Delirium - red flag symptoms

Dr Pipin Singh explores the red flag symptoms of delirium, identifies possible causes, and discusses assessment and treatment of the condition.

(Photo: Blend Images - JGI/Tom Grill/Getty Images)
(Photo: Blend Images - JGI/Tom Grill/Getty Images)

Red flag symptoms

  • New onset symptoms
  • Any history of head trauma
  • History of fever
  • Reduced level of consciousness
  • Significant alcohol history
  • Any FAST (stroke) symptoms
  • Any chest pain
  • Polypharmacy
  • New onset headache
  • Recent significant unintentional weight loss, night sweats, appetite loss


Delirium, also known as an acute confusional state, can present for several different reasons. It is a neuropsychiatric syndrome characterised by acute onset of fluctuating cognition and inattention, with various triggering factors and associated with high morbidity and mortality.1

Delirium is a manifestation of an underlying pathology and not a diagnosis itself.

In primary care, delirium may be encountered in hours or out-of-hours within the following contexts:

  • Face-to-face consultations for surgery
  • Patient’s own home
  • Sheltered/warden-controlled accommodation
  • Residential care
  • Nursing care
  • Following a recent hospital admission

It is important to search for the cause of delirium to enable appropriate investigation and management. Differentiating delirium from dementia can also be difficult at times so a good history or collateral (carer) history will be crucial.

Delirium can be hypoactive whereby a patient becomes more withdrawn, quiet, apathetic and drowsy. Alternatively, it may be hyperactive with heightened awareness of the surrounding situation and aggression, which may or may not be accompanied by agitation.

Hyperactive delirium can lead to difficulties for the patient’s carers or family members, and may possibly even threaten the safety of those around them.

Data suggests 50% of delirium is hypoactive, which together with the mixed motor subtype accounts for 80% of all delirium cases.2 Hypoactive delirium can be more difficult to recognise and is associated with worse outcomes than hyperactive delirium.2

Possible causes

There are various possible causes of delirium, which you can use the helpful mnemonic VITAMINP to remember.

  • Vascular causes: stroke, myocardial infarction
  • Infection: chest sepsis, encephalitis, other infection including septic arthritis or pressure sores, and most commonly, urosepsis
  • Trauma: head injury
  • Metabolic causes: renal impairment, hypercalcaemia, constipation hyponatraemia, hyper/hypoglycaemia, hypoxia
  • Iatrogenic causes: opiate toxicity, psychotropic drugs, `Z' drugs including zopiclone, benzodiazepines, recreational drugs; increasingly common in the elderly with increased polypharmacy
  • Neoplastic causes: delirium secondary to the primary tumour, tumour complications such as hypercalcaemia, cerebral metastasis or electrolyte disturbance
  • Psychological causes: new psychosis, dementia, alcoholic psychosis or withdrawal, drug withdrawal from opiates, selective serotonin reuptake inhibitors (SSRIs) or benzodiazepines

Other causes may include constipation, urinary retention and pain.

History and examination

Knowledge of the patient’s background is crucial, although a thorough history may be difficult to obtain depending on where you are assessing the patient, for example a walk-in centre or out-of-hours clinic.

A systemic review should be conducted to establish a physical cause if appropriate, for example to identify new onset headaches, fevers, cough, breathlessness, urinary symptoms, new onset constipation, presence of pressure sores, or new joint swelling.

Depending on where you are assessing the patient, the following questions may be helpful.

  • How did the symptoms start? What symptoms are they displaying?
  • Have they come on suddenly or gradually?
  • Has there been any recent trauma?
  • What physical and psychological comorbidities do they have?
  • Is there a history of baseline cognitive impairment?

Find out if the patient is taking any regular prescribed medication. If so, has anything been added, removed, or altered (for example, the dose)? Ask whether they are taking any non-prescribed over the counter medication, and whether they have a history of recreational drug use or excessive alcohol consumption.

The following questions may also be relevant during your history taking.

  • Have they experienced delirium before and if so, what was the cause?
  • Have there been any recent hospital admissions?
  • Does the patient have a DNACPR?
  • Does the patient have an emergency health care plan?
  • Are they currently posing a threat to themselves or others? Are they in a safe environment?
  • Is there appropriate care in place?
  • Does the patient recognise the delirium?
  • Is an admission appropriate?

In addition to taking a history from the patient, you are likely to need a collateral history from a family member or carer. It is also important to consider any family wishes.

Examination will largely depend on the clinical history but general observations should be performed, including blood pressure, pulse, temperature, respiratory rate and oxygen saturations. It is also worth considering blood glucose levels.

The following systems-level examinations may also be relevant:

  • Focused neurological examination
  • Respiratory examination
  • GI examination

An abbreviated mental test score (AMTS) will be useful, as it will allow you to gauge the patient’s orientation in time, place and person. A score of less than 8 is significant.


The investigations you conduct in primary care will depend on whether you feel an admission is necessary or not, after weighing up all the options and the circumstances that surround the case. For example, whether it is a palliative case or new onset in a previously fit and well patient will determine the investigations you undertake.

Investigations in primary care may include:

  • Blood work, including FBC, UEs, CRP, ESR, Hba1c, Ca, TSH and HIV testing
  • Urinalysis
  • Stool culture, if relevant
  • 12-lead ECG
  • Basic imaging, including chest X-ray, or more detailed imaging such as ultrasound or CT/MRI depending on your local protocols


Treatment will depend on the cause of the delirium. Sedation should be avoided where possible as it could precipitate worsening of hypoactive delirium. Aim to correct any sensory deficits, such as hearing or visual problems.

If you plan to keep the patient out of hospital, make sure they are comfortable with minimal disruption to their usual environment.

Ensure that there is appropriate social support in place and that carers and/or family are alert to symptoms that may suggest worsening of the underlying cause of delirium and require prompt referral for a medical review.

  • Dr Pipin Singh is a GP in Northumberland.

Visit MIMS Learning for an interactive version of this article and a CPD certificate


  1. American Psychiatric Association. Diagnostic and statistical manual of mental disorders (4th ed). APA, Washington, DC, 2000.
  2. Hosker C, Ward D. BMJ 2017; 357: j2047.

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