CLINICAL-CAUSES OF OCCULOMOTOR PALSY

SUMMARY

1. Central causes - vascular lesions, stroke, MS involving the brainstem.
2. Peripheral causes - pupillary PARASYMPATHETIC fibres are located on the dorsum of the CN 3 and blood supply is from the nerve sheath and not from the trunk. Hence, they are affected by pressure from mass lesions (such as aneurysms) but not infarction of the CN 3 (as in diabetes).
- Pupillary Sparing: Intrinsic lesionS (PSIS). Cause: DM.
- Pupillar Involving: Extrinsic lesionS (PIES). Causes: PCOM aneurysm, meningioma, NPC, superior orbital tumor (Talosa-Hunt Syndrome), basal meningitis.

Reference(s)

Wilkinson, I., Furmedge, D. and Sinharay, R. (2017). Oxford handbook of clinical medicine. Oxford: Oxford University Press. Get it on Amazon.
Feather, A., Randall, D. and Waterhouse, M. (2020). Kumar And Clark’s Clinical Medicine. 10th ed. S.L.: Elsevier Health Sciences. Get it on Amazon.
Hannaman, R. A., Bullock, L., Hatchell, C. A., & Yoffe, M. (2016). Internal medicine review core curriculum, 2017-2018. CO Springs, CO: MedStudy.
Therapeutic Guidelines. Melbourne: Therapeutic Guidelines Limited. https://www.tg.org.au [Accessed 2021].