Diabetes

Pathogenesis

Group of disorders characterized by glucose intolerance.  Insulin produced by beta cells in the pancreas decreases blood glucose by inhibiting glycogen breakdown and facilitates entry of glucose into the tissues.  When tissues fail to use glucose, hyperglycemia results.  Diabetes affects 2-5% of the population in the U.S.

 

Types

• Type I (IDDM) Insulin dependent diabetes was formerly called juvenile-onset diabetes but now is referred to as type I because it is not restricted to the juvenile age group. It is characterized by abrupt onset, polyuria, polydipsia, polyphagia, and often rapid weight loss.
• Type II (NIDDM) Non-insulin dependent diabetes was referred to as adult onset. Symptoms are often less pronounced than type 1.  Patients with NIDDM present with thirst, pruritus and fatigue.  Obesity is present in 60-90% of these patients.
• Secondary
  • Pancreatic disease:  Hemochromatosis, pancreatic deficiency, pancreatectomy
  • Hormonal: Cushing's syndrome, acromegaly, pheochromocytoma
  • Drug-induced: thiazides, diurectics, steroids, phenytoin
  • Genetic syndromes: lipodystrophy, myotonic dystrophy, ataxia, telangiectasia
• Impaired glucose Tolerance (IGT), also known as chemical, latent, borderline, or subclinical
• Gestational: glucose intolerance with onset during pregnancy

 

Diagnosis

• Classic symptoms: Polydipsia, Polyphagia, Polyuria
• Hyperglycemia: Fasting plasma glucose level greater than 140 mg/dL on more than one occasion
• Oral glucose tolerance test : 75g glucose dose dissolved in 300mL water after overnight fast;
  • Plasma glucose above 200 mg/dL at both 2 hours and at least one other time between 0 and 2 hours.
• Hemoglobin A1c: (glycosolated hemoglobin) concentration in normal individuals 3-6%
  • Patients with DM have 2-3 x elevation.  Is a rough reflexion of the mean level of circulating glucose for the previous 2-3 months (life of RBC - 120 days)

 

Treatment

• Diet: is the cornerstone of treatment.  Objectives include providing nutrition with a balance of protein, fat and carbohydrates and to normalized weight.
• Oral Hypoglycemics: Sulfonylureas are recommended for patients with symptomatic NIDDM who cannot be controlled by diet alone and in whom an addition of insulin is impractical or unacceptable
• Insulin: Used primarily for the type 1 (IDDM) diabetic who is hypoinsulinemic and prone to ketosis.  Also can be provided for type II diabetic who is not compliant with diet.

 

Complications

• Acute
  • Ketoacidosis: Precipitating factors - infection, omission of insulin, new onset diabetes
    • Characterized by pH <7.2, hyperglycemia, hyperventilation, increased anion gap, hyponatremia, hyperkalemia, increased BUN/Cr ketones in blood and urine
    • Absolute ....