2018 Volume 30 Issue 1 Pages 58-64
Here, we report a case of transient hyperphosphatasemia (TH) in a 32-year-old man with Behçet’s disease receiving low-dose corticosteroid and infliximab therapy for six years. In November 2016, routine laboratory data revealed an extremely high serum alkaline phosphatase (ALP) level of 1212 U/L (normal 115 - 359 U/L). There were no evidences of hepatobiliary and bone diseases on various laboratory and imaging findings. ALP iso-enzyme analysis showed the appearance of two bands on both sides of the normal liver ALP (ALP type 2), and the abnormal band at the fast 𝛼2 position were identified. Finally, a diagnosis of TH was established according to these characteristic patterns of ALP isoenzyme analysis. His serum ALP level rose to a maximum of 2783 U/L, which is an approximately eight-fold increase relative to the upper normal limit, and returned spontaneously to the normal range nine weeks later. This clinical course also indicated TH. TH is characterized by the isolated elevation of serum ALP. When a patient with connective tissue disease develops these abnormality, we are liable to suspect first the exacerbation of the underlying disease or adverse effects of therapeutic agents as a cause. ALP iso-enzyme analysis is useful for a differential diagnosis of hyperphosphatasemia. This report emphasizes that the recognition of TH is crucial to avoid unnecessary investigation and change of treatment plan.
