A 45-year-old man presented with a complaint of an increasingly persistent cough that produced moderately thick, white mucus. The patient stated that the cough had been present for several years and was particularly severe in the morning upon awakening. His wife was more bothered by the cough than he was and had sent him to the physician so that he might be convinced to stop smoking.
On questioning, the patient, who was about 30 lb overweight and had been smoking two packs of cigarettes per day for 20 years, had no other ailments. The physician recommended that he stop smoking, and the patient was lost to follow-up.
Ten years later, the patient reappeared in obvious distress, coughing with wheezing sounds in his chest and complaining of "tightness" in his chest. The condition had arisen after the patient developed an upper respiratory tract infection. He complained that the wheezing and tight feeling in his chest had occurred on other occasions over the past few years, but that he was currently suffering more than usual. Pulmonary function tests showed some decrease in FEV1. The patient was treated with bronchodilators and antibiotics, and responded satisfactorily.
Over the next several years, the patient's wife began bringing the patient for his visits. She noted that he had increasing somnolence and some personality changes, and he complained of morning headaches.
Laboratory tests repeatedly showed:
- Elevated red blood cell counts but normal white cell counts
- Low blood oxygen, elevated CO2, and marked cyanosis
Pulmonary function tests revealed:
- Increased total lung capacity
- A marked decrease in FEV1
- A decreased diffusing capacity (also called transfer factor) relative to an evaluation 14 years earlier -- diffusing capacity is one measure of the ability of the lung to transport gas into and out of the blood.
The patient also had distended neck veins and an enlarged, tender liver. A chest x-ray revealed hyperlucent lung fields and a depressed diaphragm, pulmonary hypertension as demonstrated by enlarged pulmonary arteries, right ventricular dilation and hypertrophy, and increased vascular markings at the hilum.
The patient was finally admitted to the hospital markedly cyanotic with distended neck veins and an enlarged, tender liver. After a progressively downhill course, the patient died.
Questions to answer:
1. What is the primary disease that this patient suffered from?
2. What is the most likely etiology of the disease presented by this patient, if known?
3. What is the most likely underlying mechanism that gives rise to this disease?
4. What are the key abnormal functions and/or morphologies that are presented by this patient?