The aforementioned Webster's defines panic as a sudden overpowering fright; esp: a sudden unreasoning terror often accompanied by mass flight. It's definition of attack is to set upon or work against forcefully. So the panic - or overpowering fright - works upon you forcefully by using "symptoms" to defeat you. This is a simplistic way of looking at the disorder, of course, but very effective in understanding what occurs. Remember that anxiety is not an illness - it's a behavioural condition. There is something that interferes with the brain synapsis - little electrical sparks that causes the body to react in a given way. It is normal to experience anxiety - it contributes to survival, the fight or flight principal. It is when these feelings are overwhelming that it becomes a problem. It's important to remember that if these symptoms occur while experiencing anxiety then it's a panic attack - they do not cause the attack, the attack causes them, and it is not an underlying medical condition. In other words, a medical condition would cause the anxiety, occur first with anxiety being the result. It's also essential that you understand that you cannot die from this although you may feel like it. I know that's not a lot of comfort and, personally, doesn't make the sensations any better, but it could lessen your anxiety when having an attack.
Some people can actually suffer from an axiety disorder without ever experiencing any of these symptoms, or they can be so mild that they are not aware that they are actually having a panic attack. Others only display a few, while some will suffer a full spectrum of symptoms. No matter how many of these you experience it is still a panic attack. Below are the most common symptoms of panic attacks.
1. Rapid heart beat, pounding heart or palpitations
2. Sweating
3. Shaking visibly or inside
4. Choking sensations or lump in throat
5. Smothering or shortness of breath sensations
6. Chest pain or discomfort
7. Nausea, bloating, indigestion or abdominal discomfort.
8. Dizziness or unsteadiness
9. Feeling light-headed
10. Derealisation (feeling unreal or dreamy)
11. Depersonalisation (feeling outside yourself or like you don't exist)
12. Fear of losing control or going crazy
13. Paresthesias (numbness or tingling sensations) in face, extremities or body
14. Chills or hot flushes
15. Skin losing color
16. Blushing or skin blotches
17. Urgently needing to urinate or defecate