Basic Concepts of Fluid and Electrolyte Therapy

10. The Patient with Diabetes Mellitus
Introduction
Although, with better management of diabetes in recent years,
admissions due to loss of control with or without ketosis are less frequent
than in former times, nonetheless cases of decompensated diabetes
with keto-acidosis (DKA) or hyperosmolar non-ketotic (HONK)
syndrome form an important part of every doctor’s experience of
acute medicine. Similarly, with the rising prevalence of diabetes, particularly
type 2, the perioperative fluid and metabolic management of
diabetic patients has become increasingly important.
Decompensated Diabetes
Type 1 diabetes: insulin secretion is impaired in most cases by >90%.
This means that, with reduced or absent administration of insulin or
with increased insulin demand due to intercurrent illness, not only
does the blood glucose rise but control over fat and protein metabolism
is lost, leading to keto-acidosis (-hydroxybutyrate being the
main keto-acid) and protein catabolism.
Type 2 diabetes: This is associated initially with insulin resistance but
only partial loss of secretion. At this stage, there is sufficient circulating
insulin to prevent ketosis but not to control the blood glucose.
Decompensation is usually associated with HONK in which the blood
glucose rises to higher levels than those seen in DKA (it only takes a
fraction of the amount of insulin to control ketosis as it does to control
blood glucose). With loss of insulin secretion over the years and
with severe intercurrent illness type 2 diabetics can develop keto -
acidosis, requiring insulin, even though they may be able to revert to
tablet treatment afterwards .
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