Well, people find all of rheumatology confusing, and around 25% of our patients with symptoms of autoimmune disease cannot be diagnosed.
This category is helpful, but difficult to define and name. It’s mostly been called Undifferentiated Connective Tissue Disease (UCTD) historically although the preferred term now is Undifferentiated Systemic Rheumatic Disease.
Raynaud’s phenomenon
Raynaud’s phenomenon – when fingers or toes are very sensitive to the cold and go white, blue or both – can be primary or secondary. Primary Raynaud's is common, usually starts between 15-30 years of age, and often runs in families. Primary Raynaud's is usually mild.
However, Raynaud’s phenomenon can sometimes be secondary. Underlying causes can be occupational (vibrating tools), haematological (blood disorders) and autoimmune conditions. Blood tests and analysis of the blood vessels at the nail fold (called nail fold capillaroscopy) can help to distinguish primary from secondary Raynaud's phenomenon.
Some features of the Raynaud's phenomenon are suspicious for secondary Raynaud's. Raynaud’s starting after the age of 40, Male patients, ulceration of the skin, other symptoms, abnormal nail fold capillaries, affecting just one side, abnormal autoimmune blood tests.
When we suspect the Raynaud’s may be secondary but cannot formally diagnose an underlying condition, we call this an Undifferentiated Systemic Rheumatic Disease (or UCTD).
Arthritis
Some patients have symptoms of early arthritis but do not have rheumatoid arthritis. They may describe inflammation in the joints which may be symmetrical or not, and will sometimes be ‘migratory’, affecting different joints briefly at different times. Some joints may swell. They may have early morning stiffness and their blood tests may show elevated ESR (erythrocyte sedimentation rate), positive ANA or positive rheumatoid factor. They may have a dramatic response to anti-inflammatory therapy.
Many of these patients will have rheumatoid arthritis. However, many do not satisfy the criteria for rheumatoid arthritis. These inflammatory symptoms in the joints can be another sign of systemic rheumatic disease.
About 20% of these patients will go on eventually to be diagnosed with rheumatoid arthritis. About 50% of them will resolve over a few years.
Use of ultrasound and MRI can help with early diagnosis and treatment with immunosuppressive medication such as hydroxychloroquine or methotrexate can help to reduce joint damage over time.
Lung fibrosis
There is an uncommon kind of lung inflammation called “interstitial pneumonia with autoimmune features (IPAF)” which can be associated with Undifferentiated Systemic Rheumatic Disease (or UCTD).
Underlying conditions
One of the difficulties of making a specific diagnosis of a distinct systemic rheumatic disease is that our conditions have overlapping features. There are quite a few features shared, for example, by rheumatoid arthritis (RA), Sjögren's syndrome, systemic lupus erythematosus (SLE), systemic sclerosis, and inflammatory myopathy (muscle inflammation).
The same is true of the blood tests for autoimmune diseases. Some of the positive results can be associated with a few conditions. It is associated with more than doubling of pregnancy risks such as pre-eclampsia and small foetuses (Spinillo et al, 2016).
Treatment
There was one intriguing study suggesting vitamin D supplementation is of benefit (Zold et al 2011). Treatment is targeted to the specific symptoms the patient is describing. Sometimes all that’s needed is careful observation and no treatment at all. This all needs to be carefully individualised.