Despite a number of previous studies regarding transient benign hyperphospatasemia which date back to 1954, pediatric gastroenterologists still see kids referred for this. A new study analyzes 142 previous reports which included 813 cases (JPGN 2013; 57: 167-71).
Most of the alkaline phosphatase is produced in the liver and bone. “Sometimes a marked increase in alkaline phosphatase values is found in infants and toddlers without evidence of liver or bone disease…The temporary increase in alkaline phosphatase resolves without intervention within 16 weeks…is termed transient benign hyperphosphatasemia.” With this disorder, the alkaline phosphatase is commonly ≥ 5 times the upper reference range.
- 733 cases were in patients <19 years of age; 80 cases were in those ≥ 19 years
- Among infants and toddlers, the prevalence may be between 1.1% and 3.5%
- The duration of elevation was ≤4 months in 80%
- A preceding infection often preceded the reported cases
- Our analysis “indicates that isoenzyme studies are not useful.” In about 50% the most prevalent isoform is from bone, though this may reflect poor clearance from the circulation.
Evaluation recommended by authors: aminotransferases, bilirubin, γ-glutamyl transferase, calcium, phosphorus, urea, and creatinine (eg. CMP, phosphorus, & GGT) –though they indicate that these may be waived by many experienced clinicians.
Bottom-line: Transient benign hyperphosphatasemia is likely the most common cause of elevated alkaline phosphatase in healthy infants and toddlers. Sometimes this occurs in older children and adults. Recognition of this disorder may help avoid unnecessary investigation.