We present a case of a patient with “release hallucinations” as the initial symptomatology due to acute posterior cerebral artery (PCA) occlusion.

56-year-old male with medically non-compliant history of hypertension and diabetes reported that he initially saw a beautiful array of colorful waves lasting for 2 days over his right visual field. Symptomatology was believed due to hypertension and he thus ingested a higher dose of anti-hypertensive medication. 

Visual phenomena resolved the next day and he reported right-sided visual loss. He denied alteration of consciousness or formed visual hallucinations. The prolonged symptom duration contradicted epileptiform etiology.Neurological exam showed right homonymous hemianopia. Neuroimaging showed a subacute left PCA infarct with ipsilateral PCA P1 occlusion and vertebral stenosis. Embolic etiology was favored. Charles Bonnet syndrome and occipital seizures were considered as potential etiologies but given his presentation; the visual symptoms were deemed to be related to ischemia.

Our case adds to the limited available literature regarding PCA infarct manifesting as unformed, release hallucinations. Release hallucinations have been described as flashes of white or colored lights that originate from the retina or the primary receptive area for vision in the occipital cortex. More formed, elaborate hallucinations involve damage to occipitotemporal and occipitoparietal visual association neocortex. Patients project their images in a single lateral direction, corresponding to the visual field opposite to the lesion. Our patient’s progression from positive symptoms (hallucinations) to negative symptoms (hemianopsia) can be explained by ischemia that was followed by disinhibition of higher visual centers. It is important for the clinician to consider release hallucinations as a potential initial manifestation of PCA ischemic stroke presentation.