DIABETES MELLITUS (Type 1
& Type 2) – PATHO-TO-
PRACTICE GUIDE
,SECTION 1 — OVERVIEW
• Diabetes Mellitus (DM) = chronic metabolic disorder characterized by
hyperglycemia.
• Caused by defects in insulin secretion, insulin action, or both.
• Type 1 DM: Autoimmune destruction of pancreatic beta cells → absolute
insulin deficiency.
• Type 2 DM: Insulin resistance + relative insulin deficiency → chronic
hyperglycemia.
SECTION 2 — PATHOPHYSIOLOGY
FLOWCHART
Type 1 DM (Autoimmune / Juvenile-Onset)
Genetic & environmental factors
↓
Autoimmune destruction of β-cells in pancreas
↓
Absolute insulin deficiency
↓
Glucose cannot enter cells
↓
Cells starve → body uses fat → ketone production → risk of DKA
↓
Hyperglycemia → osmotic diuresis → polyuria → dehydration
↓
Polydipsia & Polyphagia
Type 2 DM (Adult-Onset / Insulin Resistance)
,Genetic predisposition + obesity / sedentary lifestyle
↓
Peripheral insulin resistance (muscle & fat cells)
↓
Pancreas ↑ insulin production (hyperinsulinemia)
↓
Eventually β-cell failure → ↓ insulin secretion
↓
Glucose accumulates in blood → hyperglycemia
↓
Polyuria, Polydipsia, Polyphagia (classic triad)
↓
Chronic hyperglycemia → microvascular & macrovascular
complications
SECTION 3 — CLINICAL
MANIFESTATIONS
Type 2
Feature Type 1 DM Notes
DM
Often diagnosed during routine
Onset Rapid Gradual
labs
Children /
Age Adults Can occur at any age now
Adolescents
Polyuria Due to osmotic diuresis
Polydipsia Dehydration triggers thirst
Polyphagia Cells not receiving glucose
Weight Loss Sometimes Type 1 more obvious
, Type 2
Feature Type 1 DM Notes
DM
Chronic hyperglycemia &
Fatigue
dehydration
Blurred Vision High glucose → lens swelling
Ketoacidosis Rare More common in Type 1
Slow Wound Due to poor circulation &
Healing neuropathy
SECTION 4 — LABS & DIAGNOSTIC
CRITERIA
Test Diagnostic Value Notes
Fasting Plasma Glucose ≥126 mg/dL Fast 8 hrs
Polyuria, polydipsia,
Random Glucose ≥200 mg/dL + symptoms
polyphagia
Oral Glucose Tolerance Test
≥200 mg/dL after 2 hrs Often used in gestational DM
(OGTT)
Reflects 3-month glucose
HbA1c ≥6.5%
control
Ketones + in Type 1 (DKA) Not usually present in Type 2
SECTION 5 — INSULIN TYPES & USE
, Type Onset Peak Duration Example Nursing Notes
15–30 Give with meals; monitor
Rapid-Acting 1–2 hr 3–5 hr Lispro, Aspart
min for hypoglycemia
30–60
Short-Acting 2–4 hr 5–8 hr Regular Can be IV drip for DKA
min
Intermediate- Cloudy → roll vial; not for
1–2 hr 4–12 hr 14–24 hr NPH
Acting meals alone
Glargine,
Long-Acting 1–2 hr No peak 24 hr Once daily, basal insulin
Detemir
Mixed / NPH/Regular
Varies Varies Varies Covers basal + mealtime
Combination 70/30
SECTION 6 — NURSING
MANAGEMENT / INTERVENTIONS
1. Blood Glucose Monitoring
• Check fasting, pre-meal, bedtime, or continuous glucose monitor.
• Rationale: Prevent hypo/hyperglycemia; guides insulin dosing.
2. Administer Insulin / Oral Hypoglycemics
• Type 1: Insulin required for life
• Type 2: Oral meds first → insulin if needed
• Monitor for: hypoglycemia (shaky, sweating, confusion)
3. Hydration & Electrolyte Balance
• Encourage PO fluids or IV if N/V/D
• Monitor Na+, K+ (especially in DKA)
& Type 2) – PATHO-TO-
PRACTICE GUIDE
,SECTION 1 — OVERVIEW
• Diabetes Mellitus (DM) = chronic metabolic disorder characterized by
hyperglycemia.
• Caused by defects in insulin secretion, insulin action, or both.
• Type 1 DM: Autoimmune destruction of pancreatic beta cells → absolute
insulin deficiency.
• Type 2 DM: Insulin resistance + relative insulin deficiency → chronic
hyperglycemia.
SECTION 2 — PATHOPHYSIOLOGY
FLOWCHART
Type 1 DM (Autoimmune / Juvenile-Onset)
Genetic & environmental factors
↓
Autoimmune destruction of β-cells in pancreas
↓
Absolute insulin deficiency
↓
Glucose cannot enter cells
↓
Cells starve → body uses fat → ketone production → risk of DKA
↓
Hyperglycemia → osmotic diuresis → polyuria → dehydration
↓
Polydipsia & Polyphagia
Type 2 DM (Adult-Onset / Insulin Resistance)
,Genetic predisposition + obesity / sedentary lifestyle
↓
Peripheral insulin resistance (muscle & fat cells)
↓
Pancreas ↑ insulin production (hyperinsulinemia)
↓
Eventually β-cell failure → ↓ insulin secretion
↓
Glucose accumulates in blood → hyperglycemia
↓
Polyuria, Polydipsia, Polyphagia (classic triad)
↓
Chronic hyperglycemia → microvascular & macrovascular
complications
SECTION 3 — CLINICAL
MANIFESTATIONS
Type 2
Feature Type 1 DM Notes
DM
Often diagnosed during routine
Onset Rapid Gradual
labs
Children /
Age Adults Can occur at any age now
Adolescents
Polyuria Due to osmotic diuresis
Polydipsia Dehydration triggers thirst
Polyphagia Cells not receiving glucose
Weight Loss Sometimes Type 1 more obvious
, Type 2
Feature Type 1 DM Notes
DM
Chronic hyperglycemia &
Fatigue
dehydration
Blurred Vision High glucose → lens swelling
Ketoacidosis Rare More common in Type 1
Slow Wound Due to poor circulation &
Healing neuropathy
SECTION 4 — LABS & DIAGNOSTIC
CRITERIA
Test Diagnostic Value Notes
Fasting Plasma Glucose ≥126 mg/dL Fast 8 hrs
Polyuria, polydipsia,
Random Glucose ≥200 mg/dL + symptoms
polyphagia
Oral Glucose Tolerance Test
≥200 mg/dL after 2 hrs Often used in gestational DM
(OGTT)
Reflects 3-month glucose
HbA1c ≥6.5%
control
Ketones + in Type 1 (DKA) Not usually present in Type 2
SECTION 5 — INSULIN TYPES & USE
, Type Onset Peak Duration Example Nursing Notes
15–30 Give with meals; monitor
Rapid-Acting 1–2 hr 3–5 hr Lispro, Aspart
min for hypoglycemia
30–60
Short-Acting 2–4 hr 5–8 hr Regular Can be IV drip for DKA
min
Intermediate- Cloudy → roll vial; not for
1–2 hr 4–12 hr 14–24 hr NPH
Acting meals alone
Glargine,
Long-Acting 1–2 hr No peak 24 hr Once daily, basal insulin
Detemir
Mixed / NPH/Regular
Varies Varies Varies Covers basal + mealtime
Combination 70/30
SECTION 6 — NURSING
MANAGEMENT / INTERVENTIONS
1. Blood Glucose Monitoring
• Check fasting, pre-meal, bedtime, or continuous glucose monitor.
• Rationale: Prevent hypo/hyperglycemia; guides insulin dosing.
2. Administer Insulin / Oral Hypoglycemics
• Type 1: Insulin required for life
• Type 2: Oral meds first → insulin if needed
• Monitor for: hypoglycemia (shaky, sweating, confusion)
3. Hydration & Electrolyte Balance
• Encourage PO fluids or IV if N/V/D
• Monitor Na+, K+ (especially in DKA)
