This document discusses types and complications of diabetes mellitus. It begins with an outline that defines diabetes and classifies diabetes types and complications as acute or chronic. It then discusses the various types of diabetes in more detail, including type 1 diabetes pathogenesis and genetic and environmental risk factors. Type 2 diabetes risk factors and pathophysiology involving insulin resistance and secretion are covered. Other specific rare genetic types are defined. The document concludes by examining acute complications like diabetic ketoacidosis and chronic complications involving microvascular and macrovascular involvement, as well as theories around how hyperglycemia may lead to these complications. Glycemic control studies proving the benefits of control are also summarized.

1. Diabetes
mellitus
types and
complications

2. Outline of seminar
– Definition of diabetes.
– Classification of diabetes.
– Description-types of diabetes.
– Classification of complications (acute & chronic)
– Description of complications.
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3. Definition of diabetes.3

4. Classification of diabetes.4

5. Classification5

6. 6

7. Other specific types of diabetes
A. Genetic defects ofβ- cell function
characterized by mutations in:
– 1. Hepatocyte nuclear transcription factor
(HNF) 4 (MODY 1)
– 2. Glucokinase (MODY 2)
– 3. HNF-1 (MODY 3)
– 4. Insulin promoter factor-1 (IPF-1; MODY 4)
– 5. HNF-1 (MODY 5)
– 6. NeuroD1 (MODY 6)
– 7. Mitochondrial DNA
– 8. Subunits of ATP-sensitive potassium
channel
– 9. Proinsulin or insulin conversion
B. Genetic defects in insulin action
– 1. Type A insulin resistance
– 2. Leprechaunism
– 3. Rabson-Mendenhall syndrome
– 4. Lipodystrophy syndromes
C. Diseases of the exocrine pancreas—
pancreatitis, pancreatectomy,
neoplasia, cystic fibrosis,
hemochromatosis, fibrocalculous
pancreatopathy, mutations in carboxyl
ester lipase
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8. – D. Endocrinopathies—acromegaly,
Cushing's syndrome, glucagonoma,
pheochromocytoma,
hyperthyroidism, somatostatinoma,
aldosteronoma
– E. Drug- or chemical-induced—
Vacor, pentamidine, nicotinic acid,
glucocorticoids, thyroid hormone,
diazoxide, -adrenergic agonists,
thiazides, phenytoin, -interferon,
protease inhibitors, clozapine
– F. Infections—congenital rubella,
cytomegalovirus, coxsackie
– G. Uncommon forms of immune-
mediated diabetes—"stiff-person"
syndrome, anti-insulin receptor
antibodies
– H. Other genetic syndromes
sometimes associated with
diabetes—Down's syndrome,
Klinefelter's syndrome, Turner's
syndrome, Wolfram's syndrome,
Friedreich's ataxia, Huntington's
chorea, Laurence-Moon-Biedl
syndrome, myotonic dystrophy,
porphyria, Prader-Willi syndrome
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9. Classification of diabetes.
– DM is classified on the basis of the pathogenic process that leads to
hyperglycemia
– Type 1 diabetes is the result of complete or near-total insulin deficiency.
– Type 2 DM is a heterogeneous group of disorders characterized by
variable degrees of insulin resistance, impaired insulin secretion, and
increased glucose production.
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10. Gestational Diabetes
Mellitus (GDM)
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11. Spectrum of glucose
homeostasis and diabetes
mellitus (DM).
Diabetes is preceded by
a phase of abnormal
glucose homeostasis
as the pathogenic
processes progresses.
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12. Epidemiology12

14. The National Diabetes Data Group and
World Health Organization have issued
diagnostic criteria for DM
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15. Glucose tolerance
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16. Based on the OGTT-2 h after a
75-g oral glucose load
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17. Type 1 diabetes-Pathogenesis17

18. Genetic Considerations
– Susceptibility to type 1 DM involves multiple genes.
– The major susceptibility gene for type 1 DM is located in the HLA region on
chromosome 6. Polymorphisms in the HLA complex account for 40–50% of
the genetic risk of developing type 1 DM.
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19. Immunologic Markers
– Islet cell autoantibodies (ICAs) are a composite of several different antibodies
directed at pancreatic islet molecules such as GAD, insulin, and IA-2/ICA-512
and serve as a marker of the autoimmune process of type 1 DM.
– Assays for autoantibodies to GAD-65 are commercially available.
– Testing for ICAs can be useful in classifying the type of DM as type 1 and in
identifying nondiabetic individuals at risk for developing type 1 DM
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20. Environmental Factors
– Numerous environmental events have been proposed to trigger the
autoimmune process in genetically susceptible individuals; however, none
have been conclusively linked to diabetes.
– viruses (coxsackie and rubella most prominently), bovine milk proteins, and
nitrosourea compounds.
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21. Pathophysiology
– Islet cell types [alpha cells (glucagon-producing), delta cells (somatostatin-
producing), or PP cells (pancreatic polypeptide-producing)] are functionally
and embryologically similar to beta cells and express most of the same
proteins as beta cells, they are inexplicably spared from the autoimmune
process.
– Pancreatic islet molecules targeted by the autoimmune process include
insulin, glutamic acid decarboxylase (GAD, the biosynthetic enzyme for the
neurotransmitter GABA), ICA-512/IA-2 (homology with tyrosine
phosphatases), and phogrin (insulin secretory granule protein).
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23. Pathogenesis
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infection
puberty

25. Type 2 DM
– Insulin resistance and abnormal insulin secretion are central to the
development of type 2 DM.
– polygenic and multifactorial since in addition to genetic susceptibility,
environmental factors (such as obesity, nutrition, and physical activity)
modulate the phenotype.
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26. Genetic Considerations
– Individuals with a parent with type 2 DM have an increased risk of
diabetes; if both parents have type 2 DM, the risk approaches 40%.
– Insulin resistance, as demonstrated by reduced glucose utilization in
skeletal muscle, is present in many nondiabetic, first-degree relatives of
individuals with type 2 DM.
– The genes that predispose to type 2 DM are incompletely identified.
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27. Genetic Considerations
– Transcription factor 7-like 2 gene that has been associated with type 2
diabetes in several populations and with impaired glucose tolerance in
one population at high risk for diabetes.
– Genetic polymorphisms associated with type 2 diabetes have also been
found in the genes encoding the peroxisome proliferators-activated
receptor-, inward rectifying potassium channel expressed in beta cells,
zinc transporter expressed in beta cells, IRS, and calpain 10.
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28. Pathophysiology
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29. Pathophysiology
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30. Insulin resistance
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PI-3kinase
defect
Accumulation of
lipids in sk
muscles
Decreased
mitochonrial
ATP

31. Impaired insulin secretion
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33. Obesity
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adipokine

34. Risk Factors for Type 2 Diabetes
Mellitus
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36. Genetically Defined, Monogenic
Forms of Diabetes Mellitus.
– 6 different variants of Maturity
onset diabetes of the young
(MODY)caused by mutations in
genes encoding islet-enriched
transcription factors or
glucokinase are transmitted as
autosomal dominant disorders.
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37. Genetically Defined, Monogenic
Forms of Diabetes Mellitus.
– MODY 1, MODY 3, and MODY 5
are caused by mutations in the
hepatocyte nuclear transcription
factor (HNF) 4, HNF-1α, and HNF-
1β, respectively.
– These transcription factors are
expressed in the liver pancreatic
islets and kidney.
– These factors most likely affect
islet development or the
expression of genes important in
glucose-stimulated insulin
secretion or the maintenance of
beta cell mass.
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38. MODY 4
– MODY 4 is a rare variant caused by mutations in the insulin promoter factor
(IPF) 1, which is a transcription factor that regulates pancreatic development
and insulin gene transcription.
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39. MODY 2
– Mutations in the glucokinase
gene, have mild-to-moderate,
stable hyperglycemia that does
not respond to oral hypoglycemic
agents.
– Glucokinase catalyzes the
formation of glucose-6-phosphate
from glucose, a reaction that is
important for glucose sensing by
the beta cells and for glucose
utilization by the liver.
– As a result of glucokinase
mutations, higher glucose levels
are required to elicit insulin
secretory responses, thus altering
the set point for insulin secretion
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40. Acute Complications of DM
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Associated with absolute or relative
insulin deficiency, volume depletion, and
acid-base abnormalities

41. Diabetic ketoacidosis (DKA).
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42. DKA results from relative or absolute
insulin deficiency combined with counter-
regulatory hormone excess
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43. The decreased ratio of
insulin to glucagon
promotes
gluconeogenesis,
glycogenolysis, and
ketone body formation in
the liver, as well as
increases in substrate
delivery from fat and
muscle (free fatty acids,
amino acids) to the liver.
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45. Clinical Features
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46. Hyperglycemic
hyperosmolar state (HHS).
– HHS is primarily seen in individuals with type 2 DM.
– HHS is seen in an elderly individual with type 2 DM, with a several week
history of polyuria, weight loss, and diminished oral intake that
culminates in mental confusion, lethargy, or coma.
– The physical examination reflects profound dehydration and
hyperosmolality and reveals hypotension, tachycardia, and altered
mental status.
– Notably absent are symptoms of nausea, vomiting, and abdominal pain
and the Kussmaul respirations characteristic of DKA.
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47. Pathophysiology
– Relative insulin deficiency and inadequate fluid intake are the underlying
causes of HHS.
– Insulin deficiency increases hepatic glucose production (through
glycogenolysis and gluconeogenesis) and impairs glucose utilization in
skeletal muscle.
– Hyperglycemia induces an osmotic diuresis that leads to intravascular
volume depletion, which is exacerbated by inadequate fluid replacement.
– The absence of ketosis in HHS is not completely understood.
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48. Chronic Complications of DM
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49. Chronic Complications of DM
VASCULAR
Microvascular
– Eye disease
– Retinopathy
(nonproliferative/proliferative)
Macular edema
– Neuropathy
– Sensory and motor (mono- and
polyneuropathy)
– Autonomic
– Nephropathy
Macrovascular
– Coronary artery disease
– Peripheral arterial disease
– Cerebrovascular disease
NON-VASCULAR
– Gastrointestinal (gastroparesis,
diarrhea)
– Genitourinary (uropathy/sexual
dysfunction)
– Dermatologic
– Infectious
– Cataracts , Glaucoma
– Periodontal disease
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50. Chronic Complications of DM
– The risk of chronic complications increases as a function of the duration of
hyperglycemia; they usually become apparent in the second decade of
hyperglycemia.
– Since type 2 DM often has a long asymptomatic period of hyperglycemia,
many individuals with type 2 DM have complications at the time of
diagnosis.
– The microvascular complications of both type 1 and type 2 DM result from
chronic hyperglycemia.
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51. Chronic Complications of
DM
– Evidence implicating a causative role for chronic hyperglycemia in the
development of macrovascular complications is less conclusive.
– coronary heart disease events and mortality are two to four times greater
in patients with type 2 DM.
– These events correlate with fasting and postprandial plasma glucose levels
as well as with the A1C.
– Other factors (dyslipidemia and hypertension) also play important roles in
macrovascular complications
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52. Mechanisms of
Complications
– Hyperglycemia is an important etiologic factor leading to complications
of DM.
– Mechanisms by which it leads to such diverse cellular and organ
dysfunction is unknown.
– Four prominent theories, which are not mutually exclusive, have been
proposed to explain how hyperglycemia might lead to the chronic
complications of DM.
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53. THEORY 1
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55. THEORY 2
– Hyperglycemia increases glucose metabolism via the sorbitol pathway.
– Intracellular glucose is predominantly metabolized by phosphorylation
and subsequent glycolysis, but when increased, some glucose is converted
to sorbitol by the enzyme aldose reductase.
– Increased sorbitol concentration alters redox potential, increases cellular
osmolality, generates reactive oxygen species, and likely leads to other
types of cellular dysfunction.
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56. THEORY 3
– Hyperglycemia increases the formation of diacylglycerol leading to
activation of protein kinase C (PKC).
– PKC alters the transcription of genes for fibronectin, type IV collagen,
contractile proteins, and extracellular matrix proteins in endothelial cells
and neurons.
– Inhibitors of PKC are being studied in clinical trials.
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57. THEORY 4
– Hyperglycemia increases the flux through the hexosamine pathway, which
generates fructose-6-phosphate, a substrate for O-linked glycosylation and
proteoglycan production.
– The hexosamine pathway may alter function by glycosylation of proteins
such as endothelial nitric oxide synthase or by changes in gene expression
of transforming growth factor (TGF-) or plasminogen activator inhibitor-1
(PAI-1).
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58. Unifying theory
– A possible unifying mechanism is that hyperglycemia leads to increased
production of reactive oxygen species or superoxide in the mitochondria;
these compounds may activate all four of the pathways.
– Although hyperglycemia serves as the initial trigger for complications of
diabetes, it is still unknown whether the same pathophysiologic processes
are operative in all complications or whether some pathways predominate
in certain organs.
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Glycemic
Control and
Complications

60. DCCT, UKPDS, and
Kumamoto study
– chronic hyperglycemia plays a causative role in the pathogenesis of
diabetic microvascular complications.
– These landmark studies prove the value of metabolic control and
emphasize the importance of
– (1) intensive glycemic control in all forms of DM
– (2) early diagnosis and strict blood pressure control in type 2 DM.
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61. Glycemic Control and Complications
– The Diabetes Control and
Complications Trial (DCCT)
provided definitive proof that
reduction in chronic
hyperglycemia can prevent many
of the early complications of type
1 DM.
– Improvement of glycemic control
reduced nonproliferative and
proliferative retinopathy (47%
reduction), microalbuminuria (39%
reduction), clinical nephropathy
(54% reduction), and neuropathy
(60% reduction).
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62. Ophthalmologic Complications
of Diabetes Mellitus
– Diabetic retinopathy is classified into two
stages:
– nonproliferative
– proliferative
– loss of retinal pericytes, increased retinal
vascular permeability, alterations in retinal
blood flow, and abnormal retinal
microvasculature, all of which lead to retinal
ischemia.
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63. Renal Complications of
Diabetes Mellitus
– Chronic hyperglycemia leads to ESRD,
though incompletely defined, involve the
effects of soluble factors (growth factors,
angiotensin II, endothelin, AGEs),
hemodynamic alterations in the renal
microcirculation (glomerular hyperfiltration
or hyperperfusion, increased glomerular
capillary pressure), and structural changes
in the glomerulus (increased extracellular
matrix, basement membrane thickening,
mesangial expansion, fibrosis).
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64. Neuropathy and Diabetes
Mellitus
– Manifests as polyneuropathy,
mononeuropathy and autonomic
neuropathy.
– Development of neuropathy correlates with
the duration of diabetes and glycemic
control.
– Both myelinated and unmyelinated nerve
fibers are lost.
– The most common form of diabetic
neuropathy is distal symmetric
polyneuropathy.
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65. Gastrointestinal/Genitourinary
Dysfunction
– GI symptoms are delayed gastric emptying (gastroparesis) and altered
small- and large-bowel motility (constipation or diarrhea).
– Diabetic autonomic neuropathy may lead to genitourinary dysfunction
including cystopathy, erectile dysfunction, and female sexual dysfunction.
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66. Cardiovascular Morbidity
and Mortality
– Cardiovascular disease is increased in
individuals with type 1 or type 2 DM.
– The prognosis for individuals with diabetes
who have CAD or MI is worse than for
nondiabetics.
– CAD is more likely to involve multiple
vessels in individuals with DM.
– Evidence that improved glycemic control
reduces cardiovascular complications in DM
is inconclusive
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67. Cardiovascular Morbidity
and Mortality
– Individuals with insulin resistance and type 2
DM have elevated levels of plasminogen
activator inhibitors (especially PAI-1) and
fibrinogen, which enhances the coagulation
process and impairs fibrinolysis, thus
favoring the development of thrombosis.
– Diabetes is also associated with endothelial,
vascular smooth-muscle, and platelet
dysfunction.
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68. Infections
– Individuals with DM have a greater frequency and severity of infection.
– Incompletely defined abnormalities in cell-mediated immunity and
phagocyte function associated with hyperglycemia, as well as diminished
vascularization.
– Hyperglycemia aids the colonization and growth of a variety of organisms
(Candida and other fungal species).
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69. Dermatologic Manifestations
–wound healing
– skin ulcerations.
–Diabetic dermopathy
–bullosa diabeticorum
– Necrobiosis lipoidica
diabeticorum
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