Delirium

 

• Definition and causes

  Definition and prevalence:

  • An acute confusional state secondary to an underlying medical problem.
  • Affects >10% of medical admissions, and much more among the elderly.

  Causes of DELIRIUMS:

  • Drugs: medical or recreational (opiates, antiepileptics, L-dopa, sedatives, anaesthesia) or withdrawal from them (e.g. alcohol).
  • Eyes and ears: blindness or deafness.
  • Low O2: PE, COPD, anaemia. In contrast, ↑CO2 is likely to cause drowsiness.
  • Infection
  • Retention: urine or faecal.
  • Ictal: seizure or post-ictal.
  • Underhydration or undernutrition (including micronutrients e.g. thiamine, B12).
  • Metabolic: electrolyte disorders, hypoglycaemia.
  • Subdural haematoma and Stroke.

  Mimics:

  • Depression ≈ hypoactive delirium.
  • Anxiety ≈ hyperactive delirium.
  • Dementia. They can be hard to distinguish, and those with dementia are more likely to get delirium in acute illness. Establish their baseline and compare.

• Signs and symptoms

  • Acute onset of confusion or altered behaviour. There may be a prodrome of restlessness and mild confusion, as well as symptoms of the underlying condition. Patients may be sleepy and neglecting to take medication and maintain fluid intake.
  • Can be hyperactive, hypoactive (commoner), or mixed (commonest).
  • Inattention and difficulty focusing is a key feature.
  • Speech will be internally consistent but nonsense, unlike in dysphasia where the speech is incoherent.

• Investigations

  • Bloods: FBC, U+E, LFT, blood glucose, ABG.
  • Infection screen: urinalysis, CXR, blood culture.
  • Others: TFT, B12, ECG, EEG.

• Management

  • Ensure a stable environment: quiet, with moderate lighting.
  • Look for and treat precipitant, including pain, drugs, O2 levels, urinary/faecal retention, and infection.
  • Reassure, and get family if possible.
  • If disruptive, severely agitated, or a threat to themselves or others, consider PO/IM antipsychotic (e.g. haloperidol, olanzapine, or quetiapine).

• Prognosis

  • Most return to baseline within days.
  • However, there may be long-term residual effects even after apparent resolution.
  • Delirium is a risk factor for subsequent dementia, likely because it is a marker of reduced neurocognitive reserve.