Leukemic Leptomeningeal Carcinomatosis Causing 4th and 6th Nerve Palsies

𝗢𝗿𝗶𝗴𝗶𝗻𝗮𝗹 𝗗𝗲𝘀𝗰𝗿𝗶𝗽𝘁𝗶𝗼𝗻: This is a 55-yo-man with CML that recurred as AML. Diagonal diplopia developed, and on examination he was found to have a partial right 6th nerve palsy, in addition to a left hypertropia that increased in right gaze, down gaze, and in left head tilt consistent with a left 4th nerve palsy. There was 10 degrees of excyclodeviation OS with double Maddox rod testing. MRI showed enhancement of the right 6th nerve, and he was ultimately diagnosed with leukemic leptomeningeal carcinomatosis. Upon looking down and to the right and left, there was a clear left superior oblique (SO) paresis. He also had a V-pattern esotropia, presumably given his right 6th NP + left SO palsy, as the tertiary action of the SO muscle is abduction (V-pattern esodeviation is typically seen with bilateral 4th nerve palsies). 𝗡𝗲𝘂𝗿𝗼-𝗼𝗽𝗵𝘁𝗵𝗮𝗹𝗺𝗼𝗹𝗼𝗴𝘆 𝗮𝗻𝗱 𝗡𝗲𝘂𝗿𝗼-𝗼𝘁𝗼𝗹𝗼𝗴𝘆 𝗧𝗲𝘅𝘁𝗯𝗼𝗼𝗸 𝗟𝗲𝗴𝗲𝗻𝗱: This patient experienced diagonal diplopia (with both horizontal and vertical components) due to a right 6th NP and left 4th NP. While the 6th NP is marked, the evaluation of ocular alignment is essential to make the diagnosis of a 4th NP Also note the mild depression deficit OS in down/right gaze due to left superior oblique paresis. https://collections.lib.utah.edu/ark:/87278/ s63n5tg3