Endocrinology
Type 1 Diabetes Mellitus
1형당뇨
Autoimmune destruction of pancreatic β-cells leading to absolute insulin deficiency
- How common
- 0.3% children/young adults
- Typical age
- Mostly <30 yrs
What is it?
GAD65/IA-2/ZnT8 autoantibodies destroy β-cells causing absolute insulin deficiency and ketogenesis.
Commonly affected: Pancreatic islet β-cells
How it develops
- Genetic + environmental triggerHLA-DR3/DR4 + viral trigger (enterovirus)
- β-cell autoimmunityCD8+ T cells and autoantibodies infiltrate islets (insulitis)
- Absolute insulin deficiency>90% β-cell loss → near-absent C-peptide
- Hyperglycemia + ketosisLipolysis → FFA → ketogenesis
Symptoms
- Ketosis/DKANausea, vomiting, Kussmaul breathing
- Polyuria/polydipsiaOsmotic diuresis with thirst
- Weight lossDespite increased appetite
- FatigueLack of intracellular glucose
- Blurred visionLens refractive change
How it is examined
- Fasting/OGTTFasting ≥126 mg/dL or 2h ≥200 mg/dL
- HbA1c≥6.5% diagnostic
- Autoantibodies + C-peptidePositive antibodies + low C-peptide → T1DM
Imaging
Plain X-ray not used for diagnosis.
- No specific findings
Pancreatic MRI if autoimmune pancreatitis suspected.
- Pancreatic atrophy (chronic)
Non-surgical care
- Basal insulin (glargine/degludec)Insulin glargine or degludec once daily SC
- Prandial rapid-acting (lispro/aspart)Insulin lispro/aspart per carb ratio at meals
- CGM monitoringDexcom/Libre for 24h tracking
- Carb countingTeach I:CHO ratio (e.g., 1U per 10g)
- Hypoglycemia kit (glucagon)Oral glucose + IM glucagon
Conservative options are generally tried first. Medications listed here can have side effects — discuss them with your prescriber.
When surgery is considered
Refractory hypoglycemia or with kidney transplant
Procedures that may be discussed
- Pancreas transplant (alone or with kidney)
- Islet cell transplant
- Closed-loop pump (artificial pancreas)
Outlook
Near-normal lifespan with insulin/CGM/education; key is preventing micro/macrovascular complications.