Clinical Topics Conference: Chapter 28, CNS

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  1. 37 year-old man with HIV with emotional lability
  2. 47 year-old white male with anxiety, fatigue, dizziness, headache and impaired judgement.
  3. 44 year-old female with new-onset seizure disorder
  4. 3 year-old child with ataxia

Clinical vignette 1

This 37 year-old HIV-positive white male was in his usual state of deteriorating health when he suddenly developed profound anomia and emotional lability. Two weeks later he noted increasing weakness of his right leg. Upon evaluation decreased sensation was evident over the left arm and trunk. Visual testing revealed several large field cuts. A subsequent cerebral MRI demonstrated multiple lucencies in the white matter. Over the next three months the patient became completely paralysed. Prior to his death which was secondary to aspiration pneumonia he became completely blind, unresponsive and mute.

Discussion topics

  1. What is the cause of PML?

  2. Which category of patients develop this disease?

  3. Is there a serologic test of diagnostic use?

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    Clinical vignette 2

    This 47 year old white male developed a vague disorder characterized by anxiety, fatigue, dizziness, headache and impaired judgement. Two months later he suffered profound, progressive memory impairment. Shortly later, he developed bradykinesia, weakness and rigidity. He deteriorated rapidly over the next four months and his clinical descent was characterized by severe, progressive dementia, cortical blindness, seizures, cerebellar dysfunction, and myoclonus. A startle reflex was present. An EEG was unrevealing and a cerebral CT scan showed marked cerebral atrophy. The patient died 8 months after the onset of his first symptoms.

    Discussion topics

    1. What are prions?

    2. How is a startle reflex elicited and what constitutes a positive response?

    3. What EEG pattern is characteristic for Creutzfeldt-Jakob disease? Why was it not present in this case?

    4. What antiseptic is most effective?

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    Clinical vignette 3

    . A 44 year-old female was evaluated in the emergency department after suffering a witnessed seizure while at work. According to her co-workers, her seizure was preceded by twitching and tremor of her left hand and this abnormal movement rapidly increased in amplitude and distribution until there was generalized seizure activity. The patient denied any previous history of seizure and was taking no medications. She admitted to vague intermittent headaches that had become more frequent and severe over the last 6 weeks. Careful testing revealed decreased 2 point discrimination over the left arm. A cerebral MRI demonstrated a poorly circumscribed mass with irregular cysts in the right fronto-parietal region.

    1. What is the significance of new onset seizures in an adult patient? What type of seizure is described here?

    2. What is the significance of gemistocytic astrocytes?

    3. How will this patient be treated and what is her prognosis?

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    Clinical vignette 4

    The patient was a 3 year-old child who had internal strabismus for one year. For 4 months before death the child was irritable, vomited and was ataxic. The patient frequently fell to the right. At the autopsy a soft friable tumor occupied the region of the fourth ventricle.

    On microscopic examination, the tumor consists of a loose vascular hemorrhagic mass of undifferentiated small cells invading the cerebellar white matter. The cells show little interadherence. They tend to have somewhat elongated "carrot-shaped" nuclei and scanty cytoplasm which in some cells is present as a mass at one nuclear pole. In some fields the tumor cells cluster about small vessels, but true rosette formation, not surrounding a vessel is rare. Small round cells of uncertain origin are mingled with the tumor.

    Discussion topics

    1. What is the cell of origin of this tumor? What is a cerebellar sarcoma?

    2. What is the treatment and prognosis for medulloblastoma?

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