Diabetes Mellitus Flashcards
Definition of DM
A group of metabolic diseases of multiple aetiologies characterised by hyperglycaemia together with disturbances of carbohydrate, fat and protein metabolism resulting from defects in insulin secretion, insulin action or both
Types of DM
Type I Type II Recognised genetic syndromes; MODY Gestational diabetes Secondary diabetes
What is the only hormone that lowers [BG]?
Insulin
What hormone dominates the absorptive state?
Insulin
Risk to get T1DM if monozygotic twins
30-50% concordance
Risk to get T1DM if both parents have it
30%
Risk to get T1DM with father having T1DM
6%
Risk to get T1DM if mother has it
1%
Risk to get T1DM if sibling has it
8%
Effect of insulin on adipose tissue
Reduced lipolysis
Effect of insulin on liver
Reduced glucose production
Effect of insulin on muscle
Increased glucose uptake
Risk of T2DM in identical twin
90-100%
Risk of T2DM if one parent has it
15%
Risk of T2DM if both parents have it
75%
Risk of T2DM if sibling has it
10%
Risk of T2DM if non identical twin
10%
Inheritance of MODY
Autosomal dominant
What does MODY stand for?
Maturity onset diabetes in the young
Pathology of MODY
single gene defect
impaired Beta-cell function
Two types of mutations of MODY
Glucokinase mutations
Transcription factor mutations
When is the onset of diabetes in MODY glucokinase mutations patients?
Birth
Status of hyperglycaemia in MODY glucokinase mutation patients
Stable
Treatment of MODY glucokinase mutations patients
Diet
How common are complications in MODY glucokinase mutations patients?
Rare
Examples of MODY transcription factor mutations
HNF-1a
HNF-1B
HNF-4a
Age of onset of MODY transcription factor mutations
Adolescence/young adult onset
State of hyperglycaemia in MODY transcription factor mutations patients
Progressive
Treatment of MODY transcription factor mutations patients
1/3 diet
1/3 OHA
1/3 insulin
How common are complications in patients with MODY transcription factor mutations?
Frequent
Causes of secondary DM
drug therapy e.g. corticosteriods pancreatic destruction - CF - haemachromatosis - Chronic pancreatitis - Pancreatectomy Recognised genetic syndromes - DIDMOAD Cushings Acromegaly Phenochromocytoma
What can gestational diabetes be associated with?
FH of type II diabetes
What does having gestational diabetes leave you with an increased risk of developing later in life?
Type II diabetes
What trimester does gestational diabetes develop in?
2nd/3rd trimester
Who is gestational diabetes more common in?
Overweight
Inactive
Neonatal problems related to gestational diabetes
Macrosomia
Respiratory distress
Neonatal hypoglycaemia
Symptoms of hyperglycaemia
Polydipsia Polyuria Blurred vision Weight loss Infections
Long term microvascular complications of hyperglycaemia
retinopathy
neuropathy
nephropathy
Long term macrovascular complications of hyperglycaemia
Stroke
MI
PVD
What group does diabetes diagnostic criteria identify?
Those with significantly increased premature mortality and increased risk of microvascular and cardiovascular complications
What is ‘normoglycaemia’ used for?
Glucose levels associated with low risk of developing diabetes or cardiovascular disease
What group does intermediate hyperglycaemia (IGT and IFG) identify?
A group at higher risk of future diabetes and adverse outcomes such as cardiovascular disease
Diagnostic level of diabetes with HbA1c
> _ 48 mmol/mol
How many lab and symptoms are needed to diagnose diabetes?
ONE diagnostic lab glucose PLUS symptoms
or
TWO diagnostic lab glucose WITHOUT symptoms
What lab values can be diagnostic of diabetes?
Diagnostic glucose levels (venous plasma) fasting >7.0mmol/l, random > 11.1 mmol/l
OGTT 2 hours after 75g CHO >11.1 mmol/l
Diagnostic HbA1c >_ 48 mmol/mol
What is HbA1c?
Glycosated haemoglobin
What does HbA1c give an indication of?
Blood glucose levels over the last 8-12 weeks
When can HbA1c not be used for diagnosis?
T1DM
All children and young people
Pregnancy - current or recent (< 2 months)
Short duration of diabetes symptoms
Patients at high risk of diabetes who are acutely ill
Patients taking medications that may cause rapid glucose rise e.g. corticosteriods
Acute pancreatic damage or pancreatic surgery
Renal failure
Iron deficiency
B12 deficiency
HIV infection
Presentation of T1DM
Short duration of
- thirst
- tiredness
- polyuria/nocturia
- weight loss
- blurred vision
- abdominal pain
Signs of DM
Ketones on breath Dehydration May have increased - RR - tachycardia - hypotension Low grade infections - thrush/balanitis
Symptoms of T2DM
MAY HAVE NO SYMPTOMS thirst tiredness polyuria/nocturia Sometimes weight loss blurred vision symptoms of complications e.g. CVD
Signs of T2DM
NOT ketotic
Usually overweight but not always
Low grade infections; thrush/balanitis
May have microvascular or macrovascular complications at diagnosis
Risk factors for DM (any 2 present)
Overweight
FH
Over age 30 years if Maori / Asian / Pacific Island descent
Over age 40 years if European
PMH of gestational diabetes
Had a big baby (more than 4kg) - not in immediate post natal period
Inactive lifestyle, lack of exercise
Previous high blood glucose/impaired glucose tolerance
Does a drop in BP lead to acidosis or alkalosis?
Acidosis
A drop in BP leads to increased lactate
Which leads to acidosis
Treatment of DKA
Fluids - 0.9% saline
IV insulin
What do you have to keep a close eye on when treating DKA?
The electrolytes
3 things needed to diagnose DKA
Raised BG
Raised Ketones
Acidosis
Would you do venous or arterial blood gas?
Venous
Do arterial if concerned about oxygentation
Which is better to look at, blood or urine ketones?
Blood
Which type of fluids is only used now, crystalloid or colloid?
Crystalloid
What is the crystalloid of choice in DKA?
Saline
What is DKA not a usual complication of?
T2DM
What does LADA stand for?
Latent autoimmune diabetes of the adult
What kind of disease is LADA?
Autoimmune
When does LADA start?
Later in life, > 30 y/o
How much family history is needed to confirm MODY?
FH in 3 generations
Test for LADA
Autoantibodies (antiGAP)
What does OGTT stand for?
Oral glucose tolerance test
When is OGTT used?
Tricky cases
What happens during OGTT?
The patient is asked to take a glucose drink and their BG is measured before and after the sugary drink is taken
What cannot be used to diagnose diabetes mellitus (i.e. not a diagnostic test)?
Capillary blood glucose
When HbA1c
T2DM is unlikely
When HbA1c = 42-47, what does this imply?
Imparied/pre-diabetes
What HbA1c > 48, what does this imply?
T2DM
If cannot get the HbA1c <48, what value is preferable?
<53
3rd line therapy for diabetes would be what?
Triple therapy
What can progress during pregnancy and therefore must be monitored throughout?
Pre-proliferative retinopathy
Microalbuminuria
Complications of DM in pregnancy
Severe hypos +/- unawareness Progression of microvascular complications Ketogenic state due to higher ketones leading to damage to the baby Pre-eclampsia Maternal infection Pre-term labour Miscarriage Macrosomnia Hypoglycaemia (neonate) Congenital anomaly
Relationship between HbA1c and congenital anomaly
As HbA1c increases, the higher the risk of congenital anomaly increases
What helps to prevent neonatal hypoglycaemia?
Breast feeding / feeding
What happens to the insulin requirements after labour?
Drop almost immediately
Why should you always ask about steroids when there is hyperglycaemia?
Because steroids can raise blood glucose massively.
Under what values of ketones is negative?
< 0.6
What is normal body pH?
7.35-7.45
What contributes to plasma osmolarity?
Glucose
Urea
Electrolytes
Equation for calculating plasma osmolarity
2 x (Na + K) + urea + glucose
What does HHS stand for?
Hyperosmolar hyperglycaemic state
HHS vs DKA
HHS more dehydrated than DKA
HHS more serious than DKA due to mortality
HHS more gradual onset than DKA
Why does HHS have a slow onset?
Slow dehydration
No ketones present to make you unwell
What can HHS be the first presentation of? And especially in who?
T2DM
Elderly
Risk factors for HHS
Illness
Dehydration
Inability to take normal diabetes medication
What criteria is needed to diagnose HHS?
Increased BG
Hypovolaemia
Osmolarity > 320
Treatment of HHS
IV insulin
0.9% Saline
Speed of Tx of HHS compared to DKA
Treat HHS more SLOWLY than DKA to gradually improve things as it came on slower.
Do you always have to use IV insulin the treatment of HHS? Why?
Often the sugar comes down with rehydration
What can osmotic changes lead to?
Acute blurring of vision
Types of retinopathies seen in DM
Background retinopathy
Pre-proliferative
Proliferative
Eye problems seen in DM
Retinopathies
Maculopathy
Cataracts
Glaucoma
Two groups of symptoms of hypoglycaemia
Autonomic symptoms
Neuroglycopenic symptoms
Which of the two groups of hypoglycaemic symptoms come on first?
Autonomic
When do neuroglycopenic symptoms come on in hypoglycaemia?
At a lower BG
But come on rapidly
What is gastroparesis?
Delayed gastric emptying
You are more likely to have hypo unawareness if you have had diabetes for how long?
> 15 years
What must you do if you have two episodes of severe hypoglycaemia in a year?
Stop driving and inform the DVLA
What happens in terms of blood levels if have gastroporesis?
Insulin acts before the sugar rises
Treatment of gastroporesis
Prokinetics
Delayed timing of bolus of insulin after food
Liquidised or homogenised foods (absorbed more rapidly)
PEG/Jejunal feeding
Botulinum injection into pylorus
Gastric pacemaker (not always effective)
Types of neuropathy
Autonomic
Peripheral
What is the albumin:creatinine ratio more sensitive than?
The protein:creatinine ratio
Which appears in the urine first, albumin or protein?
Albumin
What result does microalbuminuria give on urine dipstick?
Negative
What result does macroalbuminuria give on urine dipstick?
Positive
Two types of dialysis
Haemodialysis
Peritoneal
What is the autonomic NS effect of DM?
Postural hypotension
When is HbA1c not a very accurate measurement?
If you are anaemic
What should be done if you are scared of having a hypo at night?
Take 20% of insulin and have a snack before bed
What type of metformin is better tolerated and why is this?
Slow release
Because of S/Es
If are on testosterone and stop taking it, what can happen?
Can become anaemic
What is faecal elastase a measurement of?
Pancreatic exocrine insufficiency
How long does it take to develop retinopathy?
5 years
Target of BG in the morning
5 - 8
Effects of fight or flight on BG
Increase in BG
Then decrease in BG due to the adrenaline
1 unit of insulin brings down the BG by how much?
4 mmol
What antibodies are looked at in T1DM and LADA?
AI2 antibodies
How many grams of CHO in 2 slices of toast?
30g
Insulin ratio and what does it mean?
1:10
1 insulin unit for every 10g of carbs
What should you do to your insulin after exercise?
Drop your insulin a bit
Because after exercise taking up glucose into muscles is easier
How long can LADA last without insulin?
6 months
What can happen to an overnight hypo?
It can rebound to high
How long does it approx. take to get normal after a correction dose?
4 hours
How often are patients with T1DM told to monitor their BG?
At least 4x a day, including before each meal and before bed
Inheritance of MODY
Autosomal dominant
T2DM BP target if NO end organ damage
< 140/80
T2DM BP target if end organ damage
< 130/80
What is the most important complication of fluid resus in DKA, and in who?
Cerebral oedema
In young patients
HbA1c level of pre diabetes
42 - 47 mmol/mol
What HLA allele is associated with T1DM?
HLA-DR4
