Is it possible to experience new symptoms of ptsd with new traumatic events if there is already a history of ptsd?

PTSD: Sure. Traumatic events can trigger anxiety symptoms in ones predisposed to having them, as in ones with history of ptsd.

PTSD: Certainly. In fact, i've observed over the years that a subgroup of ptsd pts.Seem to find themselves unconsciously drawn to potentially risky or traumatizing circumstances, repeating trauma experiences w/ out intent. A theory holds that these pts. Have emotional " blind spots", from early trauma, that allow them to be exposed to the trauma. Thus, others might pickup cues they miss.

Yes: This is common. Experiencing new traumatic events in the midst of ptsd can be like pulling the scab off a partially healed wound. It is likely to be painful & messy.