Pneumothorax and Atelectasis are medical conditions of people with a collapsed lung. The difference between these words is how extensive the collapse of the lungs is. Pneumothorax is a total collapse of the lungs, while Atelectasis is when a part of the lungs collapse.
Atelectasis is caused by a blocked airway or pressure on the outside of the lungs; common causes include a foreign object in the airway, tumor, Mucus plug, lung disease, infection, fluid buildup, or air build up around the lungs.
Pneumothorax is caused by air from the lung filling the surroundings of the lungs causes include a car accident, fall, stab wound, gunshot, surgical injury. The symptoms include trouble breathing, sharp chest pain: rapid breathing, or increased heart rate.