Diabetes Mellitus Type 1 (Study Outline) For study only—this…

Diаbetes Mellitus Type 1 (Study Outline) Fоr study оnly—this is nоt medicаl аdvice or a substitute for professional care. 1. Background Definition: Autoimmune destruction of pancreatic β-cells → absolute insulin deficiency. Pathophysiology: T-cell–mediated autoimmune attack on islet cells (especially HLA-DR3/DR4 associations). Leads to complete loss of endogenous insulin production. Onset often in childhood or adolescence but can occur at any age (“LADA” in adults). Epidemiology: Peaks at 4–6 years and 10–14 years. ~5–10% of diabetes cases in the U.S. Increased risk with family history or other autoimmune diseases (thyroiditis, celiac disease). Key Mechanism: Autoantibodies (e.g., anti-GAD65, IA-2, insulin autoantibodies) precede hyperglycemia. 2. History Typical Symptoms (Classic Triad): Polyuria, polydipsia, polyphagia. Weight loss despite normal/increased appetite. Fatigue, blurred vision. Acute Presentation: Diabetic ketoacidosis (DKA): nausea, vomiting, abdominal pain, rapid breathing, fruity breath. Risk Factors/Associations: Family history of autoimmune disease. Viral triggers (e.g., coxsackievirus). Historical Clues: Sudden symptom onset over days to weeks. No history of obesity or metabolic syndrome features. 3. Exam Findings General: Thin or underweight body habitus. Dehydration signs: dry mucous membranes, poor skin turgor. DKA Findings: Kussmaul respirations (deep, labored breathing). Fruity (acetone) odor on breath. Hypotension, tachycardia. Altered mental status in severe cases. Associated Autoimmune Conditions: Goiter (thyroid disease), vitiligo, celiac signs. 4. Making the Diagnosis Key Laboratory Findings: Fasting plasma glucose ≥126 mg/dL on two occasions. Random glucose ≥200 mg/dL with classic symptoms. A1C ≥6.5%. Oral glucose tolerance test (OGTT): 2-hour value ≥200 mg/dL. Autoimmune Markers: Positive GAD65, IA-2, insulin autoantibodies, or ZnT8 confirm autoimmune etiology. Additional Testing: Low or undetectable C-peptide (reflects lack of insulin production). Urine ketones positive in DKA or poor control. Gold Standard: Demonstration of autoimmune β-cell destruction with positive diabetes-associated autoantibodies. Distinguishing from Type 2 DM: Younger, leaner, rapid onset, ketosis-prone, autoimmune antibodies present. 5. Management (Exam Concepts) General Principles: Lifelong exogenous insulin therapy is required. Frequent glucose monitoring (SMBG or CGM). Goal A1C: generally