Acquired, transient factor X (Stuart factor) deficiency in patient with mycoplasma pneumonial infection.

A case of severe haemorrhagic diathesis due to acquired deficiency of factor X (both immunologically and in procoagulant activity) is presented. The clinical and serological features of this case indicated mycoplasma pneumonial infection. Factor X in the peripheral blood did not appear to be influenced by administration of vitamin K, prothrombin-complex concentrate, fresh plasma or fresh whole blood. Circulating inhibitors of blood coagulation were absent and systemic amyloidosis could not be demonstrated. After 20 d, factor X spontaneously returned to normal. In view of the absence of other known causes of factor X deficiency, a possible relationship with mycoplasma pneumonial infection is suggested.