The danger in albuterol abuse is that in high doses, the medication enters the bloodstream and reaches the heart.
When used at the recommended dose, albuterol only remains in the airways and lungs. But when the dose is higher, it goes past the airways and enters the blood. This is where problems and all the side effects start.
It can change blood pressure and affect the amount of oxygen that reaches the brain. This is how it can lead to death. The bad part is that the symptoms don't seem all that bad until a lot of damage has been done.