Does COPD Cause Pain?

Prevalence of Pain is More Common in COPD (41%) Than Healthy Subjects (29%)

Background: Pain and shortness of breath are both unpleasant experiences which affect an individual’s quality of life. In different studies, the frequency of pain ranges from 44% to 88% in those with COPD.

Study: Dr. Annemarie Lee and colleagues at the West Park Healthcare Centre in Toronto studied 64 patients with COPD referred to a pulmonary rehabilitation program and 64 healthy subjects of the same age. All answered questionnaires about pain over a one week period, including location, its frequency, and how long it lasts, as well as questionnaires about shortness of breath, quality of life, etc..

The study is published on-line in the Journal of the COPD Foundation [2017; 4(3): In press. doi: http://doi.org/10.15326/jcopdf.4.3.2016.0172]

Results: Age range was 48 to 91 years in the COPD group and 47 to 94 in the healthy group. Those with COPD had either severe or very severe COPD based on results of breathing tests. Pain frequency was 41% of those with COPD and 29% in healthy subjects.

anatomical locations for chest and upper back pain

Chest and upper back pain are more common in those with COPD

Pain was more common in the chest and upper back areas in those with COPD compared to healthy subjects. It was described as aching (30%), tiring (17%), and penetrating (17%). The location in the chest and upper back was associated with more air in the lungs (higher total lung capacity) as measured on breathing tests.

Those with painful experiences also had more shortness of breath with activities and higher depression scores.

Locations of the chest for pain

Rib cage

Conclusions: The authors proposed that hyperinflation of the lungs (too much air trapped in the lungs) could cause stretching of the chest wall and cause strain on ligaments between ribs as well as excessive forces on the joints.

My Comments: Unfortunately, the researchers did not evaluate the cause of pain experienced by the subjects. For example, could some of those with COPD have arthritis of the spine? 

It is important to remember that there are no pain sensors in the lung itself, but rather in the lining around the lung (called the pleura) and in areas of the muscles, joints, and ligaments in the chest wall. The treatment for too much air trapped in the lungs includes bronchodilators (inhalers that open up the breathing tubes allowing more air to exit), oxygen, and exercise training.

Obesity and Shortness of Breath in COPD

Benefit of Mild to Moderate Obesity in those with COPD

Dennis Jensen, Ph.D., Assistant Professor at McGill University, presented information on the benefit of obesity on shortness of breath in those with COPD at the CHEST Annual Meeting held October 24-28, 2015, in Montreal, Quebec, Canada.

Dennis Jensen, Ph.D., Assistant Professor at McGill University in Montreal

Dennis Jensen, Ph.D., Assistant Professor at McGill University in Montreal

First, Dr. Jensen reviewed how obesity is defined. The most widely used method is called the BMI (body mass index) which is the ratio of weight squared to height using the metric system. Studies show that 54% of the general adult population in the United States and Canada are considered obese based on a BMI of 30 or higher.

In general, studies show that obese individuals who have COPD are less active, are hospitalized more, and require more home care compared to those with COPD and are normal weight.

Paradoxes    

However, there are a few paradoxes when other outcomes are considered. For example, obese individuals with COPD:

  1. have a lower all cause mortality compared with those with COPD of normal weight
  2. can exercise to a higher level (intensity) on a stationary cycle compared with non-obese COPD individuals.
  3. report lower ratings of breathlessness (dyspnea) for the same level of breathing (ventilation) while exercising on the cycle than those with COPD of normal weight

Why? 

Extra weight on the chest limits the lungs from over-expanding (called hyperinflation) at rest and during exercise. Hyperinflation occurs in most individuals who have COPD and is a major cause of shortness of breath.

X-ray of the chest showing too much air in the lungs (hyperinflation) and the diaphragm muscle is pushed down.

X-ray of the chest showing too much air in the lungs (hyperinflation). This pushes the diaphragm muscle down and makes it less effective.

 

When the extra weight is around the chest (called central obesity- think of an apple and not a pear), not as much hyperinflation takes place with daily activities. This makes it a little easier to breathe.

My Comment

The information that Dr. Jensen presented led to an interesting discussion, particularly about what happens when someone who is overweight and has COPD loses weight. Is that good or bad for breathing? Dr. Jensen commented that there are no studies that have addressed this.

Dr. Denis O'Donnell, Professor of Medicine at Queen's University, in Kingston, Ontario, Canada

Dr. Denis O’Donnell, Professor of Medicine at Queen’s University, in Kingston, Ontario, Canada

Dr. Denis O’Donnell, another presenter at the session, commented that the benefit of obesity occurs in those with mild to moderate obesity (about 20-30 pounds of extra body weight). Extreme, or morbid, obesity causes more breathing difficulty along with other medical problems.

What Shortness of Breath feels like for Those with COPD

Work and Effort of Breathing  in COPD 

An on-line publication this week by Chang and colleagues in the journal Chest describes the experience of breathing difficulty as reported by those who have COPD.

The first author is Andrew Chang, a medical student at the Geisel School of Medicine at Dartmouth. He worked on this research study between his 1st and 2nd years of medical school with three Pulmonary doctors on the staff of Dartmouth-Hitchcock Medical Center. In the study, patients with different respiratory conditions answered “Yes” or “No” for each of 15 different statements that described  experiences of breathing discomfort. Then, each person was asked to select the “Best Three” that most closely matched how they felt when short of breath doing daily activities.

Here are the “Best Three” statements chosen by 68 individuals with COPD:

  1. I feel out of breath.
  2. My breathing requires effort.
  3. I cannot get enough air in.

Does your breathing difficulty match up with these statements?

These experiences are considered to be due to the work and effort required by the breathing muscles to breathe in (inspire). Because those with COPD have narrowed breathing tubes (airways), it is often difficult to get all of the air out when exhaling. As a result, air is trapped in the lung leading to hyperinflation of the lungs as shown in the figure.

On left: Normal size of lungs. On right: lungs are larger due to inability to exhale completely. This is called HYPERINFLATION.

On left: Normal size of lungs.
On right: lungs are larger due to inability to exhale completely. This is called HYPERINFLATION.

 

As a result of the hyperinflation of the lungs, the diaphragm (the main muscle of breathing) has to work harder when it contracts to breathe air in.  This added work and effort of the diaphragm is sensed by those who have COPD. This is the major reason why someone with COPD finds that it is hard to breathe or have shortness of breath.

Bronchodilator medications are the cornerstone for treatment of COPD because they open the breathing tubes (airways). This allows more air to be exhaled and thereby reduces hyperinflation – making it easier to breathe. Long-acting bronchodilators that last 12 – 24 hours provide more sustained benefit than the short-acting inhalers (typically last 4 hours).

Hopefully, this information will help you understand why taking your bronchodilator medications regularly is important for your breathing.