You arrive at a scene where a man is confused and has suddenly fallen to the ground shaking. What should you first suspect?

In this scenario, the sudden confusion followed by the individual falling to the ground and shaking is most indicative of a generalized seizure. Generalized seizures affect both sides of the brain and lead to a loss of consciousness along with muscle rigidity or shaking, which aligns closely with the signs presented.

When a person experiences a generalized seizure, it can often present with an aura of confusion or disorientation before the seizure occurs. The shaking, which is characteristic of a generalized seizure, suggests that there is widespread electrical activity in the brain, impacting the motor centers and leading to convulsions.

While complex seizures and partial seizures could involve some confusion or abnormal behavior, they typically do not present with the same wide-reaching effects on both sides of the brain, which would explain the total body shaking and loss of awareness. A fainting episode, or syncope, usually would not involve the intense shaking observed in a seizure and is often accompanied by a brief lapse of consciousness rather than full-body convulsions.

In summary, the combination of confusion followed by falling and shaking strongly points to a generalized seizure as the most likely cause of the symptoms displayed.