Pancreas Flashcards
Pre diabetes definition
Impaired fasting glucose = >6.1 and 7.8 but
Definition of type 1 DM
Chronic hyperglycaemia caused by absolute insulin deficiency due to autoimmune destruction of beta cells
Aetiology of type 1 DM
Genetics
HLA D3 or D4
Monozygotic twins = 36%
Mother =1-2%
Father = 3-6%
Signs and symptoms of type 1DM
Polyuria - excess urine output at 2.5/3l every 24hr
Polydipsia - excess thirst from fluid and electrolyte loss
Polyphagia - excess hunger, blood glucose can’t enter the cells due to lack of insulin
Weight loss - perceived lack of BG means that fatty acids and proteins are broken down
Islet cell autoantibodies in type 1
ia2 - tyrosine phosphatase
IAAs- insulin molecule
GAD - glutamic acid decarboxylase
What the patient needs to know about insulin regimens?
- Educate to self adjust dose in light of exercise and calorie intake
- Avoid binge drinking
- Inject at variable sites (outer thigh/ abdomen)
- Phone support (trained nurse)
Monitor blood glucose
Fingerprint glucose if type 1 DM
- Glycated haemoglobin relates to mean glucose levels over previous 8 weeks 48-57mmol/l
- Be sure to ask about hypoglycaemic attacks. Hypoglycaemia awareness may diminish control if is too tight or with time in type 1 due to decreased glucagon secretion.
Subcutaneous insulins
- Ultra fast Acting ( Humalog, novorapid)
- Isophane insulin - favoured by nice as cheap variable leak at 4-12 hr
- Premixed insulins - with ultra fast component (30% short, 70% long novomix 30)
- Long acting recombinant human insulin analogue - insulin glargine, insulin detemir
Diagnosis of diabetes
Symptomatic patients if
- plasma glucose in a random sample is >11.1mmol/l or 2hrs after an OGTT
- fasting plasma glucose >7mmol/l
-hbA1c >6.5%
In a symptomatic individuals two diagnostic tests at different occasions
Type 2 Diabetes features
85% of cases
maturity onset
insulin resistance and B-cell insulin secretory dysfunction
no associate autoantibodies
Genetics in type 2 diabetes
identical twins near 100% concordance
70-100% risk if both parents have
Secondary diabetes mellitus
- Due to pancreatic disorders causing insuling deficiency
a. pancreatitis
b. carcinoma of the pancreas
c. cystic fibrosis
d. haemochromatosis (bronze diabetes)
e. pancrectomy - Due to insulin resistance
a. endocrine causes (cushings, thyrotoxocis, acromegaly, pheochromocytoma, PCOS
b. drugs (steroids, thiazides)
Microvascular Complications of Diabetes
progress dependent on degree of glycaemic control
- retinopathy
- neuropathy
- Nephropathy
Retinopathy
annual retinal screening
- hyperglycaemia increases blood flow to the retina
- dilation of retinal cappillaries –> microaneurysms
- Increased vasoactive substances + clots cause vessels to close up –> haemorrhagic
- hypoxia occurs –> causes release of VEGF –> neovascularisation
- new vessels are fragile and leaky –> blurred vision and retinal leakage
Background (early) vs proliferative (late) retinopathy
background changes
- microaneurysms (dots), haemorrhages (blots), and hard exudates (lipid deposits) - refer if near the macula for
pre-proliferative
- cotton wool spots (eg infarcts), haemorrhages, venous bleeding- signs of retinal ischaemia
proliferative
- new vessels form
Nephropathy
increased blood flow due to hyperglycaemia
increased glomerular pressure –> hypertrophy (thickening) of epithelium and endothelium
glomerular sclerosis & loss of nephrons
Look for microalbuminaemia vs macroalbuminaemia
delayed by ACE I/ ARBS