Delirium

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Introduction

LogoKeyPointsBox.pngDelirium is associated with stupour as often as the more likely to be recognised hyperexcitable state

Delirium is a well characterised acute disorder of brain function which is usually of acute onset and able to be related to a physical cause. Use of the DSM IV diagnostic criteria is recommended, as they are very specific and help to prevent some common mistakes. These include assuming that a confused elderly patient is demented, when dementia is quite different, that a quiet patient is not in a delirious stupour, not associating delirium with prognosis and not even evaluating formally if a patient has delirium in common presentations like chest infections where the presence of delerium is associated with a worse prognosis. Among the many alternative terms that may be used are acute confusional state, acute confusion, acute cognitive impairment etc.

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British Geriatrics Society Guidelines for the prevention, diagnosis and management of delirium in older people in hospital

Definition

The DSM IV criteria are the best validated. These criteria are paraphased in Wiki format below. There are 3 standard criteria and a fourth that allows you to subclassify the likely cause of delerium

  1. Disturbance of consciousness (i.e., reduced clarity of awareness of the environment) with reduced ability to focus, sustain, or shift attention.
  2. A change in cognition (such as memory deficit, disorientation, language disturbance) or the development of a perceptual disturbance that is not better accounted for by a preexisting, established, 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 either
    • a general medical condition.
    • the symptoms in criteria 1 and 2 developed during Substance Intoxication
    • medication use is etiologically related to the disturbance
    • the symptoms in criteria 1 and 2 developed during, or shortly after, a withdrawal syndrome.
    • the delirium has more than one etiology above

Causes

These run the whole gambit of medicine. Accordingly you need excellent diagnostic skills and a rational approach. As delirium is more common in the elderly the proven approaches involve comprehensive multifactorial interventions including finding the cause and an emphasis in the developed world on meningitis/encephalitis, substance abuse/withdrawal management, CNS trauma and acute pyschosis in younger patients.

ITU

The area of most hospitals with the highest incidence of delirium is intensive care. Accordingly much of the best evidence base for what works and does not work comes from patients admitted to intensive care. There are validated mechanisms to diagnose delirium allowing for anaesthetic drug wash out etc. There is some preliminary evidence that dexmedetomidine may reduce post surgical delirium.

Prognosis

Delirium is associated with poor outcome and many studies have validated the association of acute delirium with longer term cognitive impairment, mortality, functional disability, length of hospital stay and institutionalisation. There is a strong correlation with persistent delirium and poor outcome, which occurs in a third of hospitalised patients at 3 month followup[1]. Prompt recovery of delirium within 24 hours is however favourable and this is the justification for rapid assessment and treatment of acute episodes. There appear to have been no randomised trials of rapid assessment, perhaps because of the ethics and that triage priorities may depend upon resources allocated for more defined conditions, although the evidence for cost effective prognostic benefit from multifactorial intervention is more convincing[2].

Approach to delirium

Your approach should vary with the age of the patient, as different causes are more common as a function of age. If a patient is a known diabetic, the first thought should be whether the patient is hypoglycaemic as this requires urgent, easy treatment, while all alternative diagnoses including hyperglycaemic precoma, ketoacidosis and infection or whatever have more time for intervention. It is is a trauma presentation the first thoughts should be the standard ABC, with head injury soon after. If high fever, consider all infectious causes, not just bacteria. Could it be malaria, meningitis or encephalitis ?

Ensure everyone's safety

The trade offs with the patient potentially harming health care workers and themselves are very difficult ethically. Delirious patients lack capacity so a refusal to cooperate might result in the need for sedation to allow diagnosis and treatment. Regrettably some infectious disease causes of delirium are associated with high risk to others but some causes of delirium are easy to diagnose and treat with delay being associated with poor outcome.

Diagnose

All too often neglected is the importance of an accurate history. This can usually be obtained from informants and the quick associations possible usually allow the experienced clinician to identify likely scenarios. Vital signs and a blood glucose estimation should be followed by a through physical examination and further investigation.

LogoKeyPointsBox.pngNever assume clear evidence of a cause explains the delirium eg
  • Alcoholic with hypoglycaemia or subdural
  • Cocaine addict with MI or stroke
  • Apparent serotonin syndrome (from SSRI) actually first clear presentation of CJD

Children

  • Infection

Younger Adults

Elderly

  • Infection (nitrates & leukocytes on urine dipstick are very nonspecific for UTI causing delirium, and indeed distract from considering diagnoses such as herpes simplex encephalitis which require different prompt treatments)
  • Medications - any recent change - evaluate cholinergic burden (which includes eye drops) and known side effect profiles
  • Metabolic or electrolyte disturbance
  • Alcohol or sedative withdrawal (typically from 48 hours after admission)
  • Stroke
  • Myocardial infarction

Investigations

Before getting here you have checked haven't you

  • Temperature
  • Pulse
  • Blood Pressure
  • Respiratory Rate
  • BM stix
  • PO2
  • If fever: Culture appropriately...as delirium is a marker for higher mortality don't add to the patients problems by missing this step but remember that in both meningitis and pneumonia that first dose of antibiotics administered promptly significantly reduces mortality.
  • Always if in Accident & Emergency
    • ABG (or venous blood gas) - well its there and will tell you hypoxia, CO2 retention, hypercalcaemia, hypoglycaemia, hyponatraemia, hyperkalaemia and even anaemia with modern machines.
    • Electrolytes and basic renal function - mainly to exclude hyponatraemia and renal failure
    • Calcium ...but very unlikely to be raised if normal renal function in a patient with delirium due to hypercalcaemia
    • Full blood count - anaemia...well my examination was rushed ...rarely leukaemia
    • ECG - silent MI, (brady)arrythmias

The rest follow from more directed history and examination eg

  • CRP and LFT - you should find other evidence for inflammation or jaundice/hepatitis but does tell you if you missed something
  • TFTs only likely to diagnosis thyroid storm - there should be other pointers
  • CT head scan - always if focal neurology or meningism but consultant will usually find the frontal grasp or other neurological sign that should have pointed you to the indication to do it
  • Porphyria screen...the nurses comment on the urine colour put me on to this one.

Prevention

Daily geriatrician input is proven in hip fractures to reduce delirium by 25% and severe delirium by 60% compared to usual hip fracture care in a teaching hospital:[3]

  1. Optimise oxygen delivery to the brain
  2. Optimise fluid and electrolyte balance
  3. Optimise pain management
  4. Minimise use of psychoactive drugs
  5. Intervene to maintain bowel and bladder function
  6. Nutritional supplement
  7. Early mobilization
  8. Measures to minimise postoperative complications
  9. Appropriate environment
  10. Treatment symptomatic delirium

Treat

LogoKeyPointsBox.pngAs of early 2009 there is a poor RCT evidence base to base your choice of drug sedation in delirium. Cochrane reviews of benzodiazipines[4], antipsychotics[5]. cholinesterase inhibitors [6] and preventive drug treatment[7] show unknown effectiveness.
  • Always treat the underlying cause
  • Calm surroundings once the rapidly treatable causes are eliminated
  • Sedation with care
    • Low dose haloperidol while likely to be beneficial[8] in very short term use has a poor evidence base and it is unclear if other antipsychotics have advantages due to their differing side effect profiles.
    • Atypical antipsychotics were the first known to be associated with increased risk serious adverse events in treating psychosis in patients with dementia and this has tended to dampen enthusiasm. However [[olanzapine has been shown to work in critically ill patients and it can be given intramuscularly as well as enterally[9].
    • Try to only use benzodiazepines in those with alcohol/sedative withdrawal, parkinsonism or history of neuroleptic malignant syndrome as they are known to cause delirium in other circumstances. Parental midazolam is likely to be ineffective or harmful in use relative to droperidol IM.[10][11]
    • Trazodone - only uncontrolled studies
    • One study reported that the combination of both parental lorazepam and parental haloperidol were better than either alone in controlling acute agitation[12].
    • Rivastigmine is likely to be ineffective or harmful with an increase in mortality when given with usual care using haloperidol[13].
    • Ongoing statin therapy is associated with a lower daily risk of delirium in critically ill patients[14]. Results of clinical trials are awaited. It should be noted that statin use is not clearly associated with a mortality reduction pre-operatively in patients at high risk of cardiovascular disease[15],


Read More: http://www.atsjournals.org/doi/abs/10.1164/rccm.201306-1150OC#.VEFrZES7WJA

References

  1. Cole MG, Ciampi A, Belzile E, Zhong L. Persistent delirium in older hospital patients: a systematic review of frequency and prognosis. Age and ageing. 2009 Jan; 38(1):19-26.(Link to article – subscription may be required.)
  2. Pitkala KH, Laurila JV, Strandberg TE, Kautiainen H, Sintonen H, Tilvis RS. Multicomponent geriatric intervention for elderly inpatients with delirium: effects on costs and health-related quality of life. The journals of gerontology. Series A, Biological sciences and medical sciences. 2008 Jan; 63(1):56-61.
  3. Marcantonio ER, Flacker JM, Wright RJ, Resnick NM. Reducing delirium after hip fracture: a randomized trial. Journal of the American Geriatrics Society. 2001;49:516-22.
  4. Lonergan E, Luxenberg J, Areosa Sastre A, Wyller TB. Benzodiazepines for delirium. Cochrane Database of Systematic Reviews 2009, Issue 1. Art. No.: CD006379. DOI: 10.1002/14651858.CD006379.pub2.
  5. Lonergan E, Britton AM, Luxenberg J. Antipsychotics for delirium. Cochrane Database of Systematic Reviews 2007, Issue 2. Art. No.: CD005594. DOI: 10.1002/14651858.CD005594.pub2
  6. Overshott R, Karim S, Burns A. Cholinesterase inhibitors for delirium. Cochrane Database of Systematic Reviews 2008, Issue 1. Art. No.: CD005317. DOI: 10.1002/14651858.CD005317.pub2.
  7. Siddiqi N, Holt R, Britton AM, Holmes J. Interventions for preventing delirium in hospitalised patients. Cochrane Database of Systematic Reviews 2007, Issue 2. Art. No.: CD005563. DOI: 10.1002/14651858.CD005563.pub2.
  8. Breitbart W, Marotta R, Platt MM, Weisman H, Derevenco M, Grau C, et al. A double-blind trial of haloperidol, chlorpromazine, and lorazepam in the treatment of delirium in hospitalized AIDS patients. The American journal of psychiatry. 1996;153:231-7.
  9. Devlin JW, Skrobik Y. Antipsychotics for the prevention and treatment of delirium in the intensive care unit: what is their role? Harvard review of psychiatry. 2011 Mar-Apr; 19(2):59-67.(Link to article – subscription may be required.)
  10. Martel M, Miner J, Fringer R, Sufka K, Miamen A, Ho J, Clinton J, Biros M. Discontinuation of droperidol for the control of acutely agitated out-of-hospital patients. Prehospital emergency care : official journal of the National Association of EMS Physicians and the National Association of State EMS Directors. 2005 Jan-Mar; 9(1):44-8.(Link to article – subscription may be required.)
  11. Knott JC, Taylor DM, Castle DJ. Randomized clinical trial comparing intravenous midazolam and droperidol for sedation of the acutely agitated patient in the emergency department. Annals of emergency medicine. 2006 Jan; 47(1):61-7.(Link to article – subscription may be required.)
  12. Battaglia J, Moss S, Rush J, Kang J, Mendoza R, Leedom L, Dubin W, McGlynn C, Goodman L. Haloperidol, lorazepam, or both for psychotic agitation? A multicenter, prospective, double-blind, emergency department study. The American journal of emergency medicine. 1997 Jul; 15(4):335-40.
  13. van Eijk MM, Roes KC, Honing ML, Kuiper MA, Karakus A, van der Jagt M, Spronk PE, van Gool WA, van der Mast RC, Kesecioglu J, Slooter AJ. Effect of rivastigmine as an adjunct to usual care with haloperidol on duration of delirium and mortality in critically ill patients: a multicentre, double-blind, placebo-controlled randomised trial. Lancet. 2010 Nov 27; 376(9755):1829-37.(Link to article – subscription may be required.)
  14. Page VJ, Davis D, Zhao XB, Norton S, Casarin A, Brown T, Ely EW, McAuley DF. Statin use and risk of delirium in the critically ill. American journal of respiratory and critical care medicine. 2014 Mar 15; 189(6):666-73.(Link to article – subscription may be required.)
  15. </pmid>23824754</pmid>