["Lupus anticoagulant" in immune hyperthyroidism].

A 56-year-old woman with autoimmune hyperthyroidism (Basedow) whose blood coagulation had at first been normal developed prolonged partial thromboplastin time (PTT) of 48 s and a fall in prothrombin time (Quick value) to 52%. At the same time, total activity of factor VIII was reduced to 18% and factor IX to 16%. These values not having changed after the addition of normal plasma, it is assumed that an acquired inhibitor of plasmatic coagulation was responsible. Such inhibitors were first described in lupus erythematodes and therefore called lupus anticoagulant, but later also demonstrated in other autoimmune diseases.