Nephrocalcinosis in Shwachman's syndrome

pregnancy, labour, and delivery. He was initially fed orally on a standard infant formula, but feeding became increasingly difficult and he failed to thrive. At 6 weeks of age, he was admitted to hospital, where he continued to gain weight poorly despite numerous feed changes. Nasogastric feeding was therefore started at 10 weeks of age. Investigations showed intermittent neutropenia (the lowest concentration was <0 2x 109 neutrophils/l), persistently low serum immunoreactive trypsin (0-2 Rg/l), and mildly raised plasma alanine transaminase and aspartate transaminase activities. Sweat sodium and chloride concentrations were normal. A radiograph of the chest showed broadened anterior ends of the ribs. A diagnosis of Shwachman's syndrome was made and he was treated with pancreatic enzyme supplements from 4 months of age. Severe feeding difficulty and failure to thrive persisted, however, and at 7 months he was referred to us for further investigation. On admission his weight (5450 g), length (60 cm), and head circumference (42 cm) were all below the third centile. He had a narrow chest with Harrison's sulci, mild subcostal recession, increased tone in the legs with brisk reflexes and ankle clonus, and mild hirsutism. His liver was not enlarged. Pancreatic enzyme supplements were withheld on admission. Shwachman's syndrome was confirmed by low bicarbonate production (maximum 16 mmol/l), low lipase activity (maximum 13 ,umol/ min/ml), and absent trypsin activity in duodenal fluid obtained after stimulation with secretin and cholecystokinin, together with intermittent neutropenia and typical radiological changes in the ribs. His transaminases were moderately raised (alanine transaminase 187 IU/l, and aspartate transaminase 122 IU/l). Immunological investigation showed poor neutrophil mobility. Further evaluation ofthe urinary tract was undertaken (see below) and pancreatic enzyme supplements were restarted at 8 months of age.