Essentials of Pathophysiology
CHAPTER 33
DIABETES MELLITUS AND THE
METABOLIC SYNDROME
PRE LECTURE QUIZ
T
F
T
F
F
Type 2 diabetes is more common than type 1.
 All cells can use fatty acids interchangeably
with glucose for energy.
 Insulin is produced by the pancreatic beta cells
in the islets of Langerhans.
 Hyperglycemia is characterized by headache,
difficulty in problem solving, disturbed or
altered behavior, coma, and seizures.
 Chronic complications of diabetes mellitus refer
only to type 1 diabetes mellitus.

PRE LECTURE QUIZ
Alpha
Insulin
ketoacidosis

______________ lowers the blood glucose concentration by
facilitating the movement of glucose into body tissues.

Glucagon, a polypeptide molecule produced by the
_____________ cells of the islets of Langerhans, maintains
blood glucose between meals and during periods of fasting.

Type __________ diabetes mellitus is characterized by
destruction of the pancreatic beta cells and is characterized
by an absolute lack of insulin, an elevation in blood glucose,
and a breakdown of body fats and protein.

The ________________ syndrome is a condition of
abnormalities that are identified through specific criteria
such as abdominal obesity, elevated triglycerides, elevated
blood pressure, elevated fasting plasma glucose, and
decreased high-density lipoprotein cholesterol (HDL).

Diabetic ____________________ occurs when ketone
production by the liver exceeds cellular use and renal
excretion.
Metabolic
one
ANABOLISM AND CATABOLISM
available foodstuffs
(in blood)
glucose
amino acids
free fatty acids
liver can convert amino acids
and free fatty acids into
ketones
Anabolism
insulin,
anabolic
steroids
Catabolism
glucagon,
epinephrine,
cortisol
stored foodstuffs
(in cells)
glycogen
proteins
triglycerides
INSULIN AND GLUCAGON ARE THE MAIN
CONTROLS
available foodstuffs
(in blood)
glucose
Anabolism
insulin ,
anabolic
steroids
stored foodstuffs
(in cells)
glycogen
amino acids
Catabolism
glucagon ,
proteins
free fatty acids
epinephrine,
cortisol
triglycerides
liver can convert amino acids
and free fatty acids into
ketones
QUESTION
Tell whether the following statement is true or
false.
Anabolic reactions release energy.
ANSWER
False
Rationale: Anabolic reactions use energy to
build/produce/synthesize (like building
proteins from amino acids). Catabolic reactions
break down substances, releasing energy in the
process (like digestion).
SCENARIO
Two women have benign pancreatic tumors.


In one, the tumor is an insulinoma that secretes
insulin
In the other, the tumor is a glucagonoma that
secretes glucagon
Questions:
 What differences do you expect to see between these
two women? Why?

Both of the women have arthritis, but only one is
being treated with corticosteroids. Which one? Why is
the other not receiving corticosteroids?
THE PANCREAS
pancreas
exocrine
pancreas
endocrine
pancreas
releases digestive
juices through a
duct
releases hormones
into the blood
to the
duodenum
endocrine
pancreas:
islets of
Langerhans
alpha
cells
glucagon
beta cells
delta cells
PP cells
insulin
and amylin
somatostatin
pancreatic
polypeptide
FUNCTIONS OF PANCREATIC HORMONES




Glucagon: causes cells to release stored food into
the blood
Insulin: allows cells to take up glucose from the
blood
Amylin: slows glucose absorption in small
intestine; suppresses glucagon secretion
Somatostatin: decreases GI activity; suppresses
glucagon and insulin secretion
QUESTION
Which pancreatic hormone decreases blood
glucose levels?
a. Glucagon
b. Insulin
c. Amylin
d. Somatostatin
ANSWER
Insulin
Rationale: Insulin allows cells to take glucose
from the blood and use it for energy/to make
ATP. Because it stimulates movement of
glucose out of the blood and into the cells,
blood glucose levels decrease when insulin is
released.
b.
DISCUSSION
Think back on your day so far.

When do you think you had your highest
insulin levels?

When do you think you had your lowest
insulin levels?

When did you have your highest glucagon
levels?
DISCUSSION
Review the figure on insulin’s actions.
 If someone lacks insulin, what happens to
his:






Blood glucose levels?
Blood amino acid levels?
Blood pH?
Intracellular fat levels?
Intracellular protein levels?
Cell growth?
DISCUSSION
Review the following diagrams on anabolism/catabolism and
insulin’s mechanism of action.
Questions:
 Identify five things that could go wrong to cause increased
blood glucose
 Which of the cases you identified would be least likely to
respond to insulin?
ANABOLISM AND CATABOLISM
available foodstuffs
(in blood)
glucose
amino acids
free fatty acids
liver can convert amino acids
and free fatty acids into
ketones
Anabolism
insulin,
anabolic
steroids
Catabolism
glucagon,
epinephrine,
cortisol
stored foodstuffs
(in cells)
glycogen
proteins
triglycerides
TYPES OF DIABETES MELLITUS
Type 1: pancreatic beta cell destruction
predominantly by an autoimmune process
 Type 2: a combination of beta cell
dysfunction and insulin resistance
 Other

 Genetic
defects in insulin production
 Genetic defects in insulin action
 Diabetes secondary to other diseases
 Drug interactions

Gestational diabetes mellitus
PATHOGENESIS OF TYPE 2 DIABETES
QUESTION
Tell whether the following statement is true or
false.
Type 2 DM is more common than type 1 DM.
ANSWER
True
Rationale: Type 1 DM is autoimmune (juvenile
diabetes is type 1), and affects only 5–10% of
the diabetic population. Type 2 DM is
associated with risk factors like obesity, poor
diet, and sedentary lifestyle; 90–95% of
diabetics suffer from this type.
METABOLIC SYNDROME

Abdominal obesity

Increased blood triglyceride levels

Decreased HDL levels

Increased blood pressure

Increased fasting plasma glucose
TREATMENTS FOR TYPE 2 DIABETES
ACUTE COMPLICATIONS OF DIABETES

Diabetic ketoacidosis

Hyperglycemic hyperosmolar nonketotic coma

Hypoglycemia

Somogyi effect

Dawn phenomenon
ACUTE COMPLICATIONS OF DIABETES (CONT.)
Discussion
 How would hyperglycemia with ketoacidosis cause:
 Heavy breathing?
 Polyuria?
 Dehydration?
 Which of these would you not see in hyperglycemia
without ketoacidosis?
SCENARIO
You find a man collapsed on the sidewalk.

He is wearing a diabetic alert bracelet and has an
insulin syringe in his briefcase
Questions:

Does he need insulin?

Why or why not?

What signs might help you tell whether he has a
hyperglycemic or hypoglycemic problem?
CHRONIC COMPLICATIONS OF DIABETES
MELLITUS
 Increased glucose levels allow glucose to
bind to proteins in:
 Hemoglobin
 Basement
 Hb A1C has higher O2 affinity
membranes of blood vessels
º
Nephropathy
º
Retinopathy
º
May cause increased risk of atherosclerosis
 Lens
 cataracts
(Porth, C. M. [2005]. Pathophysiology [7th ed.]. Lippincott Williams & Wilkins and
Greenspan, F. & Gardner, D. G. [2004]. Basic and clinical endocrinology [7th ed.]. McGraw-Hill.)
OSMOLARITY IN DIABETES MELLITUS
When blood glucose
is high, increased
blood osmolarity can
cause cells to shrink
 Nerve cells produce
intracellular osmoles
to keep their
osmolarity balanced
with the blood

A
Hypotonic
cell A
shrinks
Cell B is in
osmotic
balance
(Porth, C. M. [2005]. Pathophysiology [7th ed.]. Lippincott Williams &
Wilkins.)
B
OSMOLARITY IN DIABETES MELLITUS (CONT.)


When the client brings
blood glucose back to
normal, the nerve cells
are hyperosmolar to the
blood and gain water,
swelling
Nerve damage may be
caused by swelling,
demyelination, and lack
of O2 secondary to
vascular disease
A
Hypertonic
cell B
swells
Cell A is in
osmotic
balance
B
(Porth, C. M. [2005]. Pathophysiology [7th ed.]. Lippincott Williams &
Wilkins.)
DIABETIC NEUROPATHY

Somatic neuropathy
 Diminished
perception of vibration, pain, and
temperature
 Hypersensitivity to light touch; occasionally,
severe “burning” pain

Autonomic neuropathy
 Defects
in vasomotor and cardiac responses
 Impaired motility of the gastrointestinal tract
 Inability to empty the bladder
 Sexual dysfunction
QUESTION
Which of the following is not a complication of
diabetes mellitus?
a. Nephropathy
b. Retinopathy
c. Neuropathy
d. All of the above are complications of DM.
ANSWER
All of the above are complications of DM.
Rationale: Nephropathy and retinopathy are
caused by increased blood glucose levels that
cause binding of excess glucose to the
basement membranes of the blood vessels of
the kidneys and eyes. Neuropathy is due to
swelling and demyelination of nervous tissue.
d.
DIABETIC FOOT ULCER
Typical Diabetic Foot Ulcer
Advanced Diabetic Foot Ulcer