Transient hyperphosphatasemia in children revisited.

OBJECTIVE

Although transient hyperphosphatasemia (TH) has been well known for decades, its etiology and pathophysiology remain unclear. We aimed to study the clinical characteristics of children diagnosed with TH compared to older studies in order to expand our knowledge and understanding of this condition and to try and find a subgroup of children who are more prone to develop TH.

METHODS

We retrospectively studied 60 children diagnosed at Maccabi Health Services and Bnai Zion Medical Center, Haifa, Israel with TH between the years 2003-08. One hundred and twenty-two children matched by age, gender and presenting symptoms served as the control group. The patients were divided into four subgroups by their presenting symptoms: infectious disease 33%, failure to thrive 28%, diarrhea 15% and other 23%. The Hydragel 7 ISO-PAL and Hydragel 15 ISO-PAL kits were used for the identification and quantification of ALP isoenzymes in human serum.

RESULTS

The ALP levels of the study group were 805-8619 U\L (mean 2311 U\L), without differences between the subgroups. The mean duration of TH was 12 weeks. ALP isoenzymes levels were measured in one-third of the patients, and showed that the bone isoenzyme was elevated in most. Forty-three (71%) subjects were diagnosed in the second half of the calendar year.

CONCLUSIONS

We could not establish an etiological explanation for TH. We presume that it is a complex mechanism in which different stimuli led to upregulation of the enzyme.