NEW YORK (Reuters Health) - Certain high protein diets produce a reversible hypertyrosinemia that could lead to a positive screening test for phenylketonuria (PKU), according to the findings of two case reports described in the Journal of Pediatrics for February.
The first case involved a term male infant with a presumptive positive PKU screen at 7 days of age, lead author Dr. Chulaluck Techakittiroj, from Tulane University in New Orleans, and colleagues note. However, when first tested between 24 and 48 hours of life, the screen was negative.
Initially, the child was fed with Enfamil, but because of spitting up and jaundice, he was changed to a higher protein formula, Shaklee Slim Plan Drink Mix, on day 5. Aside from elevated tyrosine and phenylalanine levels, the child appeared normal at 2 weeks. Transient tyrosinemia was considered as a possible diagnosis and after changing to a lower protein diet, Isomil, his elevated levels quickly returned to normal.
The second case involved a female infant with a similar history. In this case, however, the high protein diet was Pet evaporated milk. A switch to Similac brought the elevated tyrosine and phenylalanine levels back down.
In each case, the high protein diets provided around 8 g/kg per day of protein, whereas the standard formulas provided about 4 g/kg per day, the report indicates.
“These cases highlight the importance of following infant nutritional guidelines,” the authors state. “Both patients were normal at the time of diagnosis, but the long-term effects of high protein intake in infants have not been” adequately studied, they add.
Source: J Pediatr 2005;146:281-282. [ Google search on this article ]
MeSH Headings:Diagnosis: Diagnostic Errors: Health Care Facilities, Manpower, and Services: False Positive Reactions: Health Services: Infant Food: Phenylketonurias: Medical Errors: Foods, Specialized: Analytical, Diagnostic and Therapeutic Techniques and Equipment: Health CareCopyright © 2002 Reuters Limited. All rights reserved. Republication or redistribution of Reuters content, including by framing or similar means, is expressly prohibited without the prior written consent of Reuters. Reuters shall not be liable for any errors or delays in the content, or for any actions taken in reliance thereon. Reuters and the Reuters sphere logo are registered trademarks and trademarks of the Reuters group of companies around the world.
