Abstract
Acute onset of psychosis in an older or elderly individual without history of previous psychiatric disorders should prompt a thorough workup for neurologic causes of psychiatric symptoms. This report compares and contrasts clinical features of new onset of psychotic symptoms between two patients, one with an acute basal ganglia hemorrhagic stroke and another with an acute mid-brain ischemic stroke. Delusions and hallucinations due to basal ganglia lesions are theorized to develop as a result of frontal lobe dysfunction causing impairment of reality checking pathways in the brain, while visual hallucinations due to mid-brain lesions are theorized to develop due to dysregulation of inhibitory control of the ponto-geniculate-occipital system. Psychotic symptoms occurring due to stroke demonstrate varied clinical characteristics that depend on the location of the stroke within the brain. Treatment with antipsychotic medications may provide symptomatic relief.
Highlights
Acute onset of hallucinations and delusions in older and elderly patients with no known history of previous psychiatric disorders should prompt a thorough investigation for secondary or neurologic causes of psychotic symptoms
Several different mechanisms are postulated to explain acute development of psychotic symptoms due to acquired brain lesions, including direct injury to the frontal lobes or disruption of normal frontal lobe functioning through damage to connections between the prefrontal cortices and subcortical structures causing impairment of reality monitoring functions [2, 3], direct insult to primary visual cortices (Anton’s syndrome) causing misinterpretation of signals from undamaged visual association cortex areas [1, 4], and loss of inhibitory control of ponto-geniculate-occipital connections leading to visual hallucinations that have been described as similar in nature to rapid eye movement (REM) sleep [2]
We hypothesized that new onset psychosis due to acquired brain lesions may display different clinical characteristics depending on the location of the responsible lesion and the underlying brain structures and mechanisms involved
Summary
Acute onset of hallucinations and delusions in older and elderly patients with no known history of previous psychiatric disorders should prompt a thorough investigation for secondary or neurologic causes of psychotic symptoms. Previous reports describe acute onset of psychosis resulting from acute stroke or other structural lesions affecting several different brain areas, including the prefrontal and occipital cortices, and subcortical locations such as the basal ganglia, thalamus, mid-brain, and brainstem [1, 2]. The cases discussed in this report underwent brain imaging studies, general physical and neurological examinations, routine blood tests, and other studies related to workup of stroke. In both cases the psychotic symptoms developed acutely were not the result of coexistent delirium and responded well to treatment with antipsychotic medications
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