Nahla Mahgoub

A Case of Arnold–Chiari Malformation Associated With Dementia

To the Editor: Arnold–Chiari malformation is a congenital brain anomaly that was first described by the Austrian pathologist Hans Chiari in the late 19th century. It is categorized into three types based on the degree of herniation. Type I malformation is characterized by downward displacement of the cerebellar tonsils through the foramen magnum; while in type II the cerebellar vermis and possibly the fourth ventricle and pons are involved. Type III malformation is the most severe and rarest form and consists of an encephalomeningocele that contains the brainstem and cerebellum. The malformation is known to produce variable clinical signs and symptoms of cerebellar, cervical and brainstem dysfunction. There is a paucity of literature pertaining to the neuropsychiatric illnesses associated with Arnold– Chiari malformation. To our knowledge, the only neuropsychiatric disorder reported in humans, in association with Arnold-Chiari malformation is anxiety. We now summarize a case of 53-year-old woman with Arnold–Chiari type I malformation who presented with dementia.

Late-Life Anxiety

Case Report Mr. N, a 42-year-old right handed hypertensive male patient, presented with vivid hallucinations and delusions of paranoia and control of 2–3 months’ duration in 2004. He complained of an existing person for him who would “follow him trying to harm him,” “shout his name from his window,” and “see and smile from the roadside while chasing him.” His wife denied that such things were happening to him. His social and professional life was grossly affected. Neither he nor his relatives had a history of psychiatric disorder. In 2002, he developed right-sided hemianopia with acute nonhemorrhagic infarct in posterior cerebral artery territory involving the left occipital lobe. In January 2003, he was admitted for slurring of speech and left arm weakness. Immediate magnetic resonance imaging (MRI) of the brain showed hyperacute non-hemorrhagic distal right middle cerebral artery territory infarct and chronic infarct in occipital lobes. He was sucessfully thrombolysed with complete clinical recovery. Six months later, following thrombolysis, he developed partial seizure followed by generalized tonic clonic convulsions. His laboratory workup did not reveal any abnormality. Cardiac function was normal. Computerized tomography (CT) showed dilatation of the lateral ventricle. With no history (personal or family) of psychiatric illness, and with history of preceding stroke and later a seizure, lack of insight for his illness and persistent hallucinations and delusions, diagnosis of secondary hallucination delusion syndrome was made. He responded to high dose phenytoin sodium and sodium valproate.