Diabetes Mellitus Overview of Diabetes Mellitus refers to
Diabetes Mellitus
Overview of 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
Insulin secretions, normally: • Increase after ingestion of food – enables the muscle & adipose cells to take up newly absorbed glucose from the blood • Occur between meals in smaller amounts to restrain the glucoseraising 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
Symptoms of Diabetes Mellitus • 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/d. L 2. Random times during the day Random plasma glucose of ≥ 200 mg/d. L and classic symptoms Polyuria, polydypsia, unexplained weight loss
Diagnosis of Diabetes Mellitus 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/d. L, 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/d. L ). 2 -Blood glucose between 140 – 200 mg/d. L, 2 hours after consuming 75 gram glucose load Pre-diabetes also called impaired fasting glucose
Types of Diabetes Mellitus
Diabetes Type 1 (DM 1 - T 1 DM) • Account for 5 -10 % of cases • caused by automimmune destruction of pancreatic beta cells üOccurs during childhood or adolescence üSymptoms may appear abruptly
üClassic symptoms of T 1 DM are: • Frequent urination • Weight loss • Increased thirst • Ketoacidosis may occur due to excessive production of ketone bodies
Diabetes Type 2 (DM 2 - T 2 DM) • Account for 90 -95 % of cases ü Principal defect is insulin resistance Insulin resistance : reduced sensitivity to insulin in muscle, adipose, and liver cells
üTo compensate, pancreas secretes larger amounts of insulin and hyperinsulinemia occurs 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
1 -Ketoacidosis (DM 1) üCaused by a severe lack of insulin. It Develops within hours or a few days üCauses unrestrained breakdown of triglycerides in adipose tissue excessive release of fatty acids into blood stream üBlood glucose concentrations usually exceed 250 mg/d. L and may rise above 1000 mg/d. L
üketoacidosis : results from the increased production of ketone bodies that lower blood p. H- typically falls below 7. 3
2 -Hypoglycemia • Abnormally low blood glucose levels- fall below 70 mg/d. L. üArises from inappropriate management of DM üCauses • Excessive amount of insulin or antidiabetic drugs • Prolonged exercise • Skipped or delayed meals, inadequate food intake • Consuming alcohol without any food
üMost often occurs in DM 1 but accounts for 3 -4% of deaths in insulin-treated patients üSymptoms • Sweating • Shakiness • Heart palpitations • Slurred speech • Double vision • Irritability
üMental confusion may prevent person from recognizing problem and treating it with glucose tablets, juice or candy. üIf occurs during sleep so patients may be unaware of its presence üProlonged 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
AGEs (cont’d) 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) 2. Small blood vessels (microvascular complication) 3. Nervous system ( neuropathy)
1 -Macrovascular Complications üThe damage caused by diabetes accelerates the development of atherosclerosis that affects coronary arteries and arteries in limbs üDM 2 patients usually have multiple cardiovascular risk factors ( hypertension, abnormal blood lipids, obesity üDM patients have increased tendencies for thrombosis (blood clot formation) üImpaired blood flow to limbs leads to pain upon walking and can also leads to development of foot ulcers that can
2 -Microvascular Complications 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. üOccurs in later stages of DM 1 & DM 2 üEnd-stage renal disease occurs : 30 -35% of patients with DM 1 20% of those with DM 2 üIntensive management helps slow progression
c-Diabetic Neuropathy : Nerve degeneration It occurs in 50% of DM cases ü Extent of nerve damage dependent upon severity and duration of hyperglycemia ü 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 aims to prevent or reduce the risk of complications.
Evaluating DM Treatment • Effectiveness of DM treatment is evaluated by monitoring glycemic status 1 - 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).
• DM 1 should monitor BG three or more times daily • DM 2 the recommended frequency depends on specific needs of patients.
2 - Glycated/ glycosylated hemoglobin (Hb. A 1 c): • Hb. A 1 c: 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.
üAssists health care providers to evaluate long-term glycemic control (life cycle of RBC) üHb. A 1 c < 6% for non-diabetic persons ü The goal of DM treatment is an Hb. A 1 c< 7%
3 - Monitoring for long term complications • Ketone testing – checks for development of ketoacidosis üDM 1 – 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 T 1 DM üDM 1 patients are less likely to be overweight üExcessive weight gain is unwanted side effect of improved glycemic control. üThe cause of weight gain is unclear but may be related to stimulating fat synthesis by insulin. üGrowth patterns and weight gain of growing children should be routinely monitored for sufficient energy intake.
Body weight in DM 2 ü Excessive body fat worsens insulin resistance so weight loss is recommended ü Moderate weight loss improves glycemic control, blood lipid levels, blood pressure ü Weight loss is beneficial early in course of diabetes before insulin secretion has diminished ü Positive effects appear to be related to kcaloric restriction rather than to weight loss itself ü Not all DM 2 patients are obese or overweight. Older adults often underweight. Low body weight increases risks of morbidity
Medical Nutrition Therapy
Total carbohydrate intake üThe more grams of carbohydrate the greater the glycemic response after meals. üCarbohydrate recommendation is based on metabolic needs (type of DM-degree of individual tolerance) üThe amount must be consistent at meals and snacks to help reduce fluctuations in BG between meals. üLow-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. üGlycemic 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 üHigh-fiber, whole-grain products have more moderate effects on blood glucose that highly processed foods are among the foods frequently recommended for
2 -Fiber üFiber recommendations are similar to those for general population( 21 -38 g /day). ü People with diabetes are encouraged to include fiber-rich foods such as legumes, whole-grain cereals, fruits, and vegetables üSome research suggests fiber intake of 50 g or more per day may improve glycemic control – benefits not consistent
3 -Sugars ü Sugar and sugary foods are not restricted and should be counted as part of daily carbohydrate allowance ü Choose foods and beverages with little added sugar or kcaloric sweeteners ü Sugars and sugary foods must be counted as part of the ü daily carbohydrate allowance. ü Although fructose has a minimal glycemic effect , its use as added sweetener may adversely affect blood lipid levels – not referring to naturally occurring fructose ü Artificial sweeteners may be used (aspartame, saccharin, sucralose) used in
4 -Dietary fat ü people with diabetes are at risk for cardiovascular disease üSaturated fat should be limited to < 7% of kcalories üCholesterol intake < 200 mg daily üTrans fat intake should be minimized
5 -Protein üProtein intake is 15 -20% total kcalories as healthy population üSome studies suggested that higher protein intake may improve glycemic control and increase satiety. long term effect is unknown ü in addition, higher protein intakes discouraged because it may be detrimental to kidney function
6 -Micronutrient intakes üMicronutrient intakes of DM patients are the same as healthy population ü Supplementation is not recommended unless nutrient deficiencies develop üSome studies suggest that chromium supplementation can improve glycemic control in persons with DM 2 – 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 T 1 DM and those with T 2 DM who cannot maintain glycemic control with antidiabetic drugs, diet and exercise. Ideal treatment is one that mimics insulin secretion as closely as possible: 1. high after ingestion of meals 2. low between meals and during night/ basal insulin
Insulin Preparations Forms of insulin differ by their: 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. 1. 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 : ü syringes ü Insulin pens ü Insulin pump • To eliminate the need for multiple punctures Injection ports are some times 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
• 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 T 1 DM: 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
Insulin sensitivity is determined by keeping records of food intake, insulin dosages and blood glucose levels to determine the appropriate: üCarbohydrate-to-insulin ratio to calculate insulin dosages at mealtime
Insulin regimen for T 2 DM • the initial treatment for T 2 DM may involve diet, physical activity and oral anti -diabetic agents ü as the disease progresses, pancreas may lose their ability to secrete adequate insulin and therefore require insulin injections üInsulin may be used alone or in combination with oral anti-diabetic agents
Insulin Therapy and hypoglycemia • Hypoglycemia is most common complication of insulin therapy and to less extent with oral anti -diabetic agents ü 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 T 2 DM 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
ü 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 1 st trimester reduces risks of birth defects and abortions during pregnancy • Maintaining glycemic control during 2 nd and 3 rd 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
ü 7% of women who do not have diabetes develop gestational diabetes ü Women with gestational diabetes are at greater risk for developing DM 2 later in life ü Offspring - at risk of developing obesity and DM 2 as they enter into adulthood ü Pregnant women routinely tested between 24 – 28 weeks of gestation
üRisk – highest in those who: 1. Have a family history of diabetes 2. Are obese 3. Have given birth to infants weighing over 4 kilograms üHigh-risk women – screening: • Prior to pregnancy • Soon after conception Even mild hyperglycemia can have serious adverse effects on developing fetus and complications after pregnancy
üIf 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
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