Diabetes Mellitus: Comprehensive Nursing Notes

Diabetes Mellitus

Comprehensive Nursing Notes

A Complete Guide for Nursing Students

Diabetes Mellitus Pathophysiology Illustration

Comprehensive illustration showing pancreatic beta cells, insulin pathways, and diabetes mechanisms

Learning Objectives

Understand Type 1 & Type 2 Diabetes
Recognize Symptoms & Complications
Master Management Strategies
Perform Diagnostic Investigations

Interpret OGTT Results
Understand HbA1c Significance
Manage Hypoglycemia
Apply Nursing Interventions

Introduction to Diabetes Mellitus

Diabetes Mellitus is a group of metabolic disorders characterized by chronic hyperglycemia resulting from defects in insulin secretion, insulin action, or both. It affects over 463 million people worldwide and represents one of the most significant health challenges of the 21st century. As nursing professionals, understanding diabetes is crucial for providing comprehensive patient care and education.

Key Definition

Diabetes Mellitus is defined as a fasting plasma glucose ≥126 mg/dL (7.0 mmol/L) or a 2-hour plasma glucose ≥200 mg/dL (11.1 mmol/L) during an oral glucose tolerance test, or HbA1c ≥6.5% (48 mmol/mol).

Pathophysiology of Diabetes

Normal Glucose Homeostasis

Pancreatic β-cells secrete insulin
Insulin facilitates glucose uptake
Glucose stored as glycogen
Blood glucose maintained 70-110 mg/dL

Diabetic Dysfunction

Impaired insulin secretion/action
Decreased glucose uptake
Increased hepatic glucose production
Chronic hyperglycemia

Type 1 vs Type 2 Diabetes

Type 1 Diabetes

Pathogenesis

Autoimmune destruction of pancreatic β-cells leading to absolute insulin deficiency.

• T-cell mediated destruction
• Genetic predisposition (HLA-DR3, HLA-DR4)
• Environmental triggers (viruses, stress)

Characteristics

• Age of onset: Usually <30 years
• Body weight: Normal or underweight
• Onset: Acute, rapid
• Ketosis: Prone to DKA
• Insulin requirement: Absolute

Clinical Pearl

Remember “THIN” – Type 1 patients are typically Thin, Have Insulin deficiency, and Need insulin immediately.

Type 2 Diabetes

Pathogenesis

Insulin resistance with progressive β-cell dysfunction and relative insulin deficiency.

• Peripheral insulin resistance
• Impaired insulin secretion
• Increased hepatic glucose production

Characteristics

• Age of onset: Usually >40 years
• Body weight: Often obese
• Onset: Insidious, gradual
• Ketosis: Rare, except under stress
• Insulin requirement: May be needed

Clinical Pearl

Remember “THICK” – Type 2 patients are typically Thick (obese), Have Insulin resistance, and Can be managed with lifestyle changes initially.

Symptoms and Clinical Presentation

Memory Aid: “4 P’s of Diabetes”

Primary Symptoms

Polyuria – Excessive urination
Polydipsia – Excessive thirst
Polyphagia – Excessive hunger
Pound loss – Unexplained weight loss

Secondary Symptoms

Blurred vision
Fatigue and weakness
Slow-healing wounds
Frequent infections

Polyuria

Mechanism: Osmotic diuresis due to glycosuria

Threshold: Blood glucose >180 mg/dL

Frequency: >3L/day or >50mL/kg/day

Polydipsia

Mechanism: Compensatory response to dehydration

Trigger: Increased plasma osmolality

Volume: Often >3-4L/day

Polyphagia

Mechanism: Cellular starvation despite hyperglycemia

Cause: Ineffective glucose utilization

Paradox: Increased hunger with weight loss

Complications of Diabetes

Acute Complications

Diabetic Ketoacidosis (DKA)

Triad: Hyperglycemia, Ketonemia, Acidosis

Glucose: >250 mg/dL

pH: <7.3

Ketones: >3 mmol/L

Mortality: 1-5%

Hyperosmolar Hyperglycemic State (HHS)

Glucose: >600 mg/dL

Osmolality: >320 mOsm/kg

pH: >7.3 (no significant ketosis)

Mortality: 5-20%

Hypoglycemia

Definition: <70 mg/dL

Severe: <54 mg/dL

Symptoms: Sweating, palpitations, confusion

Treatment: 15g fast-acting carbs

Chronic Complications

Microvascular

Retinopathy: Leading cause of blindness
Nephropathy: CKD, dialysis, transplant
Neuropathy: Peripheral, autonomic

Macrovascular

CAD: 2-4x increased risk
Stroke: 2-3x increased risk
PAD: Amputation risk

Other Complications

Increased infection risk
Periodontal disease
Depression (2x risk)

Management of Diabetes

Type 1 Management

Insulin Therapy

Type	Onset	Peak	Duration
Rapid-Acting	15 min	1-2 hr	3-4 hr
Short-Acting	30-60 min	2-4 hr	5-8 hr
Long-Acting	2 hr	No peak	24 hr

Basal-Bolus Regimen

• Basal: 40-50% of total daily dose
• Bolus: 50-60% divided among meals
• Correction factor: 1800 rule
• Carb ratio: 500 rule

Type 2 Management

Stepwise Approach

1. Lifestyle Modifications

↓

2. Metformin

↓

3. Add 2nd Agent

↓

4. Insulin

Medication Classes

• Metformin: First-line, ↓ hepatic glucose
• Sulfonylureas: ↑ insulin secretion
• SGLT2i: ↑ glucose excretion
• GLP-1 RA: ↑ insulin, ↓ glucagon
• DPP-4i: ↑ incretin activity

Glycemic Targets

HbA1c

<7%

(53 mmol/mol)

Fasting Glucose

80-130

mg/dL

Postprandial

<180

mg/dL

Investigations of Diabetes Mellitus

Oral Glucose Tolerance Test (OGTT)

Indications

• Impaired fasting glucose (100-125 mg/dL)
• Gestational diabetes screening
• Borderline HbA1c (5.7-6.4%)
• Strong family history + normal glucose
• Polycystic ovary syndrome
• Previous gestational diabetes

Procedure

1. Preparation: 8-12 hour fast
2. Baseline: Draw fasting glucose
3. Load: 75g glucose solution
4. Timing: Draw at 1hr, 2hr
5. Activity: Patient sits quietly
6. Restrictions: No smoking/caffeine

Interpretation

Category	Fasting (mg/dL)	2-Hour (mg/dL)	HbA1c (%)
Normal	<100	<140	<5.7
Prediabetes	100-125	140-199	5.7-6.4
Diabetes	≥126	≥200	≥6.5

Types of GTT Curves

Normal Curve

• Fasting: 70-100 mg/dL
• Peak: 120-140 mg/dL at 1 hour
• 2-hour: Returns to <140 mg/dL
• Shape: Smooth rise and fall

Diabetic Curve

• Fasting: ≥126 mg/dL
• Peak: >200 mg/dL sustained
• 2-hour: ≥200 mg/dL
• Shape: High, delayed return

Special GTT Variations

Mini GTT

• Dose: 50g glucose
• Duration: 1 hour only
• Use: Screening test
• Threshold: <140 mg/dL normal

Extended GTT

• Duration: 3-5 hours
• Samples: Every 30-60 minutes
• Use: Reactive hypoglycemia
• Indication: Post-prandial symptoms

Glucose Challenge Test (GCT)

• Timing: 24-28 weeks gestation
• Dose: 50g glucose (non-fasting)
• Threshold: ≥140 mg/dL abnormal
• Follow-up: 3-hour OGTT if positive

Intravenous GTT (IVGTT)

• Route: IV glucose bolus
• Advantage: Bypasses GI absorption
• Use: Research, malabsorption
• Calculation: K-value (glucose disposal)

HbA1c (Hemoglobin A1c)

Definition of HbA1c

HbA1c is a form of hemoglobin that is covalently bound to glucose. It represents the average plasma glucose concentration over the preceding 2-3 months, providing a reliable measure of long-term glycemic control.

Formation Process

• Non-enzymatic glycation of hemoglobin
• Irreversible process
• Proportional to glucose exposure
• Reflects 120-day RBC lifespan

Clinical Significance

• Diagnostic tool (≥6.5% = diabetes)
• Monitoring glycemic control
• Predicts complications risk
• No fasting required

Normal

<5.7%

(<39 mmol/mol)

Prediabetes

5.7-6.4%

(39-47 mmol/mol)

Diabetes

≥6.5%

(≥48 mmol/mol)

Hypoglycemia

Definition

Glucose Levels

• Level 1: 54-69 mg/dL (3.0-3.8 mmol/L)
• Level 2: <54 mg/dL (<3.0 mmol/L)
• Level 3: Severe cognitive impairment

Whipple’s Triad

1. Symptoms consistent with hypoglycemia
2. Low plasma glucose level
3. Resolution with glucose administration

Causes

Diabetes-Related

• Insulin overdose
• Sulfonylurea excess
• Missed meals
• Excessive exercise
• Alcohol consumption

Non-Diabetes Related

• Insulinoma
• Adrenal insufficiency
• Liver disease
• Renal failure
• Sepsis

Hypoglycemia Symptoms: “SWEATING”

Autonomic Symptoms

Sweating, shakiness
Weakness, fatigue
Excess hunger
Anxiety, irritability

Neuroglycopenic

Tremor, palpitations
Inability to concentrate
Neurological changes
Gait instability, coma

Nursing Implementation in Diabetes Care

Assessment & Monitoring

Glucose Monitoring

• Capillary blood glucose testing
• Continuous glucose monitoring (CGM)
• Urine ketones in Type 1 diabetes
• Document patterns and trends

Physical Assessment

• Foot examination daily
• Skin integrity assessment
• Vital signs monitoring
• Weight and BMI tracking

Patient Education

Nutrition Education

• Carbohydrate counting
• Meal planning and timing
• Reading food labels
• Portion control techniques

Medication Management

• Insulin administration techniques
• Rotation of injection sites
• Proper storage of medications
• Recognition of side effects

Emergency Management

Hypoglycemia Protocol

1. Assess: Glucose <70 mg/dL
2. Treat: 15g fast-acting carbs
3. Wait: 15 minutes
4. Recheck: Blood glucose
5. Repeat: If still <70 mg/dL
6. Follow-up: Complex carbs/meal

DKA Recognition

• Symptoms: N/V, abdominal pain
• Signs: Kussmaul breathing, fruity odor
• Labs: Glucose >250, ketones +
• Action: Immediate physician notification

Documentation Requirements

Glucose Monitoring

• Time and glucose value
• Relation to meals
• Insulin given
• Patient response

Patient Teaching

• Topics covered
• Patient understanding
• Return demonstration
• Areas needing reinforcement

Complications

• Signs and symptoms
• Interventions provided
• Patient outcome
• Physician notification

Clinical Pearls for Nursing Practice

Quick Assessment Tips

Hyperglycemia: “Hot and dry, sugar high”
Hypoglycemia: “Cold and clammy, need some candy”
DKA breath: Fruity/acetone odor
Foot care: Daily inspection essential
Sick day rules: Never skip insulin

Monitoring Priorities

Blood glucose: Before meals and bedtime
Ketones: When glucose >250 mg/dL
Blood pressure: Target <130/80
Lipids: LDL <100 mg/dL
Kidney function: Annual screening

Summary

Key Takeaways

Diabetes is a complex metabolic disorder requiring comprehensive management
Early recognition and intervention prevent complications
Patient education is crucial for successful diabetes management
Regular monitoring and assessment guide treatment decisions

Nursing Excellence

Master glucose monitoring techniques and interpretation
Develop expertise in patient education and counseling
Recognize and respond to diabetes emergencies
Advocate for patients and their families

Continue Learning

These comprehensive notes provide a foundation for excellent diabetes care. Remember to always follow your institution’s protocols and evidence-based guidelines for optimal patient outcomes.

Evidence-Based Practice

Compassionate Care

Patient Safety