Interview with Dr. James Loyd
Rudy W. Jacobson Professor of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee. July, 2003.
Questions posed and edited by Candace McIntosh and Lucille Enix
Is there any estimate of the number of people with fibrosing mediastinitis?
To my knowledge there is no reliable report of an estimate of the number of patients with fibrosing mediastinitis.
Is there a national or international database of people diagnosed with the disease?
I do not know of any database for patients with fibrosing mediastinitis at present, but I hope that a collaborative website might lead to the development of such important information.
Is all fibrosing mediastinitis histoplasmosis-related or is there such a thing as idiopathic FM?
In my opinion, there appear to be at least two forms of fibrosing mediastinitis. The most common form is a late complication of infection with Histoplasmosis and probably accounts for 80-90% of patients, and is calcified and often focally invasive. Another form is characterized by diffuse and proliferative fibrotic material in the mediastinum which is not calcified.
Is all FM essentially the same or is there such a thing as proliferative FM?
The terms idiopathic or proliferative forms of fibrosing mediastinitis are different terms for the same disorder, as opposed to Histoplasmosis-related FM. The Histoplasmosis-related form is usually localized at specific sites where lymph nodes are known to be located, along with dense calcification (deposition of calcium) seen on CT scans, and is associated with obstruction of a major pulmonary artery, vein, or airway.
The proliferative or idiopathic form of fibrosing mediastinitis appears different because it may be more widespread, usually occurs along the trachea (windpipe), and does not have calcifications. This form is rare and I know of only about a dozen patients with this form who have been reported in the medical literature. Sometimes this form even extends upwards out of the thoracic cavity, where it can be felt in the anterior neck. This form appears to have a different cause because it may be associated with fibrosing disorders in other locations, such as thyroid involvement, known as Reidel's thyroiditis, or with a different disease called retroperitoneal fibrosis, where there is scarring behind the kidneys in the retroperitoneal space, which can block the ureters (tubes from the kidneys to the bladder).
Do the treatments differ?
There are no medicines which have been shown to improve the outcome for patients who have the Histoplasmosis-related form of fibrosing mediastinitis. Some individual patients improved after mechanical approaches, such as opening a vessel with a stent or with a surgical procedure. Such approaches seem most appropriate to consider when the process affects both lungs, which carries the highest risk.
For the proliferative or idiopathic form of fibrosing mediastinitis, some reports of individual patients suggest that treatment with corticosteroids (prednisone) or Tamoxifen or both may be associated with improvement in symptoms.
How many FM patients have you treated in your career?
I have treated approximately 60 patients with FM during the last decade.
What is the survival rate for your patients?
The overall survival rate for patients with fibrosing mediastinitis is not known. It is clear that fibrosing mediastinits can be life-threatening, especially when important structures of both lungs are affected, and I know several patients who died of fibrosing mediastinitis affecting both lungs in the 1980's before current technology.
In the past, we believed that involvement of even just one lung was often life-threatening, but my experience during the past decade suggests that most patients in whom only one lung is affected usually have reasonably good long term survival.
In general, patients who have fibrosing mediastinitis which affects only the superior vena cava but not the lungs, usually have good long term survival, but they may have swelling of the arms and neck that can be very disabling.
How many patients are you currently following?
I currently follow about forty patients with fibrosing mediastinitis.
What are the symptoms of FM?
The most common symptoms of fibrosing mediastinitis are cough, breathlessness, chest pain and hemoptysis (coughing blood). They occur in any combination.
How is FM diagnosed?
Diagnosing fibrosing mediastinitis is best accomplished by chest CT scan which shows the abnormal tissue in the mediastinum (the space between the lungs). A ventilation/perfusion nuclear medicine scan is the best test to show the location of any abnormality in the distribution of airflow or blood flow to each lung. Sometimes surgical biopsy of the abnormal tissue in the mediastinum is needed to exclude malignancy, especially if the CT scan shows that the tissue does not have dense calcification which is typical for the form which occurs after Histoplasmosis.
Are surgical biopsy procedures safe for FM sufferers?
There is some risk to any biopsy, but in general it is safe to perform biopsy in most FM patients. Biopsy may be necessary in some patients to prove that the process is not some other serious disease, such as lymphoma, especially when the abnormal tissue in the mediastinum does not demonstrate significant calcification.
Have you seen complications of FM from diagnostic surgical procedures?
Yes, I have seen patients who had complications occur with diagnostic surgical procedures, so biopsies should be recommended only when the expected benefit is greater than the possible risk.
Aside from diagnostic procedures, at what point would you attempt surgery on a patient with FM?
Surgical procedures with a goal of treatment, rather than just for diagnosis, are appropriate only rarely in patients with fibrosing mediastinitis. Invasive catherization with vascular stenting by an experienced interventionalist is usually a preferred procedure for obstructed vessels, such as the superior vena cava, pulmonary artery or pulmonary veins. Pediatric interventional cardiologists generally have the most expertise in the evaluation of obstruction of pulmonary veins, which is an important component in many FM patients.
For patients who have serious hemoptysis (coughing of blood), which recurs after bronchial artery embolization, surgery may be life saving in some patients. Very rarely, surgical reconstruction of serious airway obstruction may be life-saving, but should only be done by thoracic surgeons who are very experienced with fibrosing mediastinitis.
If the fibrosis is attacking or impairing a specific structure in the mediastinum, such as a bronchial tube, might it be possible to operate to remove just enough of the mass to avoid or postpone damage to the structure? What are the risks?
In general, surgery for relieving obstruction of airways is associated with high risk because the invasive nature of the scar does not allow easy surgical separation of normal anatomic structures, so that a major complication could include hemorrhage. Surgical approaches for reconstructive procedures in mediastinal fibrosis patients should be carefully considered, and only performed by surgeons who have extensive experience operating on patients with FM.
Can you anticipate when performing surgery on an FM patient whether all of the organs in the mediastinum will be bonded together or to other structures or the chest wall so that you can take action to avoid major bleeding or damage to any of the structures?
The specific location of the bonding may differ between patients, but such complications should be expected in every patient with FM. In general, surgery should be reserved only for patients for whom there is a specific treatment goal because the risk can be very high.
Is FM always progressive or does it sometimes stabilize and stop growing?
The answer to this question is unknown, but my experience during the last decade suggests that for many patients the fibrosis has completed its growth by the time the patient develops symptoms. For the majority of patients who had the form which occurs after Histoplasmosis, we have not detected further growth of the fibrosis. In the other form, the diffuse proliferative mediastinal fibrosis, there is too little information to know about the rate of growth of new fibrosis, but I am more concerned about this possibility for these patients because I have seen at least one patient in whom it grew back very quickly (a few months) after most of the fibrosis was removed surgically.
Is FM aggravated by conditions such as stress, physical activity, obesity, or any other known factors?
The symptoms of FM can be aggravated by stress, physical activity or obesity but generally the disease process itself seems to be independent of such factors. It is important to follow good general health measures, and especially to not use tobacco products. It is helpful for patients to control weight and be as active as their disease will allow, but these factors do not affect the fibrosis itself.
Can exercise help alleviate symptoms of FM? Is any degree of exercise harmful to the patient?
Exercise is recommended for most patients with cardiac or respiratory disease, including FM, and it should be done routinely. However, it does not have any effect on the underlying fibrotic process and generally does not relieve all the symptoms. It will avoid development of associated problems, such as becoming deconditioned, which can cause additional breathlessness. Extreme exercise could be harmful to any individual, so any patient should stop if they develop chest pain, dizziness, nausea, or excessive shortness of breath while exercising.
Is there any diet that appears to benefit the FM patient or any that does harm?
There are no special dietary recommendations known to help patients with FM. Controlling weight is important for everyone, but especially for patients with any cardiorespiratory disease.
Does FM mainly affect quality of life or is it a marked factor in longevity?
It appears that FM affects mostly the quality of life when it affects only one lung, and many such patients may have good long term survivals. For patients in whom FM affects structures of both lungs, it has a greater chance to impair longevity, so it is in these patients that intervention to preserve lung function by vascular stents or by surgery seem to be most appropriate.
Do FM patients die of FM or does it make them vulnerable to other potentially fatal conditions?
Most of the patients with FM whom I have seen do not have other serious conditions. Hemoptysis (coughing blood) is a potentially serious condition caused by the FM, but current interventions are usually successful to control it.
If you suspect a new patient has FM, what protocol do you follow for diagnosis?
The tests that are the most helpful to diagnose FM are chest x-ray, ventilation/perfusion scan, and chest CT scan. Sometimes bronchoscopy and surgical biopsy, often done by a technique known as mediastinoscopy, are needed to confirm the diagnosis.
When an early diagnosis of FM has been made, are there any steps that can be taken before mediastinal structures are threatened to limit the damage by the disease?
Early in the course there are usually no symptoms to alert patients to the presence of a problem. So the opportunity to treat patients in an early stage would be rare, and treatment with medicines is not proven for the most common form of FM, which is that seen late after Histoplasmosis.
Have you had success in treating or arresting FM with drugs? If so, which ones? Are there undesirable side effects?
As best known at present, the form of FM related to Histoplasmosis cannot be affected by drug treatments. In patients who have the diffuse proliferative, idiopathic form of FM, there are a few reports of improvement with prednisone or Tamoxifen or both. I have treated a few patients with the diffuse proliferative form who had partial responses, but there are many undesirable side effects from prednisone and Tamoxifen which must also be considered.
Would Viagra help dilate any of the affected arteries and veins in the mediastinum?
Therapy with phosphodiesterase inhibitors such as sildenafil (Viagra) is being tried in primary pulmonary hypertension and other similar diseases which obstruct the very small arteries in the lungs, and the early results appear hopeful in those diseases. The disease process in FM is very different, and there is no evidence that any of the medicines used to treat other forms of pulmonary hypertension have any influence on the obstruction of the large vessels that occurs with FM.
Should a young person who has been diagnosed with histoplasmosis be placed on prednisone therapy indefinitely?
There is no evidence that prednisone therapy can prevent or reverse FM of the form related to Histoplasmosis. Prednisone has many side effects, many of which can be disabling or even dangerous. The risk of long-term prednisone therapy would probably be far greater than the chance that it might prevent FM in patients after Histoplasmosis. Even if one assumed that it could work, it would require treatment of several thousand patients to prevent FM in just one patient. In the other form, diffuse proliferative FM, prednisone appears to help some patients.
Might it be desirable for an FM patient on prednisone therapy to increase the dose any time that symptoms worsen?
Prednisone or Tamoxifen or both may be helpful in the diffuse proliferative form of FM, but the side effects can be serious, and they are related to both the dose and duration of therapy. The general strategy for using prednisone is to use the lowest effective dose. The best dose for each individual patient varies over time and between different patients, so the dose and alterations must be individualized.
Are the potential side effects of prednisone a risk worth taking if a maintenance dose appears to minimize symptoms of FM?
Prednisone or Tamoxifen or both may be helpful in the diffuse proliferative form of FM, but the side effects can be serious, and depend on both the dose and duration of therapy. The general strategy for using prednisone is to use the lowest dose that is effective. The best dose for each individual patient varies over time and between different patients, so the dose and alterations must be individualized.
Is it possible for the fibrosis to shrink on its own and are there documented cases of this?
I have not seen spontaneous resolution of mediastinal fibrosis in any patient, and I do not know of any such reports.
Is there any point in general testing for histoplasmosis in endemic areas?
In general, in endemic areas such as the Mississippi river valley, most individuals have frequent and recurrent infection with Histoplasmosis, and usually are not even aware of it. Infection with Histoplasmosis for most individuals is a minor and transient illness, much like a routine viral respiratory infection. It is rare (about 1 in 100,000 of those infected) for an individual to develop the progressive mediastinal scarring that characterizes FM, and testing for Histoplasmosis would not identify these individuals.
Is there any way to identify who will be affected by FM in advance?
To my knowledge there is no method to identify patients who will be affected. There does appear to be an individual predisposition for FM patients to respond with excessive fibrosis, so perhaps in the future such a method might be discovered.
Should a newly-diagnosed patient be treated with anti-fungals?
Antifungal therapy is proven for some other forms of Histoplasmosis such as disseminated Histoplasmosis, or chronic pulmonary Histoplasmosis, but there is no good evidence that it improves outcome in patients with FM as a late complication of Histoplasmosis. However, current antifungal treatments are effective when given by mouth, and are generally safe, so many patients and doctors choose to try them to see if they help.
Is anyone working to develop a marker for FM?
I do not know of any active research to develop a marker for FM.
Is there any correlation of incidence of FM and blood type?
To my knowledge, there is no correlation of incidence of FM with ABO blood types. FM occurs in patients of either gender, in any race, in any blood type.
Does invasion of the mediastinum ('disturbing the mass') cause the disease to flare up and/or proliferate? If so, what can be done to halt the progression?
In my experience with the form of FM related to Histoplasmosis there is no evidence that surgical intervention to diagnose a mediastinal process causes any exacerbation or increased activity of the proliferation process. Symptoms may be worse after surgery related to side effects from the surgery.
In patients with the diffuse, fibrosing, idiopathic form of FM, I do know one patient in whom most of the tissue was resected, but it recurred quickly in a few months. In patients with this form, if surgical resection is considered, subsequent therapy to prevent rapid re-growth of the fibrosis, such as with Tamoxifen or prednisone, would be a reasonable consideration.
Does steroidal therapy control the actual proliferative process or is it used only to relieve symptoms of the disease?
Corticosteroid therapy such as prednisone does seem to influence both the actual proliferation and the symptoms, but only for patients who have the rare diffuse, proliferative form. The response appears to vary among patients.
Is there a database of mortality rates for both histo-related deaths and FM deaths?
There is no database with mortality rates for either, to my knowledge.
Has any attempt been made to use a laser to destroy or arrest or de-bulk the fibrosis?
Lasers are used during bronchoscopy in some cases to remove tissue from inside the airways. New tissue may grow back quickly inside the airways that have been opened by either laser or stents. This happens as a reaction in many other conditions as well as FM, so disease of the airways may be among the most difficult manifestations to treat successfully.
Someone on the web reported having radiation treatment to shrink the fibrotic mass. Is this a possibility for most patients?
I have not found any medical reports of radiation therapy for FM. Radiation therapy is generally used only for cancers or malignancies. I have no knowledge of this treatment being used for mediastinal fibrosis, so it could be very valuable to encourage a publication of this unusual treatment in the medical literature.
Do patients suffer complications such as gastric reflux as a result of the cough, interference with the esophagus, or other effects of the FM?
Fibrosing mediastinitis or other forms of Histoplasmosis can interfere with the esophagus and cause difficulties with swallowing. Occasionally procedures, such as esophageal dilatation or even surgical procedures, are necessary to relieve esophageal obstruction. Gastro-esophageal reflux is a common problem in the general population, but is probably not directly related to FM.
If the mass assimilates or otherwise compromises veins and arteries, does the body always establish collateral circulation?
Development of collateral circulation depends on which specific vessel is obstructed and also differs between individual patients. For many patients who have superior vena cava obstruction, collateral venous circulation may develop. Some patients with superior vena cava obstruction have insufficient development of collateral circulation which is associated with serious swelling of their arms, neck or head. In these patients some procedures such as placing a stent by catheterization, or bypass by surgery, may relieve their symptoms. Collateral circulation generally does not develop within the lung.
Does the process of establishing collateral circulation lead to blood clots or other problems?
Sometimes blood clots develop in a previously obstructed vessel, perhaps due to the slower blood flow there, so blood clots seem to be more common in those patients in whom good collateral circulation did not develop.
What other complications can ensue from compromise of veins and arteries?
One of the complications which can result when arteries or veins or both are obstructed is a process called infarction. This is a condition which occurs when the lung receives inadequate blood supply. It may be associated with pleurisy with effusion, in which the pleura covering the lung becomes inflamed and painful, and fluid leaks into the pleural space around the lung, sometimes compressing the lung.
When a pulmonary artery or vein is obstructed, then arteries from the systemic arterial system such as bronchial or intercostal (under each rib) arteries can be stimulated to grow directly into the lung. These vessels may be a source to cause coughing of blood, which occasionally is serious in some patients, but can usually be treated successfully with modern techniques.
Other complications due to obstructed veins or arteries in both lungs are high blood pressure in the lungs (pulmonary hypertension) or inadequate lung function. Any individual needs the equivalent of at least one good lung to survive, so when veins or arteries are obstructed in both lungs, then respiratory failure with inadequate uptake of oxygen or elimination of carbon dioxide are among the serious complications.
What treatments are available to protect veins and arteries from the depredations of FM?
In the last five years it has been learned that some patients may be helped by catheterization with placement of stents in veins or arteries. Although there is considerable difference between individual patients, stenting appears to be effective therapy with an acceptable risk for many patients, especially those in whom the disease causes the greatest risk because both lungs are affected.
Do you recommend the use of stents? If so, what is the life expectancy of a stent and what complications can arise from the use of one?
I recommend considering stents in certain specific situations. We began using stents in only the past five years, initially in patients whose lives were threatened because the vessels in both lungs were affected, and other options were not available. The life expectancy of a stent, and other basic information is just now being learned, so this is a very new and evolving field. Some stents seem to function well for five years or more, whereas others seem to have recurrent narrowing that requires repeat catheterization and revision of the stent.
Serious complications are possible and have been reported. There is at least one report in which a stent that was placed in the superior vena cava was associated with later complications of the aorta, the main blood vessel from the heart, so this can be a very serious complication. Although stents in vessels appear to be well-tolerated in most patients, there appears to be a low but definite potential for serious or even life-threatening complications, so they should be used with careful consideration.
What role does the stent type or manufacturer play in the success rate of stents?
The technology of vascular stents is rapidly changing, and this question is best answered by the interventional experts who perform the catheterization and insertion.
Do you anticipate better results from the new antibiotic coatings on stents?
Some intravenous catheters are coated with antibiotics to prevent infection, but I do not know of any stent which has antibiotic coating. Some new stents for coronary arteries have been coated with substances that are antiproliferative, such as the immunosuppressive therapy Sirolimus (Rapamune). I have not heard whether such coatings are available for larger stents, which would be needed for the larger pulmonary vessels. In coronaries, these coatings do help prevent repeat occlusion of vessels after stent placement, but they increase the expense greatly.
What percentage of FM patients suffer from airways being blocked by the fibrosis?
In my experience involvement of pulmonary vessels is more common than involvement of airways, perhaps five times as common. One explanation for why vessels appear to be more vulnerable to the scarring process may be that the airways have a stiff cartilaginous structure that helps keep them patent.
What treatments are available for patients with blocked airways?
The treatments that are available for blocked airways seem to be less successful than those for blocked vessels. In our experience, patients who have had stents placed for blocked airways have had substantial problems with rapid regrowth of new tissue in the airways. This new tissue often blocked the airways again in a month or two, so the airways appear to react differently to a stent than do the pulmonary vessels. Perhaps some new technology will help prevent proliferation of tissue within airway stents in the future, but at present I have less enthusiasm for recommending airway stents. However, since other approaches to treat airway obstruction, such as surgery, have significant risks, it may still be reasonable to try airway stents if the severity of the problem warrants. Surgical attempts for airway reconstruction should be done only by surgeons who are experienced in surgery for mediastinal fibrosis.
What is the life expectancy for a stent placed in an airway?
This varies considerably between individuals, and also depends on the type of stent, and on the disease process. In patients with mediastinal fibrosis our experience has been that new growth occurs in the airway and can obstruct the stent, sometimes as soon as within a few months.
What can be done when a stent fails?
When an airway stent fails, then a thoracic surgeon would often do a rigid bronchoscopy in the operating room and remove the tissue that is obstructing the stent, and sometimes add another stent. Another option in that circumstance would be thoracic surgery, which has significant risk and should only be considered by surgeons with experience treating mediastinal fibrosis.
What treatments may be needed to extend the life expectancy of a stent?
The life expectancy of a stent appears to depend mostly on the type of disease process, and how active the growth of new tissue in the airway is for that individual patient.
Does the fibrosis also attack nerves in the mediastinum? If so, are the voice, esophagus, throat, heart, or other organs or functions often affected?
Fibrosing mediastinitis rarely can affect the nerves in the mediastinum. The nerves that are the most important in this region include the recurrent laryngeal nerve, which supplies the vocal cords. Paralysis of the recurrent laryngeal nerve can cause vocal cord dysfunction which weakens the voice. If the vocal cords do not close completely, aspiration can occur during swallowing, which can lead to pneumonia.
The other important nerve is the phrenic nerve that passes down each side of the mediastinum to supply the function of the diaphragm, which is the muscle under the lung which contracts to pull air into the lungs . If the phrenic nerve is injured, then the diaphragm will be paralyzed on that side.
In your experience, once a case of FM appears to have been stable (no growth in the fibrosis) for several years, is it likely that it will never start growing again?
I have seen only a few patients in whom late progression of the fibrosis has occurred. This observation applies only to patients with the Histoplasmosis-related FM. The diffuse, proliferative, idiopathic type of mediastinal fibrosis is far less common so it is less well understood. In this form I have seen rapid regrowth in at least one patient after an operation so its predictability of a stable course has less certainty.
Do all of your patients suffer some degree of disability as a result of FM?
Most patients suffer significant symptoms, but the extent of disability varies considerably. I know one patient who lost the function of one lung to mediastinal fibrosis at age 18, but continued to work productively for another 20 years before he had serious symptoms, and was then diagnosed for the first time. Conversely, the disease can be highly disabling to other individuals. Most patients who have both lungs involved will be disabled and have a potentially life-threatening disease but those with one lung involved may be able to feel reasonably well and can have good longevity.
What percentage of the FM patients you have followed have died from the FM per se? What percentage of these deaths would be considered premature statistically?
I treated several patients with fibrosing mediastinitis in the late 1980s who died from both lungs being affected, so it is clear that it can be life threatening.
In the last several years, for the most serious patients with bilateral involvement, many have been helped by vascular stents to recover some portion of their lung function. My opinion is that patients who have primarily vascular involvement have better outcomes than in the past, perhaps related to benefit from stenting. However there is still not definitive information overall about what survival that individual patients can expect. The emotional strain related to this uncertainty of the prognosis is one of the most difficult features for many patients and their families.
Patients have reported that their breathing ability is affected by changes in the weather. Why does this happen?
Changes in the weather, especially humidity and heat, can affect patients who have a wide variety of respiratory conditions, especially asthma or emphysema in which airflow is limited. Again there is substantial individual variability and some patients notice changes in weather to a much greater extent than others.
It seems that most people are diagnosed with FM in their 30's or 40's. Do you think that is because the FM has recently been contracted or is it that it takes years or even decades to progress to a stage that causes symptoms that require treatment?
Most patients with fibrosing mediastinitis are young, in their twenties to forties. The reason is unknown, but most patients probably were initially infected with Histoplasmosis in their youth. It appears that the scar process grows at about one millimeter per year, so it is very slow-growing and it may take several years before it leads to obstruction of the large arteries, veins or airways, which are about 10-15 mm in diameter.
Is FM more severe in people who are diagnosed at an early age?
The severity appears to be determined more by the extent of involvement rather than the age of involvement. It is more severe in people who have both lungs involved, but that can happen in individuals unrelated to their age.
Is it common to develop asthma and other respiratory problems as a result of FM and, if so, how are they treated?
The development of asthma is uncommon. In my experience, the patients who developed symptoms of asthma usually had direct airway involvement. In those who develop asthma-like symptoms, such as cough and wheezing, the standard therapies such as bronchodilators and steroids do help control the symptoms of asthma.
Do FM patients develop heart problems?
Patients who have involvement of both lungs may have high blood pressure in their lungs (pulmonary hypertension) that may put strain on the right ventricle which pumps blood through the lungs. If the vascular occlusion in the lungs can be relieved, the pulmonary hypertension will often improve.
Are blood clots a major risk factor? If so, do they tend to be life threatening, i.e., lead to strokes or heart attacks, or are they non-acute and treatable?
Blood clots as a part of mediastinal fibrosis are uncommon, so they are not a major risk factor. We have occasionally seen blood clots develop in the superior vena cava in patients who already had superior vena cava obstruction. Blood clots as a complication of vascular stents are another potential risk, so some patients are treated with blood thinners after placement of a stent in a vessel.
Are FM patients typically susceptible to pneumonias and other lung diseases?
Patients with airway obstruction from FM seem to be at increased risk for pneumonia. Those patients who have vessel occlusion from FM do not appear to be at increased risk for pneumonias. All FM patients should take prevention for pneumonias because the severity of disease would be higher if it did occur. Vaccination against pneumococcal pneumonia is given every five to ten years and flu vaccination is annually.
Does the typical FM patient suffer from other autoimmune diseases?
Fibrosing mediastinitis associated with Histoplasmosis is thought to be an excessive healing response of that specific individual to the Histoplasmosis organisms, and is generally not considered to be autoimmune in origin.
It is possible that the diffuse, proliferative, idiopathic form of FM is an autoimmune disease, but the mechanisms of it are not well understood. The fact that it responds to an immunosuppressant like prednisone suggests that it could have an autoimmune basis.
Are there any characteristics or other factors that seem to be common among your FM patients?
FM occurs in patients of either gender of any race, and doesn't appear to have any common characteristics except perhaps its occurrence in young individuals in their 20s to 40s.
In your experience, how long does FM remain active in the average patient, i.e., is it always becoming progressively worse or does the active stage seem to run its course and then stabilize?
In many patients with the Histoplasmosis form of FM, the process seems to stabilize without further progression. In fact, for most patients we do not really know the duration of the active stage, usually because it occurred before they developed symptoms and knew to seek help. A small percentage may have late progression.
In the diffuse proliferative idiopathic form, there are not enough patients reported to understand its course, but it does appear more unpredictable than does the Histoplasmosis related form.
Is SVC compression more serious than that of the PA?
In general, superior vena cava obstruction is less life threatening than involvement of the pulmonary artery or pulmonary vein, but is more a problem with disability and swelling. The most serious problem overall is involvement of structures of both lungs. FM involvement which is limited to one lung is less serious than that of both lungs, and then superior vena cava compression would be least life threatening.
Are there other medical centers around the US where FM sufferers can see someone with some expertise in treating the disease? If so, where, and what are the names of the doctors they should make appointments to see?
I'm sure there are other doctors around the country who have interest and expertise in fibrosing mediastinitis, but I do not know who they are. This could be an important contribution of a fibrosing mediastinitis patient group to identify physicians across the country who are interested in FM.