Stroke risk after ocular cranial nerve palsy – A systematic review and meta-analysis. (April 2022) - Shew, William
Highlights: Ocular cranial nerve palsies carry a 6x risk of subsequent stroke. Highest risk of stroke occurs within the first year of palsy. High risk of stroke in CN III palsy (up to 8x risk) Stroke risk continues even up to 12 years. Abstract: Background: Isolated ischemic ocular cranial nerve palsies (OCNP) involving the 3rd, 4th and 6th cranial nerves (CN) are prevalent conditions in ophthalmic practice. However, it is not clearly established whether such patients are at increased risk of stroke after onset of OCNPs. Methods: Medline, PubMed, Embase and Cochrane Central registers were systematically searched for eligible studies comparing isolated ischemic OCNPs against matched controls on the subsequent development of stroke with at least two years of follow up. Case reports and series were excluded. Appropriate studies were entered for meta-analysis to determine hazard ratios. Search and data extraction was completed on 22 Feb 2021. Random effect models were used to generate pooled hazard ratios (HRs) and 95% confidence intervals (CIs). Results: Three studies were suitable for meta-analysis (total n = 2, 756 OCNP cases and 21, 239 matched controls). The meta-analysis demonstrated a hazard ratio of 5.96 (4.20–8.46 95% CI) of subsequent stroke after isolated OCNP within the first year. The hazard ratio reduced to 3.27 (2.61–4.10 95% CI) after five years although remains raised at 2.49 (1.53–4.06 95% CI) up to 12 years. The highest risk was demonstrated with 3rd cranial nerve palsies. Two additional studies assessed the risk of stroke with newly diagnosed diabetics and compared OCNPs against lacunar stroke. These studies did not demonstrate a significant increased risk of stroke, although they may be statistically underpowered. Conclusion: Ischemic OCNPs represent a significant risk factor for development of subsequent stroke in a similar magnitude to transient ischemic attack within the first year.