Final answer:
A sign of a PE from a fat embolus starts with flu-like symptoms, leading to potentially fatal pulmonary edema, hypotension, pneumonia, and shock.
Step-by-step explanation:
A sign of a pulmonary embolism (PE) specific to a fat embolus includes initial flu-like symptoms such as fever and malaise, which are then typically followed by more severe signs such as pulmonary edema, hypotension, and can progress to pneumonia and potentially fatal shock. A fat embolus is a particular type of embolus that is comprised of fat, often originating from the bone marrow after a long bone fracture or during orthopedic procedures. This condition requires immediate medical attention due to the serious risk it poses to gas exchange and cardiovascular stability.