Diabetes Mellitus Pathophysiology
Diabetes Mellitus Diabetes mellitus (DM) is a group of diseases characterized by high levels of blood glucose resulting from defects in insulin production, insulin action, or both.  The term diabetes mellitus describes a metabolic disorder of multiple aetiology characterized by chronic hyperglycaemia with disturbances of carbohydrate, fat and protein metabolism resulting from defects in insulin secretion, insulin action, or both. The effects of diabetes mellitus include long–term damage, dysfunction and failure of various organs.
Insulin secretion
 
Action of insulin
Action of insulin on CHO, Fat and Protein Metabolism Carbohydrate Facilitates the transport of glucose into muscle and adipose cells Facilitates the conversion of glucose to glycogen for storage in the liver and muscle. Decreases the breakdown and release of glucose from glycogen by the liver
Protein Stimulates protein synthesis Inhibits protein breakdown; diminishes gluconeogenesis
Fat Stimulates lipogenesis- the transport of triglycerides to adipose tissue Inhibits lipolysis – prevents excessive production of ketones or ketoacidosis
Major Reason for Insulin Secretion    secretion Elevated blood glucose levels Increased fatty acids GI hormones Glucagon, growth hormone, cortisol Insulin resistance    secretion Decreased blood glucose levels Decreased food intake (fasting)
Hyperglycemia an excessive amount of glucose circulates in the blood plasma  chronic levels exceeding 125 mg/dl can produce organ damage
Glucose Homeostasis
What goes wrong in Diabetes ? Multitude of mechanisms Insulin  Regulation Secretion Uptake or breakdown Beta cells damage
Type 1 Diabetes Low or absent endogenous insulin Dependent on exogenous insulin for life Onset generally < 30 years 5-10% of cases of diabetes Onset sudden Symptoms: 3 P’s: polyuria, polydypsia, polyphagia
Type 1 Diabetes cell
 
Metabolic defects in Type 1 Diabetes Hyperglycemia and ketoacidosis Hypertriacylglycerolemia
Type 2 Diabetes Insulin levels may be normal, elevated or depressed Characterized by insulin resistance,  diminished tissue sensitivity to insulin, and impaired beta cell function (delayed or inadequate insulin release) Often occurs >40 years
Type 2 Diabetic cell
Insulin Receptors REMEMBER: the main action of the insulin receptor  is to signal the cell to absorb glucose .  A decrease in insulin receptor signaling leads to type 2 diabetes mellitus. Thus, the cells are not able to take up glucose, leading to hyperglycemia (an increase in glucose circulating in the blood), and all the resulting sequelae.
Type 2 Diabetes Risk factors: family history, sedentary lifestyle, obesity and aging Controlled by weight loss, oral hypoglycemic agents and or insulin
Metabolic defects in Type 2 Diabetes Hyperglycemia Hypertriacylglycerolemia  ----- low levels of insulin ---- decreased activity of lipoprotein lipase ------ raised plasma level of VLDL
Long term effects of Diabetes Mellitus Microvascular complications :- - retinopathy - nephropathy - neuropathy Macrovascular complications :- - stroke - cardiovascular disease
Screening/Diagnosis of Diabetes
 
Diabetic Process Decreased insulin production or action -> Increased glucose accumulates in blood  -> hyperglycemia -> need to dilute glucose in circulating blood -> fluids drawn from intracellular spaces to vascular bed -> Thirst  (polydipsia)
Diabetic Process Thirst (polydipsia) -> increased fluid intake -> increased fluid volume -> kidneys need to excrete excess volume ->  Polyuria  (frequent urination) Glycosuria (excretion of glucose into urine)
Diabetic Process: Lack of glucose for energy/metabolism -> cells starve -> increased hunger ( Polyphagia )  -> increased food intake (weight gain) No glucose to metabolize -> protein metabolism (nitrogen imbalance) -> fat metabolism: (ketone bodies (ketosis))
Diabetic Process: Polydipsia, polyuria and polyphagia can lead to a fluctuations in blood glucose levels (hyperglycemia and hypoglycemia) -> damage to small blood vessels throughout the body -> serious impairment, especially kidneys, eyes, and heart In pregnancy: decreased glucose to uterus and increased glucose to fetus  -> hypoglycemia at birth
Importance of glucose regulation The brain: normally dependent on glucose for oxidative metabolism and function  Hypoglycemia  brain fuel deprivation functional brain failure corrected by raising plasma glucose concentrations  Hyperglycemia  Osmotic water loss (cellular and systemic) Damages blood vessels
Hyperglycemia Symptoms Classic Hyperglycemic Triad (the 3 P’s of diabetes): Polydipsia  frequent thirst excessive thirst  Polyuria  frequent urination excessive urination  Polyphagia  frequent hunger pronounced hunger
Additional Symptoms of Hyperglycemia Blurred vision Fatigue Weight loss  Poor wound healing Dry mouth Dry or itchy skin Impotence  (male)  Recurrent infections  Kussmaul hyperventilation: deep, rapid breathing  Fruity/acetone smell on the breath Cardiac arrhythmia Stupor Coma Death
Glycemic Control  Glucose cycle: glucose in the bloodstream is made available to cells in the body dependent upon  glucose entering the bloodstream insulin allowing appropriate uptake into the cells of the body.  Both require management.
Glycemic Control Management  highly intrusive  compliance is an issue relies on user lifestyle change often on regular sampling and measuring of blood glucose levels  Highly individual
Glycemic Control Many of the long-term complications of diabetes, especially microvascular complications, result from many years of elevated blood glucose levels.  Good glycemic control, (70-130 mg/dl, or 3.9-7.2 mmol/L)  is  the  important goal of diabetes care.
Glycemic control The hemoglobin A1c (glycosylated hemoglobin) reveals “average” glucoses over the preceding 2-3 months.  In normal glucose metabolism, the glycosylated hemoglobin is usually 4-6% by the most common methods (normal ranges may vary by method).
Glycemic Control &quot;Perfect glycemic control&quot;  glucose levels were always within the normal range (70-130 mg/dl, or 3.9-7.2 mmol/L)  “ Perfect” glycemic control very difficult, and even &quot;good glycemic control&quot; usually describes blood glucose levels that average somewhat higher than the normal range. “ Poor glycemic control” Persistently elevated blood glucose and glycosylated hemoglobin levels May persist over months and years before severe complications develop.
Summary  Diabetes occurs when either there is inadequate insulin production in the pancreas or there is inadequate absorption of insulin into the cells. Insulin is needed for metabolism of glucose for energy at the cellular level Lack of glucose for metabolism    metabolism of fat and protein for energy, polyuria, polydipsia, and polyphagia (classic symptoms of diabetes) and others listed earlier Chronic condition that can lead to multiple serious complications  Goal: glycemic control
 
Hypoglycemia symptoms Shakiness  Nervousness  Sweating  Dizziness or light-headedness  Sleepiness  Confusion Another clue to nocturnal hypoglycemia is postprandial hyperglycemia after breakfast Difficulty speaking  Anxiety  Weakness  Hypoglycemia can also happen during sleep crying out or having nightmares  finding pajamas or sheets damp from perspiration  feeling tired, irritable, or confused after waking up
Hypoglycemia Hypoglycemia, also called low blood glucose or low blood sugar,  occurs when blood glucose drops below normal levels.  http://hubpages.com/hub/Hypoglycemia_Symptoms_and_Treatments

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  • 1.
  • 2.
    Diabetes Mellitus Diabetesmellitus (DM) is a group of diseases characterized by high levels of blood glucose resulting from defects in insulin production, insulin action, or both. The term diabetes mellitus describes a metabolic disorder of multiple aetiology characterized by chronic hyperglycaemia with disturbances of carbohydrate, fat and protein metabolism resulting from defects in insulin secretion, insulin action, or both. The effects of diabetes mellitus include long–term damage, dysfunction and failure of various organs.
  • 3.
  • 4.
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  • 6.
    Action of insulinon CHO, Fat and Protein Metabolism Carbohydrate Facilitates the transport of glucose into muscle and adipose cells Facilitates the conversion of glucose to glycogen for storage in the liver and muscle. Decreases the breakdown and release of glucose from glycogen by the liver
  • 7.
    Protein Stimulates proteinsynthesis Inhibits protein breakdown; diminishes gluconeogenesis
  • 8.
    Fat Stimulates lipogenesis-the transport of triglycerides to adipose tissue Inhibits lipolysis – prevents excessive production of ketones or ketoacidosis
  • 9.
    Major Reason forInsulin Secretion  secretion Elevated blood glucose levels Increased fatty acids GI hormones Glucagon, growth hormone, cortisol Insulin resistance  secretion Decreased blood glucose levels Decreased food intake (fasting)
  • 10.
    Hyperglycemia an excessiveamount of glucose circulates in the blood plasma chronic levels exceeding 125 mg/dl can produce organ damage
  • 11.
  • 12.
    What goes wrongin Diabetes ? Multitude of mechanisms Insulin Regulation Secretion Uptake or breakdown Beta cells damage
  • 13.
    Type 1 DiabetesLow or absent endogenous insulin Dependent on exogenous insulin for life Onset generally < 30 years 5-10% of cases of diabetes Onset sudden Symptoms: 3 P’s: polyuria, polydypsia, polyphagia
  • 14.
  • 15.
  • 16.
    Metabolic defects inType 1 Diabetes Hyperglycemia and ketoacidosis Hypertriacylglycerolemia
  • 17.
    Type 2 DiabetesInsulin levels may be normal, elevated or depressed Characterized by insulin resistance, diminished tissue sensitivity to insulin, and impaired beta cell function (delayed or inadequate insulin release) Often occurs >40 years
  • 18.
  • 19.
    Insulin Receptors REMEMBER:the main action of the insulin receptor is to signal the cell to absorb glucose . A decrease in insulin receptor signaling leads to type 2 diabetes mellitus. Thus, the cells are not able to take up glucose, leading to hyperglycemia (an increase in glucose circulating in the blood), and all the resulting sequelae.
  • 20.
    Type 2 DiabetesRisk factors: family history, sedentary lifestyle, obesity and aging Controlled by weight loss, oral hypoglycemic agents and or insulin
  • 21.
    Metabolic defects inType 2 Diabetes Hyperglycemia Hypertriacylglycerolemia ----- low levels of insulin ---- decreased activity of lipoprotein lipase ------ raised plasma level of VLDL
  • 22.
    Long term effectsof Diabetes Mellitus Microvascular complications :- - retinopathy - nephropathy - neuropathy Macrovascular complications :- - stroke - cardiovascular disease
  • 23.
  • 24.
  • 25.
    Diabetic Process Decreasedinsulin production or action -> Increased glucose accumulates in blood -> hyperglycemia -> need to dilute glucose in circulating blood -> fluids drawn from intracellular spaces to vascular bed -> Thirst (polydipsia)
  • 26.
    Diabetic Process Thirst(polydipsia) -> increased fluid intake -> increased fluid volume -> kidneys need to excrete excess volume -> Polyuria (frequent urination) Glycosuria (excretion of glucose into urine)
  • 27.
    Diabetic Process: Lackof glucose for energy/metabolism -> cells starve -> increased hunger ( Polyphagia ) -> increased food intake (weight gain) No glucose to metabolize -> protein metabolism (nitrogen imbalance) -> fat metabolism: (ketone bodies (ketosis))
  • 28.
    Diabetic Process: Polydipsia,polyuria and polyphagia can lead to a fluctuations in blood glucose levels (hyperglycemia and hypoglycemia) -> damage to small blood vessels throughout the body -> serious impairment, especially kidneys, eyes, and heart In pregnancy: decreased glucose to uterus and increased glucose to fetus -> hypoglycemia at birth
  • 29.
    Importance of glucoseregulation The brain: normally dependent on glucose for oxidative metabolism and function Hypoglycemia brain fuel deprivation functional brain failure corrected by raising plasma glucose concentrations Hyperglycemia Osmotic water loss (cellular and systemic) Damages blood vessels
  • 30.
    Hyperglycemia Symptoms ClassicHyperglycemic Triad (the 3 P’s of diabetes): Polydipsia frequent thirst excessive thirst Polyuria frequent urination excessive urination Polyphagia frequent hunger pronounced hunger
  • 31.
    Additional Symptoms ofHyperglycemia Blurred vision Fatigue Weight loss Poor wound healing Dry mouth Dry or itchy skin Impotence (male) Recurrent infections Kussmaul hyperventilation: deep, rapid breathing Fruity/acetone smell on the breath Cardiac arrhythmia Stupor Coma Death
  • 32.
    Glycemic Control Glucose cycle: glucose in the bloodstream is made available to cells in the body dependent upon glucose entering the bloodstream insulin allowing appropriate uptake into the cells of the body. Both require management.
  • 33.
    Glycemic Control Management highly intrusive compliance is an issue relies on user lifestyle change often on regular sampling and measuring of blood glucose levels Highly individual
  • 34.
    Glycemic Control Manyof the long-term complications of diabetes, especially microvascular complications, result from many years of elevated blood glucose levels. Good glycemic control, (70-130 mg/dl, or 3.9-7.2 mmol/L) is the important goal of diabetes care.
  • 35.
    Glycemic control Thehemoglobin A1c (glycosylated hemoglobin) reveals “average” glucoses over the preceding 2-3 months. In normal glucose metabolism, the glycosylated hemoglobin is usually 4-6% by the most common methods (normal ranges may vary by method).
  • 36.
    Glycemic Control &quot;Perfectglycemic control&quot; glucose levels were always within the normal range (70-130 mg/dl, or 3.9-7.2 mmol/L) “ Perfect” glycemic control very difficult, and even &quot;good glycemic control&quot; usually describes blood glucose levels that average somewhat higher than the normal range. “ Poor glycemic control” Persistently elevated blood glucose and glycosylated hemoglobin levels May persist over months and years before severe complications develop.
  • 37.
    Summary Diabetesoccurs when either there is inadequate insulin production in the pancreas or there is inadequate absorption of insulin into the cells. Insulin is needed for metabolism of glucose for energy at the cellular level Lack of glucose for metabolism  metabolism of fat and protein for energy, polyuria, polydipsia, and polyphagia (classic symptoms of diabetes) and others listed earlier Chronic condition that can lead to multiple serious complications Goal: glycemic control
  • 38.
  • 39.
    Hypoglycemia symptoms Shakiness Nervousness Sweating Dizziness or light-headedness Sleepiness Confusion Another clue to nocturnal hypoglycemia is postprandial hyperglycemia after breakfast Difficulty speaking Anxiety Weakness Hypoglycemia can also happen during sleep crying out or having nightmares finding pajamas or sheets damp from perspiration feeling tired, irritable, or confused after waking up
  • 40.
    Hypoglycemia Hypoglycemia, alsocalled low blood glucose or low blood sugar, occurs when blood glucose drops below normal levels. http://hubpages.com/hub/Hypoglycemia_Symptoms_and_Treatments