is it possible that I found an error in UW?

[jfgavina]

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individual w/ bitemporal hemianopia, double vision and sudden severe headache. decreased libido and headaches in the past. he develops cardiopulmonary collapse and dies.

I've choosen subarachnoid hemorrhage due to sudden headache and bitemporal hemianopia. the decreased libido could have been caused by the headaches from the aneurysm and not by prolactin but the correct answer is pituitary hemorrhage.

now, in the explanations it says that the 2 etiologies can be distinguished by the bitemporal hemianopia, which they say that's specific for pituitary hemorrhage. but as I'm sure that I read somewhere that ACA aneurysms can also cause bitemporal hemianopia, and it makes sense because it is near the optic chiasm. in wikipedia also says that. is this an error in UW?

 

[VisionaryTics]

ACAs are on the lateral portions of the optic chiasm, taking out the fibers coming back from the temporal retina, which transmit the central visual field. So ACA produces binasal hemianopsia.

Bitemporal hemianopsia is pathognomonic for lesions of the central portion of the optic chiasm, e.g. pituitary hemorrhage.

 

[jfgavina]

http://www.ncbi.nlm.nih.gov/pubmed/3362325 then what's this?

but for usmle purposes I believe in you

 

[VisionaryTics]

http://www.ncbi.nlm.nih.gov/pubmed/3362325 then what's this?

but for usmle purposes I believe in you

There's probably a reason that was a publishable case.

Also, that's the anterior communicating artery. Internal carotid/anterior carotid are the classic arteries of hemorrhage in loss of central visual field. There's so much variability in the communicating arteries that I wouldn't immediately snap to thinking about them with sudden bitemporal hemianopsia.

This is buzzword bingo. Bitemporal hemianopsia = pituitary lesion.

 

[jfgavina]

ok, so in my head I'll think about bitemporal when it comes up in the actual exam