I see some odd things in my clinic. One recent diagnostic dilemma was a man in his late fifties with shortness of breath.

He had been born with a ventricular septal defect and had undergone surgery for this in his infancy. During his lifetime, he had seldom gone to doctors and always thought he was in fairly good health, maybe just of a weak constitution. A smoker since age 13, he had a morning cough and got a little winded running up and down the basement stairs or shoveling snow in the winter.

A while ago he came to see me because he felt he was getting more short of breath over the winter. On exam, his vital signs were normal, and his oxygen saturation was 97 percent. He had a systolic heart murmur, and his breath sounds were diminished in his entire left lung. I didn’t see any swelling of his legs and his neck veins were not distended when he laid down flat on my exam table. His EKG was normal.

I ordered a chest x-ray and some basic blood work. His x-ray report said his left lung looked normal, but his mediastinum was shifted a little to the left. His heart was not enlarged. Routine labs were normal.

The day he came in to follow up on his testing he looked ashen. He had suddenly become much more short of breath the day before, just brushing snow off his car. He had had some vague chest pressure that lasted ten or fifteen minutes.

His physical exam and repeat EKG were essentially unchanged; perhaps he had even weaker breath sounds in his left lung. This time his oxygen saturation was only 90 percent.

I ordered a chest CT with contrast for later the same day and also put in for a chemical stress test and an echocardiogram.

A few hours later, one of the radiologists called me. The man’s IV had infiltrated, and most of the contrast ended up in the subcutaneous tissues of his right arm. His pulmonary embolism protocol CT scan would have to be postponed.

“OK, have him stop by the office on his way home,” I said.

I gave him samples of one of the new anticoagulant medications that just got approved for the initial treatment of blood clots in the lung and gave him a lot of detailed instructions.

Over the next two weeks, I received a normal stress test and an echocardiogram report that said something about decreased flow across the pulmonic valve. I wasn’t sure what to make of that in the context of my working diagnosis of one or multiple pulmonary emboli, and called radiology to please get the chest CT rescheduled.

Finally, this Monday, he had his CT scan done. The chief if radiology called me immediately after the study.

“Your Mr. Faulkner, he doesn’t have a PE, but he has agenesis of his left pulmonary artery.”

I sat back in my chair. I’d never heard of this condition. All his life, I thought, his underdeveloped left lung has been without functioning blood supply, and that’s why his mediastinum was shifted to the left and his breath sounds were so diminished. Finally, all this caught up with him, and he ended up in my clinic one day.

I did an Internet search for pulmonary artery agenesis. It is extremely rare, and usually diagnosed earlier in life. Some cases are diagnosed after an incidental abnormal routine chest x-ray. Symptoms are shortness of breath and productive cough or recurrent respiratory infections, all common concerns among middle-aged smokers in this part of the country during the winter months.

I saw him back to explain what I had found, stopped his blood thinner and told him I wanted him to see a cardiologist at Cityside Hospital. He wasn’t so sure he wanted to travel that far, but said he’d think about it.

As a rural frontline primary care doc, you just never know what’s going to walk through your door.

“A Country Doctor” is a family physician who blogs at A Country Doctor Writes:.