• • Peduncular hallucinosis as a transient ischemic attack CARL WENZEL, DO LOUIS PEARLSTEIN, DO Peduncular hallucinosis is described a variety of visual patterns and figures. characterized by vivid hallucinations as­ The disturbances included curtains ruilling in the sociated with organic midbrain disease. In house in the absence of a blowing wind, black lines the case reported here, the computed to­ circling the mouth of her daughter, and red and mography brain scan showed basilar ar­ green puffs of air floating in the room. These dis­ terial atherosclerotic disease with central turbances were perceived binocularly. The patient and cortical atrophy. Carotid imaging re­ stated that she was not frightened by the distur­ bances, and that she was well aware that they were vealed bilateral stenosis. The electroen­ not real. cephalogram and magnetic resonance im­ Review of systems revealed only a mild frontal aging of the midbrain revealed no abnor­ headache. There was no history of tonic-clonic ac­ malities. The patient's symptoms resolved tivity, loss of consciousness, focal numbness, weak­ completely in 48 hours. This is believed to ness, or language disturbance. The patient denied be the first report of peduncular hallu­ having auditory hallucinations. There was no per­ cinosis as the manifestation of a transient sonal or family history of migraine headaches, epi­ ischemic attack syndrome. lepsy, or schizophrenia. The patient's medical his­ (Key words: Peduncular hallucinosis, tory included hypertension and angina, for which transient ischemic attack syndrome, vis­ she was treated with propranolol hydrochloride and ual hallucinations, midbrain infarctions) furosemide. Significant in the surgical history was bilateral cataract surgery with intraocular lens im­ plants; the patient's visual acuity was 20/40 ocu­ Peduncular hallucinations are vivid, non­ lus dexter and 20/25 oculus sinister after the pro­ stereotypical, often colorful images of geomet­ cedure. The patient had used alcohol and tobacco ric patterns and animate and inanimate minimally in the past. objects associated with structural midbrain dis­ The hallucinations resolved completely within ease. We report a case of typical peduncular 24 hours, only to recur briefly 24 hours later . The hallucinosis that resolved over 48 hours, dem­ hallucinations resolved again before the patient's onstrating the possibility for peduncular hal­ discharge from the hospital and have not returned. lucinosis to be the manifestation of a transient ischemic attack syndrome, that is, a revers­ Discussion ibl~ ischemic neurologic deficit. To our knowl­ Peduncular hallucinations are a rare cause of edge, this is the first time peduncular hallu­ visual disturbance. Many diseases affecting cinosis has been reported as a transient the midbrain can cause peduncular hallucina­ ischemic attack syndrome. tions, including vascular, neoplastic, or infec­ tious disease, as well as intoxications. Such Report of case hallucinations most often result when exten­ An 84-year-old, right-handed woman was seen with sive damage has occurred to midbrain struc­ visual disturbances of sudden onset. The patient tures; however, there have been reportsl of From the Department of Internal Medicine, Delaware such hallucinations with only minimal patholo­ Valley Medical Center, Langhorne, Pa (Drs Wenzel and Pearlstein), and the Department of Neurology, Hahne­ gic change in the midbrain. When a patient mann University Hospital, Philadelphia, Pa (Dr has visual hallucinations in the presence of Pearlstein). clinical evidence of brain-stem abnormalities, Reprint requests to Louis Pearlstein, DO, Neshaminy Plaza II, Suite 124, 3070 Bristol Pike, Bensalem, PA the clinician should consider peduncular hal­ 19020. lucinations. Case report • Wenzel and Pearlstein JAOA • Vol 93 • No 1 • J anuary 1993 • 129 The patient was awake; alert, and coopera­ puts have been partially or completely re­ tive. The blood pressure was 160/80 mm Hg. moved and may be likened to the phantom The pulse was 86 beats per minute and regu­ limb phenomenon. West4 theorized that the lar, and the temperature was 98.6°F (37°C). brain is constantly presented with innumer­ A right carotid bruit was noted. Findings of able sensory stimuli. The brain then decides heart, lung, abdominal, and extremity exami­ from these stimuli that which is needed to main­ nations were essentially normal. Neurologic tain 'consciousness and ignores those that are examination revealed a normal mental status not. When this i¢ormational input level is· dis­ including language and praxis. Cranial nerve rupted, "percepts" or "memory traces" may be evaluation demonstrated a mild, right central, released as hallucinations. Therefore, removal facial weakness and irregular but reactive pu­ of visual stimuli via disrupted visual pathways pils with iridectomy defects. Extraocular mo­ would decrease the amount of material pre­ tility was intact. Funduscopic evaluation sented to the brain, a situation leading to hal­ showed mild hypertensive retinopathy. lucinations as a manifestation of a visual re­ Strength was full at + 5/5,and the deep ten­ lease phenomenon. Visual hallucinations sec­ don reflexes were symmetrically 2 + /4. A pro­ ondary to sensory deprivation have been de­ nator drift of the right arm was noted. Plan­ scribed in patients with blindness from many tar reflexes were downgoing. Cerebellar and causes,5-7 as well as in patients with visual sensory systems were normal. The gait was field 10ss.8 Peduncular hallucinations are be­ normal. lieved to occur because visual input to the A computed tomography (CT) scan of the rapid-eye-movement brainstem nuclei and lim­ brain revealed atherosclerotic disease of the bic structures has been removed. 1 basilar artery, as well as central and cortical Pathologic examination of peduncular hal­ atrophy. Carotid imaging demonstrated bilat­ lucinosis patients at autopsy has demonstrated eral atherosclerotic disease with 50% stenosis extensive pathologic alteration ofthe brain in of the right internal carotid artery and 10% some, whereas in others, only minimal focal stenosis of the left internal carotid artery, with­ mesencephalic involvement in the pars reticu­ out flow changes. An electroencephalogram laris of the substantia nigra has been found. 1 showed normal waves. Magnetic resonance im­ Magnetic resonance imaging may demonstrate aging demonstrated diffuse small vessel dis­ pathologic change in the clinical setting and ease in the subcortical white matter, with no help to confirm the clinical suspicion ofpedun­ discrete lesions identified in the brain stem. cular hallucinosis. Laboratory studies including immunofluores­ cence for antinuclear antibodies gave normal Comment or negative results. We describe a patient with peduncular hallu­ Cogan2 separated visual hallucinations into cinosis whose symptoms improved over 24 excitatory (irritative) and release phenomena. hours and resolved completely in 48 hours. Mag­ Excitatory visual hallucinations, first de­ netic resonance imaging of the midbrain gave scribed by Jackson3 in 1889, are analogous to normal results. This is the first report ofpedun­ epileptogenic discharges with associated sen­ cular hallucinosis as a transient ischemic at­ sory symptoms. These types of hallucinations tack syndrome. We believe the prognosis is simi­ usually arise from the occipital or temporal lar to that of other transient ischemic attack lobes. If the occipital lobe is involved, the pa­ syndromes. tient may describe unformed flashes of light that are white, colored, or zigzag. Temporal lobe foci produce complex, and frequently, References formed visual imagery. 1. McKee AC , Levin DN, Kowall W, et al: Peduncular hallu­ cinosis associated with isolated infarction of the substantia ni­ Release hallucinations are believed to be the gra pars reticulata. Ann Neurol1990;27:500-504 . 2 result of sensory deprivation. ,4 This type of 2. Cogan DG: Visual hallucinations as release phenomenon. hallucination occurs when normal visual in- A rch Klin Exp Ophthalmol 1973;118:139-150. (continued on page 133) 130 • JAOA • Vol 93 • No 1 • J anuary 1993 Case report • Wenzel and Pearlstein 3. Jackson IN: On a particular variety of epilepsy (intellectual Ophthalmal Sac 1916;36:412-444. aura): One case with symptoms of organic brain disease. Brain 6. Weinberger LM, Grant FC: Visual hallucinations and their 1889;11:179-207. neuro-optical correlates (review). Arch Ophthalmol1940;23:166- 4. West CJ: Hallucinations. New York, NY, Grune & Stratton, 199. 1962. 7. Peatfield RC , Rose FC: Migrainous visual symptoms in a 5. Uulson SAK: Dysmetropsia and its pathogenesis. Trans woman without eyes. Arch N eural 1981;38:466. Case report· Wenzel and Pearlstein JAOA . Vol 93 • No 1 • January 1993 • 133 .