1. Adult Medical-Surgical Nursing
Endocrine Module:
Diabetes Mellitus
(Lecture 1): Introduction

2. The Role of Insulin
Anabolic role: regulates the uptake and storage of glucose by the cells: insulin binds to cell surface receptors allowing uptake of glucose (storage as glycogen)
Controls the level of glucose in the blood (together with glucagon)

3. Diabetes Mellitus: Definition
Diabetes is a metabolic problem of hyperglycaemia resulting from defects in either or both of the following:
Insulin production: pancreatic β cells may stop secreting insulin (type 1)
Insulin action: the body cells may stop responding to insulin (insulin resistance) (type 2)

4. Diabetes Mellitus: Classification
Type 1: (5-10% of cases)
Type 2: (90-95% of cases)
Gestational DM (in pregnancy, similar to type 2 but resolves at end of pregnancy: may lead to type 2 at later date)

5. Complications of Diabetes Mellitus
Hyperglycaemia leads to both acute and longterm complications

6. Acute Complications of Diabetes Mellitus
Diabetic ketoacidosis (type 1 DM)
Hyperglycaemic hyperosmolar non-ketotic syndrome (type 2 DM)
Hypoglycaemia and coma

7. Longterm Complications of Diabetes Mellitus
Macrovascular → coronary artery disease, cerebro-vascular disease, peripheral vascular disease
Chronic microvascular → nephropathy, retinopathy
Neuropathy

8. Diabetes Mellitus: USA Factsheet
Leading cause of blindness in working-age adults, non-trauma amputation and end-stage renal disease
Leading cause of hospitalisation
Third leading cause of death from disease: mainly coronary artery disease and cerebro-vascular disease
Source: Centre for Disease Control, 2008; American Diabetic Association, 2008 in Brunner & Suddarth, 12th edition, 2010

9. Diabetes Mellitus: Type 1
Absence of insulin secretion due to auto-immune destruction of the β cells of the Islets of Langerhans
Usually onset at a younger age(<30 years)
Acute onset requiring urgent treatment
Genetic predisposition: HLA tissue-typing DR3/DR4 has ↑ risk up to 20 times, but stressors may trigger or enhance disorder
Insulin required as treatment

10. Type 1 Diabetes Mellitus: Pathophysiology
Auto-immune destruction of β cells: ↓ insulin and unchecked hyperglycaemia
If > renal threshold (9.9 m mol/l) kidneys may not reabsorb glucose → glycosuria
Osmotic diuresis: polyuria, dehydration
No insulin to control catabolic action of glucagon (glycogen, fat, protein)
Breakdown of fat → ketone bodies (Diabetic ketoacidosis)may→ coma/ death

11. Type 1 DM: Clinical Manifestations (Acute Onset)
Polyuria (↑ urine output)
Polydipsia (thirst)
Polyphagia (↑ appetite)
Weight loss
Fatigue, weakness
Dehydration, dry skin
Recurrent infections, poor wound healing
Maybe ↓ vision, numb, cool extremities

12. Diabetes Mellitus: Type 2
Reduced cell sensitivity to insulin (“insulin resistance”) therefore reduced uptake of glucose: reduced action of insulin
Age of onset usually >30 years
Insidious, gradual onset (75% detected incidentally and may have complications)
Family history common
Associated with obesity: Diet to ↓ weight, and exercise are first line of treatment

13. Type 2 Diabetes Mellitus: Pathophysiology
Insulin resistance reduces uptake of glucose by cells
In an attempt to control (reduce) blood glucose level, β cells ↑ insulin production
Eventually inadequate insulin, relative to elevated glucose levels → hyperglycaemia (type 2 DM) (exhaustion of β cells)
As some insulin present, uncontrolled fat breakdown and ketoacidosis is prevented

14. Type 2 DM: Clinical Manifestations (Gradual Onset)
Polyuria
Polydipsia
Maybe associated with obesity (central)
Fatigue, weakness
Dehydration, dry skin
Recurrent infections, poor wound healing
Maybe ↓ vision, numb, cool extremities
*May be unaware until complications arise

15. Diabetes Mellitus: Diagnosis
Patient history and clinical picture
Random blood glucose
Fasting blood glucose
Oral glucose tolerance test (GTT)
Glycosylated Haemoglobin (Hb A1C)
Screen for complications: BP, ECG, arterial pulses, lipid profile, kidney function test, urine protein (24 hour), eye examination, neurological assessment

16. Positive Diagnosis of Diabetes Mellitus
Random (RBS): >11.1 m mol/l (200mg/dl)
Fasting (FBS): >7 m mol/l (126mg/dl) (With symptoms or more than once)
GTT (fasting, 50-75g glucose orally): if 2 hours postprandial, 11.1 m mol/l or above
Glycosylated Haemoglobin (Hb A1C): >6%
(When blood glucose elevated, molecules attach to haemoglobin for lifespan of RBCs: average 2-3 month glucose level)

17. Diabetes Mellitus: Treatment Plan
Control blood glucose levels
Prevent acute or longterm complications which occur with lack of control