Type 1 diabetes

Type 1 Diabetes

Type 1 diabetes usually starts in early childhood or adolescence.   Type 1 diabetics make up 5-10% of diagnosed diabetics. The Beta cells are destroyed, which eliminates the production of insulin. Insulin transports glucose to skeletal muscle and adipose tissue, increases glycogen synthesis, and decreases gluconeogenesis. Type 1 diabetes individuals must rely on exogenous insulin to control hyperglycemia and avoid ketoacidosis. For individuals with DM that require insulin therapy, standard treatment involves injection of insulin twice daily.

Other hormones that affect glucose

  • Glucagon= promotes glycogen breakdown, increases gluconeogenesis, increases conversion of amino acids into glucose precursors, increases transport of amino acids into hepatic cells.
  • Catecholamines (Epinephrine and norepinephrine)= helps tomaintain blood glucose levels during periods of stress.
  • Growth hormone= increases protein synthesis in all cells of the body, mobilizes fatty acids from adipose tissue, and antagonizes the effects of insulin
  • Glucocorticoids= important in survival during periods of fasting and starvation. Stimulates gluconeogenesis by the liver.


Subdivisions of type 1 diabetes

  • Type 1A= immune-mediated diabetes
  •  Type 1B= idiopathic diabetes


Factors involved in Type 1A diabetes

  • Genetic predisposition
  • A triggering event that involves an environmental agent that incites an immune response
  • Immunologically mediated beta cell destruction


Factors involved in Type 1B diabetes

  • Beta cell destruction in which no evidence of autoimmunity is present
  • Type 1B diabetes is strongly inherited.
  • Only a small number of people with type 1 diabetes fall into this category; most are of African or Asian descent.
  • People with the Type 1B diabetes have episodic ketoacidosis due to varying degrees of insulin deficiency.
  • Type 1B diabetes is strongly inherited.

Causes of beta cell destruction

  • A decrease in the beta cell mass
  • Increased beta cell apoptosis with decreased regeneration
  • Long-standing insulin resistance
  • Chronic hyperglycemia that induces beta cell desensitization
  • Chronic elevation of free fatty acids that cause toxicity to beta cells
  • Amyloid deposition in the beta cell can cause dysfunction.


The 3 P’s of DM (All types)

  • Polyuria= excessive urination
  • Polydipsia= excessive thirst
  • Polyphagia= excessive hunger


Symptoms of hyperglycemia

  • Weight loss
  • Vision problems
  • Fatigue
  • Paresthesias
  • Skin infections


Acute complications of DM

  • Diabetic ketoacidosis (DKA)
  • Hyperosmolar hyperglycemic state (HHS)
  • Hypoglycemia


The types of insulin include:

 Rapid-acting (short duration)

  • Lispro (Humalog)
  • Aspart (Novolog)
  • Glulisine (Apidra)

Rapid acting insulin (onset less than 15 minutes, peak 1-2 hrs, 4 hr duration) is administered with meals to control the postprandial rise in blood sugar and to provide glycemic control between meals and at night. {Most rapid acting insulins end in “log” think of a log rolling down a hill- it will roll rapid!} More expensive than regular insulin!

 Short-acting (short duration)

  • Regular (Humulin, Novolin)

(Short acting insulins end in “lin”- think of a short actress named “Lin” with a short lived career}


  • NPH
  • Lente

 Onset is delayed and cannot be administered at mealtime to control postprandial hyperglycemia. Administered twice daily to control blood sugar between meals and during the night. NPH is the only insulin suitable to mix with short acting insulins.

 Long-acting (Basel)

  • Ultralente
  • Lantus Glargine (22-24 hrs)
  • Levemir (insulin detemir) (12-20 hrs)

For long acting insulin, onset is 12 hrs, no peak

{For long acting insulin think of a pirate-Glarrrrr (Glargine) that is old-because he has lived a long time} These are the Peakless insulins! Action is predictable from day to day. Expensive (NPH is the cheapest)! For APRN’s & PA’s, increase basil insulin by 2-3 units every 2-3 days until fasting glucose is at goal. Start about 0.1-0.2 units/kg as bolus at bedtime or 10 units.

 Pre-mixed (various premixed combinations).  The ADA does not recommend premixed insulin for type 1 diabetics

  • NovoLog Mix 70/30
  • Humalog Mix 75/25, 50/50
  • Humulin 70/30

Prolonged duration of action (24 hrs) and administered once daily at bedtime.


Adverse side effects of insulin

  • Headache
  • Anxiety
  • Tachycardia
  • Confusion
  • Vertigo
  • Diaphoresis
  • Lipodystrophy
  • Hypersensitivity


When you should prescribe insulin

  • When A1C > 10% (double digit A1C)
  • Fasting glucose >250 mg/dl
  • After maxing out orals
  • Symptoms of hyperglycemia (3 P’s)
  • Pregnant patients
  • Consider it early (insulin preserves pancreatic function!)


American Diabetic Association (ADA) A1C goals

  • A1C < 7% for most adults with type 2 DM
  • A1C < 8% for older patients
  • A1C < 6% for type 1 DM
  • A1C < 6% for pregnant patients


ADA screening recommendations

  • Annual screening for BMI >25 kg/m and one or more risk factors for DM
  • Entire population 45 years and older every 3 years if screening in normal


Risk factors for DM

  • Age 45 years and older
  • BMI > 25kg/m
  • Family history (first degree relative)
  • Habitual physical inactivity
  • HTN 140/90 or greater
  • HDL 35 and less and/or triglycerides 250 and greater
  • Women with PCOS
  • History of vascular disease
  • Delivery of a macrosomic infant or gestational diabetes
  • African American, Hispanic, Native American, Asian-American, Pacific Islanders
  • Previously identified A1C > or = 5.7%, impaired glucose tolerance, or impaired fasting glucose


Key Notes:

  • HgA1C treatment goal for DM is < 7% is the goal!


  • HgA1C provides information on glucose control over the past 90-120 days


  • Generally, testing for type 2 DM in asymptomatic, undiagnosed individuals older than 45 years should be conducted every 3 years


  • DM is the leading cause of chronic renal failure


  • Acanthosis nigricans– hyperpigmentation of the skin often in the neck and axilla is correlated with insulin resistance and most common in children and young adults with insulin resistance


  • Low birth weight for gestational age is also correlated with increased risk for insulin resistance


  • A common cause of poor control of type 1 DM during adolescents is a denial of the severity of the condition


  • Always stop any Sulfonylureas when you add insulin to the treatment plan


  • Do not use any oral anti diabetic drugs on type 1 diabetics


  • Diabetics are at higher risk for cataracts and glaucoma




DCCT (Diabetes Control & Complication Trial) http://www.niddk.nih.gov/about-niddk/research-areas/diabetes/dcct-edic-diabetes-control-complications-trial-follow-up-study/Documents/DCCT-EDIC_508.pdf