The word idiopathic means of unknown cause. The main symptoms start insidiously as shortness of breath on exertion and diminished stamina. Common symptoms include coughing, loss of appetite, weight loss, tiredness, weakness, and vague chest pains. Late in the disease as the level of oxygen in the blood decreases, the skin may take on a bluish tinge, and the ends of the fingers may become thick or club-shaped. Strain on the heart may cause heart failure.
Heart failure caused by underlying lung disease is called cor pulmonale.
A chest x-ray may indicate lung scarring and cyst formation. However, a chest x-ray occasionally can be normal, even when symptoms are severe. Analysis of blood gases shows a low level of oxygen in the blood. Many times, a larger specimen is needed and must be removed surgically. Desquamative interstitial pneumonia, a variant of idiopathic pulmonary fibrosis, has the same symptoms, but the microscopic appearance of the lung tissue is distinctive.