the course of the day

Confusion for time, place, person

Use a mental test score tool


Diagnostic criteria from the American Psychiatric Association for delirium

1. Disturbance of consciousness (ie. reduced clarity of awareness of the environment) with reduced ability to focus, sustain or shift attention.

2. A change in cognition (such as memory defect, disorientation, language disturbance) or the development of a perceptual disturbance that is not better accounted for by a pre-existing or evolving dementia.

3. The disturbance develops over a short period of time (usually hours to days) and tends to fluctuate during the course of the day.

4. There is evidence from the history, physical examination, or laboratory findings that the disturbance is caused by the direct physiological consequences of a general medical condition, substance intoxication or substance withdrawal.



A more descriptive term for acute brain syndrome is diffuse encephalopathy.


Age is a risk factor as older people have less redundancy, (spare capacity) in terms of cortical neurones and cerebral perfusion.


Causes of secondary confusion

Migraine in children                                                                        Cerebrovascular insufficiency

Cerebrovascular disease                                                   Respiratory disease

Anaemia                                                                                Space occupying lesions

Toxic problems                                                                     Malnutrition

Dehydration                                                                          Electrolyte disturbance

Systemic infections                                                             Hypothermia

Hyperthermia                                                                        Post operative

Depression                                                                           Psychosis

Concussion                                                                          Constipation

Terminal illness                                                                    Heart failure





Confusion has been defined as `a state of altered consciousness in which patients are bewildered and misinterpret the world around them`(Kumar and Clark, 1994). This should not be confused with stupor which is an abnormal sleepy state. Traditionally, delirium has been described as a state of high arousal with acute confusion and agitation often accompanied by hallucinations. However, the current trend is to classify any acute confusional state as delirium, (American Psychiatric Association 1994). 


Clinical features

In confusion there may be alterations in orientation, cognition, general behaviour, motor activity and features of psychotic or neurotic conditions, (Hadley Vermeersch and Henly 1997). Thinking becomes disorganised and there is usually memory disturbance. Alteration in the sleep - wake cycle is common, (Bennett and Plumb, 1995). Distress is another possible manifestation, (Barraclough, 1997). The severity of confusion may fluctuate during the course of the day. In mild confusion there may be disorientation for time, this means the patient does not know where they are in time. This may be for the hour, day, month or year. As the condition becomes more severe place is also confused so the individual does not know where they are, often believing they are somewhere else. In still more severe states there is disorientation for person, for example nurses may be believed to be members of the patients family. Table 1 gives the diagnostic criteria from the American Psychiatric Association for delirium, (ie. acute confusion). A more descriptive term for acute brain syndrome is diffuse encephalopathy, which describes the behavioural state produced by a group of brain effecting disorders, (Bennett and Plum, 1995).


Age is a risk factor as older people have less redundancy, (spare capacity) in terms of cortical neurones and cerebral perfusion. Those with memory impairment, sight or hearing problems are at increased risk, (Barraclough, 1997).


Causes of confusion

Confusion is a potentially serious feature. Flaherty, (1998) points out that acute confusion is associated with significant morbidity and mortality among older persons. This means that confusion should be explained as it may be a symptom of a potentially serious underlying condition. It is sometimes useful to differentiate between primary and secondary causes of confusion.



Primary confusion is caused by a direct pathology in the central nervous system. This could be caused by CNS injury or occur as part of a dementia resulting in chronic confusion. Primary causes of confusion may therefore include, Alzheimer's disease, Pick`s disease, Creutzfeldt-Jakob Disease and HIV dementia. Dementia is a chronic brain syndrome characterised by a progressive irreversible impairment of intellectual function often caused by loss of cortical neurones. Typically the onset in these conditions is insidious, and there are no effective curative treatments.


Individuals with dementia may become acutely more confused if they acquire another condition also causing confusion as a secondary effect. This is referred to as an acute on chronic confusion.


So called sundown syndrome has been identified in 24% of patients with Alzheimer's disease. This is characterised by restlessness and other multiple behavioural disturbances in the evening and may be related to use of sedatives, particularly chloral hydrate and length of time spent in hospital, (Little et al, 1995).



In secondary confusion, the function of the brain is embarrassed secondary to an underlying medical condition. It is important that any underlying contributory condition is identified as this is often reversible. When the underlying condition is corrected the confusion will usually be reversed. The onset of secondary confusion is often relatively acute occurring over hours or days. Acute confusion is a common complication of hospitalisation in the elderly that impacts on both the use of health care resources and the functional status of individuals, (Kozak-Campbell and Hughes 1996).


Although confusion is usually associated with the elderly this is not always the case. For example migraine in children can present as a state of confusion or agitation with or without a history of headaches. These features can arise spontaneously or can be triggered by mild head trauma. Transient blindness and hemiplegia may accompany the confusional state, (Ferrera and Reicho 1996). A typical duration of confusion associated with migraine in children has been found to be 2-24 hours, (Shaabat 1996). The cause of confusion in migraine is probably localised cerebral hypoperfusion, (Nezu, 1997)


In addition to the primary causes of dementia discussed above, irreversible impairment of brain function may occur secondary to cerebrovascular insufficiency which will lead to neuronal hypoxia. As well as hypoxia, an inadequate perfusion of the brain will deprive nerve cells of essential nutrients and waste products of metabolism may not be removed efficiently. Over time these factors can cause neuronal death and consequent irreversible damage to the brain leading to dementia. This condition may be due to ischaemic changes secondary to atherosclerosis or occur as a result of multiple cerebral infarcts. Emboli, often blood clots, may arise from thrombosis in the heart or in atheromatus arteries anywhere between the heart and the brain. Acute confusion may also be seen following a cerebrovascular accident. Other possible causes of prolonged cerebral hypoxia include pulmonary disease which may result in hypoxaemia, anaemia which reduces the oxygen carrying capacity of the blood, hypotension which reduces cerebral perfusion and heart disease which may also lead to impaired cerebral circulation.


Another possible cause of organic brain pathology leading to confusion are space occupying lesions. These may occur as a result of primary or secondary neoplasms, haematoma or as a result of infections such as tuberculosis. These conditions may be complicated by raised intracranial pressure.


Older patients are more likely to suffer from confusion in response to prescribed and non - prescribed drugs than younger people, (McMinn, 1995). Over use of medications has been identified as the most common cause of delirium by Jorden and Torrance, (1995). Polypharmacy should be avoided in the elderly as the risk of adverse drug events rises exponentially with the number of medications prescribed, (Flaherty, 1998). Confusion may also be a feature of drug withdrawal, particularly when patients have used alcohol, opiates or benzodiazepines, (Barraclough, 1997). A variety of non - prescribed drugs may lead to confusion, for example alcohol, hallucinogens, opiates and amphetamines, (Bennett and Plumb 1995). Malnutrition and dehydration may also complicate non - prescribed drug use. Toxicity from non - pharmacological causes can also result in confusion, this may be caused by uraemia or electrolyte imbalance secondary to renal or hepatic disfunction. Metabolic or endocrine disorders are further possible causes.


Nutritional deficiencies are may causes of confusion in the elderly. Hypoglycaemia may lead to reduced cerebral function as glucose is essential for neuronal metabolism. Lack of the B vitamins is a well known cause of confusion. Vitamin B acts as a cofactor, or co enzyme, these factors are non - proteins which combine with protein based components to form a complete functional enzyme, (Anderson, 1994). Nutrients may be supplemented, but the use of supplements should always be accompanied by the restitution of a normal adequate balanced diet. Dehydration is another frequent cause of confusion in the elderly, (Mentes and  Buckwalter, 1997). Dehydration may be caused by diarrhoea and vomiting, environmental heat, reduced fluid intake, fever or use of diuretics. Ideally these deficiencies should be prevented, however if they present the confusion should be rapidly reversed with appropriate management. Electrolyte disturbance may independently cause confusion or may complicate dehydration.


Infections and fevers are an additional possible cause of confusion. This may result from almost any systemic infection however respiratory and urinary infections are frequent causes. Confusion may be caused by the presence of bacterial toxins in the blood or by dehydration caused by the increase in insensible loss of fluid as a result of fever. Hypothermia is another cause which may be encountered in the community. Abnormally high or low temperature can adversely effect the enzymic systems in the neurones which facilitate intracellular energy production.


Post operative confusion in the elderly is frequently seen, this has been related to reduced cerebral perfusion as a contributory factor, (Kessler et al, 1997). Post operative confusion has been associated with prolonged hospital stays and increased postoperative mortality, (Ballard-Ferguson, 1997).


Brooking, (1992) includes environment a cause of confusion. Sensory deprivation may be a factor especially when older people are removed from their familiar home environment. Other contributory factors may include noise in a hospital ward, unfamiliar people, lack of clocks or calendars and lights being kept on overnight.


Confusion may arise as a result of major depression or psychoses, (Espino et al 1998). In addition acute and transient functional psychosis may sometimes mimic acute confusional states  (Murai, Toichi and Sengoku, 1996). Other possible causes include Parkinson's disease, constipation and Huntington`s disease. Often in older patients several factors may contribute towards confusion in an individual. Interestingly the common causes of confusion may vary with geographical location, for example in Ethiopia the most common cause was found to be infections, (Melka, Tekie-Haimanot and Assefa, 1997).


Confusion may occur in terminal care and may be part of terminal agitation. Here the underlying cause will vary with the cause of the patients terminal condition but may include ureamia, dehydration and cerebral hypoxia or metastasis.


Nursing measures

Espino et al (1998) has claimed all but the rarest causes of confusion can usually be identified based on the complete history, medication review, physical examination, mental status evaluation and laboratory evaluation with longitudinal revaluation. Given the multiple possible causes of confusion accurate nursing assessment is vital, (MIller et al, 1996), Confusion has been considered to be a symptom of a failure in brain function with many possible causes, (Feske, 1998). As many of these conditions may progress and lead to further morbidity or death the cause of the confusion should be identified. Thurston, (1997) warns that nurses should not to succumb to the temptation of assuming that confusion is merely part of a progressive dementia in an elderly person and therefore incapable of treatment, as a cause may be found with appropriate investigations.


Use of a specific cognitive screening tool may aid in assessment and monitoring the evolution of a confusional state, (Jitapunkul, Pillay and Ebrahim, 1991),  (table 2). However it is important to remember such assessments will not differentiate between chronic confusion resulting from dementia and the delirium of acute confusion.


Basic nursing observations may yield useful information for example pyrexia or hypothermia may be identified, irregularities in the pulse may indicate a cardiac component, abnormal or reduced respirations may lead to hypoxia and observation of blood pressure may indicate hypo or hypertension.


Kozak-Campbell and Hughes, (1996) identify three aspects of nursing care necessary to provide optimum nursing care in confused patients, Firstly the nurse's ability to differentiate acute confusion from other common conditions in the hospitalised elderly, chiefly dementia or depression. Secondly the nurse's ability to identify factors contributing to confusion and thirdly the implementation of interventions to minimise the effects of these factors on the patient.


Very often confused patient may not be able to tell nurses if they are in pain or suffering something. This means that in addition to trying to improve communication nurses need to assess what other problems an individual has which they may be unable to communicate. Acute confusion is a significant problem among elderly surgical patients, and it can impair the older persons ability to localise, interpret, or communicate discomfort to care-givers. Discomfort is a common experience for hospitalised older patients, especially those recovering from trauma or surgery. Self-report is not a reliable indicator of discomfort in elderly confused patients. Miller, Moore and  Schofield, (1996) recommend that health care providers focus on discomfort as they provide care to these patients, and intervene in a preventive fashion.


It has been suggested that primary nursing is a useful approach when nursing a confused patient, (Saunders, 1995). This will allow opportunity for the person to get to know a few individual nurses who have a consistent approach with which the person may become familiar. Patients should be nursed in a well lit room single room and should not be moved around the ward or from ward to ward.


Clear communication is essential to reduce confusion. A relaxed non - threatening approach may help to put an individual at ease. Nurses should communicate at the same level as the patient and touch may be used where appropriate. Patients should be given information to improve orientation whenever possible, probably with every intervention, (Jones 1995). This may be achieved by reminding patients where they are whenever necessary, clocks and calendars should be clearly visible. Orientation may be improved by frequent visits from friends and family. Even in severely demented patients, people known for many years are usually recognised and help to put the individual at ease. In addition the introduction of familiar objects and other changes which make a hospital environment more homelike can be beneficial, (Forreman and Zane, 1996).


Confused patients are at increased risk of injury, nurses need to think about the environment to reduce the risk of any untoward incidents such as falls or burns with hot drinks. They are also more likely to climb out of bed and pull out catheters, nasogastric tubes and intravenous lines, (Sanders, 1995). Wandering behaviour may also occur, this may be due to disorientation for place but may also have a cause such as looking for the toilet or food. Other complications confused patients are at increased risk of include pressure sores, nosocomial infections and continence problems.


It has been demonstrated that simple nursing strategies such as using a toileting regimen for patients who were both confused and had mobility problems could significantly reduce falls, (Bakarich, McMillan and  Prosser, 1997). These workers demonstrated a 53% reduction in falls, (n = 2, 023) when a regular toileting protocol was introduced. Ensuring adequate nutrition and hydration are basic but essential nursing functions. Excessive activity leading to fatigue may contribute to confusion so nurses should ensure adequate rest periods. Constructive activity should also be employed to increase the interest an individual takes in his or her environment.


There is a potential danger to nurses from confused patients especially when care on the person is being performed. Patients may mis - interpret a nurses action so it should be ensured the patients is fully informed of all interventions and their co-operation gained as much as possible. Sedation may be required in extreme circumstances to manage acute confusion and if so haloperidol is most appropriate. Foreman and Zane, (1996) claim that with proper management acute confusion should resolve in three to four days.




Delirium is characterised by a disturbance of consciousness and a change in cognition that develop over a short period of time. The disorder has a tendency to fluctuate during the course of the day, and there is evidence from the history, examination or investigations that the delirium is direct consequence of a general medical condition, drug withdrawal or intoxication.



1. Disturbance of consciousness (ie. reduced clarity of awareness of the environment) with reduced ability to focus, sustain or shift attention.

2. A change in cognition (such as memory defect, disorientation, language disturbance) or the development of a perceptual disturbance that is not better accounted for by a pre-existing or evolving dementia.

3. The disturbance develops over a short period of time (usually hours to days) and tends to fluctuate during the course of the day.

4. There is evidence from the history, physical examination, or laboratory findings that the disturbance is caused by the direct physiological consequences of a general medical condition, substance intoxication or substance withdrawal.


Table 1. After the American Psychiatric Association 1994, (DSM IV)



The patient is asked the following questions

1. Age

2. Time (to the nearest hour)

3. Address for recall at end of test, (eg. 7 Bridge St.)

4. Year

5. Name of hospital patient is in

6. Recognition of 2 persons, (eg. doctor, nurse)

7. Date of birth

8. Year of 1st World War

9. Name of present monarch

10. Count backwards from 20 to 1


Table 2. Abbreviated Mental Test Score, (AMT). A score of less than 8 out of 10 is abnormal, (Jitapunkul, Pillay and Ebrahim, 1991)



American Psychiatric Association, (1994),  Diagnostic and Statistical Manual of Mental Disorders,  (4th Ed.) Washington DC., American Psychiatric Association.

Anderson KN. Anderson LE. Glanze WD. (1994), Mosby`s Dictionary, (4th. Ed), Moseby, St. Louis.

Bakarich A.  McMillan V.  Prosser R. (1997), The effect of a nursing intervention on the incidence of older patient falls,  Australian Journal of Advanced Nursing,  15(1):26-31.

Barraclough J (1997), Depression, anxiety and confusion, BMJ, vol. 315, 1365 - 1368

Bennett and Plumb, (1995)  Textbook of Medicine, Volume 2, (20th Ed.) WB. Saunders Co. Philadelphia.

Brooking JI. Ritter SA. Thomas BL, (1992), Psychiatric and Mental Health Nursing, Churchill Livingstone, Edinburgh

Espino DV.  Jules-Bradley AC.  Johnston CL.  Mouton CP. (1998), Diagnostic approach to the confused elderly patient, American Family Physician,  57(6):1358-66.

Ferrera PC.  Reicho PR. (1996)  Acute confusional migraine and trauma-triggered migraine. American Journal of Emergency Medicine.  14(3):276-8, 1996 May.

Flaherty JH.  (1998),  Psychotherapeutic agents in older adults. Commonly prescribed and  over-the-counter remedies: causes of confusion.  Clinics in Geriatric Medicine,  14(1):101-27.

Forreman MD,  Zane D,  (1996),  Nursing Strategies for Acute Confusion in Elders,  American Journal of Nursing, 97 (4) 44 - 49

Jitapunkul S, Pillay I,  Ebrahim S, (1991), The abbreviated mental test: its use and validity.  Age and Ageing, 20 332 - 336

Jones A (1995) How effective is reality orientation for elderly , confused patients, British Journal of Nursing, 4 (9) 519 - 522

Jorden and Torrance (1995), Bionursing: confusion in the elderly, Nursing Standard, 10 (6) 30 - 32

Kumar P.  Clark M.  (1995)  Clinical Medicine, (third ed.) Bailliere Tindale, London

Kozak-Campbell C.  Hughes AM. (1996) The use of Functional Consequences Theory in acutely confused hospitalized elderly. Journal of Gerontological Nursing.  22(1):27-36.

Little JT.  Satlin A.  Sunderland T.  Volicer L. (1995), Sundown syndrome in severely demented patients with probable Alzheimer's disease.  Journal of Geriatric Psychiatry & Neurology.  8(2):103-6.

Melka A.  Tekie-Haimanot R.  Assefa M. (1997),  Aetiology and outcome of non-traumatic altered states of consciousness in north western Ethiopia,  East African Medical Journal.  74(1):49-53.

Mentes J.  Buckwalter K. (1997),  Getting back to basics: maintaining hydration to prevent acute confusion in frail elderly,  Journal of Gerontological Nursing,  23(10):48-51.

Miller J.  Moore K.  Schofield A.  Ng'andu N.  (1996), A study of discomfort and confusion among elderly surgical patients, Orthopaedic Nursing.  15(6):27-34, 1996 Nov-Dec.

Miller J.  Neelon V.  Dalton J.  Ng'andu N.  Bailey D Jr.  Layman E. (1996), The assessment of discomfort in elderly confused patients: a preliminary study.  Journal of Neuroscience Nursing.  28(3):175-82.

Murai T.  Toichi M.  Sengoku A. (1996), Functional psychosis mimicking acute confusional state: longitudinal neuropsychological assessment of an acute and transient psychotic patient.  Psychiatry & Clinical Neurosciences.  50(5):257-60.

Nezu A.  Kimura S.  Ohtsuki N.  Tanaka M.  Takebayashi S. (1997), Acute confusional migraine and migrainous infarction in childhood.  Brain & Development.  19(2):148-51.

Sanders P (1995) Caring for confused people in the general hospital setting, Nursing Times, 91 (47) 27 - 29

Shaabat A. (1996),  Confusional migraine in childhood,  Pediatric Neurology, 


World Health Organisation, (1992),  International Statistical Classification of Disease and Related Health Problems, 10th Revision, WHO, Geneva


Answer the following questions.

1. What clinical features may lead you to believe a patient is confused?

2. What is meant by the term primary confusion?

3. Give some examples of diseases which lead to dementia.

4. List some conditions which may lead to secondary confusion.

5. How does the American Psychiatric association describe an acute confusional state?

6. Explain in pathophysiological terms why the following conditions may cause confusion

i.          Obstructive airways disease          ii.         Carotid arterial atherosclerosis

iii         Malnutrition                                       iv.        Infections

v.         Dehydration                                      vi.        Hypothermia

7. How would you distinguish between acute and chronic confusion in a newly admitted patient.