Percutaneous needle biopsy of quadriceps muscle: Potassium analysis in normal children

Abstract

Previous investigators have documented changes in muscle potassium concentrations in a variety of diseases. Extension of these studies has been limited because of the need for an acceptable procedure for obtaining muscle samples without risk. A percutaneous needle biopsy of quadriceps muscle provides a relatively atraumatic approach to the study of cellular chemistry in children. Evidence is presented that a sample less than 10−3 the mass of the quadriceps may give significant insight into muscle electrolyte physiology. A preliminary study of muscle potassium in normal children is described which shows that the potassium content of muscle increases with age from 1 to 2,000 days. This represents a significant reduction in the infant's chemical immunity against secondary disorders of potassium depletion during the early postnatal period. Previous investigators have documented changes in muscle potassium concentrations in a variety of diseases. Extension of these studies has been limited because of the need for an acceptable procedure for obtaining muscle samples without risk. A percutaneous needle biopsy of quadriceps muscle provides a relatively atraumatic approach to the study of cellular chemistry in children. Evidence is presented that a sample less than 10−3 the mass of the quadriceps may give significant insight into muscle electrolyte physiology. A preliminary study of muscle potassium in normal children is described which shows that the potassium content of muscle increases with age from 1 to 2,000 days. This represents a significant reduction in the infant's chemical immunity against secondary disorders of potassium depletion during the early postnatal period.