diabetes mellitus diabetes mellitus. diabetes mellitus diabetes mellitus epidemiology world who 2004...

Diabetes MellitusDiabetes Mellitus

Diabetes Mellitus Diabetes Mellitus epidemiology

• World World WHO 2004 > 150 million WHO 2004 > 150 million

• China China at present > 40millionat present > 40million

• The second in the wordThe second in the word

• annual gain >10% annual gain >10%

conceptconcept• Diabetes Mellitus is a syndrome with

chronic hyperglycemia due to either a deficiency of insulin secretion or to a combination of insulin resistance and inadequate insulin secretion to compensate and leads to dysmetabolism of proteins, lipid as well as many other metabolites and elements.

• Type 1 diabetes is due to pancreatic islet B cell destruction predominantly by an autoimmune process , and these patients are prone to ketoacidosis.

• Type 2 diabetes is the more prevalent form and results from insulin resistance with a defect in compensatory insulin secretion.

• CLASSIFICATION AND PATHOGENESIS

• Clinical findings

• Differential Diagnosis

• Treatment : Diabetes Mellitus Diet

CLASSIFICATION AND CLASSIFICATION AND PATHOGENESISPATHOGENESIS

• Diabetes is now classified according to its etiology recommended by the American Diabetes Association (ADA) in 1997 and revised by WORLD Health Organization in 1999(usually referred to WHO/1999 Recommendation

TYPE 1 DIABETES MELLITUSTYPE 1 DIABETES MELLITUS

• The form of diabetes is immune –mediated in over 90% of cases and idiopathic in less than 10% .The rate of pancreatic B cell destruction is quite variable ,being rapid in some individuals and slow in others


• It can occur at any age but most commonly arises in children and young adults with a peak incidence before school age and again at around puberty before last century


• It is a catabolic disorder in which circulating insulin is very low or virtually absent .

• The insulin secretion, due to the pancreatic B cell destruction ,fails to meet the requirement of nutrient absorption.


• Exogenous insulin is therefore required to reverse the metabolic state, prevent ketosis, reduce the hyperglucagonemia ,and maintain glucose homeostasis.


• Certain human leukocyte antigens (HLA) are strongly associated with the development of type 1 diabetes.

• About 95% of type 1 patients possess either HLA-DR3 or HLA-DR4, compared with 45%-50% of white controls


• HLA-DQ genes with even more specific ,markers of type 1 susceptibility, since a particular variety (HLA-DQB1*0302 )is found in the DR4 patients with type 1,while a “protective ”gene (HLADQB1*0602) is often present in the DR4 controls.


• Recently it was found the freqency of “susceptible” genotype decreases and the frequency of “protective ”genotype increased as the onset age of a subject becomes older.


• In addition , most patients with type 1 diabetes at diagnosis have circulating antibodies to islets (islet cell antibodies, ICA), insulin antibodies(IAA) ,glutamic acid decarboxylase (GAD 65),and to tyrosine phosphatases(IA-2 and IA2-b, IA is the abbreviation for insulinoma associated antigen).


• The antibody levels decline with increasing duration of the disease.

• Also, once patients are treated with insulin ,low levels of anti-bodies develop.


• More recently regulatory T cell and cytotoxic T cell abnormality were considered to be critical in the development of isletitis and b cell destruction.


• The polymorphism in gene encoding cytotoxic lymphocyte antigeng4 (CTLA-4) was found related to development of autoimmune diabetes as well as autoimmune thyroiditis.

• B-cell reactive T cell avidity was proposed at the beginning of isletitis.


• Certain unrecognized patients with a milder expression of type 1 diabetes initially retain enough b cell function to avoid ketosis but later in life develop increasing dependency on insulin therapy as b cell mass diminishes (usually 6 years after dignosis).


• Islet cell antibody survey among northern Europeans indicate that up to 15% of “type 2”patients may actually have this mild form of type 1 diabetes (latent autoimmue diabetes of adulthood, LADA)


• This presents a heterogeneous group comprising milder forms of diabetes that occur predominantly in adults but occasionally in juveniles.

• More than 90% of all diabetes in the United States and China are included under this classification .

• In most cases of this type of diabetes, this cause is unkown.


• The pathogenesis currently received is illustrated in (Figure 6-18-1 )

• Tissue insensitivity to insulin has been noted in most type 2 patients irrespective of weight and has been attributed to several interrelated factors

Figure 6-18-1 pathogenesis of type 2 Figure 6-18-1 pathogenesis of type 2 diabetes mellitusdiabetes mellitus


• These include a putative(and as yet undefined ) genetic factor ,which is aggravated in time by additioal enhancers of insulin resistance such as aging ,a sedentary lifestyle, and abdominal –visceral obesity .

• In addition ,there is an accompanying deficiency in the response of pancreatic b cells to glucose .


• Both the tissue resistance to insulin and the impaired b cell response to glucose appear to be further aggravated by increased hyperglycemia (glucose toxicity), and both defects are ameliorated by treatment that reduces the hyperglycemia toward normal


• Most epidemiologic data indicate strong genetic influences.

• Attempts to identify genetic markers for type 2 have as yet been unsuccessful.

Other specific types of diabetes mellitusOther specific types of diabetes mellitus

• Other specific types of diabetes mellitus is relatively rare

• Maturity –onset diabetes of the young (MODY) is a subgroup due to monogenic disorder characterized by non-insulin –dependent diabetes with autosomal dominant inhenritantance and an age at onset of 25 years or younger.


• Diabetes due to mutant insulin is a very rare subtype of nonobese type 2 diabetes ,with no more than ten families having been described.


• Diabetes duo to a mutation of mitochondrial DNA that impairs the transfer of leucine or lysine into mitochondrial , proteins has been described.


• Since sperm do not contain mitochondria, only the mother transmits mitochondrial genes to her offspring.

Gestational diabetes mellitus (GDM)Gestational diabetes mellitus (GDM)

• GDM is defined as any degree of glucose intolerance with onset or first reconition during pregnancy.

• The definition appleies regardless of whether insulin or only diet modification is used for treatment or whether the condition persists after pregnancy.


• It does not exclude the possibility that unrecognized glucose intolerance may have antedated or begun concomitantly with the pregnancies.

• The prevalence may range from 1%-14%of pregnancies, depending on the population studied


• GDM represents nearly 90% of all pregnancies complicated by diabetes.

• Insulin is recommended as the only modality of treatment even trial of oral agents that are undertaken showed safe.


• Deterioration of glucose tolerance occurs normally during pregnancy , particularlyi n the 3rd trimester.

Clinical findingsClinical findings

• Symptoms and signs

• Laboratory findings



• The principal clinical features of the two major types of diabetes mellitus are listed for comparison in (Table 6-18-3)

Diabetes Mellitus: Signs & Diabetes Mellitus: Signs & SymptomsSymptoms

Three polys: polyphagia, polyuria, & polydipsia

Weight lossFatigueHyperglycemia



• Patients with type 1 diabetes present with a characteristic symptom complex.

• An absolute deficiency of insulin results in accumulation of circulating glucose and fat acids,with conseqent hyperosmolality and hyperketonemia.



• Patients with type 2 diabetes may or may not present with characteristic features.

• The presence of obesity or a strongly positive family history for mild diabetes suggests a high risk for the development of type 2 diabetes.

Laboratory findingsLaboratory findings

• Urinary analysis

• Blood test procedures

• B cell Reserve Evaluation

• Autoantibodies

• Lipoprotein Abormalities in Diabetes


• Laboratory findings

• Urinary analysis

• Glycosuria and ketonuria can be found in diabetic patients.

Clinical findingsClinical findings• Laboratory findings

• Blood test procedures

• A. Glucose Tolerance Test• B. Glycated Hemoglobin (Hemoglobin A1)

measurements• C. Serum Fructosamine• D. Self –Monitoring of Blood Glucose• E.Continuous Glucose Monitoring Systems

Blood test proceduresBlood test procedures

• A. Glucose Tolerance Test

• Criteria for laboratory confirmation of diabetes mellitus if the fasting plasma glucose level is 7.0 mmol/L(126mg/dL) or higher on more than one occasion , further evaluation of the patient with a glucose challenge is unnecessary .


• A. Glucose Tolerance Test

• However ,when fasting plasma glucose is less than 7.0 mmol/L(126mg/dL) in suspected cases ,a standardized oral glucose tolerance test may be ordered .


B. Glycated Hemoglobin(HemoglobinA1) measurements

Glycated hemoglobin is abnormally high in diabetics with chronic hyperglycemia and reflects their metabolic control.

It is produced by nonenzymatic condensation of glucose molecules with free amino groups on the globin component of hemoglobin.



The higher the prevailing ambient levels of blood glucose, the higher will be the level of glycated hemoglobin.

The major form of glycohemoglobin is termed hemoglobin A1c,which normally comprises only 4%-6% of the total hemoglobin



• Since glycohemoglobins circulate with in red blood cells whose life span lasts up to 120 days, they generally reflect the state of glycemia over the preceding 8-12 weeks, thereby providing an improved method of assessing diabetic control.



• Measurements should be made in patients with either type of diabetes mellitus at 3-to 4 month intervals so that adjustment in therapy can be made if glycohemoglobin is either subnormal or if it is more than 2% above the upper limits of normal for a particular laboratory.


• C. Serum Fructosamine

• Serum fructosamine is formed by nonenzymatic glycosylation of serum proteins (predominantly albumin).



• Since serum albumin has a much shorter half-life than hemoglobin, serum fructosamine generally reflects the state of glycemic control for only the preceding 2 weeks.



• Normal values vary in relation to the serum albumin concentration and are 1.5-2.4mmol/L when the serum albumin level is 5 g/dL


• D.Self –Monitoring of Blood Glucose

• Capillary blood glucose measurements performed by patients themselves, as outpatients, are extremely useful.


E. Continuous Glucose Monitor Systems

The main value of these systems appears to be in identifying episodes of asymptomatic

hypoglycemia, especially at night.

B cell Reserve EvaluationB cell Reserve Evaluation

• It is estimated more than 50% of b cell were lost at the onset of diabetes.

• The b cell reserve is usually measured in its secreted functional proteins-insulin.

B cell Reserve EvalutionB cell Reserve Evalution

• Measurement of insulin is usually used for functional evaluation in those not on insulin, and C-peptide can be used as an alternative toolin those on insulin.

• Fasting and 2-hour after stimulator insulin or C-peptide are usually measured .

• The stimulator can be glucose , arginine, glucagons.

B cell Reserve EvalutionB cell Reserve Evalution

• Glucose is often replaced by standard meal equivalent to 75g glucose.

• Reference values should be setup in each laboratory and should be interpreted according to adiposity, or insulin resistance

• The evaluation is not a routine practice in clinics, but is used in research protocol.

AutoantibodiesAutoantibodies

• It is gradually acccepted that determination of islet b cell autoimmunity is usual in typing of diabetes

• Insulin autoantibody (IAA), glutamic acid decarboxylase (GADA), islet cell antibodies ( ICA) ,-now replaced by tyrosine phosphatase autoantibodies (IA-2,IA2-b) are the most commonly used tests


• Several other antibodies were studied for their utility in predicting type 1 diabetes.

• One is carboxypeptidase antibody (CPH) that is thoroughly studied a Chinese group.

• IAA is more frequently detected in very young child diabetes.


• ICA, in juvenile diabetes.

• GADA, in elder diabetes.

• The autoantibodies profile can change during the progression of disease.

• GADA appears relatively late.

• A positive result predicts the need for insulin in 6 years.

Lipoprotein Abnormalities in Lipoprotein Abnormalities in DiabetesDiabetes

• Circulating lipoprotein are just as dependent Circulating lipoprotein are just as dependent on insulin as the plasm glucose .on insulin as the plasm glucose .

• In type 1 diabetes , moderately deficient In type 1 diabetes , moderately deficient control of hyperglycemia is associated with control of hyperglycemia is associated with only a slight elevation of only a slight elevation of LDL cholesterolLDL cholesterol and and serum serum triglyceridestriglycerides and little if any change in and little if any change in HDL cholesterolHDL cholesterol

Lipoprotein Abormalities in DiabetesLipoprotein Abormalities in Diabetes

• Once the hyperglycemia is corrected, Once the hyperglycemia is corrected, lipoprotein levels are generally normal.lipoprotein levels are generally normal.

• However ,in obese patients with type 2 However ,in obese patients with type 2 diabetes, a distict “diabetic dyslipidemia” is diabetes, a distict “diabetic dyslipidemia” is characteristic of the insulin resistence characteristic of the insulin resistence syndromesyndrome. .


• Its feathers are a high serum triglyceride level(300-400mg/L), a low HDl cholesterol (less than 30mg/dL), and a qualitative change in LDL particles, producing a smaller dense particle whose membrane carries supro-normal amountes of free cholesterol.


• These small dense LDL particles are more susceptible to oxidation, which renders them more atherogenic.

• Since primary disorders of lipid metabolism may coexist with diabetes, persistence of lipid abnormalities after restoration of normal weight and blood glucose should prompt a diagnostic workup and possible pharmacotherapy of the lipid disorder.

Differential DiagnosisDifferential Diagnosis

• Hyperglycemia secondary to other sources

• Secondary hyperglycemia has been associated with various disorders of insulin target tissues (liver, muscle , and adipose tissue)(Table 6-18-5).


• Other secondary cause of carbohydrate intolerance include endocrine disorders-often specific endocrine tumors-accociated with excess production of growth hormone, glucocorticoids, catecholamines, glucagon , or somatostatin.


• A rare syndrome of extreme insulin resistance associated with acanthosis nigricans afflicts either young women with androgenic features as well as insulin receptor mutations or older people , mostly women , in whom a circulating immunoglobulin binds to insulin receptors and reduces their affinity to insulin.


• Medications such as diuretics , phenytoin , niacin, and high-dose glucocorticoids can produce hyperglycemia that is reversible once the drugs are discontinued or when diuretic-induced hypokalemia is corrected


• Chronic pancrearitis or subtotal pancreatectomy reduces the number of functioning b cells and can result in metabolic derangement very similar to that of genetic type 1 diabetes except that a concomitant reduction in pancreatic a cells may reduce glucagon secretion so that relatively lower doses of insulin replacement are needed.


• Insulin-dependent diabetes is occassionally associated with Addison’s disease and autoimmune thyroiditis (Schimidt’s syndrome, or polyglandular failure syndrome).


• This occurs more commonly in women and represents an autoimmune disorder in which there are circulating antibodies to adrenocortical and thyroid tissue, thyroglobulin,and gastric parietal cells.

Nondiabetic GlycosuriaNondiabetic Glycosuria

• Nondiabetic glycosuria(renal glycosuria) is a benign asymptomatic condition wherein glucose appears in urine despite a normal amount of glucose in blood , either basally or during a glucose tolerance test.

Nondiadetic GlycosuriaNondiadetic Glycosuria

• Its cause may vary from an autosomally transmitted genetic disorder to one associated with dysfunction of the proximal renal tubule (Fanconi’s syndrome ,chronic renal failure), or it may merely be a consequence of the increasd load of glucose presented to the tubules by the elevated glomerular filtration rate during pregnancy.

Nondiabetic GlycosuriaNondiabetic Glycosuria

• As many as 50% of pregnant women normally have demonstrable sugar in the urine, especially during the third and fourth months.

• This sugar is practically always glucose except during the late weeks of pregnancy , when lactose may be present.

TreatmentTreatment

• Diabetes mellitus requires ongoing medical care as well as patient and family education both to prevent acute illness and to reduce the risk of long-term complications.

TreatmentTreatment

• Diet• A well-balanced， nutritious diet remains a

fundamental element of therapy.• However, In more than half of case ,diabetic

patients fail to follow their diet . • In prescribing a diet, it is important to relate

dietary objectives to the type of diabetes.

TreatmentTreatment

• Diet• In obese patients with mild hyperglycemia,

the major goal of diet therapy is weight reduction by caloric restriction.

• Thus ,there is less need for exchange lists, emphasis on timing of meals ,or periodic snacks, all of which are so essential in the treatment of insulin – requiring nonbese diabetics.

TreatmentTreatment

• ADA Recommendations• The American Diabetes Association release

an annual position statement on medical nutrition therapy that replaces the calculated ADA diet formula of the past with suggestions for an individully tailored dietary prescription based on metabolic , nutritional, and life style requirements .

TreatmentTreatment

• ADA Recommendations• They contend that the concept of one diet for

“diabetes” and the prescription of an “ADA diet” no longer can apply to both major type of diabetes.

• In their recommendations for persons with type 2 diabetes, the 55%-60% carbohydrate content of previous diets has been reduce considerably because of the tendency of high carbohydrate intake to cause hyperglycemia, hypertriglyceridemia, and a lowered HDL cholesterol

TreatmentTreatment

• ADA Recommendations• .In obese type 2 patients, glucose and lipid

goals join weight loss as the focus of therapy .

• These patients are advised to limit their carbohydrate content by substituting noncholesterologenic monounstaturated oils such as olive oil ,rapeseed (canola) oil, or the oil in nuts and avocados.

TreatmentTreatment

• ADA Recommendations

• This maneuver is also indicated in type 1 patients on intensive insulin regimens in whom near-normoglycemic control is less achievable on higher carbohydrate diets.

TreatmentTreatment

• ADA Recommendations• They can administer 1 unit of regular insulin

or insulin lispro for each 10 or 15 g of carbohydrate eaten at a meal .

• In these patients , the ratio of carbohydate to fat will vary among individuals in relation to their glycemic responses ,insulin regiments, and exercise pattern.

TreatmentTreatment

• ADA Recommendations

• The current recommendations for both types of diabetes continue to limit cholesterol to 300 mg dairly and advise a daily protein intake of 10%-20% of total calories

TreatmentTreatment

• ADA Recommendations• They suggest that saturated fat be no

higher than 8%-9% of total calories with a similar proportion of polyunsaturated fat and that the remainder of caloric needs be made up of an individualized ratio of monounsaturated fat and of carbohydrate containing 20-35 g of dietary fiber .

TreatmentTreatment

• ADA Recommendations• Poultry ,veal, and fish continue to be

recommended as a substitute for red meats for keeping saturated fat content low.

• The present ADA position statement proffers no evidence that reducing protein intake below 10% of intake (about 0.8 g/kg/d) is of any benefit in patients with nephropathy and renal impairment ,and doing so may be detrimental.

TreatmentTreatment

• Dietary Fiber• Plant components’ such as cellulose ,gum,

and pectin are indigestible by humans and termed dietary “fiber”.

• The ADA recommends food such as oatmeal , cereals, and beans with relatively high soluble fiber content as staple components of the diet in diabetics.

TreatmentTreatment

• Dietary Fiber

• High soluble fiber content in the diet may also have a favorable effect on blood cholesterol levels.

TreatmentTreatment

• Artifficial SweetenersArtifficial Sweeteners

• The latest position statement of ADA The latest position statement of ADA concludes that all concludes that all nonnutritive nonnutritive sweetenerssweeteners that have been approved by that have been approved by the FDA (such as aspartame and the FDA (such as aspartame and saccharin) saccharin) are safe forare safe for consumption by consumption by all people with diabetes.all people with diabetes.

TreatmentTreatment


• Two other nonnutritive sweeteners Two other nonnutritive sweeteners have been approved by the FDA as safe have been approved by the FDA as safe for general use: sucralose(Splenda) for general use: sucralose(Splenda) and acesulfame potassium and acesulfame potassium (Sunett ,Sweet one, DiabetiSweet)(Sunett ,Sweet one, DiabetiSweet)

TreatmentTreatment


• Nutritive sweetenersNutritive sweeteners such as sorbitol such as sorbitol and fructose have increased in and fructose have increased in popularity .popularity .

• Except for acute diarrhea induce by Except for acute diarrhea induce by ingestion of large amounts of sorbitol –ingestion of large amounts of sorbitol –containing foods, their relative risk has containing foods, their relative risk has yet to be established.yet to be established.

TreatmentTreatment

• Artifficial SweetenersArtifficial Sweeteners• Fructose represents a “natural ”sugar

substance that is a highly effective sweetener which induces only slight increases potential adverse effects of large amounts of fructose (up to 20% of total calories) on raising serum cholesterol and LDL cholesterol , the ADA feels it may have no overall advantage as a sweetening agent in the diabetic diet.

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