Brisket Disease

Shortly after moving to the scenic mountain forests of western Arizona, near the border with New Mexico, a friend of mine, a middle-aged woman in previous good health, began to experience progressively worsening shortness of breath with exertion. She had been vigorously active helping her partner tend acreage, and she was unable to keep up this effort.  The altitude of this land is over 7,000 feet above sea level.

She was evaluated by her family physician:  a thorough physical exam, a chest x-ray, and ECG and screening laboratory tests were normal.  He found no cause for her dyspnea.

Her symptoms worsened, and she was referred for pulmonary function tests that were interpreted as normal.  The arterial blood gases were normal for the altitude.

She saw a cardiologist who performed an echocardiogram.  The valves were normal; the ejection fraction was greater than 60%.  There was mild pulmonary hypertension.  She was considered to have become a victim of her own imagination.

I talked to her partner, and I reviewed her medical records, and I suggested that she might have high-altitude pulmonary hypertension, and I recommended that they should try living at a lower altitude.  This idea was resisted until winter when they vacationed in Florida:  after a few days at sea level her dyspnea greatly diminished and then disappeared; it returned when they returned to the mountains.

Her pulmonary artery pressures were never measured, but based on her medical history, I felt, more likely than not, that she had high altitude induced pulmonary hypertension.

It turns out that some humans are more susceptible to hypoxic pulmonary hypertension than is the general population; perhaps she was one of these individuals.

Susceptibility to constriction of the pulmonary arteries when exposed to reduced levels of oxygen is modeled by a dramatically instructive animal condition known as Brisket Disease of Cattle. 

Cattle ranchers with herds in the Rocky Mountains are well acquainted with Brisket Disease of Cattle. As their herds are moved from lower winter pastures that are less than five thousand feet to the high altitude pastures above 7,000 feet in the spring and summer. There, some of the herd, as many as twenty per-cent, develop high altitude pulmonary hypertension and as a consequence failure of the right side of the heart. 

In cattle the congested state caused by right heart failure does not cause swelling of the ankles and legs, known in humans by the archaic term dropsy, instead the fluid gravitates to their most dependent part, the brisket.

Beefeaters recognize the brisket as that cut of meet from the chest muscles, the pectoralis major and minor.  The brisket is the preferred cut for barbecued beef and is used as well for corned-beef and pastrami.  

          

Above, The Bovine Brisket

Below, a Bovine with Brisket Disease

                             

Colorado ranchers take brisket disease seriously because of its grave economic consequences, and in the spring a veterinarian goes up to the high altitude pastures with the herd.   The vet then does a right heart catheterization on each of the bovines, and if the pulmonary artery pressure is at all elevated, these animals are returned to lowland pastures and feed.

Well, my friend never developed overt right heart failure with dropsy, and she was never interested in getting a right-heart catheterization, but the ameliorization of her dyspnea when she lived at sea level, convinced her to avoid the mountains, and they moved to Iowa altitude 1,503 feet above the sea level. 

Recently, while on vacation from their new home they returned to visit old friends in the mountains.  In a few days her dyspnea returned, and they promptly returned to Iowa.  Her dyspnea again disappeared.