The estimated frequency of idiopathic pulmonary fibrosis diagnosis is 13-20 individuals in every 100,000, with about 100,000 total people diagnosed with this rare disease in the U.S. The more common form of IPF diagnosed is sporadic, meaning that no other members of the family have this rare disease. There are some cases where multiple family members are diagnosed, following an autosomal dominant pattern of inheritance but with an unknown genetic cause. 

The underlying cause of IPF is unknown, which is why the condition is 'idiopathic’. Scientists believe that it is a combination of genetic and environmental factors (http://rarediseases.org/rare-diseases/idiopathic-pulmonary-fibrosis/). The damage that causes the severe symptoms takes place in the delicate epithelial cells that line the alveoli of the lungs. These are the millions of tiny, thin-walled air sacs found in the lungs, where exchange of oxygen and carbon dioxide occur between the respiratory and circulatory systems (http://rarediseases.org/rare-diseases/idiopathic-pulmonary-fibrosis/). A likely explanation is that the body attempts to repair damaged epithelial cells as a part of normal wound healing. However this process occurs abnormally, leading to progressive scarring and damage to the alveoli and surrounding lung tissue. The root cause of the disease is not known, but it is understood that genetic changes will increase a person's risk of developing IPF. Then, exposure to certain environmental factors acts as a “trigger” to cause the symptoms (http://ghr.nlm.nih.gov/condition/idiopathic-pulmonary-fibrosis). TERC and TERT are two mutated genes which have been found in about 15 percent of all IPF cases. Pulmonary fibrosis can also occur as a small part of another genetic disorder such as Hermansky-Pudlack syndrome. This disease is characterized by albinism, vision abnormalities and platelet dysfunction leading to prolonged bleeding (http://rarediseases.org/rare-diseases/idiopathic-pulmonary-fibrosis/).

The early stages of IPF can present no symptoms at all (asymptomatic). The initial, characteristic symptom is shortness of breath during exertion such as exercise (http://rarediseases.org/rare-diseases/idiopathic-pulmonary-fibrosis/). Patients may also develop a dry, hacking cough that produces little to no sputum (phlegm, saliva etc.) (http://ghr.nlm.nih.gov/condition/idiopathic-pulmonary-fibrosis). Some additional symptoms include a loss of appetite leading to weight loss, and clubbing of the fingers and toes due to a lack of oxygen supply. If the disease continues to progress, severe symptoms such as respiratory failure, collapsed lungs (pneumothorax), and heart disease can occur (http://rarediseases.org/rare-diseases/idiopathic-pulmonary-fibrosis/). Patients suffering from IPF are also at a higher risk of developing lung cancer.

The diagnosis of IPF can be done initially through identification of characteristic symptoms. These include blue extremeties such as the hands and feet due to lack of oxygen in the blood, clubbing or swelling of the fingers and toes, and a high-pitched crackling sound when examining the lungs. This diagnosis will also depend on risk factors such as smoking and family history of this rare disease to rule out other potential disease causes of these symptoms. 

Diagnosis of idiopathic pulmonary fibrosis can be confirmed by specialized tests including traditional chest x-rays (radiography), computer tomography (CT) scans, pulmonary function tests, blood tests, and the surgical removal and microscopic examination of lung tissue (lung biopsy). The X-ray is the most common way of examining lung tissue for any damage. However, a special type of CT scanning known as high resolution computed tomography (HRCT) is often used for diagnosis because it produces detailed cross-sectional images of lung tissue structures. A doctor can also conduct pulmonary function tests, which measure how well the lungs exchange oxygen and how efficiently oxygen is transferred to and from the blood. Finally, if a conclusive diagnosis cannot be made through the previously mentioned tests, a lung biopsy can be implemented. In this procedure, samples of lung tissue from several places within the lungs for inspection.

The main goal of IPF treatment is to prevent more lung scarring, relieve symptoms, maintain the ability to be active, and improve the quality of life for the patient (https://rarediseases.info.nih.gov/gard/8609/idiopathic-pulmonary-fibrosis/resources/8). Recently in 2014, the Food and Drug Administration (FDA) approved two drugs for the treatment of the disease. The first, Ofev (nintedanib), is a kinase inhibitor that blocks multiple pathways that may be the cause of the scarring of lung tissue (http://rarediseases.org/rare-diseases/idiopathic-pulmonary-fibrosis/). Esbriet (pirfenidone), another drug, also operates in a similar manner. Many IPF patients will undergo oxygen therapy at some point to increase oxygen levels in the bloodstream. In this treatment, supplemental oxygen is provided to the patient to compensate for the damaged lungs, and will reduce breathlessness and allow individuals to participate in physical activity (https://rarediseases.info.nih.gov/gard/8609/idiopathic-pulmonary-fibrosis/resources/8). If the patient does not respond well to other available treatments, a lung transplant may be required, provided that the patient is does not have any other medical conditions.

Unfortunately, the prognosis for most IPF patients is quite poor, since only 20-30% of affected people survive at least 5 years after diagnosis. Although the disease is variable in different patients, there are three main courses that could occur. IPF can be a slow progressive disease (the most common), a disease marked by episodes of acute exacerbations, or a rapidly progressive disease. The main factors that inhibit long-term survival include older age at diagnosis, extensive cigarette smoking, lower body mass index (BMI), more severe physiologic impairment, and the possible development of other complications (eg, pulmonary hypertension, emphysema, and bronchogenic cancer) (https://rarediseases.info.nih.gov/gard/8609/idiopathic-pulmonary-fibrosis/resources/15).

1. http://rarediseases.org/rare-diseases/idiopathic-pulmonary-fibrosis/

2. http://ghr.nlm.nih.gov/condition/idiopathic-pulmonary-fibrosis

3. https://www.nhlbi.nih.gov/health/idiopathic-pulmonary-fibrosis