There is no diagnostic test for ABD. Diagnosis depends on the recognition of its clinical features and exclusion of differential diagnoses.
Investigations are required to exclude other causes of altered mental behaviour and to assess for complications such as acidosis, cardiac arrhythmias, hyperkalaemia, hyperthermia, and rhabdomyolysis.
The following investigations are suggested:
CT brain may be required if there is suspicion, from history and examination features, of trauma or other intracranial event, e.g. intracranial haemorrhage, space-occupying lesion or meningoencephalitis.