Pulmonary fibrosis (idiopathic) - Diagnosing idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) can be hard to diagnose because its main symptoms are similar to those of other lung diseases and the exact cause is not known.

You will usually be referred to a chest (respiratory) specialist in hospital for diagnosis. They will work closely with radiologists (specialists in X-rays and scans) and specialist lung nurses to help identify the cause of your symptoms.

In most areas, specialist interstital lung disease (ILD) centres have been identified and will be responsible for prescribing any medication you need, such as pirfenidone.

Medical history and physical examination

Your doctor will ask about your medical history and whether there are other factors that could contribute to the diagnosis of IPF, such as whether you:

• are a smoker
• have been exposed to occupational contaminants
• have other medical conditions

They will physically examine you and check the sound of your breathing through a stethoscope. A crackling sound can suggest fibrosis.

They will also look for thickening of tissue at the base of your fingers and toenails (digital clubbing).

Breathing tests

Lung function tests (also called pulmonary function tests) assess how well your lungs work. These tests measure:

• how quickly you can move air in and out of your lungs
• how much air they can hold
• how well they transfer oxygen into, and remove carbon dioxide from, your blood

The tests require you to breathe in and out of a lung function machine. Information collected will help diagnose different lung diseases, measure their severity and check how well treatment for a particular lung disease is working.

Chest X-ray

Chest X-rays are a good way of looking for changes or abnormalities in your lungs to help diagnose particular conditions. Although major organs and blood vessels do not show up as clearly on X-rays as bones, they are still visible.

CT scan

Similar to an X-ray, a CT (computerised tomography) scan can provide a sharper and more detailed image of your lungs.

Your radiologist may be able to identify a honeycomb effect in the lungs. This honeycomb effect suggests lung scarring and damage to your air sacs.

Further tests

If the initial exam, tests and scans could not confirm the diagnosis, your consultant may suggest further tests, such as:

• a bronchoscopy
• a lung biopsy (removing a small piece of your lung)

Bronchoscopy

Bronchoscopy is a method of looking inside your airways. A narrow, flexible tube called a bronchoscope is introduced through your nose or throat and down into your airways. The tube has an eyepiece so the doctor can see inside.

The doctor then looks for anything abnormal and can take cell samples for testing. They can also take photographs of the inside of your airways if necessary.

You usually have the test under local anaesthetic. This means you are awake for the test but your throat is numbed. The procedure can be a bit uncomfortable but does not last long.

Lung biopsy

A biopsy of the lung can usually be obtained using a keyhole procedure. The modern technique is called video-assisted thoracoscopic surgery, or VATS.

VATS is performed under a general anaesthetic, so you are asleep throughout. A surgeon makes several small incisions (cuts) in your side and an endoscope (a thin tube with a camera and a light at the end) is inserted into the area between the lungs and the chest wall.

The surgeon is able to see the lung tissue through the endoscope and obtain a sample, which can be examined under a microscope for signs of fibrosis.