Abnormal pupils at the bedside: rapid recognition of neurologic and systemic emergencies in acute care settings

Pupillary abnormalities are critical bedside findings that may indicate both benign physiologic variation and life-threatening neurologic emergencies. In emergency and urgent care settings, rapid interpretation of pupillary findings is essential for early recognition of intracranial pathology, vascular lesions, toxicologic syndromes, and ocular disease. To summarize clinically significant pupillary abnormalities encountered in acute care and propose a structured bedside framework to distinguish benign from emergent etiologies. A narrative review of the literature was conducted, focusing on pupillary neuroanatomy, examination techniques, and underlying pathophysiologic mechanisms relevant to emergency practice. Results Key conditions reviewed include physiologic anisocoria, Horner syndrome, Adie tonic pupil, Argyll Robertson pupil, relative afferent pupillary defect, Hutchinson pupil, and oculomotor nerve palsy. A practical bedside approach to anisocoria is emphasized, including identification of the abnormal pupil (dilated vs. constricted) and integration of associated neurologic findings to guide diagnostic evaluation and imaging. Emerging tools such as quantitative pupillometry and point-of-car ultrasound are highlighted as adjuncts for assessing pupillary function in complex or resource-limited settings. A systematic approach to pupillary examination can facilitate early detection of neurologic emergencies, guide appropriate imaging decisions, and improve clinical documentation in acute care settings.