What Is Plastic Bronchitis?

Plastic bronchitis is a rare condition that children experience more often than adults, although it can occur at any age. The incidence of plastic bronchitis is unknown, but researchers state that it is an underreported condition.

When fluid collects in the lungs, it can lead to plastic bronchitis. If fluid leaks into the airways, it can form rubbery plugs called casts. The casts block the airways and make it difficult to breathe.

Plastic Bronchitis Symptoms

The casts that develop due to plastic bronchitis cause coughing and difficulty breathing. In some cases, you may have a severe bout of coughing and cough up the casts, which are white to tan in color and branch shaped.

Symptoms seen in plastic bronchitis include:

• Shortness of breath
• Coughing
• Coughing up bronchial casts: The casts may be large and look almost tree-like. Studies report they can be up to 30.5 centimeters (1 foot) long and branch into many long, thin offshoots. They can be dramatic to see and are very different from the type of casts sometimes seen in asthma, lung infection, or allergic bronchopulmonary aspergillosis.
• Respiratory distress: This may include having trouble breathing, working harder to breathe, and not getting enough oxygen to the blood.
• The requirement for supplementary oxygen

Causes

Although the formation of plastic bronchitis casts is still not well understood, lymphatic disease or congenital heart disease are among the most common causes.

Extra fluid and protein from body tissues create lymphatic fluid. It moves through the lymphatic system, which is a drainage network in the body. When your lymphatic fluid does not drain away from the lungs, it can become solid and form casts. This is what causes plastic bronchitis.

Conditions that can potentially lead to plastic bronchitis include: 

• Congenital heart disease (most often when treated with a Fontan procedure). In congenital heart disease, a heart defect or condition develops in the baby before birth. The Fontan procedure redirects blood flow from the lower body to the lungs to treat congenital heart disease. Plastic bronchitis may occur in 4% to 14% of Fontan patients.
• Lymphatic disorders are more often associated as a cause of plastic bronchitis in adults. 
• Certain lung conditions such as severe asthma, allergic bronchopulmonary aspergillosis, cystic fibrosis, or smoke inhalation have been known to cause plastic bronchitis.
• Sickle cell anemia, an inherited red blood cell disorder, is also associated with plastic bronchitis.

Diagnosis

Several tests can be used to help diagnose plastic bronchitis, including:

• Chest X-ray: A small dose of radiation produces pictures of the inside of the chest.
• Magnetic resonance imaging (MRI): An MRI is a type of scan that produces detailed images of organs and tissues in the body. A particular type of MRI called dynamic contrast magnetic resonance lymphangiography can help diagnose abnormalities of the lymphatic system.
• Bronchoscopy: In this procedure, a tiny camera is used to look inside the airways of the lungs.

Treatment

In order to treat plastic bronchitis, the doctors first need to find out the cause of the buildup of lymphatic fluid in the lungs. The treatment plan will depend on what is causing the fluid collection and the patient’s age and anatomy.

Treatment options include:

• Intranodal lymphangiography is used to map the lymphatic system using a catheter and an MRI, ultrasound, or X-ray. This may be done in preparation for an embolization procedure.
• Selective lymphatic duct embolization is a procedure used to seal abnormal ducts in the lymphatic system.
• Medication can also be prescribed to help dissolve the casts or reduce inflammation. Specifically, inhaled mucolytics that dissolve mucus and fibrinolytics that dissolve fibrin can be used to loosen casts.
• Supplementary oxygen may be required if oxygen levels are low due to airway blockage.
• Chest physiotherapy can be used to help break down, loosen, and remove the casts.

Patients with congenital heart disease may also require some additional heart procedures such as balloon dilation or stent dilation of a narrow blood vessel.

Prognosis

Plastic bronchitis is very rare but can be fatal. However, treatment options such as lymphangiography and lymphatic duct embolization are continuously developing and show very promising results.

Summary

Plastic bronchitis is a rare condition in which lymphatic fluid doesn’t drain from the lungs and creates casts that can block airways. It may be seen in infants treated for congenital heart disease with Fontan surgery or adults with lymphatic disorders or other conditions.

Significant symptoms include breathing problems and coughing up large, branching bronchial casts. The treatment of plastic bronchitis is challenging as no intervention has been proven effective in all groups of patients.

A Word From Verywell

Management of plastic bronchitis is still debated. Despite this, research and treatments continue to evolve and are improving all the time. If you or your child has been diagnosed with plastic bronchitis, work closely with your healthcare professional on a treatment plan.