Role of thymic ultrasonography in the diagnostic workup of infants with protein–energy malnutrition

Purpose: The aim of this study was to report the significance of quantitative thymic gland analysis using ultrasonography (US) in the diagnostic workup of infants with protein–energy malnutrition (PEM) to assess thymic index and correlate it with anthropometric and peripheral blood lymphocyte subset measurements. Patients and methods: US assessment of thymic size was carried out prospectively in 36 infants with PEM, compared with 16 control infants. Correlation with anthropometric measurements and peripheral total leukocytic count as well as peripheral CD4/CD8 T-lymphocytes ratio was made. Results: Significant thymic atrophy and reduced anthropometric measurements were found in all patients. Leukopenia and significantly lower CD4/CD8 ratio were also found. A positive weak correlation was noted between the thymic index and the CD4/CD8 ratio in PEM infants (r=0.4695; P=0.004). A weak negative correlation was found between the thymic index and the CD4/CD8 ratio in controls (r=0.0813; P=0.76). Conclusion: An easy, rapid, and especially noninvasive method such as US provides a suitable quantitative method to assess the thymus gland. In infants with PEM, thymic atrophy is associated with changes in the peripheral lymphocyte subsets with detrimental sequelae on the immune system, justifying the use of US for indirect evaluation of the immunocompetence level in malnourished children.