Center for Interstitial Lung Disease

What is cryptogenic organizing pneumonia?

Cryptogenic organizing pneumonia (COP) is a rare form of interstitial lung disease.  The small airways (bronchioles) and tiny air sacs (alveoli) become inflamed. COP leads to breathing difficulties and a flu-like illness. It also can cause lung scarring. Cryptogenic organizing pneumonia was previously known bronchiolitis obliterans with organizing pneumonia (BOOP).

The condition is considered “cryptogenic” because the cause is unknown in most cases. COP is thought to come from injury to the alveoli.  

Cryptogenic organizing pneumonia vs. secondary organizing pneumonia

Cryptogenic organizing pneumonia has similar symptoms to secondary organizing pneumonia (SOP). Unlike COP, secondary organizing pneumonia has known causes, which include lung infections, complications to autoimmune disease and side effects of certain medications.  It is important for your doctor to rule out SOP, as cryptogenic organizing pneumonia and secondary organizing pneumonia are treated differently.

Signs and Symptoms

Cryptogenic organizing pneumonia frequently starts with flu-like symptoms. But it is not an infection. It can progress into a worsening cough with shortness of breath during exertion. If the disease remains untreated, patients may experience shortness of breath even at rest.

Common Symptoms of COP

• Persistent dry cough (often lasting 2-4 months)
• Shortness of breath
• Fever
• Chills and shaking
• Fatigue
• Loss of appetite
• Weight loss

In rare cases, COP symptoms may include:

• Chest pain
• Collapsed lung
• Coughing up blood
• Low blood oxygen level (hypoxemia)
• Joint pain

Risks

Men and women are equally at risk of developing cryptogenic organizing pneumonia. The average age at the time of diagnosis is between 50 to 60 years old. Inflammatory illnesses may increase COP risk, including:

• Inflammatory bowel disease (Crohn’s disease or ulcerative colitis)
• Lupus
• Multiple sclerosis
• Rheumatoid arthritis
• Scleroderma

Causes

Although the cause of cryptogenic organizing pneumonia is unknown, doctors believe possible causes include:

• Exposure to certain chemicals
• Exposure to birds
• Lung abscesses, lung cancer and lymphoma
• Post respiratory infections
• Side effect of organ transplantation
• Side effect of taking certain medications

Diagnosis

Cryptogenic organizing pneumonia is typically diagnosed by ruling out other diseases such as infectious pneumonia. Your doctor will review your medical history, ask about your symptoms and conduct a physical examination. COP can only be diagnosed after your pneumonia symptoms don’t improve with antibiotics and blood and sputum cultures are negative.

Conditions with similar signs and symptoms that need to be ruled out include:

• Bacterial, fungal or viral pneumonia
• Chronic eosinophilic pneumonia
• Hypersensitivity pneumonitis
• Primary pulmonary lymphoma
• Secondary organizing pneumonia (from autoimmune issues, infection or medications)

Your doctor may suggest tests to diagnose cryptogenic organizing pneumonia, including:

Breathing and Exercise Tests

Pulmonary function testing: This measures how much air you can inhale and exhale within a specific time frame. It may also look at how easily oxygen can get into your circulation. The test shows if your lungs are functioning normally or if there is an abnormality.

Pulse oximetry: This test measures your blood oxygen level.

Imaging Tests

Chest X-ray: These show a collapsed lung or fluid in the lung cavity.

High-Resolution Computed Tomography (HRCT) scan: HRCT scans are an accurate and noninvasive way to identify conditions in the lungs.

Lab Tests

Blood tests: Blood tests can rule out other conditions.

Sputum culture: This test examines thick mucus (sputum) coughed up from the lungs to detect bacteria that can cause infections.

Procedures

Bronchoscopy with bronchoalveolar lavage: A scope is inserted into the nose and down through the trachea to look inside the lungs and airways. A tissue sample may be taken for a biopsy.

Lung biopsy: A thoracoscopy or thoracotomy collects tissue from the lung for evaluation.

Thoracentesis and pleural fluid culture: Your provider will use a needle to drain extra fluid from around the lungs. The fluid is tested for infection.

Treatment

Most people with cryptogenic organizing pneumonia make a full recovery – about 50% of patients with mild cases of COP recover without any treatment. Early diagnosis is key so you can get monitoring and treatment. Without treatment, cryptogenic organizing pneumonia can cause serious lung damage and scarring.

Medications

Cryptogenic organizing pneumonia does not respond to antibiotics, so steroid treatment is required. Medication is usually taken over three to 12 months to reduce the likelihood of a recurrence.

Some symptoms may return if steroids are stopped or the dosage is lowered too quickly. Your doctor will continue to monitor you or perform follow-up testing after you finish treatment to ensure you stay healthy.

Alternative immune suppressing medications may be used to avoid side effects from long-term steroids.  

Clinical Trials

At this time, there are no clinical trials for cryptogenic organizing pneumonia.