L 13a

TYPE 2 DIABETES MELLITUS

  • A group of metabolic disorders of carbohydrate metabolism characterized by:

    • Underutilization of glucose as an energy source

    • Overproduction of glucose due to inappropriate gluconeogenesis and glycogenolysis

    • Results in hyperglycemia

  • Insulin is essential for transporting glucose from plasma into cells.

  • Elevated plasma sugar levels lead to systemic issues.

Classification of Diabetes

Type 1 Diabetes Mellitus (T1DM)

  • Autoimmune β-cell destruction

  • Leads to an inability to produce insulin.

Type 2 Diabetes Mellitus (T2DM)

  • Characterized by:

    • Decreased insulin secretion

    • Decreased sensitivity to insulin in peripheral tissues.

Gestational Diabetes (GDM)

  • Diabetes diagnosed during the 2nd or 3rd trimester of pregnancy.

  • Not present before gestation.

  • Placental human lactin may excessively take glucose from the mother to the baby.

Secondary Diabetes

  • Diabetes due to other causes, which may include:

    • Monogenic diabetes syndromes (Mutations in beta cell genes)

    • Diseases of the exocrine pancreas

    • Drug or chemical-induced (e.g., chronic steroid use)

    • Infections (e.g., Rubella, mumps, Hepatitis C)

    • Other disease states.

Epidemiology

  • In 2021:

    • 38.4 million Americans (11.6% of the population) had diabetes.

  • Complications of T2DM include:

    • Kidney failure

    • Amputations

    • Stroke

    • Heart failure

    • Hyperglycemic crises

  • Prevalence higher in those with less than high school education (13.1%) compared to those with more (6.9%).

  • Obesity Statistics:

    • 42% of the US population

    • 19.7% of children aged 2-19 living with obesity.

Pathophysiology of T2DM

Causes of Hyperglycemia

  • Decreased insulin secretion

  • Increased glucagon secretion

  • Neurotransmitter dysfunction

  • Decreased glucose uptake

  • Increased glucose reabsorption

  • Increased lipolysis

  • Decreased incretin effect

  • Islet alpha cell activity

  • Increased age

Major Risk Factors for T2DM

  • Obesity: The most significant modifiable risk factor.

    • Highest insulin resistance associated with waist circumference obesity.

  • Physical inactivity

  • Genetic predisposition: First-degree relative with diabetes.

  • Ethnic background: Membership in a high-risk ethnic population.

  • History of GDM: Increases risk of T2DM later in life for females.

  • History of cardiovascular disease (CVD)

  • Hypertension (HTN): Diagnosed as ≥ 140/90 mmHg or on antihypertensive therapy.

  • Lipid abnormalities:

    • HDL cholesterol level <35 mg/dL (0.90 mmol/L)

    • Triglyceride level >250 mg/dL (2.82 mmol/L)

  • Polycystic ovary syndrome in females.

  • Hemoglobin A1c ≥5.7%, impaired glucose tolerance, or impaired fasting glucose from previous tests.

Other Clinical Conditions Associated with Insulin Resistance

  • Severe obesity

  • Acanthosis nigricans: Skin condition that may indicate insulin resistance.

Clinical Presentation

  • Many patients experience a slow onset of hyperglycemia and may be asymptomatic initially:

    • Importance of screening for early detection.

    • Approximately 25% of those with T2DM already have one or more microvascular complications at diagnosis.

Suspicious Clinical Signs & Symptoms

  • Obesity: Significant or central obesity.

  • Weight circumference: >40 inches in males, >35 inches in females.

  • Clinical features include:

    • Polysymptoms:

    • Polydipsia (increased thirst)

    • Polyuria/nocturia (increased urination)

    • Polyphagia with weight loss (body breaking down muscles for glucose)

    • Chronic skin infections

    • Signs/symptoms of microvascular and macrovascular complications:

    • Peripheral neuropathy

    • Blurred vision

    • Gastroparesis

    • Presence of acanthosis nigricans:

    • High insulin levels bind to IGF receptors in skin cells.

Additional Signs in Women

  • Chronic candida vulvovaginitis.

  • History of delivering large babies (>9 lbs).

  • History of polyhydramnios, preeclampsia, or unexplained fetal loss.

Diagnosis of T2DM (ADA, 2026)

  1. Fasting Plasma Glucose (FPG) ≥126 mg/dL (7.0 mmol/L), fasting defined as no caloric intake for at least 8 hours.

  2. 2-Hour Plasma Glucose ≥200 mg/dL (11.1 mmol/L) during an Oral Glucose Tolerance Test (OGTT) with a 75g glucose load.

  3. Hemoglobin A1c ≥6.5% (48 mmol/mol).

  4. In a patient with classic hyperglycemia symptoms, a random plasma glucose ≥200 mg/dL (11.1 mmol/L).

  5. Diagnosis needs 2 abnormal test results from the same sample or two separate samples in the absence of unequivocal hyperglycemia.

Laboratory Tests for Diabetes Mellitus

  1. Fasting Plasma Glucose:

    • Serum test to quantify free glucose in the bloodstream.

    • Must occur after fasting (no food or drink for <8 hours).

    • Thresholds:

      • ≥126 mg/dL (7.0 mmol/L) → Diabetes Mellitus.

      • 100 mg/dL – 125 mg/dL → Prediabetes.

      • <100 mg/dL → Normal.

  2. 2-Hour Oral Glucose Tolerance Test (OGTT):

    • Patient NPO after midnight.

    • Load: 75g glucose in 300 mL water consumed in 5 mins.

    • Blood samples: Taken at 0 and 120 minutes.

    • Thresholds:

      • ≥200 mg/dL → Diabetes.

      • 140–199 mg/dL → Prediabetes.

      • <140 mg/dL → Normal.

  3. Hemoglobin A1c:

    • Also known as Glycohemoglobin or Hemoglobin A1c (HbA1c).

    • Reflects blood glucose levels over the previous 120 days.

    • Thresholds:

      • ≥6.5% → Diabetes.

      • 5.7%–6.4% → Prediabetes.

      • <5.7% → Normal.

  4. Glucosuria: Testing for urine glucose is an insensitive method for detecting T2DM; not all patients with glucosuria have diabetes.

Diabetic Ketoacidosis (DKA)

  • Must-Not-Miss Diagnosis!

    • Lack of insulin leads to no glucose uptake → cellular starvation → excess glucagon and pro-inflammatory markers → hyperglycemia and dehydration.

    • Increased fatty acid breakdown → elevated triglycerides → conversion to ketones → severe acidosis.

  • Triggers: Infection, improper medication usage, cardiovascular events, trauma, alcohol use.

  • Diagnosis Indicators:

    • Hyperglycemia >200 mg/dL on metabolic panel.

    • Anion gap >12 indicating metabolic acidosis.

    • Elevated serum ketone levels (norm mainly in T1DM but can occur in T2DM).

    • Symptoms: Kussmaul respirations (to expel CO2), fruity breath.

    • Glucose Levels: 200 to 300 mg/dL; significant AG acidosis.

    • Treatment: Administer insulin with potassium to facilitate K+ uptake into cells.

Hyperglycemic Hyperosmolar State (HHS)

  • Must-Not-Miss Diagnosis!

    • Characterized by decreased insulin sensitivity causing significant hyperglycemia, preventing ketosis.

    • Results in profound dehydration due to increased serum osmolality.

  • Triggers: Infection, improper medication management, cardiovascular events, trauma, alcohol use.

  • Diagnosis Indicators:

    • Hyperglycemia >600 mg/dL on metabolic panel.

    • Increased serum osmolality >320 mOsm indicating severe dehydration requiring fluid replacement.

    • Normal anion gap, no acidosis (pH >7.3), no ketosis.

    • Symptoms: Polyuria, thirst, visual changes, lethargy.

    • Complications: Arrhythmia, cerebral edema, respiratory failure.

    • Treatment:

    • Address underlying stressors.

    • Volume resuscitation and insulin therapy.

    • Monitor electrolytes.

Diagnosis of Prediabetes

Criteria

  • Fasting Plasma Glucose:

    • 100–125 mg/dL (5.6–6.9 mmol/L)

    • Considered Impaired Fasting Glucose (IFG).

  • 75-g Oral Glucose Tolerance Test (OGTT):

    • 140–199 mg/dL at 2 hours (7.8–11.0 mmol/L).

    • Considered Impaired Glucose Tolerance (IGT).

  • Hemoglobin A1c:

    • 5.7%–6.4% (39–47 mmol/mol).

Screening Recommendations for Diabetes or Prediabetes

  • Screen all adults who are overweight or obese and have one or more of the following risk factors:

    • BMI ≥25 kg/m² or BMI ≥23 kg/m² for Asian Americans.

    • First-degree relative with diabetes.

    • High-risk race or ethnicity.

    • History of cardiovascular disease.

    • Hypertension (≥140/90 mmHg or on treatment).

    • HDL cholesterol <35 mg/dL and/or triglycerides >250 mg/dL.

    • Women with polycystic ovary syndrome.

    • Physical inactivity.

    • Clinical conditions linked to insulin resistance (e.g., severe obesity, acanthosis nigricans).

Screening Guidelines

  • Patients with prediabetes should be tested yearly.

  • Women diagnosed with GDM should undergo lifelong testing every 3 years, even if not obese.

  • Other patients should begin testing at age 45 years.

  • Testing frequency should increase based on risk factors.

    • Consider using fasting plasma glucose, 2-h plasma glucose during OGTT, or A1c for screening.

Comprehensive Diabetes Medical Evaluation

Initial Evaluation of a Patient with DM

  • Components include:

    • Medical history (tailored medication needs, co-morbidities)

    • Physical examination

    • Laboratory evaluation

    • Management plan including patient education.

  • Goals:

    • Identify and confirm diagnosis.

    • Evaluate for diabetes-related complications.

    • Assess social determinants of health (SDOH) and identify support systems.

    • Develop a patient-centered care plan.

Medical History Considerations

  • Assess for co-morbidities and medications:

    • Obesity

    • Hypertension

    • Hyperlipidemia

    • Obstructive Sleep Apnea (OSA)

    • Other endocrinopathies and malignancies.

    • Current medication regimen encompassing adherence behaviors and side effects.

    • Ensure vaccination updates (COVID-19, Hep B, flu, pneumonia, RSV, zoster).

  • Review recent visits, particularly with dentists and specialists.

Diabetes History

  • Assess onset characteristics (age, symptoms) and treatment responses.

  • Document hypoglycemic events (number, frequency, severity).

  • Examine frequency and causes of past hospitalizations or surgeries.

Complications of Diabetes

Macrovascular Complications

  • Include:

    • Coronary heart disease

    • Cerebrovascular disease

    • Peripheral arterial disease.

  • 10-year risk assessment of first atherosclerotic cardiovascular disease events using race and sex-specific Pooled Cohort Equations.

Microvascular Complications

  • Include:

    • Retinopathy

    • Nephropathy (Stage Chronic Kidney Disease)

    • Neuropathy (sensorimotor, autonomic dysfunction, sexual dysfunction, gastroparesis, hypotension).

Family and Social History

Family History

  • Family history of diabetes (first-degree relatives) or autoimmune disorders.

Social History

  • Dietary habits, weight history, sleep behaviors, and physical activity level.

  • Assess familiarity with carbohydrate counting and use of tobacco, alcohol, and substances.

  • Identify social determinants of health and support systems.

Diabetes Self-Management Education and Support

  • Evaluate past interactions with dietitians or diabetes educators.

  • Assess self-management skills, noted barriers to effective diabetes management.

  • Technology Use: Monitor use of health apps, online education resources, patient portals, and glucose monitoring data.

Psychosocial Conditions

  • Screen for:

    • Depression, anxiety, disordered eating.

    • Assess cognitive impairment in patients aged 65 and older.

Screening Guidelines for Anxiety Disorders

  • Indicators include:

    • Patients’ worries about diabetes management or complications interfering with self-management.

    • Avoidance behavior and social withdrawal due to anxiety.

Screening for Depression in Patients with Diabetes

  • Annual screening recommended, especially for those with depression history.

    • Utilize age-appropriate depression measurement tools (e.g., PHQ-9 for adults).

Screening for Disordered Eating

  • Symptoms include binge eating, intentional insulin omission.

Screening for Diabetes Distress (DD)

  • Routine monitoring for diabetes distress is critical, particularly with unmet treatment targets.

Physical Examination

  • Comprehensive checks including:

    • Vital signs (height, weight, BP) including orthostatic measurements.

    • Cognitive and physical ability assessment.

    • Fundoscopic exam (to check for retinal complications).

    • Oral exams for periodontal issues.

Comprehensive Foot Examination

  • Visual inspection of feet:

    • Assessment of peripheral neuropathy and skin integrity.

    • Evaluation for peripheral arterial disease and sensory response tests using monofilament exams.

Laboratory Evaluation

  1. Hemoglobin A1c should be checked if results not available within 3 months.

  2. Additional tests: lipid profile, liver function tests, urinary albumin-to-creatinine ratio, serum creatinine, TSH and screenings for celiac disease in T1DM, complete blood count, vitamin B12 checks for long-term metformin use.

  3. Serum potassium levels if on ACE inhibitors or other medications.

  4. Vitamin D, calcium, phosphorous, and DEXA scans for bone health assessments.

Referrals

  • Refer for comprehensive dental exams, reproductive health, eye care, behavioral health, diabetes self-management education, registered dietitians, podiatric care, and social work for community resources.

Patient Education

Key Areas for Education

  • Diabetes Self-Management Education and Support

  • Medical Nutrition Therapy: Tailored dietary plans.

  • Physical Activity: Moderate-to-vigorous exercise for at least 150 min/week recommended for both T1DM and T2DM to improve blood glucose control.

    • Emphasize starting slowly with realistic goals.

  • Smoking Cessation: Important for reducing cardiovascular and microvascular risks.

  • Immunizations: Follow vaccination schedules, especially for flu, pneumonia, and RSV.

    • Recommendations for pneumococcal vaccines based on age and history.