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Chapter 6. Behavioral Neurology

A 67-year-old woman with chronic alcoholism is admitted to the hospital because of fever and shortness of breath. She is diagnosed with community-acquired pneumonia and admitted for management with antibiotics and respiratory support. On the third day of admission, she begins to complain of seeing insects crawling on the walls of her room and along her bed. Neurological examination is nonfocal but the patient appears to be anxious and concerned over the “insects.” This patient's visual hallucinations are most likely due to

(A) Charles Bonnet syndrome

(B) Anton syndrome

(C) Heidenhain variant of Creutzfeldt–Jakob disease

(D) delirium secondary to alcohol withdrawal

(E) peduncular hallucinosis

(D) The patient in the vignette is having visual hallucinations due to delirium secondary to alcohol withdrawal. Visual hallucinations are the most common type of hallucination apparent in delirium and occur in over a quarter of patients with delirium. Seeing crawling insects is a classic visual hallucination seen by those withdrawing from alcohol or other drugs.

Charles Bonnet syndrome is marked by visual hallucinations of people, faces, animals, inanimate objects, or colored patterns. Charles Bonnet syndrome occurs in patients with vision loss, usually due to damage to the visual pathways. Anton syndrome refers to denial of blindness or cortical blindness in patients with lesions in bilateral occipital regions. The Heidenhain variant of Creutzfeldt-Jakob disease is characterized by visual disturbance that involves color changes, visual field defects, cortical blindness, metamorphopsia, and micropsia. This occurs within the context of progressive neurocognitive decline. Periodic non-generalizing complexes over the occipital region on EEG are a classic diagnostic feature of this entity. Peduncular hallucinosis refers to visual hallucinations that arise following an infarct to the midbrain. (Critchley, 156; Furlan, 312–314; Lang, 553–555; Manford and Andermann, 1819–1840; Moellentine and Rummans, 260–263; Webster and Holroyd, 519–522)


Critchley M. Modes of Reaction to Central Blindness. New York, NY: Raven; 1979:156.

Furlan AJ, Henry CE, Sweeney PJ,. Focal EEG abnormalities in Heidenhain's variant of Jakob-Creutzfeldt disease. Arch Neurol. 1981;38:312–314.

Lang UE,. Charles Bonnet syndrome: successful treatment of visual hallucinations due to vision loss with selective serotonin reuptake inhibitors. J Psychopharmacol. 2007;21:553–555.

Manford M, Andermann F. Complex visual hallucinations: clinical and neurobiological insights. Brain. 1998;121: 1819–1840.

Moellentine CK, Rummans TA. The varied neuropsychiatric presentations of Creutzfeldt-Jakob disease. Psychosomatics. 1999;40:260–263.

Webster R, Holroyd S. Prevalence of psychotic symptoms in delirium. Psychosomatics. 2000;41:519–522.

An 80-year-old woman with a history of hypertension presents with forgetfulness. According to her son, she has been increasingly forgetful over the past ...

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