Type 1 Diabetes Mellitus

Aka: Type 1 Diabetes Mellitus, Type I Diabetes Mellitus, Insulin Dependent Diabetes Mellitus, IDDM, Type I Diabetes

1. See Also
   1. Diabetes Mellitus
   2. Type II Diabetes Mellitus
   3. Insulin Resistance Syndrome
   4. Glucose Metabolism
   5. Diabetes Mellitus Education
   6. Diabetes Mellitus Complications
   7. Diabetic Ketoacidosis
   8. Hyperosmolar Hyperglycemic State
   9. Diabetes Mellitus Control in Hospital
   10. Diabetes Mellitus Glucose Management
   11. Hypertension in Diabetes Mellitus
   12. Hyperlipidemia in Diabetes Mellitus
   13. Diabetic Retinopathy
   14. Diabetic Nephropathy
   15. Diabetic Neuropathy
2. Epidemiology
   1. Typically onset before age 30 years
   2. Non-obese patients
   3. Prevalence: 5-10% of total Diabetes Mellitus patients (3 million cases in United States)
3. Etiology
   1. Type 1A
      1. Environmental and genetic factors
      2. HLA-DR4 association
      3. Cell mediated pancreatic beta cell destruction
   2. Type 1B (uncommon)
      1. Primary autoimmune condition
      2. Associated with other Autoimmune Conditions
         1. Hashimoto's Thyroiditis
         2. Grave's Disease
         3. Myasthenia Gravis
      3. HLA-DR3 association
      4. Incidence highest in 30-50 year olds
   3. Secondary Diabetes Mellitus
      1. Cystic Fibrosis
   4. Environmental Factors
      1. Medications
         1. Streptozocin
         2. Pentamidine
      2. Viruses
         1. Mumps
         2. Coxsackie
            1. Enterovirus IgM linked to IDDM in adolescents
               1. Studied 128 children with new onset IDDM
               2. Non-specific to subtype (coxsackie, echovirus)
               3. Helfand (1995) J Infect Dis 172:1206-11
         3. Congenital Rubella
            1. Late Type I Diabetes Mellitus develops in 40%
         4. Cytomegalovirus (CMV)
4. Symptoms and Signs
   1. See Diabetes Mellitus
5. Common Presentations
   1. Diabetic Ketoacidosis
      1. Major presenting syndrome in 25% of cases
      2. More common in under 3 years and adolescence
   2. Incidental glucosuria or Hyperglycemia
   3. Acute Abdominal Pain
   4. Influenza-like illness
6. Diagnosis
   1. See Diabetes Mellitus
   2. Oral Glucose Tolerance Test
   3. Fasting Blood Glucose or Random Blood Glucose
   4. Two hour post-prandial Glucose
   5. Intravenous Glucose Tolerance Test
7. Labs
   1. Initial studies
      1. Urinalysis
      2. Blood Glucose
      3. Electrolytes
      4. Glycosylated Hemoglobin (Hemoglobin A1C)
      5. Thyroid Stimulating Hormone (TSH)
   2. Diagnostics in Atypical Presentation
      1. Anti-Glutamic Acid Decarboxylase Antibody (Anti-GAD65 Antibody) - most useful of markers
         1. Test Sensitivity in Type I Diabetes: 60% in adults (60-73% in children)
         2. Not specific, also found in 7-34% in adults and children with Type II Diabetes
            1. Absence of Antibody makes requring inulin withn 6 years in adults unlikely (NPV 94%)
      2. Anti-islet cell surface Antibody (ICA)
         1. Test Sensitivity in Type I Diabetes: 75-85% in adults and children
         2. Not specific for Type I Diabetes (seen in up to 21% of Type II Diabetes adults)
      3. Anti-insulin Antibody (IA-2a and IA-2b)
         1. Test Sensitivity in Type I Diabetes: 40% in adults and 40-86% in children
         2. More specific for Type I Diabetes (only present in ~2% of Type II Diabetes)
      4. C-peptide low or absent (<1.51 ng)
         1. Consider after Sustacal challenge
         2. Not specific for Type I Diabetes Mellitus (also seen in Type II)
   3. References
      1. Patel (2010) Am Fam Physician 81(7): 863-70
8. Management: Initial
   1. Treat acute problems (includes non-diabetic issues)
   2. Set initial goals and targets
      1. See Diabetes Mellitus Glucose Management
   3. Initiate Insulin therapy
      1. See Insulin Dosing
      2. If atypical presentation, then base on ketones
         1. Ketones positive: Start Insulin
         2. Ketones negative: Consider treating as Type II
   4. Education
      1. See Diabetes Mellitus Education
      2. Teach survival skills
      3. Establish plan for ongoing care and education
      4. Review importance of intensive therapy (compared with conventional care)
         1. See Diabetes Mellitus Glucose Management
9. Management: Follow-up
   1. Initial
      1. Daily phone contact for first 3 days
      2. Office visit within 2 weeks
      3. Emergency 24 hour phone number given
   2. Adjustment phase
      1. Consider weekly phone call
      2. Monthly office visit
   3. Maintenance Phase
      1. Office visit every 3-4 months
      2. Review Blood Sugar Log
         1. Hypoglycemic Episodes
         2. Hyperglycemia
         3. Ketones
      3. Review food plan
      4. Review Exercise program
      5. Review Medications
      6. Exam
         1. Height and Weight
         2. Growth rate (pediatric Diabetes Mellitus)
         3. Blood Pressure
      7. Labs
         1. Check Glucose Meter against Serum Glucose
         2. Hemoglobin A1C
      8. Education
         1. Nutrition in Diabetes Mellitus
         2. Exercise in Diabetes Mellitus
   4. Yearly Exam
      1. Health Maintenance Exam
      2. Fasting lipid profile within 6 months of diagnosis
         1. Triglycerides commonly elevated
      3. Neurologic Exam
      4. Dental exam
      5. Optometry or Ophthalmology Exam
         1. Age over 12 years or Diabetes Mellitus for 5 years
      6. Urine Microalbumin yearly
         1. Age over 12 years or Diabetes Mellitus for 5 years
10. Management: New Tools
    1. Monitoring
       1. Continuous Blood Sugar Monitoring (24 hour)
       2. Transcutaneous Serum Glucose monitoring (watch)
    2. Treatment options
       1. Islet Cell Transplants (high efficacy in trials)
       2. Insulin Pump