Indirect Indicators of Muscle Mass in Malnourished Infants

Abstract

The 24-hour creatinine output was measured in malnourished infants at intervals after the loss of edema. After 2 months’ treatment on milk diets the output more than doubled. This increase in creatinine excretion was relatively greater than the increase in body weight over the same period. It is argued that, if creatinine output is a measure of muscle mass, the deficit in muscle mass at the time of admission to the hospital was considerably greater than the deficit in body weight. Measurements were also made at intervals of limb circumference and skin-fold thickness. From these, estimates were calculated of “muscle bulk” and “fat bulk.” Over the period of observation both of these increased relatively more than the body weight. The fat increased most in the children who were initially most underweight. It is concluded that in these malnourished babies, even in the absence of edema, the bodyweight deficit underestimates the degree of protein depletion of the tissues. The variability of the measurements is such that a single measurement cannot give a valid estimate of the degree of depletion in an individual case.