A nurse is assessing a client who reports a severe headache. Which of the following findings should the nurse recognize as red flag symptoms requiring immediate evaluation? (Select All that Apply.)

Rationale: A. A severe headache following trauma may indicate a subdural or epidural hematoma, intracranial hemorrhage, or other serious brain injury. Any new or worsening headache after a head injury warrants immediate evaluation. B. Altered mental status, including confusion, disorientation, or decreased level of consciousness, can signal increased intracranial pressure, stroke, infection, or other neurological emergencies. This is considered a red flag symptom. C. A sudden, severe “thunderclap” headache reaching maximum intensity within seconds to minutes can indicate subarachnoid hemorrhage or other vascular emergencies. Rapid onset headaches should be treated as urgent. D. Neck stiffness or rigidity, especially when associated with headache, may suggest meningitis or subarachnoid hemorrhage. This combination requires immediate assessment and intervention. E. Headaches that improve with rest are generally tension-type headaches or benign causes and are not considered red flag symptoms. While they may still require evaluation, they do not indicate an urgent or emergent condition.