Stage III and Stage IV are classified as the last stages of COPD, also referred to as severe and end-stage COPD. Of the four stages of COPD, these phases include the most severe symptoms, need the most progressive treatments and can be life-threatening. COPD is the acronym for chronic obstructive pulmonary disease. It is caused by long-term exposure to lung irritants to include cigarette smoking, air pollution, chemical fumes and dust. Symptoms of the last stages of COPD include wheezing, shortness of breath, fatigue, tightening of the chest and coughing, which produces mucus. In Stage III, symptoms of shortness of breath increase under exertion (walking fast and exercising). Airflow is decreased during breathing test (spirometry) and medical attention is required. Stage IV causes shortness of breath with just limited physical activity. This stage may cause respiratory failure and/or right-sided heart failure symptoms. Conditions at this stage may be life-threatening. Currently there is no cure for COPD, treating symptoms is the main focus. COPD treatment options may include smoking cessation, bronchodilators, steroids, pulmonary rehabilitation, oxygen therapy and surgery.