Jim is 80 years old and has had no recent health problems. He attends the GP surgery with his wife. According to Jim there is nothing the matter, but his wife says that for the past year he has become increasingly forgetful. Though he is normally an excellent driver, the previous day Jim had ignored a no entry sign while driving back from their daughter's house and only narrowly avoided crashing the car.
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a. What diagnostic possibilities would you consider?
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Correct answer:
The forgetfulness with gradual onset and the apparently reduced competence in a complex task (driving) suggest a dementia syndrome. The commonest causes of dementia are Alzheimer’s disease and vascular dementia, but dementia with Lewy bodies and alcohol-related dementia are also relatively common. The apparent sudden worsening in cognitive function also suggests the possibility of an acute confusional state (delirium). This could be secondary to a stroke, a myocardial infarction or an acute (respiratory or urinary) infection.
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b. What questions would you ask Jim and his wife before proceeding to a physical examination?
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Correct answer:
Your questions should attempt to establish whether Jim has lost competence in other daily living skills, to narrow down the diagnostic possibilities and also to assess risk. What are the main problems from his wife’s point of view? Does he have any problems with washing, dressing, managing money, etc.? Has he had any previous episodes of sudden confusion or of unilateral loss of power or coordination? Has he ever put himself or his wife at risk by his behaviour (e.g. getting lost, leaving pans to boil dry)? Has he ever been verbally or physically aggressive towards his wife (see Chapter 4)? Does he ever seem suspicious or express delusional ideas? Is there any suggestion of auditory or visual hallucinations?
Jim repeats that he has no problems at all. His wife tells you that over the past year she has taken over most of the tasks that had been his responsibility throughout their marriage, such as paying bills and arranging for the car to be serviced. He can no longer use the TV remote control properly. He has never been physically aggressive, but he sometimes shouts at his wife when he is at his most confused and frustrated. She finds it difficult to cope with his changing personality, his lack of initiative and his loss of active interest in her and their family.
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c. What features would you look for particularly in the examination of the mental state and the physical examination?
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Correct answer:
Systematic assessment of cognitive function is essential and using a standardized screen such as the Mini Mental State Examination can be helpful. The change in personality suggests the possibility of frontal lobe involvement so frontal lobe tests such as verbal fluency may be revealing (see Chapter 2). On physical examination it is important to examine blood pressure and look for evidence of vascular disease (weak or absent pulses, fundal examination), of lateralizing neurological signs, Parkinsonian features and signs of hypothyroidism.
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d. What tests would you order and why?
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Correct answer:
The most informative test is a CT or MRI scan which may show generalized atrophy suggestive of Alzheimer’s disease, and/or cortical or subcortical infarction. Other useful tests include TFTs (because of the bradycardia and goitre), ECG (to exclude recent myocardial infarction), full blood count (anaemia may aggravate cognitive impairment) and urea and electrolytes (both because he is on a diuretic and because renal failure can worsen cognitive function) (see Chapter 31 for full confusion screen).
Jim’s MMSE score is 18/30, indicating moderate cognitive impairment. He performs particularly badly on short-term memory. He is only able to name six animals in a minute and only four fruits. His pulse is 60 and regular, his blood pressure is 120/75, fundoscopy is normal and there are no abnormal neurological signs. He has a small smooth goitre. The CT scan shows generalized atrophy. All other results are normal.
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e. What is the likeliest diagnosis?
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Correct answer:
Alzheimer's disease.
