Which symptom is considered a red flag for headaches indicating a potential subarachnoid hemorrhage?

A sudden severe headache, often described as a "thunderclap" headache, is considered a red flag for potential subarachnoid hemorrhage. This type of headache typically comes on abruptly and is markedly different from a person's usual pattern of headaches. The sudden onset can indicate a rupture of a cerebral aneurysm or other serious vascular issues, as it is often accompanied by other symptoms such as neck stiffness, nausea, vomiting, and altered mental status.

Understanding the characteristics of headaches is crucial in nursing practice, especially when differentiating between benign and life-threatening conditions. Other symptoms, while potentially concerning, do not carry the same immediate risk of indicating a subarachnoid hemorrhage as the sudden onset does. Therefore, recognizing the nature and quality of a headache can guide prompt evaluation and intervention, which is critical for patient safety and management.