Update February 7, 2020

Diabetes mellitus describes several diseases of abnormal carbohydrate metabolism that are characterized by hyperglycemia.

 

  1. Type 1 DM

  2. Type 2 DM

    1. Caused by a progressive loss of beta cell insulin secretion frequently with underlying insulin resistance

    2. A heterogeneous disorder related to inflammation, metabolic stress, and genetic factors

  3. Other, less common causes of diabetes

    1. Monogenic diabetes syndromes

    2. Exocrine pancreatic diseases that lead to the destruction of beta cells (pancreatitis, trauma, cystic fibrosis, pancreatectomy, pancreatic carcinoma)

    3. Endocrinopathies (acromegaly, Cushing syndrome, glucagonoma, pheochromocytoma)

    4. Drug or chemical-induced (corticosteroids, HIV/AIDS medications, after organ transplantation)

  4. Gestational diabetes

Type 1 DM generally occurs in children, although approximately 7.5–10% of adults assumed to have type 2 DM actually have type 1, as defined by the presence of circulating antibodies. Type 2 DM is becoming more prevalent in teenagers and young adults, presumably related to the increased prevalence of obesity.

In most patients, the distinction between type 1 and type 2 DM is clear. Thus, the primary tasks of the clinician are to determine who should be tested for diabetes, who has diabetes, which complications to monitor, and how to treat the patient.

 

 

 

1. Type 1 diabetes (β-cell destruction, usually leading to absolute insulin deficiency)

a. Immune mediated

b. Idiopathic

 

2. Type 2 diabetes (may range from predominantly insulin resistance with relative insulin deficiency to a predominantly secretory defect with insulin resistance)

3. Other specific types, such as

    1. Genetic defects of β-cell function

    2. Genetic defects in insulin action

    3. Diseases of the exocrine pancreas (pancreatitis, trauma, cystic fibrosis, etc.)

    4. Endocrinopathies (Cushing's syndrome, pheochromocytoma, hyperthyroidism, somatostatinoma, glucagonoma, etc.)

    5. Drug- or chemical-induced (interferon-α, β-adrenergic agonists, diazoxide, phenytoin [Dilantin®], glucocorticoids, nicotinic acid, pentamidine, thiazides, thyroid hormone, pyrinuron [Vacor®], etc.)

    6. Infections (congenital rubella, cytomegalovirus, etc.)

    7. Uncommon forms of immune-mediated diabetes

    8. Other genetic syndromes sometimes associated with diabetes (Down's syndrome, Klinefelter's syndrome, Turner's syndrome, etc.)

  • Gestational diabetes mellitus
  • Other specific types of diabetes mellitus.

    Genetic defects of pancreatic B cell function

     MODY 1 (HNF-4alpha); rare

     MODY 2 (glucokinase); less rare

     MODY 3 (HNF-1alpha); accounts for two-thirds of all MODY

     MODY 4 (PDX1); very rare

     MODY 5 (HNF-1beta); very rare

     MODY 6 (neuroD1); very rare

     Mitochondrial DNA

    Genetic defects in insulin action

     Type A insulin resistance

     Leprechaunism

     Rabson-Mendenhall syndrome

     Lipoatrophic diabetes

    Diseases of the exocrine pancreas

    Endocrinopathies

    Drug- or chemical-induced diabetes

    Other genetic syndromes (Down, Klinefelter, Turner, others) sometimes associated with diabetes

    MODY, maturity-onset diabetes of the young; PDX1, pancreatic duodenal homeobox 1.

  • +++++++++++++++++
  • Etiologic classification of diabetes mellitus
    Type 2 diabetes (may range from predominantly insulin resistance with relative insulin deficiency to a predominantly secretory defect with insulin resistance)
    Other specific types
    A. Genetic defects of beta cell function
    1. Chromosome 12, HNF-1-alpha (MODY3)
    2. Chromosome 7, glucokinase (MODY2)
    3. Chromosome 20, HNF-4-alpha (MODY1)
    4. Chromosome 13, insulin promoter factor-1 (IPF-1; MODY4)
    5. Chromosome 17, HNF-1-beta (MODY5)
    6. Chromosome 2, NeuroD1 (MODY6)
    7. Mitochondrial DNA
    8. Others
    B. Genetic defects in insulin action
    1. Type A insulin resistance
    2. Leprechaunism
    3. Rabson-Mendenhall syndrome
    4. Lipoatrophic diabetes
    5. Others
    C. Diseases of the exocrine pancreas
    1. Pancreatitis
    2. Trauma/pancreatectomy
    3. Neoplasia
    4. Cystic fibrosis
    5. Hemochromatosis
    6. Fibrocalculous pancreatopathy
    7. Others
    D. Endocrinopathies
    1. Acromegaly
    2. Cushing's syndrome
    3. Glucagonoma
    4. Pheochromocytoma
    5. Hyperthyroidism
    6. Somatostatinoma
    7. Aldosteronoma
    8. Others
    E. Drug or chemical induced
    1. Vacor
    2. Pentamidine
    3. Nicotinic acid
    4. Glucocorticoids
    5. Thyroid hormone
    6. Diazoxide
    7. Beta-adrenergic agonists
    8. Thiazides
    9. Atypical antipsychotics
    10. Dilantin
    11. Alpha interferon
    12. Others
    F. Infections
    1. Congenital rubella
    2. Cytomegalovirus
    3. Others
    G. Uncommon forms of immune-mediated diabetes
    1. "Stiff man" syndrome
    2. Anti-insulin receptor antibodies
    3. Others
    H. Other genetic syndromes sometimes associated with diabetes
    1. Down syndrome
    2. Klinefelter syndrome
    3. Turner syndrome
    4. Wolfram syndrome
    5. Friederich's ataxia
    6. Huntington's chorea
    7. Laurence-Moon-Biedl syndrome
    8. Myotonic dystrophy
    9. Porphyria
    10. Prader-Willi syndrome
     
    Gestational diabetes mellitus

     

    Patients with any form of diabetes may require insulin treatment at some stage of their disease. Such use of insulin does not, of itself, classify the patient.

    2007 American Diabetes Association From Diabetes Care Vol 30, Supplement 1, 2007.

 

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