Diabetes Mellitus
Diabetes Mellitus refers to a Group of disorders characterized by:
• Elevated blood glucose concentrations
• Disordered insulin metabolism
• Unable to secrete sufficient insulin, use insulin effectively or both
Normal Insulin secretions
• Insulin Increase after ingestion of food – enables the muscle &
adipose cells to take up newly absorbed glucose from the blood
• Insulin Occur between meals in smaller amounts to restrain the
glucose-raising actions of glucagon and the breakdown of liver
glycogen.
In diabetes:
• Insulin secretions may be impaired Cells that are normally responsive
to insulin may become resistant to its effects or both.
• This leads to: Reduced utilization of glucose in muscle and adipose
cells and unrestrained gluconeogenesis in the liver – resulting in
hyperglycemia
• The result is: Hyperglycemia which can cause damage to blood
vessels, nerves, and tissues
• Hyperglycemia: marked elevation in blood glucose levels
Symptoms of Diabetes Mellitus
• Glycosuria
(At the concentration at which the kidney begin to pass glucose into urine)
• Frequent urination (polyuria)
(The presence of glucose in the urine draws additional water from the
blood and increasing the amount of urine)
• Dehydration, dry mouth
• Increased thirst (polydipsia)
• Weight loss
• Increased hunger (polyphagia)
• Blurred vision
• Fatigue
• (related to altered energy metabolism and dehydration )
• Increased infections
(Due to impaired circulation or weakened immune function).
Diagnosis of Diabetes Mellitus
Based primarily on plasma glucose levels, which can be measured
1-Under fasting conditions
Fasting plasma glucose (≥8 hours) ≥126 mg/dL
2-Random times during the day
Random plasma glucose of ≥200 mg/dL and classic symptoms
Polyuria, polydypsia, unexplained weight loss
3-Oral glucose tolerance test
Patient ingests a 50 or 75 gram glucose load Plasma glucose is measured
at one or more time intervals following glucose ingestion.
• Plasma glucose of ≥200 mg/dL, 2 hours after consuming 75-gram
glucose load
Pre-diabetes
The term pre-diabetes is used when:
1- Fasting glucose between normal and diabetic ( 100 – 125 mg/dL ) .
2-Blood glucose between 140 – 200 mg/dL, 2 hours after consuming 75gram glucose load
Pre-diabetes also called impaired fasting glucose
Types of Diabetes Mellitus
Diabetes Type 1 (DM1- T1DM)
 Account for 5-10 % of cases
 caused by automimmune destruction of pancreatic beta cells
 Occurs during childhood or adolescence
 Symptoms may appear abruptly
 Classic symptoms of T1DM are:
• Frequent urination
• Weight loss
• Increased thirst
• Ketoacidosis may occur due to excessive production of
ketone bodies
Diabetes Type 2 (DM2- T2DM)
Account for 90-95 % of cases Principal defect is insulin resistance .To
compensate ,pancreas secretes larger amounts of insulin and
hyperinsulinemia occurs
Insulin resistance : reduced sensitivity to insulin in muscle, adipose, and
liver cells
Hyperinsulinemia : abnormally high levels of insulin in the blood
• Over time, pancreas becomes less able to compensate
and hyperglycemia worsens
•
This leads to impaired insulin secretion and reduced
plasma insulin concentrations
Acute Complications of Diabetes Mellitus
Caused by a severe lack of insulin. It Develops within hours or a few
days.Causes unrestrained breakdown of triglycerides in adipose tissue excessive release of fatty acids into blood stream.Blood glucose
concentrations usually exceed 250 mg/dL and may rise above 1000 mg/dL
ketoacidosis : results from the increased production of ketone bodies that
lower blood pH- typically falls below 7.3
2-Hypoglycemia
• Hypoglycemia : Abnormally low blood glucose levels- fall below
70mg/dL.
• Arises from inappropriate management of DM .Most often occurs in
DMI but accounts for 3-4 % of deaths in insulin treated patients .
Causes
•
•
•
•
Excessive amount of insulin or antidiabetic drugs
Prolonged exercise
Skipped or delayed meals, inadequate food intake
Consuming alcohol without any food
Symptoms
• Sweating
• Shakiness
• Heart palpitations
• Slurred speech
• Double vision
• Irritability
o Mental confusion may prevent person from recognizing
problem and treating it with glucose tablets, juice or candy.
o If occurs during sleep so patients may be unaware of its
presence
o Prolonged hypoglycemia may result in permanent brain
damage
Chronic Complications
• Prolonged exposure to high glucose concentrations destroys cells and
tissues.
• Glucose and glucose fragments react with proteins to form advanced
glycation end products (AGEs) these compounds accumulate and
cause damage within cells and blood vessels.
• Excessive glucose promotes also the production and accumulation of
sorbitol which increases oxidative stress and in turn contributes to
cell injury
Complications typically affect :
1-Large blood vessels (macrovascular complication)
 The damage caused by diabetes accelerates the development
of atherosclerosis that affects coronary arteries and arteries in
limbs
 DM2 patients usually have multiple cardiovascular risk factors
( hypertension, abnormal blood lipids, obesity
 DM patients have increased tendencies for thrombosis (blood
clot formation)
 Impaired blood flow to limbs leads to pain upon walking and
can also leads to development of foot ulcers that can lead to
gangrene and may require amputations.
2-Small blood vessels (microvascular complication)
a-Diabetic retinopathy: damage to small vessels in the retina
80% of patients with diabetes develop retinopathy by 15 yrs. after
diagnosis . Intensive management substantially reduces risk
b-Diabetic nephropathy :damage to small vessels (glomeruli) of the kidneys
prevents adequate filtration of the blood.Occurs in later stages of DM 1 &
DM 2
• End-stage renal disease occurs : 30-35% of patients with DM 1
20% of those with DM 2.Intensive management help slow progression.
3-Nervous system ( neuropathy)
Diabetic Neuropathy: Nerve degeneration It occurs in 50% of DM cases
 Extent of nerve damage dependent upon severity and duration
of hyperglycemia
 Other manifestations include sweating abnormalities, sexual
dysfunction, constipation, and delayed stomach emptying.
Goals of DM Treatment
1. Maintain blood glucose levels within a desirable range
2. Maintain healthy blood lipid concentrations
3. Controlling blood pressure
4. Managing weight
All the previous goals aim to prevent or reduce the risk of complications.
Evaluating DM Treatment
• Effectiveness of DM treatment is evaluated by monitoring glycemic
status
• Good glycemic control requires frequent home monitoring of blood
glucose (BG) using a glucose meter ( self-monitoring of blood glucose
–SMBG:Home monitoring of glucose levels using a glucose meter).
• DM1 should monitor BG three or more times daily
•
DM 2 the recommended frequency depends on specific needs of
patients.
Glycated/ glycosylated hemoglobin (HbA1c):
• HbA1c: is a blood test to determine how well blood glucose has been
controlled for the last 2-3 months . It measures the hemoglobin
molecules to which glucose has been attached.
• Assists health care providers to evaluate long-term glycemic
control (life cycle of RBC)
• HbA1c < 6% for non-diabetic persons
•
The goal of DM treatment is an HbA1c< 7%
Monitoring for long term complications
• Ketone testing – checks for development of ketoacidosis
 DM1 – during acute illness, stress & pregnancy
• Blood pressure monitoring
• Lipid screening – annually
• Physical examinations ( eyes-foot)
Body weight in DM 1 and 2
 Body weight in DM 1
 DM 1 patients are less likely to be overweight
 Excessive weight gain is unwanted side effect of improved
glycemic control .
 The cause of weight gain is unclear but may be related to
stimulating fat synthesis by insulin.
 Growth patterns and weight gain of growing children should
be routinely monitored for sufficient energy intake.
Body weight in DM 2
 Excessive body fat worsens insulin resistance so weight loss is
recommended
 Moderate weight loss improves glycemic control, blood lipid
levels, blood pressure
 Weight loss is beneficial early in course of diabetes before
insulin secretion has diminished
 Positive effects appear to be related to kcaloric restriction
rather than to weight loss itself
 Not all DM 2 patients are obese or overweight. Older adults
often underweight. Low body weight increases risks of
morbidity and mortality in these persons
Medical Nutrition Therapy
1-Total carbohydrate intake
 The more grams of carbohydrate the greater the glycemic
response after meals.
 Carbohydrate recommendation is based on metabolic needs
(type of DM-degree of individual tolerance)
 The amount must be consistent at meals and snacks to help
reduce fluctuations in BG between meals.
 Low-carbohydrate diets (<130 grams/day) are not
recommended
Carbohydrate Sources
• Different carbohydrate-containing foods have different effects on
blood glucose levels; for example, consuming a portion of white rice
may cause blood glucose to rise more than would consuming a
similar portion of barley.
Glycemic effect of foods is influenced by
• Type of carbohydrate
• How food processed or prepared
• Fiber content
• Other foods included in the meal
• Individual tolerances
The glycemic index (GI):A ranking of carbohydrate foods based on their
average glycemic effect.
• The glycemic index may be helpful when making food choices - not
primary consideration when treating DM
• High-fiber, whole-grain products have more moderate effects on
blood glucose that highly processed foods are among the foods
frequently recommended for persons with diabetes.
Fiber
 Fiber recommendations are similar to those for general
population( 21-38 g /day).
 People with diabetes are encouraged to include fibenter-rich
foods such as legumes, whole-grain cereals, fruits, and
vegetables
 Some research suggests fiber intake of 50 g or more per day
may improve glycemic control – benefits not consist
Sugars
 Sugar and sugary foods are not restricted and should be
counted as part of daily carbohydrate allowance
 Choose foods and beverages with little added sugar or kcaloric
sweeteners
 Sugars and sugary foods must be counted as part of the
 daily carbohydrate allowance.
 Although fructose has a minimal glycemic effect , its use as
added sweetener may adversely affect blood lipid levels – not
referring to naturally occurring fructose
 Artificial sweeteners may be used (aspartame, saccharin,
sucralose) used in place of sugar
Dietary fat
 people with diabetes are at risk for cardiovascular disease
 Saturated fat should be limited to < 7% of kcalories
 Cholesterol intake < 200 mg daily
 Trans fat intake should be minimized
Protein
 Protein intake is 15-20% total kcalories as healthy population
 Some studies suggested that higher protein intake may
improve glycemic control and increase satiety. long term effect
is unknown
 in addition, higher protein intakes discouraged because it may
be detrimental to kidney function
Micronutrients intake
 Micronutrient intakes of DM patients are the same as healthy
population
 Supplementation is not recommended unless nutrient
deficiencies develop
 Some studies suggest that chromium supplementation can
improve glycemic control in persons with DM2 – results
inconsistent
Insulin Therapy
• Insulin therapy is necessary for people who cannot produce enough
insulin to meet metabolic needs
• So it is requited by people with T1DM and those with T2DM who
cannot maintain glycemic control with antidiabetic drugs, diet and
exercise.
Ideal treatment is one that mimics insulin secretion as closely as possible:
 high after ingestion of meals
 low between meals and during night/ basal insulin
Insulin Preparations
Forms of insulin differ by their:
1. Onset of action,
2. Timing of peak activity
3. Duration of effects
( rapid acting -short acting-intermediate acting- long acting)
Rapid/ short acting is used at meal time whereas intermediate / long acting
is used at night or between meals.
Most production of human insulin is made by bacteria and yeast
Insulin delivery
Insulin is most often administered by subcutaneous injection through the
use of :
 syringes
 Insulin pens
 Insulin pump
To eliminate the need for multiple punctures Injection ports are sometimes
inserted to the skin and left in place for several days
Insulin pen looks like permanent marking pen.
It is available as disposable pens and reusable pens
• Insulin pump is a computerized device that can be programmed to
deliver continuously and bolus doses at meal time. The pump can
be worn under clothes or attached to a belt
Why insulin must be taken by subcutaneous injection and not orally??
Because insulin is a protein, it would be destroyed by digestive processes if
taken orally.
Insulin regimen for T1DM:
Type 1 is managed with multiple daily injections( 2-4 Times) of several types
of insulin - require intermediate or long-acting insulin to meet basal insulin
needs, and rapid or short-acting insulin before meals
Amount required before a meal depends on:
1. The pre-meal blood glucose level.
2. The carbohydrate content of the meal
3. Body weight
4. Insulin sensitivity
Insulin sensitivity
is determined by keeping records of food intake, insulin dosages and
blood glucose levels to determine the appropriate:
 Carbohydrate-to-insulin ratio to calculate insulin dosages at
mealtime
Insulin regimen for T2DM
• the initial treatment for T2DM may involve diet, physical activity and
oral anti-diabetic agents
 as the disease progresses, pancreas may lose their ability to
secrete adequate insulin and therefore require insulin
injections
 Insulin may be used alone or in combination with oral antidiabetic agents
Insulin Therapy and hypoglycemia
• Hypoglycemia is most common complication of insulin therapy and
to less extent with oral anti-diabetic agents
 Usually, 15-20 grams carbohydrate will relieve hypoglycemia
within 15 minutes
Each of the following provides approximately 15 g of carbohydrate:
2-3 glucose tablets
4 tea spoon sugar
½ cup canned orange juice
½ cup grape juice unsweetened
• Foods that provides pure glucose yield a better response than foods
that contain other sugars such as sucrose or fructose
• Severe hypoglycemia - treated with glucagon in in the case of
unconsciousness
Antidiabetic Drugs
• Treatment of T2DM often require the use of Antidiabetic drugs
besides the diet therapy
•
These drugs improve hyperglycemia by:
1. Stimulating insulin secretion
2. Suppressing glucagon secretion
3. Decreasing insulin resistance
4. Reducing glucose production in the liver, improving glucose
utilization in tissues
5. Delaying stomach emptying
6. Delaying carbohydrate absorption
The treatment may be monotherapy or combination therapy.
Diabetes Management in Pregnancy
Health risks for both mother and fetus
1. Linked to increased rate of miscarriages
2. Birth defects and fetal deaths higher than normal
3. Newborns more likely to experience: respiratory distress
and metabolic problems (hypoglycemia, jaundice, and
hypocalcemia)
4. Have baby with macrosomia
Pregnancy with Type 1 or type 2 DM:
• Achieving glycemic control at conception and during 1st trimester
reduces risks of birth defects and abortions during pregnancy
• Maintaining glycemic control during 2nd and 3rd trimester minimizes
the risks of macrosomia and morbidity of newborn infants
Type 1 or type 2 DM:
• Nutrient requirements similar to those without DM
• Regular meals and snacks to avoid hypoglycemia
• Evening snack to prevent overnight hypoglycemia and ketosis
• Insulin and medication changes often needed
• 7% of women who do not have diabetes develop gestational diabetes
• Women with gestational diabetes are at greater risk for developing
DM2 later in life
• Offspring - at risk of developing obesity and DM 2 as they enter into
adulthood
• Pregnant women routinely tested between 24 – 28 weeks of
gestation
Risk – highest in those who:
• Have a family history of diabetes
• Are obese
• Have given birth to infants weighing over 4 kilograms
High-risk women – screening:
• Prior to pregnancy
• Soon after conception
• Even mild hyperglycemia can have serious adverse
effects on developing fetus and complications after
pregnancy
If obese
• A modest caloric reduction - 30% less than total energy
needs
• Restricting carbohydrates to about 40% total energy
intake
• Reduce carbohydrate at breakfast because it is poorly
tolerated in the morning.
• Regular aerobic activity
• May require insulin or antidiabetic drug