A panic attack is a common form of panic disorder that is caused by extreme anxiety.
An attack can occur due to a perceived threat or a perceived fear.
This attack happens suddenly and without warning.
It can last anywhere from a few minutes to even a few hours.
In some rare cases, the attacks have lasted up to a day.
A person suffering from one of these attacks may show two or more symptoms including:

• Increased heart rate
• Shortness of breath
• Sweating
• Nausea
• Hyerventilation
• Chest pain
• Dizziness
• Throat tightness
• Sense of looming death
• Headache

After the attack, the individual will usually feel worn out and tired.
They also typically worry that they'll have another attack and wonder when it will occur.
They start to avoid places or situations that they feel may trigger another attack.
The more nervous they are, the better the chances are that they'll have another one.
Nobody thoroughly understands the cause or causes of these attacks yet, but the medical community has introduced many theories that often include the involvement of one or more of the following factors:

• Genetics
• Brain abnormalities
• Some psychotic disorders
• Chemical imbalances in the nervous system
• Natural alarm system
• Major life stresses
• Series of smaller stresses
• Trauma
• Personality traits

Panic attacks, like other anxiety disorders, can be treated through therapy, medications, natural remedies, exercises, relaxation techniques, breathing techniques or dietary changes.
Usually the most effective treatments are a combination of two or more of these.
And, of course, anyone suffering from these attacks should talk to their doctor.
Their doctor can diagnose if they, indeed, have panic attacks and can decide on the best treatments for that individual.