Diabetes Flashcards
What are the symptoms of diabetes?
- polyuria
- polydipsia
- lethargy
- boils
- pruritus vulvae
- blurred vision
- CVD and PVD
- nephropathy
- neuropathies
- diabetic foot ulcers
- frequent infections
- DKA/hyperosmolar hyperglycaemic state
What are the screening criteria for diabetes?
- FHx
- CVD and PVD and risk factors
- SE Asian
- BMI>30
- age
- prior gestational diabetes
What are the functions of insulin?
Stimulate:
- glucose uptake in liver, muscle, and adipose
- clearance of free fatty acids
- active transport of amino acids into cells
Inhibit:
- liver glycogenolysis
- liver gluconeogenesis
- protein catabolism
How is diabetes diagnosed?
Symptoms + 1 abnormal result
OR 2 abnormal results at 2 different times
- fasting glucose >7mmol/l
- random plasma glucose >11.1mmol/l
- glucose tolerance test > 11.1mmol/l
- HbA1c > 6.5%
Outline the features of type 1 deficiency.
Short Hx of polyuria, polydipsia, lethargy, and weight loss
Usually present in teens-early adulthood, but can get presentations later in life (latent autoimmune Type 1 diabetes)
Autoimmune destruction of beta-cells leading to absolute insulin deficiency (associated with other immune disorders)
What level of ketones indicates immediate insulin therapy?
Urine ketones >3-4mmol/l
Capillary blood ketones >1mmol/l
Outline the features of type 2 diabetes.
Potential reversible metabolic disorder precipitated by chronic intra-organ fat deposition
Risk factors:
- central obesity
- SE Asian/Black
- Hx of gestational diabetes
- drugs
- PCOS
- FHx
What metabolic changes occur post-bariatric surgery?
7 days: fasting blood glucose normalises and Type 2 diabetes disappears
–> reduced liver fat content and return of normal insulin sensitivity
–> reduced pancreatic fat content over 8wks normalises beta-cell function so that the first phase insulin release and maximal rates of insulin release returns to normal
Outline the features of gestational diabetes.
Usually develops at ~28wks
Any form of glucose intolerance with onset during pregnancy
Up to 4% of pregnancies
Check HbA1c 3 months post-pregnancy
What are some causes of secondary diabetes?
Pancreatic disease: cystic fibrosis, chronic pancreatitis, pancreatectomy, pancreatic carcinoma
Endocrine: Cushing’s, acromegaly, thyrotoxicosis, phaeochromocytoma, glucagonoma
Drug-induced: thiazide diuretics, corticosteroids, atypical antipsychotics, antiretroviral protease inhibitors
Congenital lipodystrophy
Acanthosis nigricans
Genetic: Wolfram’s syndrome (diabetes insipidus, diabetes mellitus, optic atrophy, deafness), Friedreich’s ataxia, dystrophi myotonica, haemochromatosis, glycogen storage disorders
What is the management of type 1 diabetes?
HbA1c target = 7%-9% to avoid hypoglycaemia
Insulin = intermediate-acting, rapid-acting (e.g. Humalog), long-acting (e.g. glargine), mixed action (e.g. Novomix-30), insulin analogues
Patient education = home blood glucose monitoring, DAFNE course
Regular HbA1c testing
What is the management of type 2 diabetes?
Diet, exercise
Anti-obesity drugs
Oral hypoglycaemic agents: metformin, sulfonylureas, gliptins
Insulin
Injectable GLP-1 agonists
What are the features of metformin?
500mg-2.5g
1st choice in overweight/obese unless contraindicated
Contraindications = eGFR<30, heart failure
Mechanism = lowers HbA1c by ~1%, reduces hepatic glucose production
Benefits = limited weight gain, fewer CV events, low risk of hypoglycaemia
ADRs = GI symptoms, lactic acidosis
How much glucose is used per day?
~250g/day
~180g from diet, ~70g from glycogenolysis/gluconeogenesis
What are the features of sulfonylureas?
e.g. gliclazide, glimepride
2nd or 3rd lime
Mechanism of action = increased insulin release from beta-cells
Benefits = reduced microvascular risk
ADRs = higher risk of hypoglycaemia, promotes weight gain
What are the feature of pioglitazone?
Mechanism = reduces insulin resistance
ADRs = bladder cancer, osteoporosis, dilutional anaemias
What are the features of GLP-1 agonists?
e.g. exenatide
Indicated for Type 2 diabetics with poor glucose control/not able to lose weight
Benefits = low risk of hypoglycaemia
ADRs = nausea, ?pancreatitis/pancreatic cancer
What are the features of gliptins/DPP-4 inhibitors?
e.g. sitagliptin, saxagliptin
Mechanism = inhibits DPP-4 activity to increase postprandial active GLP-1 concentrations, modest HbA1c reduction
Benefits = weight neutral, low risk of hypoglycaemia
What are the features of glifozins?
e.g. dapaglifozin
Mechanism = selective inhibiton of SGLT2 to reduce amount of glucose reabsorbed
Benefits = lose weight, low risk of hypoglycaemia
ADRs = LUTS (UTIs, thrush, polydipsia)
What are the effects of GLP-1?
- reduced glucagon secretion
- increased insulin secretion, release, and biosynthesis
- reduced ghrelin
- reduced liver gluconeogenesis
- reduced appetite, increased satiety, reduced gastric emptying
- increased glucose uptake into muscles
- reduced BP
- reduced inflammation
- reduced non-alcohol fatty liver disease
What are the features of diabetic retinopathy?
BACKGROUND:
Hyperglycaemia causes basement membrane thickening and weakness –> outpouchings (microaneurysms and blot haemorrhages) and leaking protein causes nard, shiny exudates in macula
PRE-PROLIFERATIVE:
Capillary closure –> retinal infarcts (soft fluffy exudates) and release of vasoactive growth factors from dying retina
PROLIFERATIVE:
Proliferation of vessels in attempt to re-vascularise –> can grow anteriorly from retina where unsupported by collagen (friable) –> vitreous haemorrhage
COMPLEX:
- fibrosis
- retinal detachment
- blindness
What are the features of diabetic nephropathy?
Capillary closure –> glomerulosclerosis –> Kimmelstiel-Wilson nodules (periodic acid Schiff positive) –> reduced eGFR
What are the consequences of diabetic peripheral neuropathy?
Ulcers typically located on plantar aspect of foot, esp. underneath metatarsal heads
Reduced light touch and vibration sense
Neuropathic (Charcot) foot = grossly disorganised foot joint +/- fractures –> collapse of foot due to demineralisation of bones, trauma, and stretching of ligaments
Cellulitis –> osteomyelitis
Toe ischaemia –> Buerger’s sign (lift foot up –> white, put foot down –> purple –> takes time to return to previous colour)
What are the indications for IV insulin?
- DKA/hyperosmolar hyperglycaemic syndrome
- surgical patients who are NBM or miss more than one meal
- vomiting
- major vascular event e.g. MI, CVA
- TPN pts
- steroid use
- metabolically unwell: not eating and drinking
What are the advantages and disadvantages of IV insulin?
ADV
- target driven glucose control for specific indication for use
- avoid metabolic decompensation
DISADV
- frequent blood glucose monitoring (hrly in first 12hrs)
- IV infusion intrusive
- difficult to manage if pt is eating
What are the risks of IV insulin?
- hypo/hyperglycaemia (inadequate monitoring/rate of infusion)
- rebound hyperglycaemia/DKA if IV access lost/stopped
- fluid overload
- hypokalaemia + hypernatraemia
- infection
Describe the method of administering IV insulin.
Types of insulin rate: reduced rate (sensitive pts), standard rate, increased rate (resistant)
Take blood glucose readings for first 12hrs and rate adjusted if no response
Ensure:
- infusion equipment is working
- substrate infusion running at correct rate
- patient cannula
If blood glucose < 4mmol/l:
- stop insulin infusion
- give 75ml of 20% IV glucose over 15min (and repeat if still <4mmol/l)
- restart IV insulin once >4mmol/l
- do not let blood glucose >6mmol/l in pts with acute coronary syndrome/CVD
- hrly monitoring of blood glucose, daily U&Es, review need for infusion
Do not discontinue infusion until 30min after usual diabetes treatment has been restarted and pt is able to eat and drink; check blood glucose 1hr after discontinuation and at least 4 times for first 24hrs
