This young lady came for pre-employment medical check up. She gave no specific symptoms or significant past medical history. Her physical examination did not reveal anything significant either.
However, her chest x-ray showed prominent main pulmonary artery. Both right and left pulmonary arteries are large but taper rapidly. The peripheral pulmonaries are inconspicuous. The lungs are relatively oligaemic. These findings are consistent with Pulmonary Arterial Hypertension (PAH).
PAH can be due to many causes. It is most commonly due to chronic left to right shunt such as chronic left to right shunts such as in atrial septal defect (ASD), ventricular septal defect (VSD) and patent ductus arteriosus (PDA). It can also be due to pulmonary artery stenosis or chronic thrombosis in the pulmonary artery. There are also less common causes related to arteritis such as polyarteritis nodosa (PAN), systemic lupus erythematosus (SLE), Takayasu arteritis and Wegener granulomatosis causing an increase in pulmonary arterial pressure.
If there is no known cause, then it is called primary pulmonary hypertension. This is rare.
Patients may present with shortness of breath on exertion, syncope, easy fatigability, hyperventilation and chest pain.
However, be careful in the following situations when the pulmonary artery may appear large:
- It can be normal in young patients especially women
- It can be projectional due to rotation or lordotic view
- It can be due to rotation of the heart such as in pectus excavatum
Thus, good x-ray technique is important.