Acute presentation of dementia with Lewy bodies

Acute presentations for dementia, particularly dementia with Lewy bodies (DLB), are rare and can pose diagnostic challenges.We present a case of a 75-year-old woman who was previously fit, well and independent in all activities of daily living. She had no history of psychiatric, cognitive or memory problems. She presented with 2 weeks of sudden onset confusion, paranoia, dizziness and reduced oral intake. Thorough investigations for causes of delirium including blood tests, cerebrospinal fluid analysis obtained via lumbar puncture, electroencephalography, computed tomography, and magnetic resonance imaging were within normal limits. Further neurological examination demonstrated she had subtle Parkinsonian signs (cogwheel rigidity, bradykinesia) and was hypersensitive to small doses of antipsychotic (haloperidol and risperidone). A positive dopamine transporter scan was done confirming a diagnosis of an acute presentation of DLB. She has been commenced on a cholinesterase inhibitor (rivastigmine) and is presently settled in care.