Transient Charles Bonnet syndrome in a patient with reversible cerebral vasoconstriction syndrome

Abstract

Charles Bonnet syndrome (CBS) was first described by a Swiss philosopher named Charles Bonnet in 1760. For a long time, this syndrome was considered to be rare; however, in 1996, Teunisse et al. [1] reported psychopathological characteristics of 60 patients with CBS and questioned the rarity of CBS. CBS is diagnosed if the following criteria are fulfilled: (a) the presence of formed and complex, persistent, or repetitive visual hallucinations; (b) full or partial retention of insight; (c) the absence of delusions; (d) and the absence of hallucinations in other modalities [2]. Reversible cerebral vasoconstriction syndrome (RCVS) is a disorder characterized with reversible segmental and multifocal vasoconstriction of cerebral arteries and severe headaches with or without focal neurological deficits or seizures. Calabrese et al. described the following features for RCVS: (a) transfemoral angiography or indirect [computed tomography (CT) or magnetic resonance (MR)) angiography showing segmental cerebral artery vasoconstriction; (b) no evidence for aneurysmal subarachnoid hemorrhage; (c) normal or near-normal findings for cerebrospinal fluid analysis (protein level \80 mg/dL, white blood cell count\10 cells/lL, normal glucose level); (d) severe, acute headache with or without additional neurological signs or symptoms; and (e) the diagnosis cannot be confirmed until reversibility of the angiographic abnormalities is documented within 12 weeks after onset and if death occurs before the follow-up examinations are completed, the autopsy rules out conditions such as vasculitis, intracranial atherosclerosis, and aneurysmal subarachnoid hemorrhage, which can also manifest with headache and stroke [3]. Here, we report transient visual hallucinations resembling the ones in CBS in a patient with RCVS. A 64-year-old woman experienced severe thunderclap headache when she was skiing. CT and MR imaging (MRI) of her brain performed at that time revealed no abnormality. MRI and magnetic resonance angiography (MRA) conducted about 3 weeks later revealed convexity subarachnoid hemorrhage in the right frontal lobe and multiple segmental cerebral artery vasoconstrictions (Fig. 1). Her blood pressure was 130/96 mmHg, her body temperature was 36.2 C, and she was alert. She had no visual loss but experienced formed and complex visual hallucination such as ‘‘people walking down the street’’ or ‘‘people acting in a theater’’ only when she closed her eyes, and she had full retention of insight. Her visual hallucinations began about 3 weeks after the onset of headache, and lasted for about a week. 99mTc-ECD single-photon emission computed tomography showed diminished blood flow in both the occipital lobes (Fig. 2). Her headache eventually resolved without any neurological deficit. MRA performed at about 5 weeks after the onset of headache showed more cerebral artery vasoconstrictions, but the vasoconstrictions resolved 2 weeks after that, and the patient was diagnosed with RCVS. Y. Yagi (&) Y. Watanabe H. Yokote T. Amino T. Kamata Department of Neurology, Musashino Red Cross Hospital, Kyonancho 1-26-1, Musashino, Tokyo 180-8610, Japan e-mail: yyagi-tmd@umin.ac.jp