Diabetes Flashcards
Type 1 diabetes is
a progressive metabolic disorder of catastrophic beta cell failure with normal tissue insulin sensitivity
Immune mediated
Type 2 diabetes is
a progressive metabolic disorder of beta cell dysfunction and/or insulin resistance where fasting gluscose is > 7mmol/L
What defines metabolic syndrome?
Waist >102cm BP> 130/85 TG>1.7mmol/l Glucose>6mmol/L HDL
Actions of insulin
Anabolic hormone Increased glycogenesis and glucose uptake Decreased hepatic gluconeogenesis TG synthesis and protein synthesis Decreased ketones
What is hormone sensitive lipase activated by?
Starvation
Low glucose
Low insulin
Therefore lipolysis can occur
Signs and symptoms of DKA
High blood glucose (>15mmol/L) Ketones in blood/urine Diuresis Thirst Tired/lethargy Blurry vision Nausea and vomiting Deep sighing breaths Smell of ketones on breath Collapse/unconciousness
Why does ketone synthesis occur in DKA?
Low glucose in cells, low insulin -> lipolysis
NEFA from lipolysis enter carnitine shuffle
Not enough insulin for acetyl coA for fatty acid synthesis (acetyl-coA carboxylase doesn’t work) to occur so instead ketones are made
Name the 3 ketones
Acetone, acetoacetate and 3-hydroxybutyrate
Why does glucose build up in the blood in DKA?
Glucose can’t enter cells because of lack of insulin
Oxaloacetate can’t be used in FA synthesis so is used in hepatic gluconeogenesis
Treatment of DKA?
Resuscitation (0.9% IV saline)
Insulin (0.1units/kg/hr IV)
Potassium IV
What % of diabetic patients develop foot ulcers?
15%
Why does retinopathy occur in diabetes?
Microvascular disease -> increased vascular permeability and haemorrhage
Inflammatory changes and angiogenesis
Osmotic effects and cell damage
Plaques, exudate, haemorrhage
Ischaemic changes, proliferative retinopathy
Erectile dysfunction affects up to:
50% of men with chronic diabetes
3 pathophysiology pathways?
Glycosylation of proteins
Polyol pathway
Protein kinase C activation
Explain the glycosilation of proteins pathophys?
Glycation-> abnormal function
Glycated collagen-> LDL trapped in arterial walls
Glycated cell surface receptors-> activation of inflammatory cells and cytokine release
Explain the polyol pathway
Raised intracellular glucose conc
- > sorbitol and fructose
- > cellular swelling
- > impaired protein/ion pump function
- > pro-inflam cytokine production
- > damage to cells
Explain the protein kinase C activation
Hyperglycaemia
- > PKC activation
- > intracellular signal transduction pathway
- > VEGF -> new vessels
- > pro inflam cytokines
- > endothelin-1, lowered NO -> vasoconstriction
2 main types on insulin regimen
Premixed insulin 1/2/3 times per day Basal bolus (long acting at bedtime, soluble/rapid at meals)
What proportion of inpatients have diabetes?
10-15%
When a diabetic patient is unwell, what happens?
Stress of illness increases need for insulin due to catabolic hormone action
Never withhold insulin in a type 1 diabetic!
IV insulin + glucose may be needed if pt not eating
Primary treatment of type 2 diabetes mellitus
Lose weight & achieve healthy BMI Decrease fat intake, esp sat Decrease sugar intake Eat food with low GI, slower absorption Increase wholegrains, veg and fibre 150mins moderate exercise/week Smoking cessation
What is the aim for blood sugar levels in critically ill/elderly patients?
6-12
Avoid risk of hypos
Main complications of diabetes?
Kidneys Retina UTI Hypos/hypers Feet Macrovascular
Why hyperglycaemic?
Missed oral hypoglycaemic dose? Are doses sub-optimal? Insulin device failure? New diagnosis of diabetes? Stress of infection/illness? Steroid treament? Vomiting/new pancreatic disease?
Features of hypoglycaemia
Sweating, palpitations Hunger, shaking Confusion, drowsiness Odd behaviour Speech difficulty Headache, nausea
Causes of hypoglycaemia?
Missed meal? Less snacks? NBM/nausea/vomiting? Gastric surgery Terminal illness Steroids acutely stopped Incorrect dose of insulin IV insulin without glucose Renal failure/hepatic dysfunction Insulin out of date?
