Late onset acute psychosis secondary to primary brain tumour: An initial misdiagnosis

To the Editor

It is essential to determine if late onset psychosis is secondary to a medical condition, as patients may suffer undue morbidity and/or mortality if this is not identified. This is a case of late onset, acute psychosis in which an acute medical cause was not identified on initial presentation, leading to serious medical sequelae.

AB is a 60 year old divorced male on welfare who presented to a rural hospital with a three to four week history of paranoid delusions, auditory hallucinations and pressure sores. He had a current diagnosis of bipolar I disorder, managed with olanzapine and sodium valproate since 2007. He recently had been non-compliant with his medications and recommenced cannabis use. Upon arrival to the emergency department, his symptoms were ascribed to a manic relapse of bipolar I disorder, with psychotic features, and he was admitted to the inpatient mental health unit.

On psychiatric review four days later, AB described multiple paranoid delusions, including poisoning of his water supply, cameras in his light bulbs and that a gang of men had held him prisoner in his apartment, to which he attributed his pressure sores. He reported hearing God telling him of a highway accident, and elaborated with complex visual and auditory hallucinations involving him driving to the scene of the accident, personally comforting the victims and seeing the motor vehicles catch fire. His ex-wife reported that AB had been mentally stable, well and ambulant four weeks previously. On physical examination AB had extensive necrotic pressure areas over his sacrum and thoracic spine and a widespread fungal infection over his buttocks. Biochemistry revealed raised urea and creatinine levels.

The treating team diagnosed acute, late onset psychosis. A CT brain demonstrated a 4cm space occupying lesion in the right temporal lobe with significant surrounding oedema, marked midline shift and raised intracranial pressure. Medical review revealed right papilloedema, wide based gait and mild left sided hemiparesis. AB was urgently transferred to a neurosurgical unit, in which a biopsy revealed a stage four glioblastoma multiforme tumour. AB was not suitable for surgery, and subsequently returned to his hometown for palliative care.

This case highlights the importance of not overlooking medical causes of first episode psychotic symptoms. Brain tumours are an uncommon, but important, cause of secondary psychosis (Keshavan and Kaneko, 2013). This case serves as a reminder that neuroimaging on presentation is recommended in older patients presenting with new-onset psychosis (Hollister and Boutros, 1991).