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U N I T 9
Endocrine System
blood glucose levels also may impair host defenses
such as the function of neutrophils and immune cells.
Polymorphonuclear leukocyte function, particularly
adherence, chemotaxis, and phagocytosis, is depressed
in persons with diabetes, particularly those with poor
glycemic control.
R E V I EW E X E R C I S E S
1.
A 6-year-old boy is admitted to the emergency
department with nausea, vomiting, and abdominal
pain. He is very lethargic; his skin is warm, dry, and
flushed; his pulse is rapid; and he has a sweet smell
to his breath. His parents relate that he has been very
thirsty during the past several weeks, his appetite has
been poor, and he has been urinating frequently. His
initial plasma glucose is 420 mg/dL (23.1 mmol/L),
and a urine test for ketones is strongly positive.
A.
What is the most likely cause of this boy’s
elevated blood glucose and ketonuria?
B.
Explain his presenting signs and symptoms
in terms of the elevated blood glucose and
metabolic acidosis.
C.
What type of treatment will this boy require?
2.
A 53-year-old accountant presents for his routine
yearly examination. His history indicates that
on two prior occasions he had a fasting plasma
glucose of 120 mg/dL (6.7 mmol/L). Currently
he is asymptomatic. He has no other medical
problems and does not use any medications. He
neither smokes nor drinks alcohol. His father was
diagnosed with type 2 diabetes at age 60 years. His
physical examination reveals a blood pressure of
125/80 mm Hg,
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Pharmacologic agents used in the management
of diabetes include injectable insulin, injectable
non-insulin agents including amylin and GLP-1
analogs, and oral diabetic drugs.Type 1 diabetes
(and sometimes type 2 diabetes) requires
treatment with injectable insulin. Oral antidiabetic
drugs include the insulin secretagogues,
biguanides,
α
-glucosidase inhibitors,
thiazolidinediones, and incretin-based therapies.
These drugs require a functioning pancreas and
may be used in the treatment of type 2 diabetes.
■■
The metabolic disturbances associated with
diabetes affect almost every body system.The
acute complications of diabetes include diabetic
ketoacidosis, hyperglycemic hyperosmolar state,
and hypoglycemia in people with insulin-treated
diabetes.The chronic complications of diabetes
affect the microvascular system (including the
retina, kidneys, and peripheral nervous system)
and the macrovascular system (coronary,
cerebrovascular, and peripheral arteries).The
diabetic foot is usually a combination of both
microvascular and macrovascular dysfunction.
Infection is also a frequent occurrence and is
more likely to be severe in the diabetic patient.
SUMMARY CONCEPTS
■■
Diabetes mellitus is a disorder of carbohydrate,
protein, and fat metabolism resulting from an
imbalance between insulin availability and insulin
need. In type 1 diabetes, there is destruction of
beta cells and an absolute insulin deficiency.Type
2 diabetes is characterized by a lack of insulin
availability or effectiveness. Diabetes can also
occur secondary to some other condition that
destroys beta cells (e.g., pancreatic disorders)
or endocrine diseases that cause increased
production of glucose by the liver and decreased
use of glucose by the tissues (e.g., Cushing
syndrome). Gestational diabetes develops during
pregnancy.
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The metabolic syndrome represents a
constellation of metabolic abnormalities
characterized by obesity, insulin resistance,
high triglyceride levels and low HDL levels,
hypertension, cardiovascular disease, and
increased risk for development of type 2 diabetes.
■■
The most commonly identified symptoms
of type 1 diabetes are polyuria, polydipsia,
polyphagia, and weight loss despite normal or
increased appetite. Although persons with type 2
diabetes may present with one or more of these
symptoms, they are often asymptomatic initially.
The diagnosis of diabetes mellitus is based on
clinical signs of the disease, fasting blood glucose
levels, random plasma glucose measurements,
and results of the glucose tolerance test.
Glycosylation involves the irreversible attachment
of glucose to the hemoglobin molecule; the
measurement of glycosylated hemoglobin (A1C)
provides an index of blood glucose levels over
several months. Self-monitoring of capillary
blood glucose provides a means of maintaining
near-normal blood glucose levels through
adjustment of insulin dosage.
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Dietary management of diabetes focuses on
maintaining a well-balanced diet, controlling
calories to achieve and maintain an optimum
weight, and regulating the distribution of
carbohydrates, proteins, and fats.
