Visual hallucinations in consultation-liaison neuropsychiatry

Frightening Complex Visual Hallucinations in an Elderly Patient with Ophthalmological Pathology and Vascular Dementia

A lady in her 90s was referred to the Later Life Team (LLT) in a rural area of the United Kingdom with complex visual hallucinations (VH). She had significant ophthalmological pathology, including cataracts, a branch retinal vein occlusion, and vitreous haemorrhage. The hallucinations included seeing monkeys ripping the heads off of her cats and lions prowling the garden. The patient was distressed by the hallucinations and believed them to be real events. Her management involved low dose olanzapine and requesting that her ophthalmological surgery be expedited. The surgery resulted in a significant reduction in VH. A diagnosis of vascular dementia went on to be made following cognitive testing and imaging. The cognitive impairment may have contributed to the patient's inability to identify her experiences as hallucinations and thus render her without insight. A review of the computed tomography (CT) scans performed prior to the patient's presentation to our service confirmed significant vascular pathology including small vessel disease and lacunar infarcts. Cognitive testing confirmed a cognitive impairment which had gone unnoticed by her family. This case leads to an interesting discussion regarding diagnosis in complex VH in cases of significant ophthalmological pathology but a lack of insight. Various authors have proposed theories to explain VH; cortical release and the Perception and Attention Deficit (PAD) model are explored as possible explanations for the experiences of this patient.

Distinguishing Neuroimaging Features in Patients Presenting with Visual Hallucinations

Visual hallucinations are relatively uncommon presentations in medical and psychiatric clinics, where they are generally regarded as a marker of possible underlying "organic" brain disease. Thus, patients with visual hallucinations are often referred for imaging of the brain. This article presents a pragmatic approach for the radiologist reviewing such imaging. Because conditions that can present with visual hallucinations are legion, a familiarity with the features of the hallucinations themselves, which can serve as clues to the underlying cause, can be helpful in interpreting such cases. We consider the nature of visual hallucinations and the mechanisms underlying their formation. We then provide a framework to guide the search for their cause, first in terms of focal lesions along the visual pathway and then global conditions affecting >1 region.

Complex visual hallucinations and occipital seizures

BACKGROUND

We describe the presentation of a young woman with long-standing complex partial seizures with occasional secondary generalization, who presented with complex visual hallucinations (CVHs) and delusions.

METHODS

Routine biological workup including magnetic resonance imaging revealed an area of significant left-sided occipital gliosis. Video telemetry monitoring revealed a left occipital focus for the origin of the electrographic seizure discharge.

CONCLUSION

CVHs occur in a range of organic states, including epilepsy, and can be understood in terms of the underpinning neuroanatomy and neurotransmitter systems of the visual system.