Acute laryngotracheobronchitis and associated transient hyperphosphatasemia: a new case of transient hyperphosphatasemia in early childhood.

We report the case of a 20-month old boy with markedly elevated serum alkaline phosphatase (ALP) levels, documented during an episode of acute laryngotracheobronchitis. Biochemical investigations and imaging studies revealed no evidence of bone or liver disease. Transient hyperphosphatasemia (TH) was confirmed when serum ALP levels normalized within 2 months. Several theories were suggested for TH pathophysiology, viral infections among them; the exact causes, however, remain unclear. It is important to recognize TH and avoid misdiagnosis and unnecessary investigations.