Basic Concepts of Fluid and Electrolyte Therapy

DKA and HONK represent the two extremes of the spectrum of
decompensated diabetes (Table 23), although intermediate cases are
not infrequent, depending on the precipitating cause and the percentage
loss of insulin secretion. In both situations, hyperglycaemia causes
an osmotic diuresis with excessive urinary losses of salt, water, and
potassium, leading to ECF and intravascular volume depletion and the
risk of prerenal acute kidney injury (AKI).
With both types of decompensation, potassium is lost from cells and
excreted in the urine causing a deficit, which only becomes apparent
as hypokalaemia once the anabolic effect of insulin treatment is felt.
In severe cases the rate of K + loss from cells, combined with pre-renal
AKI, can cause hyperkalaemia (>5.5 mmol/l) with the risk of cardiac
arrest.
The presence of acidosis may present diagnostic problems. Although
most cases with ketonuria and features of metabolic acidosis are suffering
from ketoacidosis, this cannot always be assumed, particularly
where there are other potential causes of acidosis, e.g. renal or circulatory
failure. For this reason it is important to measure blood concentrations
of lactate and of ketones, particularly -hydroxybutyrate
and chloride, including the anion gap and strong ion difference in
order to establish the diagnosis beyond doubt.
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