Hypoglycaemia Flashcards
Definition of hypoglycaemia
Blood glucose below 4mM
Sweating, tachycardia and agitation due to activation of SNS and release of adrenaline and glucagon
Signs and symptoms
Faintness, numbness, blurred vision, confusion, memory loss, dizziness, lethargy
Loss of consciousness at 2.5mM
Rapid restoration of blood glucose can lead to permanent brain damage
Causes
Fasting/exercise Excess of exogenous/endogenous insulin Hypernatraemia (diabetes insipidus) Hypovolaemia (vomiting) Adrenal insufficiency
Metabolism of alcohol
Ethanol -> acetaldehyde - cytosol (uses alcohol dehydrogenase and converts NAD+ to NADH)
Acetaldehyde -> acetic acid - occurs in mitochondria (using aldehyde dehydrogenase and converts NAD+ to NADH)
What reactions does a high NADH:NAD+ ratio cause
pyruvate to lactate
OAA to malate
DHAP to glycerol-3-phosphate
Reduces the availability of substrates for entry into gluconeogenesis
When does alcohol induced hypoglycaemia occur
12-24 hours after a meal
What do high levels of NADH cause (long term)
Inhibit fatty acid oxidation
Fatty acid synthesis
TGs accumulate - fatty liver
What is acetate converted into
Acetyl CoA
What prevents acetyl CoA from entering the TCA cycle
High levels of NADH inhibits citrate synthase and alpha ketoglutarate dehydrogenase
Short term problems with alcohol (hypoglycaemia related)
Additional stresses on gluconeogenesis (after depletion of glycogen stores)
Consequences of accumulation of acetyl CoA
Production of ketone bodies - exacerbate acidic conditions
Less processing of acetate - build up of acetaldehyde which is highly toxic
What enters hepatic vein after ethanol has been processed by the liver
VLDL - hyperlipidaemia (due to lots of acetyl coa)
Acetate
Ketones (from lots of acetyl coa)
Lactate - lactic academia (from pyruvate)
Alcohol induced hepatomegaly
Alcohol consumption decreases the activity of the proteasome (increases oxidative stress)
Leads to protein accumulation - liver enlargement
What percentage of alcoholic has a thiamine deficiency
50%
Symptoms of thiamine deficiency
Anorexia, irritability, short term memory loss
