mixed connective-tissue disease
TRANSCRIPT
T h e n e w e ngl a nd j o u r na l o f m e dic i n e
TEACHING points
MANIFESTATIONS, DIAGNOSIS, AND TREATMENT OF UNDIFFERENTIATED CONNECTIVE-TISSUE DISEASE
• Narrow-complex tachycardia originates above the atrioventricular node and is char-acterized by a heart rate of more than 100 beats per minute and a narrow QRS complex (<120 msec). Variations of narrow-complex tachycardia can be distin-guished from other arrhythmias by examining the regularity of ventricular complex-es on electrocardiogram and the pattern of atrial activity (P waves); in atrial fibrilla-tion, there is irregularly irregular ventricular activity and an absence of organized P waves.
• Common causes of pericardial effusion include infectious pericarditis, autoim-mune rheumatic diseases, trauma to the chest, malignant effusion in the presence of a neoplasm, severe hypothyroidism, uremic renal failure, and myocardial infarc-tion (Dressler’s syndrome). In the absence of hemodynamic instability and of the suspicion of cardiac tamponade, emergency pericardiocentesis is not indicated, and other means of evaluation should be pursued to determine the cause.
• Systemic symptoms are often seen in patients with autoimmune connective-tissue diseases. In the early stages of disease, symptoms may not conform to classifica-tion criteria. Physical manifestations and serologic findings may be characteristic of several different autoimmune connective-tissue diseases, making it challenging to distinguish a particular disease. Patients with undifferentiated connective-tissue disease should be monitored carefully and their condition reassessed over time, since symptoms and physical manifestations may gradually evolve to more closely fit the diagnosis of a particular connective-tissue disease.
• Serologic tests for an antinuclear antibody and its subtypes are frequently used in the diagnosis of systemic rheumatic diseases. Autoantibodies may be present before the manifestation of symptoms characteristic of a specific systemic rheu-matic disease. The presence of an autoantibody is not sufficient for diagnosis; other signs and symptoms must also be present.
These teaching points are drawn from the Interactive Medical Case. For more complete information, see Vaidya A, Price CN, Lee YC. Disconnected. N Engl J Med 2012:367:e10.