Diabetes mellitus

THE ENDOCRINE PANCREAS
 Learning Objectives
• Understand the structure of the Pancreas
• Basic understanding of its function
• Endocrine hormones secreted by the Pancreas
• Diabetes Mellitus
• Types of Diabetes
• Risk Factors
• Pathogenesis
• Clinical features
• Complications
•Management
•Islet Tumor
5/20/2013 Dr. Ahmed M Siad
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The Endocrine Pancreas
5/20/2013Dr. Ahmed M Siad
3
 The Pancreas consists of two separate functional
units.
 The exocrine Pancreas 80-85%
 Secretes digestive enzymes into the doudenum
 The Endocrine Pancreas 20-15%
 Secretes a number of different hormones
 The Endocrine pancreas consist of
 One Million of Islets of Langerhans, which are scattered
throughout the gland.
 Each Islet is composed of a cluster of a number of
different cell types.
 Each cell type synthesizing and secreting a

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
Cell Type Hormone Synthesize Hormone action
Beta Cells Insulin Increases glucose entry into cells
Promotes glycogen synthesis
Prevents its breakdown
Promotes libogenesis and prevents
lipolysis
Alpha Cells Glucagon Promotes glycogen breakdown
Promotes gluconeogenesis
Delta Cells Somatostatin Inhibits secretion of insulin glucagon
PP Pancreatic polypeptide Exerts a number of gastrointestinal
affects
Entrochromafin Cells Vasoactive intestinal
polypeptide
Stimulates intestinal fluid secretion
D1 Serotonin Potent vasodilator increases
intestinal motility

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 Insulin
 Glucagon
These Hormones are responsible for maintaining blood sugar
levels.
 Insulin exerts hypoglycemic effect.
 Glucagon exerts hyperglycemic effect.
The two main disorders of the Islet cells are:
Diabetes mellitus
 Islet Tumors

Diabetes mellitus
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 Is a chronic progressive disorder characterized by
an absolute or relative deficiency of Insulin and/or
Insulin resistance, inducing hyperglycemia.
 Classification.
 There are two main types of Diabetes mellitus
1- Type I ( Insulin dependent Diabetes mellitus ( IDDM )
Also called juvenile onset diabetes, which occurs 10% of all
cases.

DM CLASSIFICATION
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 Results from decreased insulin
sensitivity and decreased
pancreatic beta-cell function
2- Type II ( None Insulin
dependent Diabetes Mellitus )
NIDDM
Also called adult onset diabetes,
which accounts for 80-90% of all
cases.

Types of Diabetes Mellitus
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3- Gestational Diabetes.
Induced pregnant diabetes,
usually appear in women
with a family history of
diabetes.
 usually disappears after
delivery but about 1/3 will
develop diabetes within 10
years
 risks of developing are
increased if
 obese
 family history

DM - Risk factors
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 Weight. Being overweight is a primary risk factor for type 2
diabetes. The more fatty tissue you have, the more resistant
your cells become to insulin.
 Fat distribution. If your body stores fat primarily in your
abdomen, your risk of type 2 diabetes is greater than if your
body stores fat elsewhere, such as your hips and thighs.
 Inactivity. The less active you are, the greater your risk of
type 2 diabetes. Physical activity helps you control your
weight, uses up glucose as energy and makes your cells
more sensitive to insulin.
 Family history. The risk of type 2 diabetes increases if your
parent or sibling has type 2 diabetes.
 Race. Although it's unclear why, people of certain races —
including blacks, Hispanics, American Indians and Asian-
Americans — are more likely to develop type 2 diabetes than
whites are.

DM - Risk factors
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 Age. The risk of type 2 diabetes increases as you get
older, especially after age 45. That's probably because
people tend to exercise less, lose muscle mass and gain
weight as they age. But type 2 diabetes is also increasing
dramatically among children, adolescents and younger
adults.
 Prediabetes. Prediabetes is a condition in which your
blood sugar level is higher than normal, but not high
enough to be classified as diabetes. Left untreated,
prediabetes often progresses to type 2 diabetes.
 Gestational diabetes. If you developed gestational
diabetes when you were pregnant, your risk of later
developing type 2 diabetes increases. If you gave birth to
a baby weighing more than 9 pounds (4 kilograms), you're
also at risk of type 2 diabetes.

Pathogenesis of DM
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1- Type I of DM
Typically present in the childhood and is characterized
by complete lack of insulin. Insulin secretion is
inadequate because of destruction of the beta cells in
the Islets.
Three separate but interrelated mechanisms appear to
have a role in this destructive process.
I. Genetic susceptibility
II. Autoimmune reaction
III. Environmental event

Pathogenesis of DM
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 It has been hypothesized that genetic susceptibility
influences certain individuals to the development of an
autoimmune reaction against the beta cells of the islets, and
that this autoimmune reaction is triggered by an
environmental events, e.g. viral infection. Exposure to
chemical toxins.
 Type II of DM
 This type of diabetes usually present in middle age. The
precise pathogenic mechanism is unknown, but obesity and
the genetic factors are important,
 Two mechanism have been theorized.
1- Defective secretion of Insulin by beta cells
2- Resistance of peripheral tissues to the effects of insulin due
to obesity.

How obesity causes diabetes
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 It is ascertained that fat cells release a protein
called pigment epithelium-derived factor (PEDF).
 when this protein is released into the
bloodstream, it causes the liver and muscles to
become resistant to insulin. Insulin causes cells
to take up glucose in the bloodstream, store it
and convert it to energy for the body. When the
cells resist insulin due to excess fat, more insulin
is then produced by the pancreas to counteract
the negative effects, thereby overworking the
pancreas and eventually slowing and stopping
insulin. OR
 Target cell resistance to insulin. Due to decreased
number of insulin receptors.

Clinical Features
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 Type I DM
 The chemical features are related to increased gluconeogenesis and
the hyperglycemia resulting for a lack of insulin.
 Polyuria,
 polydipsia
 Pholyphagia
 Ketoacidosis
 Fats and proteins are metabolized excessively, and
byproducts known as ketone bodies are produced. These
are released to the bloodstream and cause:
Decreased pH (so increased acidity)
 Compensations for metabolic acidosis
 Acetone given off in breath

Type II DM Clinical Features
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DM Complication
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Microvasuclar:
damage to eyes,
kidneys, nerves
(retinopathy,
nephropathy,
neuropathy)
Macro vascular: 2X
risk for heart attack
and stroke, peripheral
vascular disease

DM Complication
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 Eye disease
 important cause of blindness associated with
 Microaneurysm
 Retinal hemorrhage
 retinal edema and exudates
( cotton wool spots )
 Kidney disease
 diabetic nephrosclerosis
 most common cause of renal failure in US
 atherosclerosis of renal arteries
 infections of bladder & kidney

Peripheral neuropathy
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 With damage to the nervous system, a person with
diabetes may not be able to feel his or her feet properly.
Normal sweat secretion and oil production that lubricates
the skin of the foot is impaired. These factors together can
lead to abnormal pressure on the skin, bones, and joints
of the foot during walking and can lead to breakdown of
the skin of the foot. Sores may develop.
 Damage to blood vessels and impairment of the immune
system from diabetes make it difficult to heal these
wounds. Bacterial infection of the skin, connective tissues,
muscles, and bones can then occur. These infections can
develop into gangrene. Because of the poor blood
flow,antibiotics cannot get to the site of the infection
easily. Often, the only treatment for this is amputation of
the foot or leg. If the infection spreads to the bloodstream,
this process can be life-threatening.

Complications of GDM
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 Pre-eclampsia
 Over weight babies

Islet tumors
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 These tumors are quite rare, and they can arise from any of
the cell types present in the islets. The tumors become
manifest through hypersecretion of the hormone produced
by cell type from which the tumor is derived. Islet tumors
may follow a benign or malignant course. The various types
are:
1. Insulinoma: the commonest tumor, It produces insulin,
resulting hypoglycemia.
2. Glucagonoma: induces diabetes. It produces glucagon and
exerts hyperglycemia.
3. Gastrinoma: hypersecrates gastrin, which leads to acid
hypersecretion, resulting zollinger-ellison syndrome.
4. VIPomas: induces watery diarrhea.
5. Somatostatinomas. It produces Somastotatin, which
inhibits insulin secration, hence diabetes.

Patient education
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Food, exercise, meds
Treatment plan
Goals / targets
Self-monitored blood
glucose
Hypoglycemia
Emergency numbers
If insulin: injection
technique, syringe
disposal, storage, etc.
Foot care
Ophthalmic exams
Diabetes Survival Skills:

Diabetes mellitus

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