Carbohydrate Metabolism
- Blood glucose concentrations increase after trauma:
- Stimulated by cortisol and catecholamine
- Due to increased hepatic glycogenolysis and gluconeogenesis
- Peripheral glucose utilisation also decreases
- Increase in concentration proportional to the degree of injury
- Hyperglycaemia persists due during catabolic phase:
- Usual homeostatic mechanisms ineffective
- Hormones continue to promote glucose production
- Relative lack of insulin and peripheral insulin resistance observed
Protein Metabolism
- Protein catabolism occurs to mobilise amino acids:
- Stimulated by cortisol
- Amino acids used for energy or converted to acute-phase proteins
- Predominantly skeletal muscle is broken down:
- Results in marked wasting and weight loss
- Visceral protein also catabolised:
- Can predispose to organ dysfunction
Fat Metabolism
- Increased lipolysis mobilising triglycerides to glycerol and fatty acids
- Plasma levels may remain unchanged:
- Glycerol acts as substrate for gluconeogenesis in the liver
- Fatty acids re-esterized converted to ketone bodies
- Stimulated by cortisol, catecholamines and growth hormone