An 82-year-old resident of a residential home was seen at the Emergency department for restlessness and
aggressive behaviour.
He has been incontinent of urine and also had few falls. He was placed in the residential home after the death
of his wife due to severe arthritis in his hands and knees. His only past medical history includes
hypothyroidism, for which he takes thyroxine 50 µgrams per day.
On examination he is disorientated in time, place and person and smells strongly of urine. There are no focal
neurological signs.
What is the likely diagnosis?
Delirium (Correct)
Dementia
Hypoglycaemia
Myxoedema madness
Transient ischaemic attack (TIA)
Delirium is a common neuropsychiatric syndrome in the elderly characterised by concurrent impairments in
cognition and behaviour. There are numerous causes, but it is commonly associated with underlying medical
illness and medication. Untreated it has significant morbidity and mortality.
The cardinal features of delirium are recent onset of fluctuating awareness, impairment of memory and
attention and disorganised thinking. Additional features may include visual hallucinations and disturbance of the
sleep-wake cycle. Three subtypes are increasingly recognised: hypoactive, hyperactive and mixed.
Delirium is a clinical diagnosis, but there are a number of assessment tools which can aid the clinician. The
mini-mental state examination (MMSE) and abbreviated mental test score (AMTS) can assess cognition but
not all features of delirium. In the UK (and USA) guidelines recommend the Confusion Assessment Method
(CAM) for detecting delirium. The diagnosis requires criteria 1 and 2 to be present, plus either 3 or 4. This has
been shown to have a sensitivity and specificity of over 90%:
- Acute onset and fluctuating course
- Inattention
- Disorganised thinking
- Altered level of consciousness
Distinguishing between delirium and dementia can be difficult, and often they coexist. It is safest to assume
delirium is present, and attempt to find an underlying cause before settling on a diagnosis of dementia.
Delirium should be avoided if possible by reducing the risk factors, in particularly predisposing medications.
Orientating communication, therapeutic activities, early mobilisation, non-pharmacological approaches to sleep
and anxiety, maintaining nutrition and hydration, adaptive equipment for vision and hearing impairment and
pain management have also be shown to reduce the incidence.
Immediate identification and treatment of precipitatins, withdrawal of culprit drugs and supportive care
(correction of hypoxia, hydration, nutrition, mobilisation) are critical in the treatment of delirium. Drug treatment
should be reserved for patients who pose a risk to themselves or others.
A patient on replacement thyroxine is unlikely to have severe hypothyroidism (myxoedema madness) as
thyroid-stimulating hormone (TSH) should have been regularly checked. However, non-compliance with
medication is possible.
All confused patients should be checked for hypoglycaemia, however, given the information available this is not the answer.
TIA may present with confusion but dysphasia and weakness are prominent symptoms