578
P A R T 6
Drugs acting on the endocrine system
for more information about managing glucose levels
during stress.
Hyperglycaemia
Hyperglycaemia
, or high blood sugar, results when
there is an increase in glucose in the blood. Clinical
signs and symptoms include fatigue, lethargy, irritation,
glycosuria, polyphagia, polydipsia and itchy skin (from
accumulation of wastes that the liver cannot clear). If the
hyperglycaemia goes unchecked, the person will experi-
ence ketoacidosis and CNS changes that can progress to
coma. Signs of impending dangerous complications of
hyperglycaemia include the following:
• Fruity breath as the ketones build up in the system
and are excreted through the lungs
• Dehydration as fluid and important electrolytes are
lost through the kidneys
• Slow, deep respirations (Kussmaul respirations) as the
body tries to rid itself of high acid levels
• Loss of orientation and coma
This level of hyperglycaemia needs to be treated immedi-
ately with insulin. Where available, intravenous insulin
will most rapidly reduce blood glucose levels.
Hypoglycaemia
Hypoglycaemia
, or a blood glucose concentration lower
than 4.4 mmol/L (40 mg/dL), occurs in a number of
clinical situations, including starvation, and if treatment
of hyperglycaemia with insulin or oral agents lowers
the blood glucose level too far. The body immediately
reacts to lowered blood glucose because the cells require
glucose to survive, the neurons being among the cells
most sensitive to the lack of glucose. The initial reaction
to falling blood glucose level is parasympathetic stimu-
lation—increased GI activity to increase digestion and
absorption. Rather rapidly, the SNS responds with a
“fight-or-flight” reaction that increases blood glucose
levels by initiating the breakdown of fat and glycogen to
release glucose for rapid energy. The pancreas releases
glucagon, a hormone that counters the effects of insulin
and works to increase glucose levels and somatosta-
tin, which help the body to conserve energy. In many
cases, the response to the hypoglycaemic state causes a
hyperglycaemic state. Balancing the body’s responses
to glucose is sometimes difficult when one is trying to
treat and control diabetes. Table 38.1 offers a compar-
ison of the signs and symptoms of hyperglycaemia and
hypoglycaemia.
INSULIN
Insulin is the only parenteral hypoglycaemic agent avail-
able for exogenous replacement (Table 38.2). It is used
to treat type 1 diabetes and to treat type 2 diabetes in
adults who have no response to diet, exercise and other
agents. (See Box 38.1 for considerations related to the
use of insulin based on age.) The types of insulin that are
available include insulin analogue or lispro (
Humalog
),
insulin aspart (
NovoRapid
), insulin glargine (
Lantus
),
insulin glulisine (
Apidra
), insulin detemir (
Levemir
),
regular (neutral) insulin (
Actrapid, Humulin R
) and
isophane insulin (
Humulin NPH
).
Originally, insulin was prepared from pork and
beef pancreas. Today, virtually all insulin is prepared
by recombinant DNA technology and is human insulin
produced by genetically altered bacteria. This purer
form of insulin is not associated with the sensitivity
problems that many people developed when using the
animal products. Animal insulins may still be obtained
for people most responsive to them, but they are not
generally used. Box 38.5 describes the various forms
■■
TABLE 38.1 Signs and symptoms of hypoglycaemia and hyperglycaemia
Clinical effects
Hypoglycaemia
Hyperglycaemia
Central nervous
system
Headache, blurred vision, diplopia; drowsiness
progressing to coma; ataxia; hyperactive
reflexes
Decreased level of consciousness, sluggishness
progressing to coma; hypoactive reflexes
Neuromuscular
Paraesthesias; weakness; muscle spasms;
twitching progressing to seizures
Weakness, lethargy
Cardiovascular
Tachycardia; palpitations; normal to high blood
pressure
Tachycardia; hypotension
Respiratory
Rapid, shallow respirations
Rapid, deep respirations (Kussmaul); acetone-
like or fruity breath
Gastrointestinal
Hunger, nausea
Nausea; vomiting; thirst
Other
Diaphoresis; cool and clammy skin; normal
eyeballs
Dry, warm, flushed skin; soft eyeballs
Laboratory tests Urine glucose negative; blood glucose low
Urine glucose strongly positive; urine ketone
levels positive; blood glucose levels high
Onset
Sudden; person appears anxious, drunk;
associated with overdose of insulin, missing a
meal, increased stress
Gradual; person is slow and sluggish; associated
with lack of insulin, increased stress
