Early deterioration in isolated pontine stroke: predictors and outcomes

Background and aims: Pontine ischemic strokes are feared for their propensity to undergo early neurological deterioration (END). This study aimed to assess clinical and imaging predictors of END in patients with isolated pontine stroke and develop a candidate END risk score. Methods: We retrospectively analyzed 91 patients admitted to our stroke center (2009-2024) with confirmed isolated pontine infarction. Patients with ≥ 50% basilar stenosis were excluded; END was defined as a ≥ 2-point NIHSS worsening within 48 h. Results: END occurred in 28.5% (26/91) of cases and was associated with higher premorbid disability (mRS ≥ 2: 38.5% vs. 15.4%, p = 0.025) and greater small vessel disease burden (Fazekas ≥ 2: 69.2% vs. 47.7%, p = 0.030) compared with the non-END group. Pontine warning syndrome (PWS) was more frequent among END cases (19.2% vs. 6.2%, p = 0.11). All END cases involved anteromedial lesions (100% vs. 58.5%, p < 0.001), more frequently extending to the ventral pontine surface (84.6% vs. 33.8%, p < 0.001) and exhibiting larger infarct volume (0.45 vs. 0.26 mL, p < 0.001). END was associated with higher NIHSS at discharge (median 6 vs. 2, p < 0.001) and worse functional outcome at 90 days (median mRS 3 vs. 1, p < 0.001). A five-variable END risk score based on clinical and imaging predictors showed good discriminative performance (optimism-corrected AUC = 0.84; 95% CI 0.80-0.88). Conclusions: In isolated pontine stroke, END was associated to anteromedial lesion location, surface extension, premorbid disability, small vessel disease burden, and clinical PWS. If validated in future studies, the proposed END risk score may support early patient risk stratification.