6 Causes of a Barrel Chest

Medical Causes of Abnormal Chest Expansion

closeup of a young caucasian doctor man sitting at his office desk observing a chest radiograph in a tablet computer

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A barrel chest is a generalized description of a rounded, bulging chest that is similar in shape to a barrel. The term is sometimes used to describe to men who have excessively large rib cages and the appearance of great upper body strength, such as weightlifters or bodybuilders. Even women or children may be considered barrel-chested if the circumference of their thorax, including the sternum (breastbone) and ribs, is as deep as it is wide.

While not technically a medical term, a "barrel chest" is often used by doctors to describe a physical characteristic consistent with a specific disease, disorder, or defect. One such example with emphysema, a later stage feature of chronic obstructive pulmonary disease (COPD) in which the chest may become fixed in an outward position.

There are also genetic, atmospheric, and aging-related causes for a barrel chest, many of which are not fully reversible. Here are 6 possible causes, both typical and unusual:

Emphysema

Emphysema is one of the two diseases that comprise COPD. It is typically accompanied by chronic bronchitis, an inflammatory condition characterized by the narrowing of the airways and the excessive production of mucus.

Emphysema specifically refers to the destruction of the air sacs of the lung, called alveoli. These are the tiny organs at the end of the air passages through which oxygen is transferred to the blood and carbon dioxide is extracted.

With fewer and fewer alveoli available to facilitate the exchange, the lungs have to work harder with deeper and longer inhalations. As the condition progresses, the lungs will tend to remain in a hyperinflated state, leaving the rib cage expanded.

Over time, the distention of the rib cage will not only affect the anterior (forward-facing) chest wall but the posterior (back-facing) wall as well. As muscle wasting develops in later stage disease, the loss of external support will further promote the deformity.

With emphysema, the depth-to-width proportion of the chest will typically increase from 1:2 (normal size) to 1:1 (barrel chest). Moreover, as the posterior bulging progresses, the spine will be pushed back as the shoulders roll forward, creating a stooped posture.

While the control of COPD symptoms may lessen the appearance of a barrel chest, it cannot erase it. As COPD is a progressive disease, any damage sustained by the lungs cannot be reversed.

Osteoarthritis

Osteoarthritis, also known as "wear-and-tear arthritis," is the most common form of the disease. While it typically affects the hands, neck, lower back, knees, and hips, it can also cause progressive damage to the middle back and thorax.

The condition, referred to as thoracic arthritis, is caused by the degeneration of the cartilage and bone of the middle spine. As the joint bones start to compress and rub against each other, the ensuing inflammation can trigger the overproduction of bone tissue and the gradual malformation of the spine.

As muscle loss further weakens the external support, the rib cage can develop a splayed, barrel-like appearance which can eventually become permanent as the joint bones fuse. Low calcium levels can further accelerate the problem, causing deformity of the sternum and a condition known as dorsal kyphosis in which the back becomes rounded and hunched.

While surgery may help restore spinal movement, any damage sustained by the rib cage or sternum will be difficult to reverse.

Cystic Fibrosis

Cystic fibrosis can often cause a barrel chest in children and younger adults affected by the disease. The inheritable genetic disorder triggers the overproduction of mucus, clogging the alveoli and restricting the amount of air entering the lungs.

Over time, the exertion needed to fill the lungs can cause air to become trapped, leaving the chest in a partially inflated position. As a chronic, irreversible condition, cystic fibrosis requires constant surveillance to help clear the lungs and prevent hyperinflation.

Cystic fibrosis also affects lung development, due in part to the recurrent bouts of bacterial infection. As lung capacity decreases, the development of barrel chest is enhanced. This is especially true in adults with cystic fibrosis who have an average lifespan of around 37 years.

Severe Asthma

Severe asthma is a common cause of barrel chest in children. As opposed to cystic fibrosis in which the air passages become clogged, asthma causes the passages to constrict and narrow.

When asthma symptoms are severe, the passages are in a persistently narrowed state (in some cases, even after bronchodilators are used). As the air in the lungs becomes trapped and unable to escape, the child's chest can take on a barrel-like appearance (in part, because the cartilage of the rib cage is still so flexible).

Barrel chest in children with asthma will generally reverse once the symptoms are brought under control. The greater concern is, that if left untreated, severe asthma may lead to impaired growth.

Genetic Disorders

While some people are born with larger rib cages, there are rare genetic disorders for which barrel chests are characteristic.

One such example is Dyggve-Melchior-Clause (DMC) syndrome, a rare, progressive condition characterized by short stature, skeletal deformity, and microcephaly (an abnormally small head). So rare is DMC syndrome that only around 100 cases have been reported.

Sialidosis, also known as mucolipidosis type 2, is another rare disorder characterized by the abnormal accumulation of toxic substances in the body. Symptoms usually develop during infancy or later childhood and may include short stature, barrel chest, mild cognitive impairment, and cherry-red spots in the eyes,

Spondyloepiphyseal dysplasia tarda is a rare, hereditary disorder that only affects males. Symptoms tend to appear between the age of 6 and 10 and include short stature, spinal deformity, barrel chest, and premature osteoarthritis.

Any skeletal malformations resulting from these disorders are considered permanent.

Extreme Altitudes

Because the air is thinner in extremely high altitudes, the lungs have to work harder to maintain the exchange of oxygen and carbon dioxide. As such, people who live in areas higher than 16,500 feet (5,000 meters) will almost invariably have evidence of a barrel chest.

While there are only a handful of formal communities that meet this criterion—among them, La Rinconada in Peru (16,830 feet) and Tuiwa in Tibet (16,630 feet)—there are informal settlements that are situated ever higher.

While visiting high altitudes will not cause barrel chest, the thorax may appear larger as you expand the chest to take in deeper breaths.

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