The stages of emphysema and life expectancy

Emphysema is a subtype of Chronic Obstructive Pulmonary Disease or COPD. It is a lung disease notable for a permanent enlargement and destruction of small alveoli (air sacs).

Symptoms of emphysema

Emphysema causes a chronic cough, increased mucus production, an uncomfortable sensation during breathing (i.e. dyspnea), and wheezing. Morning is often a worse time for symptoms. 

Most people will first notice they have a significant problem when they experience exertional dyspnea, i.e. people with emphysema become very short of breath with only modest exercise. Not all of the symptoms will occur early in the disease; usually patients have mild symptoms (e.g. smokers cough) that they ignore for years while the damage of emphysema is taking place in the lungs.

Late in the disease, patients with emphysema may have cyanosis (a blue tint to the lips and skin due to poor blood oxygenation), swelling of the arms and legs, an enlarged chest cavity, and engorgement of the jugular veins.

Stages of emphysema

The Global Initiative for Chronic Obstructive Lung Disease (GOLD) has divided emphysema into four stages of severity based on pulmonary function tests:

• GOLD stage 1 – Mild: Forced expiratory volume in one second (FEV1) ≥ 80% of predicted
• GOLD stage 2 – Moderate: FEV1 is between 50% and 80% of predicted
• GOLD stage 3 – Severe: FEV1 is between 30% and 50% of predicted
• GOLD stage 4 – Very severe: FEV1 <30% of predicted

Formal pulmonary function testing is done in a medical laboratory, but devices have been developed for hospital and home use that provide a portable and reasonably accurate estimate of FEV1.

A potentially more useful scale that roughly correlates to stage of emphysema is based on the Modified Medical Research Council (MMRC) for Dyspnea score.

• MMRC 1 – Shortness of breath (dyspnea) on walking a slight hill
• MMRC 2 – Shortness of breath (dyspnea); must stop occasionally
• MMRC 3 – Must stop after walking 100 meters or after a few minutes from dyspnea
• MMRC 4 – Cannot leave house; breathless on dressing/undressing 

Severity of emphysema correlates with survival

As you may expect, people with severe emphysema have shortened life expectancies. In 2004, researchers published a paper in the New England Journal of Medicine that estimates survival based on overall symptom severity.

The BODE index (Body Mass Index, Airflow Obstruction, Dyspnea and Exercise Capacity) takes into account FEV1 after a person uses a bronchodilator, the distance someone can walk in 6 minutes, Modified Medical Research Council Scale for dyspnea and body mass index (BMI). The score correlates with the four-year survival rate. People who score 0-2 points have an 80% chance of living for four years, while people who score 7-10 points have only 18% chance.

What causes emphysema?

Smoking

By far the most common cause of emphysema is cigarette smoking

Emphysema is found much more commonly in individuals who smoke than in those who do not. In fact, the more cigarettes that one smokes (i.e. more cigarettes per day, more years of smoking, etc.) the earlier that emphysema starts, the worse it becomes and the faster it becomes a impact in ones life. Approximately 20 to 25% of people who smoke will develop COPD, including emphysema. On the other hand, about 9 out of 10 people with emphysema have smoked at some point in their lives. 

Environmental risk factors and genetics

While smoking is the main cause of emphysema, environmental risk factors and genetics can play a part. People with deficiency in an enzyme called alpha-1-antitrypsin are very likely to develop emphysema if they smoke, although almost never develop emphysema if they do not smoke. Exposure to dust, fumes, gases, or environmental antigens may place people at increased risk for COPD. In fact, having asthma is a predisposing factor to later developing emphysema.

Is emphysema reversible? Is there a cure for emphysema?

Smoking cessation is the most effective treatment available for emphysema. 

Smoking cessation can stop the progression of emphysema in relatively young people with GOLD stage 1 or 2 disease. In older individuals and those with more severe disease GOLD stage 3 or 4, it is not clear whether smoking cessation can stop the progression of the emphysema. It may be that the disease is too far gone at this point for smoking cessation to be effective. That said, those who stop smoking at any point in the disease will likely enjoy fewer symptoms, thus every effort should be made to stop smoking.

The only cure for emphysema is to never smoke.

Even in people who have genetic defects that affect the lung, such as alpha-1-antitrypsin, are unlikely to get emphysema if they never smoke. Emphysema is progressive. Once someone begins smoking and emphysema takes hold, it continues to get worse throughout life. Early in the disease, those who can stop smoking can halt the progression, though the damage of emphysema has already been done to the lungs. In later stages, even those who stop smoking may not be able to hold the progression of the disease.

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