Transient Hyperphosphatasemia: A Case Report

Abstract

T ransient hyperphosphatasemia (TH) in infancy and childhood is a condition of elevated serum alkaline phosphatase (ALP) level without evidence of bone or liver disease. The common age at presentation is younger than 5 years old. However, investigations are needed to exclude other serious conditions such as liver disease or bone disease. 1 Transient hyperphosphatasemia is not associated with any anthropometric measurement or biochemical markers of calcium and vitamin D metabolism. 2 This condition is postulated to be from the immaturity of the mechanism responsible for ALP clearance resulting in an increasing level of plasma ALP. The associations between transient hyperphosphatasemia and viral, protozoal or other infections have been reported, such as gastrointestinal disease, respiratory infections, 3 and the duration of the elevation of serum alkaline phosphatase was less than 4 months in 80% of cases. 4 This condition resolves without intervention.5 Most TH cases were found to be associated with upper airway diseases, suggesting that TH might be caused by enterovirus infection. 6 This report describes a case of TH which might be associated with viral infection, TH resolved without intervention. assessed to be normal for his age. He was admitted twice in the past year for viral gastroenteritis and his last admission was 4 months ago from upper respiratory tract infection. Physical examination revealed a thin boy with a weight of 9.4 kilograms (< P3) and 82 centimeters in height (< P3). He had no dysmorphic feature, no rachitic rosary nor swelling of wrists and knees, no bowed legs or genu varus. The rest of the physical examination was normal. Abstract We report a case of a 2-year-3-month-old boy who had poor weight gain since 1 year of age. He had a history of difficulty eating since he was 6 months old. Vaccinations were up to date and his developmental assessment was normal. Physical examination revealed no dysmorphic features. His weight was 9.4 kilograms (< P3) and he was 82 centimeters in length (< P3). He had no rachitic rosary nor swelling of wrists or knees, no bowed legs or genu varus. He was referred to Burapha University Hospital for evaluation of failure to thrive. The laboratory investigations showed serum calcium of 10.2, phosphorus 4.5, magnesium 2.3 mg/dL and alkaline phosphatase 1,603 U/L. The x-ray on both knees and wrists showed no fraying and no flaring of the metaphyses. Serum 25-OH vitamin D and parathyroid hormone levels were 27.4 ng/mL and 24.7 pg/mL, respectively. The serum alkaline phosphatase decreased to 494 U/L. After 2 weeks of follow-up it further decreased to 185 U/L in 3 months with normal levels of calcium 9.8, phosphorus 5.3 mg/dL. The diagnosis of transient hyperphosphatasemia is crucial to avoid excessive investigations.