| DIABETES MELLITUS: THE PRINCIPAL DISORDER OF FUEL METABOLISM
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Table 20-3.
Classification of diabetes. |
| Body_ID: None |
| Classification of diabetes |
| Body_ID: T020003.50 |
| Syndrome | Comments |
| Body_ID: T020003.100 |
| Type 1 | autoimmune destruction of β-cells |
| Body_ID: T020003.150 |
| Type 2 | insulin resistance and β-cell failure |
| Body_ID: T020003.200 |
| Other types | genetic defects of β-cells (e.g. mutations of glucokinase gene). Rare insulin resistance syndromes. |
| Body_ID: T020003.250 |
| | Diseases of exocrine pancreas. Endocrine diseases (acromegaly, Cushing's syndrome). Drugs and chemical-induced diabetes, Infections (e.g. mumps). |
| Body_ID: T020003.300 |
| | Rare syndromes with the presence of antireceptor antibodies. |
| Body_ID: T020003.350 |
| | Diabetes accompanying other genetic diseases (e.g. Down syndrome) |
| Body_ID: T020003.400 |
| Gestational diabetes | any degree of glucose intolerance diagnosed in pregnancy |
| Body_ID: T020003.450 |
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| Body_ID: T020003.500 |
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| Body_ID: T020003.550 |
Type 1 (insulin-dependent) diabetes and type 2 (noninsulin-dependent) diabetes.
Approximately 90% of all diabetic patients have type 2 diabetes.
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| Diabetes mellitus is a heterogeneous metabolic disease characterized by hyperglycemia and by the presence of long-term vascular complications. Diabetes has been defined as 'a lifestyle disorder with the highest prevalence seen in genetically susceptible populations, where the disease is unmasked lifestyle-associated environmental factors'. It is a common
disease. Alarmingly, its prevalence has been increasing worldwide. Type 2 diabetes affects approximately 8% of the population of the USA, and in 1995 its worldwide prevalence was approximately 4% (Table 20.3).
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| There are two main forms of diabetes: type 1 and type 2. Ten percent of all diabetic patients have type 1 and 90% have type 2 diabetes (Table 20.4). While type 1 patients are unable to produce insulin and need exogenous insulin to survive, type 2 patients secrete insulin, but are insulin-resistant. Importantly, some diabetic patients may have no clinical symptoms at all, with the diagnosis made exclusively on the basis of laboratory results. The diagnostic criteria are summarized in Table 20.5.
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| CATABOLIC STATE AFTER ROAD TRAFFIC ACCIDENT |
| A 60-year-old man was admitted to an Intensive Care Unit following multiple trauma in a road traffic accident. He developed respiratory failure and was intubated. On the third day he was still unable to eat. His fasting blood glucose was 6.7 mmol/L (121 mg/dL), he had mild ketonuria (+), and his 24-h urine collection revealed the excretion of 600 mg of α-amino nitrogen/24 h (normal 50-300 mg/24 h). |
| Comment. This patient is hypercatabolic as a result of the stress response to injury. He is not able to take food. His high urinary nitrogen loss indicates excessive catabolism of muscle protein. He requires nutritional support. The patient was prescribed an intravenous nutrition regimen containing 2000 kcal (8374 kJ) as 50% glucose solution, 1000 kcal (4187 kJ) as lipid emulsion, and amino acid solution containing the equivalent of 18 g of nitrogen/day. |
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