Diabetes Flashcards
what is diabetes mellitus?
It’s when your pancreas doesn’t produce enough insulin to control the amount of glucose, or sugar, in your blood
what causes diabetes?
Insulin deficiency (Type 1) or resistance (Type 2) or a combination of both
what is type 1 diabetes?
Absolute insulin deficiency
Autoimmune (insulitis): The body’s t-lymphocytes (immune system) attacks and destroys the beta cells that produce insulin.
Onset typically <40 yrs. – but can present at any age
Onset of symptoms are “dramatic”
Family history is less common
Presence of ketones in urine and breath
Insulin is required to sustain life
Usually normal weight or slim
what is type 2 diabetes?
Insulin resistance (mainly by skeletal muscle and liver)
Relative insulin deficiency
Beta cell dysfunction leading to a relative reduced insulin secretion
Where the body doesn’t produce enough insulin or the body’s cells don’t react to insulin.
Onset typically >40 yrs (but now getting younger!)
Genetic predisposition (family history) E.g. really obese person may have no signs of type 2 but someone who weighs less may have type 2 due to their genetic predisposition. If both parents have type to the chances of the children developing type 2 could be as high as around 25%
Insidious (slow) onset of symptoms
Associated with obesity
Insulin not required to sustain life
No ketones as insulin is present.
evaluate the glucose profile of someone with diabetes compared to w/o
Dawn phenomenon (Diabetes patient): High [BG] (5-7am) as cortisol levels are higher in the morning.
Evening meal: Blood glucose levels tend to rise when we have our evening meal.
Mean [BG] is much higher for patient with diabetes, peaks are more pronounced and there is much more variability.
what are important BG values that we need to note
Hypo: below 4mmol/L (four is the floor)
DVLA: 5 mmol/L (5 to drive) - lower levels cause confusion
NICE Targets:
Premeal: 4-7 mmol/L
Waking: 5-7 mmol/L
90 mins after a meal: 5-9 mmol/L
what are common symptoms in both type 1 & 2 diabetes?
Sometimes asymptomatic
Weight loss
Tiredness => coma: brain not getting enough glucose from the blood
Infection – as blood glucose increases, immunity decreases
Candidiasis (fungal infection) , urine infection or abscesses (swelling- accumulation of puss)
what are the 3 osmotic symptoms of diabetes?
Polyuria: because glucose levels are so high some glucose has to excreted via urine. When glucose enters the urine, it pulls a lot of water with it via osmosis forming a large volume of urine.
Thirst: polydipsia
Blurred vision: high glucose in the blood causes water to be pulled out of the lens via osmosis so the lens changes shape causing blurred vision. Once glucose levels return to normal with management, blurred vision should subside.
how many tests do you need to do to diagnose diabetes mellitus?
If you have symptoms of diabetes you only need 1 diagnostic test to confirm diabetes
If you don’t have symptoms you need two tests to confirm diabetes
what is the problem with urine analysis?
Not sensitive or specific enough as there is lowered renal threshold in pregnancy.
However, any glucose in the urine should be investigated.
when testing, what should random glucose and fasting glucose values be?
Random glucose > 11.1 mmol/l = diabetes
Fasting glucose > 7.0 mmol/l = diabetes
explain the procedure of the gold standard oral glucose test
Patient must be in a fasting state
Measure glucose levels at time = 0
Patient then drinks 75g glucose drink over 5 mins
Wait 2hrs
Measure glucose levels at time = 2hrs
Compare values to healthy patient below:
Impaired fasting glycemia/Impaired glucose tolerance: at risk of developing diabetes
what is the glycated haemoglobin test (HbA1c) and who is it appropriate for?
Reflects previous 10 weeks of ambient circulating glucose
a good tool for monitoring whether an individual has good long term control of diabetes.
≥ 48mmol/mol = diabetes
inappropriate for:
for all children & young people
Pregnant women
patients on medication that may cause rapid glucose rise i.e. steroids
suspicion of type 1 diabetic symptoms for less than 2 months
what tests would you carry out immediately after diagnosing diabetes?
After diagnosis of diabetes obtain a HBA1C (to see starting point of diabetes), check kidney function (e.g. no proteins in the urine), retinography - eyes, and feet.
where is insulin produced and what does it do to glucose?
Produced in by pancreatic beta cells (located in islets of Langerhans)
Moves glucose out of the blood stream for storage/building - decreasing blood glucose levels.
where is glucose stored?
first in liver
when these stores are full it is stored in the muscle
when these stores are full it then goes into fat.
how does proinsulin get converted into insulin?
Proinsulin (active insulin and c peptide) is cleaved in secretory vesicles by proteases to form mature insulin
c-peptide (connecting peptide) is also secreted alongside insulin and is then excreted via urine.
Serum c-peptide can be used to distinguish between certain diseases with similar clinical features to DM (i.e. low c-peptide indicates low endogenous insulin)
what is ketoacidosis?
- Lack of insulin causes fat (triglycerides) to break down.
- This causes an excess of fatty acids which (after the maximum can be placed into the TCA cycle to produce energy) are converted to acetoacetate.
- This is why people with type 1 diabetes will become very skinny if not treated with insulin - all the bodies fat is broken down…
- Acetoacetate are converted into ketone bodies:
Acetoacetate is found in urine – measured by peeing on a stick
Acetone - Breathed out (pear drop smell)
Beta-hydroxybutyrate which can be measured in the blood using blood ketone meter
what are the types of meal time insulin formulations?
Meal time insulins (insulin is injected before meals):
Soluble (old):
- Actrapid,
- Humulin S
Rapid Acting Insulin (new):
- Aspart (Novorapid)
- Lispro (Humalog)
- Glulisine (Apidra)
https://www.youtube.com/watch?v=LWDQyaKVols
what are the types of longer acting insulin formulations?
Longer acting insulins:
Zinc insulins (old):
- Insulatard
- Humulin I
Long Acting (new):
- Determir (Levermir)
- Glargine (Lantus)
- Glargine U300 (Toujeo)
- Degludec (Tresiba)
