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Faecal chymotrypsin concentrations in neonates with cystic fibrosis and healthy controls
G A Brown1, R B Halliday, P J Turner
1Institute of Child Health, University of Birmingham.
Insights
Faecal chymotrypsin levels in newborns rise initially then fall. Significantly reduced levels in infants with cystic fibrosis suggest this enzyme test reliably detects pancreatic exocrine insufficiency.
Area of Science:
- Biochemistry
- Pediatrics
- Gastroenterology
Background:
- Pancreatic exocrine insufficiency is a serious condition in newborns.
- Early diagnosis is crucial for effective management and improved outcomes.
Purpose of the Study:
- To investigate the normal range of faecal chymotrypsin concentrations in healthy newborns.
- To evaluate the utility of faecal chymotrypsin measurement in diagnosing pancreatic exocrine insufficiency, particularly in cases of suspected meconium ileus and cystic fibrosis.
Main Methods:
- Sequential collection of meconium and stool specimens from healthy newborns over the first 8-14 days of life.
- Measurement of faecal chymotrypsin concentrations using a standardized assay.
- Comparison of enzyme levels in healthy newborns versus those with suspected meconium ileus and confirmed cystic fibrosis.
Main Results:
- Faecal chymotrypsin concentrations in healthy newborns peaked around 4 days of age and then declined.
- Newborns with cystic fibrosis exhibited significantly reduced faecal chymotrypsin concentrations.
- Infants with suspected meconium ileus but negative sweat tests had normal chymotrypsin levels.
Conclusions:
- Faecal chymotrypsin concentration follows a distinct pattern in healthy newborns.
- Measurement of faecal chymotrypsin is a reliable diagnostic tool for identifying pancreatic exocrine insufficiency in neonates.
- This assay aids in differentiating cystic fibrosis from other causes of intestinal obstruction in newborns.
Abstract:
Specimens of meconium and random stools were collected sequentially from 25 healthy newborn babies over the first 8-14 days of life. The stool chymotrypsin concentrations increased from birth to a maximum at 4 days of age and then fell again over the next four days. The lowest individual stool concentrations either side of the four day peak were both, coincidentally, 120 micrograms/g stool. In a second group of 22 newborn babies suspected of meconium ileus and later confirmed to have cystic fibrosis, faecal chymotrypsin concentrations were all appreciably reduced. In eight babies, also with suspected meconium ileus but with negative sweat tests, chymotrypsin concentrations were within the healthy newborn range. Measuring faecal chymotrypsin concentrations is a reliable procedure for identifying pancreatic exocrine insufficiency in the newborn.
