Overview
The Clinical Pattern
Mixed connective tissue disease is an autoimmune overlap disorder characterised by high titre anti U1 ribonucleoprotein (anti U1 RNP) antibodies and inflammation involving sever...
Mixed connective tissue disease is an autoimmune overlap disorder characterised by high-titre anti-U1 ribonucleoprotein (anti-U1 RNP) antibodies and inflammation involving several connective-tissue disease patterns. The clinical picture may include features of systemic lupus erythematosus, systemic sclerosis, polymyositis or dermatomyositis, and Raynaud phenomenon. Raynaud phenomenon is often an early clue. Cold or emotional stress causes episodic vasospasm, producing pale or white digits followed by blue or dusky colour and then redness as blood flow returns. Numbness, tingling, or pain may accompany the colour change. Persistent discoloration, a digital ulcer, or tissue breakdown is not a routine Raynaud episode; it suggests impaired perfusion requiring prompt assessment. Puffy hands and “sausage-like” fingers may appear early. Other findings reflect the involved tissue: - Joints: inflammatory polyarthritis, stiffness, swelling, and reduced function. - Muscle: symmetric proximal weakness, such as difficulty rising from a chair, climbing stairs, or lifting the arms; muscle enzymes may rise when myositis is active. - Skin and vessels: sclerodactyly, telangiectasia, or digital ischemia. - Oesophagus: reflux, dysphagia, or a sensation that food is sticking. - Lungs and pulmonary circulation: exertional dyspnoea,...