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I'd like to just talk briefly about infectious

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Choreas because they are extremely relevant in

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today's society because of the number one

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cause of primary infectious chorea,

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and I'll leave you hanging with that to see if

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you can figure it out while I'm talking.

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Here is an axial view of a 67-year-old man

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with a chorea, namely Huntington's chorea.

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He's got some cerebellar atrophy,

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he's got a lot of Sylvian atrophy.

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He's got some, but not very prominent

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temporal atrophy.

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Notice the temporal horns are not very big,

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and he's got generalized cortical atrophy which

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you can see if I zoom out a little bit and just

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take a quick look at the cortex from

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inferiorly to superiorly.

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Now, the condition that is most important

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as a primary cause of infectious chorea

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is a neurotrophic viral condition known as HIV.

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So, we don't think about this very often because of

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the suppression of symptoms of

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HIV by multidrug therapy.

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But anytime you have somebody

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who looks a little bit thin,

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a little bit cachectic and presents with a

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chorea with no other known risk factors,

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especially no genetic risk factors,

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you've got to think about this particular entity.

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Now, I didn't list Sydenham's chorea

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caused by beta hemolytic strep

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as the number one infectious cause

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because it's actually immune mediated.

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In other words,

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you generate antibodies that then dissolve the putamen.

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So, it's an attack against itself,

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whereas in HIV,

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it's a direct microorganism destruction

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of the putamen.

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Another condition,

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which is far rarer in the United States but still

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seen in some third world countries,

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is rubella,

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and this can occur through either direct attack

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or through autoimmune phenomenon.

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So, don't forget HIV as an important infectious

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primary cause of a chorea or choreiform

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movement disorder.