endocrinology Flashcards
what is the underlying issue in type one diabetes?
There is severe insulin deficiency due to pancreatic beta cell destruction
what genes can increase the susceptibiltiy of type 1 diabetes?
Mainly HLA DR
what can cause the beta cell destruction in type 1 diabets?
Can be immune mediated or idiopathic
what is the underlying issue in type 2 diabetes?
Insulin resistance or a less severe insulin deficienc. often there are defects in secretion
What are causes of type 2 diabetes?
Low birth weight and poor nutrition show an association
Insulin resistance is worsened by ageing, in activity and obesity.
genetic links with TCF 7 and KCNQ1
what is often the presentation of a patient with new onset type 1 diabetes?
Triad: polyuria, weight loss, thirst
juvenille onset
Severe cases: DKA
weight loss, blurred vision, nausea, abdo pain
what is often the presentation with new onset type 2 diabetes>
Often asymptomatic for many years
Frequent UTI’s and infections
fatigue, blurred vision, polydipsia, polyuria
Older age
what is the diagnostic criteria for type 1 diabetes?
two of:
- a random plasma glucose of 11 or higher
- a fasting plasma glucose of over 6.9
- a 2 hour plasma glucose of over 11
what is the criteria for the diagnosis of type 2 diabetes?
A fasting plasma glucose of over 6.9
a random plasma glucose of over 11
2 hour post load glucose of over 11
what is the diagnosis for impaired glucose tolerance?
Oral glucose tolerance test at fasting below 7 and two hours later between 7.8-11
what drugs can cause drug induced diabetes?
corticosteroids glucocorticoids decrease insulin action GH decreases insulin action thiazide diuretics decrease insulin action and secretion beta blockers statins
what are the signs of DKA?
- hyperventilation
- weakness
- sweet smelling breath
- nausea and vomiting
- sometimes abdominal pain
- dry skin
what blood results are seen in DKA?
- hyperglycaemia
- acidotic
- ketonaemia
- low bicarbonate
- hypokaelaemia
What is the pathophysiology of DKA?
- insulin deficiency
- raised glucose and ketone bodies
- insulin deficiency leads to increased lipolysis and more FFA taken up by the liver which are converted to ketones in the mitochondria
- hyperglycaemia leads to osmotic diuretisis and electrolye depletion.
Renal hypoperfusion
Also increase in counter regulatory hormones
what can trigger DKA in a patient?
They have un-diagnosed diabetes
There insulin therapy has been interrupted
intercurrent illness has caused extra stress
Drugs that affect carb metabolism: corticosteroids, thiazides and dobutamine
What general test results would be seen in DKA?
- ketones and glucose in urine
- acidosis
- hypokalaemia
- low bicarbonate
- high blood ketones
- low oxygen sats can be seen
- elevated anion gap
what are the test results seen in mild DKA?
Plasma glucose >13.9 ph 7.25-7.3 bicarbonate 15-18 positive urine ketone positive serum ketone anion gap over 10
what are the test results in severe DKA?
plasma glucose >13.9
serum bicarbonate <19
positive urine ketone
positive serum ketones
arterial pH <7
anion gap over 12
mental state affected
what is emergency management of DKA?
- soluble insulin iv 0.1kg/hr
- fluid and electrolyte replacement with 0.9% nacl
adjust KCL amount according for hypokalaemia - give sodium bicarbonate if necessary
in management of DKA in what order should insulin and potassium treatment be given and why?
insulin should always be given first because it causes an uptake of potassium into cells causing a further fall in plasma potassium
what is hyperosmolar hyperglycaemic state?
A complication of type 2 diabetes where there is uncontrolled hyperglycaemia causing a hyperosmolar state in the abscnece of significant ketosis.
what is the pathophysiology of a hyperglycaemic hyperosmolar state?
insulin deficiency with increased counter regulatory hormones
unlike DKA the insulin deficiency is less severe so still suppresses lipolysis and ketogenesis but is bad enough to stop regulation of hepatic glucose
what are signs of a hyperglycaemic hyperosmolar state?
dehydration coma dry mucous membranes poor skin turgor hypotension
what are the test results in a hyperglycaemic hyperosmolar state?
elevated glucose above 33
negative ketones in urine and serum
elevated urea and creatinine due to volume depletion
high serum osmolality
what are simliarities and differences in test results of DKA and hyperglycaemic hyperosmolar states?
both have hypokalaemia
DKA has reduced bicarbonate
HONK has increeased urea
DKA has marked acidosis
what are the main macrovascular complications of diabetes?
Atherosclerotic process
MI
ischaemic stroke
gangrene and amputation
what is the process for the risk of macrovascular complications of diabetes?
hyperglycaemia leads to oxidative stress and the cytokine cascade
hyperglycaemia increases plasminogen activator inhibitor type 1 and decrease free tissue plasminogen activator
increased hypertension risk
what can be done to reduce the risk of macrovascular complications in diabetes?
Good BP control statins for lipid management good glycaemic control Ace inhibitor or AGII antagonist low dose aspirin smoking cessation
what are the main three microvascular complications of diabetes?
retinopathy
neuropathy
nephropathy
what changes can be seen in a diabetic eye exam and why?
- cotton wool spots due to micro infarcts leading to debris and ischaemia
- haemorrhages due to retinal capillary leakage
- microaneurysms due to damage to the small vessels of the retina
what is the process of damage in diabetic nephropathy?
- poor glycaemic control leads to kidney damage
- the afferent arteriole becomes vasodilated more than the efferent leading to increased intra-glomerular pressure
- shearing forces lead to mesangial cell hypertrophy and increased secretion of extracellular mesangial matrix material
- glomerular sclerosis and leakage
TGF beta is signalled causing fibrosis