What are the other Names for this Condition? (Also known as/Synonyms)

• Idiopathic Mediastinal Fibrosis
• IgG4-Related Mediastinitis
• Sclerosing Mediastinitis

What is Fibrosing Mediastinitis? (Definition/Background Information)

• Fibrosing Mediastinitis is a condition that affects the area between the lungs (mediastinum), which contains the heart, large blood vessels, windpipe (trachea), esophagus, and lymph nodes
• People with Fibrosing Mediastinitis have varying amounts of scar tissue in the mediastinum which may cause problems for the organs located there
• For example, some affected people may develop blocked airways that can interfere with lung function. Others may have compressed blood vessels, which can slow or prevent blood flow to and from the heart
• The exact cause of Fibrosing Mediastinitis is not fully understood, but it is not inherited. Many cases are linked to a specific type of fungal infection called histoplasmosis
• Treatment depends on which structures of the mediastinum are affected, the severity of the scarring and, in some cases, the cause of the condition

(Source: Fibrosing Mediastinitis; Genetic and Rare Diseases Information Center (GARD) of National Center for Advancing Translational Sciences (NCATS), USA.)

Who gets Fibrosing Mediastinitis? (Age and Sex Distribution)

• Fibrosing Mediastinitis is an extremely rare and late complication of histoplasmosis. Less than 1% of those who have the fungal infection develop Fibrosing Mediastinitis 
• The presentation of symptoms may occur at any age
• Both males and females may be affected
• Worldwide, individuals of all racial and ethnic groups may be affected

What are the Risk Factors for Fibrosing Mediastinitis? (Predisposing Factors)

• A bout of histoplasmosis is a major risk factor for Fibrosing Mediastinitis
• Living in histoplasmosis-endemic regions is a risk factor for this histoplasmosis-related complication as well
• Individuals, who have autoimmune diseases, may be at a higher risk for non-histoplasma related Fibrosing Mediastinitis

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one’s chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Fibrosing Mediastinitis? (Etiology)

• Most cases of Fibrosing Mediastinitis are caused as a late complication to histoplasmosis, due to an abnormal immune response of the body to the pathogen
  • Histoplasmosis is a fungal infection caused by Histoplasma capsulatum, which is present in bird and bat droppings in the soil
  • When the spores are inhaled, it may result in the development of histoplasmosis
• In some cases, the cause of Fibrosing Mediastinitis may not be known (10-20% of cases); or rarely, it may be associated with conditions such as autoimmune disorders, tuberculosis, Behcet’s disease, sarcoidosis, or even certain medications
• Genetic and environmental factors may play a role in the development of Fibrosing Mediastinitis, although it is not an inherited condition

What are the Signs and Symptoms of Fibrosing Mediastinitis?

The signs and symptoms of Fibrosing Mediastinitis depend on which structures of the mediastinum are affected (i.e. the heart, large blood vessels, windpipe, esophagus, and lymph nodes) and the severity of the scarring. Many symptoms of Fibrosing Mediastinitis arise when the esophagus, blood vessels and/or airways become blocked or compressed.

Signs of these problems may include:

• Cough
• Shortness of breath
• Recurrent lung infection
• Hemoptysis
• Pleuritic chest pain
• Difficulty swallowing
• Cor pulmonale

(Source: Fibrosing Mediastinitis; Genetic and Rare Diseases Information Center (GARD) of National Center for Advancing Translational Sciences (NCATS), USA.)

How is Fibrosing Mediastinitis Diagnosed?

Fibrosing Mediastinitis is diagnosed on the basis of the following information:

• Complete physical examination
• Thorough personal and family medical history evaluation, with emphasis on whether the affected individual lives in or travels to histoplasmosis-endemic regions
• Assessment of signs and symptoms
• Culture of body fluids, such as sputum, to identify the fungus
• Detection of histoplasma antigen in urine
• Blood test to measure antibodies in blood against the fungus
• Imaging studies, such as chest x-rays and CT scan of the chest
• Bronchoscopy: It is a surgical procedure in which the airways and lungs are examined with the help of a scope and simultaneously tissue is also taken for biopsy (examination under microscope by the pathologist)

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Fibrosing Mediastinitis?

The complications of Fibrosing Mediastinitis may include:

• Severe scarring in lung tissue leading to obstructive lung disease
• Development of blood clots in the lungs, which may be life-threatening

Complications may occur with or without treatment, and in some cases, due to treatment also.

How is Fibrosing Mediastinitis Treated?

There is no cure for Fibrosing Mediastinitis and the benefits of current treatments are unclear.

• In general, treatment options depend on which structures of the mediastinum are affected (i.e. the heart, large blood vessels, windpipe, esophagus, and lymph nodes), the severity of the scarring and, in some cases, the cause of the condition
  • Fibrosing Mediastinitis caused by histoplasmosis may be treated with antifungal medications 
  • Cases caused by autoimmune disorders may respond best to corticosteroids
• Other treatment options include surgery to remove scarred tissue and local therapies to treat specific problems (i.e. stents, laser therapy)

(Source: Fibrosing Mediastinitis; Genetic and Rare Diseases Information Center (GARD) of National Center for Advancing Translational Sciences (NCATS), USA.)

How can Fibrosing Mediastinitis be Prevented?

• Avoiding exposure to soils with high concentration of Histoplasma capsulatum spores may help minimize or prevent histoplasmosis, and resultant Fibrosing Mediastinitis 
• Seeking medical attention for signs and symptoms of the condition may help avoid life-threatening complications
• Regular medical screening at periodic intervals with tests and physical examinations are recommended

What is the Prognosis of Fibrosing Mediastinitis? (Outcomes/Resolutions)

• The prognosis of Fibrosing Mediastinitis is dependent upon the structures affected in the mediastinum, the severity of the signs and symptoms, extent of tissue scarring and associated complications, if any
• Individuals with mild conditions have better prognosis than those with severe symptoms and complications
• Typically, the prognosis may be assessed on a case-by-case basis

Additional and Relevant Useful Information for Fibrosing Mediastinitis:

• Fibrosing Mediastinitis is also known as Mediastinal Fibrosis

The following DoveMed website link is a useful resource for additional information:

http://www.dovemed.com/diseases-conditions/rare-disorders/