A client with post-traumatic stress disorder (PTSD) describes having nightmares about their traumatic experience and feeling 'like it's happening again during the day.' What is the term for this daytime re-experiencing symptom?

PTSD DIAGNOSTIC CRITERIA (DSM-5): The diagnosis requires exposure to actual or threatened death, serious injury, or sexual violence, plus symptoms from four clusters: (1) INTRUSION: Flashbacks (re-experiencing as if event is happening now), nightmares, intrusive memories, distress at cues; (2) AVOIDANCE: Avoiding thoughts, feelings, or external cues associated with trauma; (3) NEGATIVE COGNITIONS/MOOD: Distorted blame, estrangement, anhedonia, persistent negative emotional state; (4) AROUSAL/REACTIVITY: Hypervigilance, exaggerated startle, sleep disturbance, irritability, reckless behavior. FLASHBACKS vs NIGHTMARES: Flashbacks = waking re-experiencing; nightmares = sleep re-experiencing; both are intrusion symptoms; TREATMENT: Trauma-focused CBT (Prolonged Exposure, Cognitive Processing Therapy); EMDR; SSRIs/SNRIs (medication); NURSING ROLE: De-escalate during a flashback episode — ground the patient in present reality using sensory grounding ('Tell me 5 things you can see'); do not touch without warning; speak calmly and slowly; reassure they are safe.