[Transient hyperphosphatasemia observed in a boy with acute lymphoblastic leukemia]

Area of Science:

• Biochemistry
• Pediatric Oncology
• Clinical Chemistry

Background:

• Elevated alkaline phosphatase (ALP) activity can indicate serious conditions like liver or bone disease.
• Transient hyperphosphatasemia (TH) is a rare, benign condition characterized by temporary high ALP levels.
• Understanding TH is crucial for accurate differential diagnosis in patients with elevated ALP.

Observation:

• A 9-year-old boy with acute lymphoblastic leukemia (ALL) presented with a transient, significant increase in serum ALP activity (49x upper limit of normal).
• The patient experienced fever and diarrhea, with Enterococcus faecium identified in stool samples.
• Two other patients in the same ward exhibited TH during the same period, suggesting an infectious etiology.

Findings:

• Serum ALP activity in the patient normalized with a calculated half-life of approximately 10 days.
• Isoenzyme analysis indicated extensive sialylation, with electrophoretic patterns suggesting liver and bone origins.
• The co-occurrence of TH in multiple patients points towards infectious states as a potential cause.

Implications:

• This case highlights a benign cause of hyperphosphatasemia in a pediatric oncology patient, distinct from malignancy-related ALP elevation.
• Recognizing TH associated with infectious states is vital for clinicians to avoid misdiagnosis and unnecessary interventions.
• Further research into infectious triggers for TH could improve diagnostic strategies for elevated ALP in children.