Mixed Connective Tissue Disease

Raynaud PhenomenonMany patients with rheumatic complaints do not fulfill diagnostic criteria for any particular disease. Such patients are labeled as having undifferentiated connective tissue disease (UCTD). Most common features of UCTD are Raynaud’s phenomenon (fingers and turn pale on cold exposure and become bluish and pink later on), joint pains, joint swellings, loss of hair, dryness of eyes and mouth, rashes on exposure to sunlight and thickening of skin of fingers (sclerodactyly). Anaemia and diminution of white cells or platelets may also be seen. Most patients of UCTD remain undifferentiated for many years although some may evolve into a defined disease over 5-10 years.
Upto 25% patients fulfill diagnosis of two or more rheumatic diseases. These patients are defined to have an overlap syndrome. Overlap of SLE and rheumatoid arthritis as also that of polymyositis and systemic sclerosis are not uncommon.
Mixed connective tissue disease (MCTD) is a distinct clinical entity with specific set of symptoms (combined features of SLE, systemic sclerosis and polymyositis), association with genetic markers and presence of anti-U1-RNP autoantibodies.
Females are more often affected by this disease. The clinical picture of MCTD usually evolves slowly over a period of 5-6 years and can be difficult to identify in initial stages. Raynaud’s phenomena, severe arthritis, puffy hands or fingers and breathlessness can be initial features of MCTD. Later stages are characterized by symptoms involving various body systems. These include abnormal movements of food pipe (esophagus) and bowel, involvement of lungs and right heart, fluid around lungs (pleural effusion), thickening of skin of fingers, ulcers and gangrene of fingers and anaemia. Kidney and nervous system involvement is less common in MCTD.
Blood examination reveals many autoantibodies- anti-U1-RNP antibodies and rheumatoid factor being most common. Various tests are also required to be performed to rule out involvement of other organs such as heart, lungs and esophagus.
One-third cases of MCTD have a benign course whereas another one-third requires long-term medication. Fertility is normal although pregnancy must be planned during controlled disease. Death is usually due to severe involvement of heart or kidneys and infections following long term steroid use.
Treatment of MCTD must be under guidance of a rheumatologist with necessary help from other super specialists such as cardiologists, pulmonologists and nephrologists. Treatment must be aggressive when heart or kidney involvement is suspected. One must stop smoking and avoid cold exposure by wearing warm gloves as well as socks if Raynaud’s phenomenon is a problem. Treatment of digital ulcers is very tedious as they heal slowly over months.

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