Author Response: Pearls & Oy-sters: Isolated Oculomotor Nerve Palsy due to Pituitary Apoplexy Missed on CT Scan

Abstract

We appreciate the comments and helpful tips by Dr. Zhang et al. on our paper.1 We agree with their comment that a negative CT scan cannot rule out the possibility of a subarachnoid hemorrhage (SAH) or apoplexy, which makes having a low threshold for follow-up scanning with MRI imperative. Had the MRI scan also been unremarkable, we agree that it would have been reasonable to consider a lumbar puncture to explore a possible bleed in the context of a severe headache and focal neurologic signs before attributing it to other, less-serious etiologies. Interestingly, some subarachnoid hemorrhages may be due to non-aneurysmal events of venous origin, particularly in the perimesencephalic areas and not necessarily due to missed aneurysms.2 Finally, it is important to note that a critical take away from this case is that pituitary apoplexy can mimic a subarachnoid hemorrhage presenting with a third nerve palsy, and it is, therefore, important to have on the differential diagnosis of patients presenting with thunderclap headache, in addition to the typically considered diagnosis of SAH.