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Diabetes mellitus (DM) → group of metabolic disorders → hyperglycemia caused by defect in insulin secretion &/or insulin action

  • Type 1 (DM1) → immune-mediated insulin deficiency; rate of beta-cell destruction much faster in children than in adults; many adults initially diagnosed with type 2
  • Type 2 (DM2) → (90–95% of patients) insulin resistance is primary abnormality → obesity, relative insulin deficiency (often hyperinsulinemic), frequently diagnosed years after onset; may present with complications, but can be asymptomatic
    • DM2 risk factors → overweight (BMI ≥25kg/m2), physically inactive, 1st-degree relative with DM2, history of gestational diabetes or delivery of infant >9lb, HTN, hyperlipidemia, signs of insulin resistance, CVD, or belonging to high-risk race/ethnicity (African America, Latino, Native American, Asian American, Pacific Islander) (Diabetes Care 2011;34:S11)
  • Gestational diabetes (GDM) → glucose intolerance during pregnancy → 2/2 worsening of insulin resistance & insulin secretion
  • Other types of diabetes → genetic defects of β-cell function; genetic defects in insulin secretion; diseases of the pancreas; chemical or drug induced

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Clinical Pearl 23-1

Idiopathic diabetes → rare, non-immune mediated; prone to DKA 2/2 varying insulin requirements (may require zero insulin at times) → strongly inherited, most patients African or Asian descent

(Diabetes Care 2011;34:S62)

  • Normoglycemia → fasting plasma glucose (FPG) <100mg/dL; 2h postprandial glucose (PG) <140mg/dL
  • ↑ risk of DM → A1C 5.7–6.4%; FPG 100–125mg/dL; 2h PG 140–199mg/dL
  • Diabetes → FPG ≥126mg/dL; 2h PG ≥200mg/dL; symptoms of DM plus glucose ≥200mg/dL; A1C ≥6.5%; diagnosis must be confirmed on another day unless overt symptoms/evidence of DM
  • Signs/symptoms directly related to hyperglycemia
    • Polyuria → ↑ in frequency & volume of urination; may have nocturia
      • Plasma glucose level exceeds renal reabsorption threshold; excess glucose excreted in urine, water follows ∴ excessive urine formation
    • Polydipsia → ↑ thirst 2/2 volume loss from polyuria
    • Polyphagia → excessive hunger & weight loss despite eating large amounts → ↓ cellular glucose 2/2 insulin resistance/lack of insulin (↓ glucose entry into cells) → stimulates hunger
      • Weight loss & fatigue → 2/2 to ↓ available cellular glucose
    • Blurred vision → accumulated glucose in lens of eye converted to sorbitol by aldose reductase → ↑ tonicity & fluid influx to lens ∴ blurred vision (short-term); long-term hyperglycemia → retinopathy

Goals of treatment → patient to be symptom-free & complication-free

  • All patients can benefit from lifestyle changes, medical nutrition therapy (MNT), & diabetes education
    • ↓ saturated fat, cholesterol & trans-fat intake; ↑ omega-3 & viscous fiber intake
    • Smoking cessation, physical activity, & weight loss (if needed)
  • BP goal <130/80mmHg → ACE inhibitor/ARB DOC; if inadequate control → add thiazide (Clcr  ≥30mL/min) or loop diuretic (Clcr <30mL/min) (Diabetes Care 2011;34:S11) → monitor K+ & Scr
  • Lipids → ↑ prevalence of lipid abnormalities & CVD; typical pattern → ↑ TGs, ↓ HDL, normal or ↑ LDL that is small & dense → ↑ CV events; ...

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