Connective Tissue Disease and Interstitial Lung Disease

A large Scleroderma Support Group joined our Interstitial Lung Disease Support Group yesterday for Dr. Deborah Assayag's presentation on Connective Tissue Disease (CTD) and Interstitial Lung Disease (ILD). Canadian Dr. Assayag has been in SF for the last year and a half to study CTD and ILDS.

CTDs are a group of inflammatory diseases affecting the structural portions of the body, form the framework, are composed of collagen and proteins. It can directly affect the joints, cartilage, skin, ligaments and blood vessels.  It is autoimmune in nature, the immune system reacts to proteins. Inflammation is a major component of these diseases.

The diseases:
Rheumatoid Arthritis - affects joints
Sjogren's - affects dry eyes and mouth, lung disease features cysts in the lungs
Lupus - affects joints, only 1% develop an ILD.
Scleroderma - affects skin, lungs, blood vessels, kidneys, largest group of CTD who develop an ILD.
Dermatomyositis (and Polymyositis) - affects muscles, skin, joints, weakness in thigh or arm muscles
Mixed CTD - This is a specific disease not just a pile to put something that doesn't fit with the other diseases. It has its own auto antibodies in the blood.

Usually, the lung clinics see these patient after they have been diagnoses and treated by a Rheumatologist for a CTD. The diagnosis of a CTD bases on the organs involved and then confirmed with blood tests. Each disease has specific auto antibodies. If the patient complains about symptoms of lung disease, they are sent for Pulmonary Function Tests : Forced Vital Capacity (the clear box) and Diffusion Capacity (DLCO). Then, they are sent for a high resolution CT Scan. Blood tests will include serology to check the auto antibodies, some general tests (ANA, RF) and some are disease specific ( SC1-70, AntiCCP, RNP). With an ILD, it is often helpful to have a lung biopsy. As the cause of the ILD is a CTD, there is no need for a lung biopsy.

Natural History of CTD-ILD:
With a diagnosis of RA or Dermatomyositis, the disease progresses very slowly. With all CTDs, the younger the patient, the better they do. There is no difference in gender. If the severity of the CTD is present at the diagnosis of ILD, these patients do worse. It all depends on the amount of fibrosis present in the lungs at the time of diagnosis.

Treatment:
Rehab! A formal exercise program is highly encourages.
Supplemental Oxygen - to protect against the heart damage, blood vessels issues, pulmonary hypertension and strokes.
Medications -
Prednisone is used to help kick start CTDs to help suppress the inflammation. There usually is an initial run of 6-8 weeks.
Mycophenolate (Cellcept) My old friend. This is the first line of medication used on RA, Scleroderma, Sjogren's and Mixed CTD. The side effects are nausea and bone marrow suppression.
Cyclophoshamide - This drug is mostly prescribed for more severe cases of Scleroderma or if the patient did not respond well on the other drugs. It is not used for other CTD-ILDs. The side effects are liver toxicity, bladder cancer 20-30 years later.
Azathioprine (Imuran) I have been on this drug for over 7 years. The side effect can be bone marrow suppression and liver toxicity.
Rituximab - The hot new drug. It is given by infusion followed by another infusion two weeks later then another infusion six months to a year later. It is currently being prescribed mostly for patients with Dermatomyositis. The UK is currently using this drug with other CTDs, not just Dermatomyositis.The possible side effect is lymphoma.

In my ILD Clinic, they treat 40-45% of their patients for Idiopathic Pulmonary Fibrosis (IPF) , 23% for Connective Tissue Diseases( CTD) and 12% for Hypersensitivity Pneumonitis (HP).