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Table 4.1

Differential Diagnosis of Acutely Disturbed Behaviour or Language

DiagnosisComment
DeliriumDiagnostic criteria:*
  • There is a disturbance of consciousness, that is, reduced clarity of awareness of the environment, with reduced ability to focus, sustain or shift attention.
  • There is 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 pre-existing dementia.
  • The disturbance has developed over a short period of time (usually hours to days) and tends to fluctuate during the course of the day.
  • There is evidence from the history, examination or laboratory findings that the disturbance is caused either by the direct physiological consequences of a general medical condition, or by substance intoxication/withdrawal, or by medication.
Acute psychosis (manic or schizophrenic)Typical features of acute psychosis include: Assume a diagnosis of delirium rather than acute psychosis if:
  • The patient is older than 40 with no previous psychiatric history
  • There is a history of alcohol or substance-use disorder
  • There are major medical comorbidities
  • There is disorientation, clouding of consciousness or decreased alertness, or
  • Physiological observations are abnormal
Other psychiatric disordersAgitated depression, anxiety disorder, borderline and anti-social personality disorders may result in acutely disturbed behaviour.
Non-convulsive status epilepticus (NCSE)In NCSE, there are often mild clonic movements of the eyelids, face or hands, or simple automatisms. The EEG is abnormal.
Transient global amnesia

Abrupt onset of antegrade amnesia without clouding of consciousness or loss of personal identity.

Cognitive impairment is limited to amnesia, and there are no focal neurological or epileptic signs.

Symptoms resolve within 24 h.

Fluent dysphasia

Speech is fluent but with meaningless words, unnecessary phrases and nonsensical grammar.

There is no clouding of consciousness.

* Source: American Psychiatric Association (2000) Diagnostic and Statistical Manual, 4th edition.