Risk factors and prognosis of isolated ischemic third, fourth, or sixth cranial nerve palsies in the Korean population

Abstract

Background: To investigate the risk factors and prognosis for ischemic third, fourth, and sixth cranial nerve palsies in a Korean population.

Methods: A pair-matched case-control study of 54 Korean patients who were diagnosed with ischemic third, fourth, or sixth cranial nerve palsies was performed to evaluate their risk factors. Using conditional logistic regression analysis, prevalence of potential risk factors in patients and controls, included diabetes mellitus, hypertension, hyperlipidemia, ischemic heart disease, left ventricular hypertrophy (LVH), and smoking were examined retrospectively. A cohort study by Kaplan-Meier method was performed to analyze the recovery period in relation to the number of risk factors or intracranial abnormalities detected by brain computed tomography or magnetic resonance imaging.

Results: The mean age of onset was 64.5 years. Of the 54 patients, 16 (29.6%) developed a third nerve palsy, 19 (35.2%) a fourth nerve palsy, and 19 (35.2%) a sixth nerve palsy. The risk factors of diabetes mellitus, hypertension, and hyperlipidemia were significantly more prevalent than other risk factors of heart disease, LVH, and smoking. The mean number of risk factors was 2.3 ± 0.6 in the third nerve palsy group, 1.7 ± 0.9 in the fourth nerve palsy group, and 1.6 ± 1.0 in the sixth nerve palsy group. Patients with 2 or more risk factors showed a longer recovery period (9.0 ± 5.1 weeks) than did patients who had 1 risk factor (6.1 ± 2.2 weeks). Patients with intracranial abnormalities on neuroimaging showed a longer recovery time (10.4 ± 2.7 weeks) than did those without intracranial abnormalities (7.5 ± 4.8 weeks).

Conclusions: Ischemic ocular motor cranial nerve palsy is closely related to diabetes mellitus, hypertension, and hyperlipidemia in Korean patients. Compared with the fourth or sixth nerve palsy groups, the third nerve palsy group showed a tendency to have multiple risk factors. Recovery takes longer when 2 or more risk factors were present or when abnormal findings were observed on neuroimaging.