Glucagon Is Very Unlikely to Have Caused Hyponatremia

To the Editior—

Belik et al ¹ recommend that glucagon should not be used to treat hypoglycemia in preterm infants. This is because they believe that it caused marked hyponatremia in a 35-week gestation triplet. We believe they have misinterpreted their patient’s pathophysiology, and suggest an alternative explanation for the hyponatremia.

It is difficult to reinterpret their case precisely because their figure has a number of errors, including a nonlinear x axis, and individual clinical laboratory measurements that have been ascribed error bars (and which vary widely between spot values of similar magnitude). Most importantly, the graphs of plasma sodium concentrations and platelet counts must be wrong because the values reported in the text do not correspond with the plotted values. Neither swapping their labels nor their axis scales corrects this. However, the graphed and described values correspond if it is assumed that the upper line represents the platelet count and should have the 0 to 200 scale from the lower axis, and that the lower line is the sodium concentration with a range of 110 to 140 mmol/L.

What is clear is that the infant had been hypoglycemic and had an unexplained convulsion at 93 hours of age. Assuming the graph correction we describe above, the plasma sodium …