CASE STUDIES
Case 1: Mr. Cook, a 68-year-old man, was taken by his daughter to their
family physician. Mr. Cook lives alone after his divorse 10 years previously.
He has been having trouble taking care of himself lately; e.g. he has not
paid his bills on time, has not been eating well or keeping ordinary kinds
of food in his house, and neighbors have said he does odd things in the
yard sometimes. A series of tests ruled out metabolic disorders; CT scan
showed only mild cortical atrophy.
1. What is the most likely diagnosis?
2. What would be needed for a definitive diagnosis?
Answers:
1. The most likely diagnosis is Alzheimer's disease. After a progressive
history of dementia has been established and after treatable causes of dementia
have been ruled out, the most common cause of dementia is Alzheimer's disease.
2. Brain autopsy after the patient's death is necessary for a definitive
diagnosis. Large numbers of neuritic plaques and neurofibrillary tangles
in the cortex and hippocampus are the microscopic criteria for AD pathologic
diagnosis.
Case 2: A 58-year-old man went to his physician complaining of generalized
muscular weakness and increased clumsiness. During examination the patient
demonstrated bilateral weakness of legs and arms, and atrophy of some of
the intrinsic muscles of the hands. Deep tendon reflexes in the upper limbs
were depressed and in the lower limbs DTRs were increased. Babinski signs
were present bilaterally. The patient said he had noticed "rippling"
of the muscles in his arms periodically.
1. From the symptoms described, which, if any, of the long sensory and motor
tracts are involved (corticospinal tract, spinothalamic tract, dorsal column/medial
lemniscus system)?
2. Which of the symptoms described would suggest the involvement of upper
motor neurons? lower motor neurons?
3. What is the most likely diagnosis?
4. Describe the pattern of lesions expected.
Answers:
1. Corticospinal tract
2. Upper motor neuron involvement: increased DTRs in legs, Babinski signs;
lower motor neuron involvement: decreased DTRs in arms, fasciculations ("rippling
of muscles"), muscle atrophy.
3. The most likely diagnosis is amyotrophic lateral sclerosis (ALS)
4. Lesions are expected in the cerebral cortex motor neurons (cell bodies
of upper motor neurons), axons of the corticospinal and corticobulbar tracts,
ventral horn cells in the spinal cord and brainstem motor neurons (cell
bodies of lower motor neurons), lower motor neuron axons in peripheral nerves.
Case 3: A 20-year-old woman was referred to a neurologist for additional
analysis after a possible diagnosis of schizophrenia. She had always been
a good student, but had just failed all her courses that semester in college.
She lost interest in everything and everyone, including her boyfriend. She
did not seem to be happy, but smiled a lot with no stimulus (a fixed sardonic
smile). Liver tests had been done as part of a complete work-up, and were
mildly abnormal. After talking with the woman, performing a focussed neurologicl
exam, and looking in her eyes, the neurologist told her she was not "going
crazy", and could be cured.
1. How would you classify the fixed sardonic smile?
2. What is the diagnosis? What did the physician see in her eyes? Where
would major lesions be expected?
3. What kind of treatment would be appropriate?
Answers:
1. The fixed sardonic smile is an example of dystonia, a class of abnormal
involuntary movements that cause an abnormal posture. Dystonias as well
as other types of abnormal movements such as tremor and chorea are associated
with lesions in the basal ganglia.
2. Wilson's disease (hepatolenticular degeneration). The neurologist saw
Kayser-Fleischer rings (deposits of copper around the outer edge of the
cornea). Lesions are expected in the liver and the lenticular nucleus (putamen
and globus pallidus).
3. Treatment with a copper chelator (e.g. penicillamine) can produce rapid
improvement and long-term control of Wilson's disease.