Alzheimer' s Disease

The patient is a 78 year old left handed woman with a diagnosis of a left parietal infarct in 1995, bilateral carotid artery stenosis and hypertension. She was first seen in August 1997 for evaluation of involuntary movements of the lower face in the setting of rapidly progressive dementia and was admitted to hospital with a presumptive diagnosis of CNS Whipple's Disease. The patient was an executive secretary and retired some years ago. She had been an avid reader, and had enjoyed a very high functioning life and dressed meticulously. In late 1996, she developed some "psychiatric difficulties" and the visiting nurse became concerned. According to the care giver, the patient then had a dramatic decline with the onset of confusion, forgetfulness, and inability to care for herself and remain independent. She was admitted to a nursing facility where she disturbed other patients by climbing into their bed. A neurologist confirmed that she was demented and noted that her body and limb movements were generally bradykinetic. She walked without swinging her arms and turned en bloc. She was minimally interactive but pleasant and reasonably cooperative with the examiner. She had a tremor of the chin, lips and throat, but no apparent dysarthria and no resting tremor of the limbs. In the upper extremities, there was an increase in tone of the cog wheel type. The reflexes were brisk throughout and the plantar responses were equivocal. Root, snout and suck reflexes were present and Hoffman and Wartenberg's signs were also mildly present. The glabella tap was positive. Sensation to all modalities throughout was normal. Differential Diagnosis of Dementia. Top of the list, as the commonest cause of Dementia in the US is Alzheimer's Disease, which was the diagnosis in this patient. It was essential, however, to exclude: 1)Whipple's Disease 2)Paraneoplastic Limbic Encephalitis 3)Progressive Supranuclear Palsy (PSP) and, less likely 4)Creutzfeld-Jakob Disease (CJD) in the absence of myoclonus and ataxia Alzheimer's Disease (AD) The criteria for probable AD include the presence of dementia, progressive worsening of memory and other cognitive functions, deficits in two or more areas of cognition, no disturbance of consciousness, age of onset between 40 and 90, and the absence of systemic or central nervous system disorders that could account for the dementia. Use of these clinical criteria has yielded diagnostic accuracy in autopsy series of greater than 80%. Whipple's Disease is characterized by a supranuclear paralysis of vertical up and down gaze (See #932-1) and progressive dementia. In this case Whipple's was ruled out by a normal jejunal biopsy, a normal stereotactic brain biopsy and a negative PCR for Whipple's on the CSF. Paraneoplastic Limbic Encephalitis was considered and ruled out by negative serology for antibodies associated with paraneoplastic disease including anti-Yo, anti-Ri, and anti-Hu. PSP was seriously considered because of the overlap of many clinical signs i.e. 1.Extrapyramidal features of her face with a positive Glabella tap, plus cogwheel rigidity of the limbs and bradykinesia 2.A brisk jaw and facial jerks 3.Slow saccadic eye movements i.e. a Slow Saccade Syndrome. A significant negative for PSP was the absence of a supranuclear vertical downgaze palsy. CJD was ruled out by documentation of normal serial EEG recordings. See also: http://content.lib.utah.edu/cdm/ref/collection/ehsl-shw/id/116