314 - Peduncular Hallucinosis as Sequela of Distal Basilar Artery Occlusion

Thursday, February 19, 2026

5:00 PM - 6:30 PM AST

Presenting Author(s)

MA

Muzammil Ali Khan, DO

Resident Physician
Parkview Health
Palos Hills, Illinois, United States

Corresponding Author(s)

SS

Saleh Sheikh, DO

Department of Physical Medicine & Rehabilitation
Parkview Health
Fort Wayne, Indiana, United States

Submitter(s)

MA

Muzammil Ali Khan, DO

Resident Physician
Parkview Health
Palos Hills, Illinois, United States

Case Diagnosis: Inferior Colliculus Infarct with Peduncular Hallucinosis

Case Description: An elderly woman presented after a fall with unresponsiveness at home. CTA of the head and neck revealed an acute thrombus at the basilar tip extending into the proximal bilateral posterior cerebral arteries. MRI of the brain showed ischemia in the left inferior colliculus. She underwent emergency mechanical thrombectomy, achieving successful TICI 3 reperfusion. Ten days after stroke onset, upon admission to acute inpatient rehabilitation, she developed vivid, well-formed hallucinations of birds and people. These hallucinations lasted for two days. During this time, she remained fully lucid, oriented, and aware that her experiences were hallucinations. No agitation, cognitive fluctuations, or changes in consciousness were observed. Her symptoms resolved spontaneously without medication or behavioral treatment.

Discussions: Peduncular hallucinosis, marked by vivid, well-formed hallucinations with preserved consciousness and insight, is an uncommon but significant complication of distal basilar artery infarcts. Unlike delirium, these hallucinations are usually harmless, happen with maintained orientation, and often resolve on their own. Recognizing this benign course is crucial in the rehabilitation setting, where new-onset hallucinations might otherwise lead to unnecessary tests, inappropriate drug use, and interruption of therapy.

Conclusions: Peduncular hallucinosis can occur as a manifestation of ischemia in the rostral midbrain from distal basilar artery strokes. Differentiating it from delirium is crucial to optimize care, avoid unnecessary interventions, and support rehabilitation progress. Recognizing its clinical features and self-limited nature helps physiatrists reassure patients and stay focused on functional recovery.