Medical Mystery: Short of breath, but why?

A 57-year-old man came to see me complaining of increasingly severe shortness of breath over the last year and a half. It was worse with exertion and got better with rest, although it never went away completely. He did get a bit short of breath when he tried to lie flat in bed. He had never smoked, he wasn't coughing, he had never had symptoms of asthma before.

He did have obstructive sleep apnea and was religiously using his CPAP - a machine that exerts slight airway pressure through a face mask to prevent throat obstructions that interrupt breathing at night. Measures from a sleep study had improved but he wasn't feeling any better.

He described a tightness rather than pain in his chest, and because his father had suffered from congestive heart failure, he was worried about his heart.

So was I. He took medications for high blood pressure and high cholesterol, so although he didn't have diabetes, he was still loaded with risk factors for heart disease.

His physical exam was basically normal. He was a big guy, so I couldn't feel much in his neck or abdomen. Lungs were clear, heart exam normal. No swelling in his legs. I did an EKG in the office: normal. I drew some blood work: cholesterol was pretty good, no diabetes, thyroid normal. I also had him blow into a peak flow meter to do a rough assessment of his lung function. It was slightly decreased, about 75 percent of predicted.

Coronary artery disease was definitely the diagnosis to rule out. When the arteries supplying the heart begin getting clogged with plaque, they can't carry the extra blood required for increased activity, like running up the stairs. Patients often present with trouble breathing on exertion, and the classic description of chest tightness. Then again, the decreased peak flow could indicate asthma.

I ordered a chest X-ray and a cardiac stress test, and offered him a trial of an asthma inhaler, which he accepted.

Then I saw his X-ray. Frantically, I grabbed for the phone.

"DO NOT do that stress test," I told him. "If you've already scheduled, cancel it! We need to do something different."

The X-ray showed an enormous mass in his chest.

The mediastinum is the area of the chest between the lungs. It contains the heart and the so-called great blood vessels, the trachea and main bronchial tubes, the esophagus, plus assorted lymph nodes and other soft tissues. My patient had an enormous mass in the front of his chest - so big it was impossible to tell from the X-ray where it had originated. It was pressing on his trachea, pushing it off to one side, nearly strangling him. That's why he couldn't breathe.

He had a CT scan, which showed the mass was his thyroid gland, hugely enlarged.

The thyroid is a butterfly-shaped gland at the base of the neck whose function is to produce thyroid hormone, which is responsible for numerous metabolic functions. Over- or underactive thyroid glands are common, and are typically managed easily with simple medications.

Thyroid enlargement is also common, known as a goiter. But it's usually confined to the base of the neck. The most common cause of goiter worldwide is deficiency of iodine, which the thyroid needs to produce the hormone. This causes it to enlarge as it struggles to keep up, sort of like an overworked, enlarged heart. But my patient's thyroid was functioning normally, at least according to his blood levels.

No one knows why, but apparently my patient's thyroid gland grew downward into his chest, expanding and pressing on his airway until we finally figured out what was happening.

He went downtown to a specialty care center, where they had to open his chest to get the whole gland out. Surprisingly - and gratifyingly - the pathology came back with no evidence of cancer anywhere within it. He made a complete recovery and is happily back to his usual life, having been liberated from his monstrous goiter.