Clinical value of plasma creatine kinase and uric acid levels during first week of life

History of medical understanding and misunderstanding of Acid base balance

To establish how controversies in understanding acid base balance arose, the literature on acid base balance was reviewed from 1909, when Henderson described how the neutral reaction of blood is determined by carbonic and organic acids being in equilibrium with an excess of mineral bases over mineral acids. From 1914 to 1930, Van Slyke and others established our acid base principles. They recognised that carbonic acid converts into bicarbonate all non-volatile mineral bases not bound by mineral acids and determined therefore that bicarbonate represents the alkaline reserve of the body and should be a physiological constant. They showed that standard bicarbonate is a good measure of acidosis caused by increased production or decreased elimination of organic acids. However, they recognised that bicarbonate improved low plasma bicarbonate but not high urine acid excretion in diabetic ketoacidosis, and that increasing pCO2 caused chloride to shift into cells raising plasma titratable alkali. Both indicate that minerals influence pH. In 1945 Darrow showed that hyperchloraemic metabolic acidosis in preterm infants fed milk with 5.7 mmol of chloride and 2.0 mmol of sodium per 100 kcal was caused by retention of chloride in excess of sodium. Similar findings were made but not recognised in later studies of metabolic acidosis in preterm infants. Shohl in 1921 and Kildeberg in 1978 presented the theory that carbonic and organic acids are neutralised by mineral base, where mineral base is the excess of mineral cations over anions and organic acid is the difference between mineral base, bicarbonate and protein anion. The degree of metabolic acidosis measured as base excess is determined by deviation in both mineral base and organic acid from normal.

Malignant hyperthermia susceptibility. Management during pregnancy and labour

A case of pregnancy complicated by malignant hyperthermia susceptibility is reported. Serum CPK and electrolyte concentrations were measured during pregnancy and labour. Labour and delivery were managed successfully under epidural analgesia using plain bupivacaine 0.5%.

Possible urate nephropathy of the newborn infant as a cause of transient renal insufficiency

Oliguric renal failure, bilateral renal enlargement, and hyperuricemia were noted in three term infants. The findings on intravenous pyelography and radionuclide renography were consistent with intratubular obstruction to urinary outflow in two of the infants. The onset of diuresis appeared to follow intravenous pyelography in these infants. Urinary urate crystalluria was prominent in each infant in the first few days after the onset of diuresis, during which normal serum urate concentrations and normal renal function were established.

Neonatal hyperuricemia

Serum concentrations and urinary excretion of uric acid were measured in ten normal newborn infants and in 13 patients with the idiopathic respiratory distress syndrome. In the normal infants, serum urate increased from a mean value of 6.0 mg/dl in cord blood to 7.0 mg/dl at 24 hours, followed by a decrease to 3.5 mg/dl over the next three days. The infants with IRDS had higher serum urate concentrations during the first three days of life, and the urinary excretion of uric acid over the period of 12 to 36 hours of age was also higher than in the normal infants. In both groups of neonates the correlation of maximal serum urate values with the urinary excretion was positive, which indicates that neonatal hyperuricemia is not due to renal retention but to increased production of uric acid. It is postulated that this overproduction results from increased nucleotide breakdown associated with perinatal hypoxia. Because of high serum and urinary uric acid concentrations, maintenance of adequate hydration and urinary flow as well as alkalinization of urine is recommended.

Fractional excretion of uric acid in infancy and childhood. Index of tubular maturation

Normal newborns had a low glomerular filtration rate measured by creatinine clearance which progressively increased to reach adult levels by one year of age when corrected for surface area. There was also an increased fractional excretion of uric acid (34·6% ± 11·2 SD). Progressive maturation of this tubular function was observed within the first year of life. Thereafter, stable levels approaching adult levels of excretion were maintained. Linear regression functions of log-transformed values of fractional excretion of uric acid by weight were fitted separately to the newborns, infants <1 year, and children aged 1 to 7 years. The 3 groups were found to constitute three distinct populations with regard to both the slope of the regression lines and the scatter of values about the line, which decreased significantly from the youngest to the oldest group. In low birthweight infants both glomerular and tubular maturation, as evidenced by these parameters, were related to age rather than to weight. It is suggested that the large urinary uric acid load excreted in the first days of life is facilitated by the concomitant deficiency of acidification and concentration of urine.

A multi-disciplinary catalogue of uric acid literature of interest to behavioural scientists

The research on uric acid encompasses a large number of disciplines and their respective journals. This bibliography (1948 to 1972) was assembled to provide a co-ordinated reference to this source material for behavioural scientists.